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Mica is one of the common associated minerals of quartz sand. For quartz sand, mica is an impurity. The removal of mica is an important part of quartz sand purification.

一. What is mica?

Mica is the general name of the mica group minerals, which are aluminosilicates of potassium, aluminum, magnesium, iron, lithium and other metals. They are all layered and monoclinic. The crystal is in the form of pseudo-hexagonal sheet or plate, and occasionally columnar. The layered cleavage is very complete, with glass luster, and the thin sheet is elastic. There are biotite, phlogopite, muscovite, etc.

二. How to remove mica?

a. Crushing, screening and separation

This method has simple process flow, less equipment, high production efficiency and strong separation ability. The required sorting equipment is basically the same as the main processing equipment of the gravel processing system, and can be used in the gravel processing system. Mica separation can be realized by carrying out targeted de-mica transformation on the ordinary crushing and screening process.

b. Shaking table gravity separation

The process of shaking table gravity separation is simple and the separation capacity is good, but it requires additional equipment such as shaking table, high energy consumption, large water consumption and large site occupation. Before considering the shaking table equipment, the sand and stone processing system needs to carry out the shaking table separation test on the broken ore, and weigh the advantages and disadvantages according to the separation effect.

c. Magnetic separation

Some mica has weak magnetism, which can be removed by magnetic separation. Magnetic separation can remove ferriferous mica. Before considering the magnetic separation operation, the sand processing system needs to conduct chemical analysis on the properties of the raw ore and the mica minerals contained in the sand to determine whether there is iron, and conduct magnetic separation test according to the iron content.

d. Wind selection

The mica air separation method is based on the difference in the settlement speed of mica and gangue in the air flow. Generally, the process of “crushing and grading air separation” is adopted, in which special equipment is required for air separation. This method needs to be combined with screening and other methods to achieve mica separation effect.

At present, there are many types and models of air separators with mature technology, which can be directly used in sand and stone processing system. The principle of air separation is similar to that of the dust collector of the sand and gravel system, which requires the raw ore to be kept dry, so the air separation method is only suitable for the sand and gravel processing system produced by dry method. According to the data, when the moisture content of the raw ore exceeds 2%, the fine sand is easy to adhere to the surface of the mica, resulting in the blocking of the screen of each section of the vibrating screen and affecting the removal effect of the mica.

e. Flotation

The mica and quartz sand are sorted according to their different surface physical and chemical properties. The quartz ore is broken and ground to separate the mica monomer. Under the action of reagents, mica becomes a foam product and is separated from gangue. Mica flotation can be carried out in acidic or alkaline pulp. Cations of long-chain amine acetate and anions of fatty acids are used as collectors for mica.

The flotation method is mainly used for the recovery of broken mica and fine mica in the sand and gravel industry, especially the mica resources in tailings. In practical production application, the preliminary process flow should be determined according to the nature and characteristics of the actual ore, and then enriched and optimized through a series of conditional tests to obtain better technical and economic indicators.

The flotation method has strict requirements on the pH value of the pulp, and a large number of chemical reagents such as adjusting agents (pH adjusting agents and dispersants), collectors, inhibitors, etc. need to be added. The flotation method has large water consumption, high cost and great difficulty in wastewater treatment.

三. Summary

Due to the particularity of the sand and stone processing system, the physical separation method for removing mica is a reasonable choice. The mica separation method of crushing and vibration screening can be selected by using the existing crushing and screening equipment of the sand and stone system. This method has certain requirements for crushing and screening equipment. The sand and stone processing system with more mica should carry out a series of targeted crushing and screening tests before selecting equipment and determining processing technology.

Magnetic separation and shaking table gravity separation require more equipment and large site, and the production cost is high. The sand processing system needs to decide whether to use this method according to the properties of sand raw materials and the results of preliminary tests. The separation principle of air-separated mica is simple and the production cost is moderate. It is more practical for the sand and stone processing system produced by dry method. The mica separation can be carried out by selecting appropriate air-separated equipment and process.

Mica will have a certain impact on the quality of photovoltaic glass quartz sand products, such as iron and aluminum content. The removal amount of mica depends on the quality index requirements of the finished sand. If you have the need for quartz sand purification, Fodamon engineers will give a reasonable plan and equipment according to your situation.

Raymond mill is a new type of high-efficiency pulverizing machinery and equipment, which has the production advantages of energy conservation and environmental protection. It has good processing performance for non-metallic ores such as marble, limestone, dolomite and calcite with Mohs hardness below 7. Efficient processing and utilization can bring good market benefits to enterprises. How to maintain the marble calcium powder processing equipment to extend its service life? Fodamon engineer summarized as follows:

A. During the use of Raymond mill, there should be fixed personnel to take care of it, and the operators must have a certain technical level. Before the installation of the mill, the operators must receive necessary technical training to make them understand the principle and performance of the mill and be familiar with the operating procedures.

B. In order to ensure the normal operation of Raymond mill, the “safe operation system for equipment maintenance” shall be formulated to ensure the long-term safe operation of the mill, and necessary maintenance tools, lubricating grease and corresponding accessories shall be provided.

C. After Raymond mill has been used for a period of time, it should be overhauled. At the same time, wear parts such as grinding roll, grinding ring, blade, etc. should be overhauled and replaced. Before and after the use of the grinding roll device, the connecting bolts and nuts should be carefully checked to see whether there is looseness and whether the lubricating grease is sufficient.

D. When the grinding roll device has been used for more than 500 hours and the grinding roll is replaced again, all rolling bearings in the roll sleeve must be cleaned, and the damaged parts should be replaced in time. The oil filling tools can be the manual oil pump and grease gun.

E. Add oil to the grinding roller bearing every shift, the central bearing of the main engine every 4 shifts, and the blower bearing every month. The maximum temperature of the bearing chamber shall not exceed 70 ℃. If the bearing is found to be overheated, remove and clean the bearing, bearing chamber and other accessories for once.

Careful maintenance of marble calcium powder mill can prolong the service life of marble calcium powder mill and reduce the comprehensive investment cost of enterprises.

Many customers with mineral processing needs are not very familiar with middling product. Fodamon engineers explain that in the flotation process, the cleaned tailings or swept foam products are generally called middling product. Generally, the grade of middling ore is lower than that of concentrate but higher than that of raw ore, and its floatability is also lower than that of concentrate but higher than that of tailings. For the treatment of middlings, first analyze the situation of intergrowth in middlings, study the floatability of middlings and requirements for concentrate quality, and then determine the treatment method of middlings. Whether the middling treatment method is appropriate or not is very important to improve the beneficiation index. The following four common methods are used.

(1) Return the middling to the appropriate place in the front of flotation. If the useful minerals of the middling have been basically separated, return it to the appropriate place in the front of flotation. There are two methods.

① Sequential return is shown in Figure 6-27. Sequential return means that the middlings obtained from later operations return to the previous operation in turn. When the floatability of useful minerals is poor, in order to reduce the metal loss of return and re concentration and ensure the recovery rate, the number of re concentration of middlings should be reduced. It is better to use sequential return for middlings treatment.

② Centralized return is shown in Figure 6-28, that is, all middlings are combined and returned to the front of flotation for proper operation. The floatability of middlings is good, and centralized return of middlings is appropriate when the requirements for concentrate quality are high. As the middling ore has been cleaned for many times, the concentrate quality can be improved most.

(2) When there are many intergrowths of middlings returning to grinding classification cycle, it is better to return to grinding classification cycle, as shown in Fig. 6-29.

If the middling contains some mineral particles separated from the intergrowth and some monomer, they can be returned to the classification operation. In order to increase the mechanical scrubbing of the middling surface, they can also be returned to the grinding machine.

(3) If the middling is treated separately, the nature of the middling is more complex, such as complex inlaying, the floatability is greatly different from that of the raw ore, and there is more slime, if the middling is returned to the original flotation cycle, the whole flotation process will be deteriorated. In this case, middlings should be treated separately, as shown in Figure 6-30.

(4) If the above methods can not achieve good results in processing middlings by other methods, chemical methods can be considered for processing, but experimental research work should be carried out for middlings. According to the test results, comprehensive technical and economic indicators should be compared for the schemes used, and the scheme that is technically reasonable and economically cost-effective should be adopted. In addition, it can also consider whether it is possible to sell low-grade concentrates without further treatment.

In a word, in the flotation process, the middling treatment method should be carefully studied and a reasonable scheme should be selected, which is of great significance for improving the beneficiation index. In general, the middling should be returned to the operation with similar grade. If the middling concentration is too low or the drug content is too large. So as to affect the normality of the near return operation, it is necessary to return after dehydration and drug removal.

Different minerals have different beneficiation methods. Today, Fodamon engineers summarized some types of mineral resources for your understanding and classification. Mineral resources refer to mineral resources with economic value that can be developed and utilized underground or on the surface. Mineral resources are classified into the following categories according to their nature and use:

1、 Metallic mineral resources

The useful mineral resources from which metal raw materials can be extracted can be divided into:

1. Ferrous minerals: such as iron, manganese, chromium, vanadium, titanium, nickel, cobalt, tungsten, molybdenum, etc;
2. Non ferrous metal minerals: such as copper, lead, zinc, tin, bismuth, antimony, mercury, aluminum, magnesium, etc;
3. Precious metal minerals: such as gold, silver, platinum, palladium, osmium, iridium, ruthenium, rhodium, etc;
4. Rare metal minerals: such as niobium, tantalum, beryllium, lithium, zirconium, cesium, rubidium, strontium, etc;
5. Rare earth metal mineral resources（ Σ REE): 16 elements including atomic numbers 57-71 and 39 (yttrium) are classified into the following two categories according to their geochemical properties and symbiotic relationship:

(1) Light rare earth metal mineral (cerium group element Σ Ce): such as lanthanum, cerium, praseodymium, neodymium, promethium (artificial element), samarium, europium, etc;

(2) Heavy rare earth metal mineral (yttrium group element Σ Y) : such as yttrium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, etc;

6. Disperse element minerals: such as germanium, gallium, indium, thallium, cadmium, hafnium, rhenium, scandium, selenium, tellurium, etc.

2、 Nonmetallic mineral

From which non-metallic elements can be obtained or minerals or mineral aggregates can be directly utilized. In industry, except a few non-metallic minerals are used to extract non-metallic elements, such as sulfur and phosphorus, most non-metallic minerals use some physical, chemical and technological properties of minerals or mineral aggregates. For example, diamond mostly uses its hardness and luster; Mica uses its transparency and insulation; Crystal uses its optical and piezoelectric properties and so on. It can be divided into:

1. Metallurgical auxiliary raw materials: such as fluorite, magnesite, refractory clay, dolomite and limestone;
2. Raw materials for chemical industry: such as apatite, phosphorite, pyrite, potassium salt, rock salt, alunite, limestone, etc;
3. Industrial raw materials: such as graphite, diamond, mica, asbestos, barite, corundum, etc;
4. Piezoelectric and optical raw materials: such as piezoelectric quartz, optical quartz, iceland spar and fluorite;
5. Raw materials for ceramics and glass industry: such as feldspar, quartz sand, kaolin and clay;
6. Building materials and cement materials: such as sand, gravel, pumice, chalk, gypsum, granite, perlite, turquoise, marble, etc.

3、 Gem and jade materials

Such as diamond, ruby, sapphire, jadeite, jadeite, crystal, serpentine, pyrophyllite, turquoise, agate, etc.

4、 Combustible organic rock mineral

It refers to underground resources that can provide organic energy for industry and civil use. They are not only the most important fuel, but also important chemical raw materials. From the perspective of chemical composition, they are mainly composed of hydrocarbons, which should belong to non-metallic minerals, but their formation conditions and uses are obviously different from the above non-metallic minerals, so they can be separately classified into a large category. According to their physical state, they can be divided into three categories:

1. Solid combustible organic rock minerals: such as coal, peat, coal, oil shale, wax, asphalt, etc;
2. Gas combustible organic rock mineral: such as natural gas;
3. Liquid combustible organic rock mineral: such as petroleum, etc.

If you have questions about mineral processing and demand for processing machinery, please contact us. Our engineers with years of experience will give you appropriate solutions and preferential prices according to the nature of your minerals.

Cyanide (often referred to as sodium cyanide and potassium cyanide) is a chemical product, which is mainly used in gold production, electroplating and other industries, resulting in a large number of toxic cyanide containing wastewater in these industries. At the same time, most gold ores are associated with a variety of valuable elements such as silver, copper, lead, zinc and sulfur. However, many gold mining enterprises only focus on the recovery of heavy gold, and the recovery rate of associated elements is generally low, resulting in waste of resources. In addition, cyanide is widely used in metallurgy, electroplating, printing and dyeing, daily chemical industry and agriculture. Fodamon engineers summarized that cyanide widely exists in various organisms, including photosynthetic bacteria, algae and animals. More cyanide comes from human production activities, such as electroplating, smelting, printing and dyeing wastewater, landfill leachate, cyanide containing chemicals, etc. From the perspective of environmental engineering and biosafety, great attention should be paid to the detoxification of cyanide containing wastewater.

Cyanide consumption in production is mainly in the following aspects:

(1) Mechanical consumption, such as running, running, etc.

(2) When the pH value in the pulp is too low, HCN will escape.

(3) The formation of thiosulfate is easy to form CNS when there is a large amount of S2 – in the pulp.

(4) Generate metal complexes, such as those with Cu2S, ZnS, FeS, etc. in minerals. 2.7, 3.0 and 5.26 g sodium cyanide are consumed per gram of copper, zinc and iron respectively.

(5) Silicate colloid or silicon oxide in the pulp adsorbs cyanide.

1. Hazards of cyanide

Cyanide refers to the substance containing cyano group (CN -) in the compound molecule. Cyanide can be divided into two categories according to whether the elements or groups connected with cyano are organic or inorganic, namely, organic cyanide and inorganic cyanide. Inorganic cyanide is widely used and comes from many varieties. According to its nature and composition, it can be divided into two types, namely simple cyanide and complex cyanide.

As we all know, most inorganic cyanide is highly toxic and highly toxic. A very small amount of cyanide will kill people and livestock in a very short time, and also cause crop yield reduction. Cases of acute poisoning of fish, livestock and people caused by cyanide pollution of water have been reported at home and abroad.

1.1 Impact of cyanide on human

Cyanide does great harm to warm blooded animals and people, characterized by high toxicity and quick action. CN – generates hydrogen cyanide after entering the human body, which has a very rapid effect. In the air containing hydrogen cyanide at a very low concentration (0.005 mg/L), it will cause headache, discomfort, palpitations and other symptoms in a very short time; In the air with high concentration (>0.1mg/L) of hydrogen cyanide, people can die in a very short time. The United States Environmental Protection Agency (USEPA) proposes that the maximum cyanide concentration in drinking water and ecological water is 0.05mg/L and 0.20mg/L respectively. The maximum mass concentration of cyanide in domestic drinking water and industrial wastewater is 0.05mg/L and 0.50mg/L respectively.

1.2 Toxicity of cyanide to aquatic organisms

Cyanide is very toxic to aquatic organisms. When the concentration of cyanide ion is 0.02~1.0 mg/L (within 24 hours), the fish will die. When the concentration was 3.4 mg/L, Daphnia died in 48 hours; The maximum allowable concentration of cyanide in water by plankton and crustaceans is 0.01mg/L. Microbes in water can destroy cyanide with low concentration (<2 mg/L), making it a simple non-toxic substance, but it will consume dissolved oxygen in water, reduce biochemical oxygen demand, reduce digestion, and cause a series of water quality problems.

1.3 Effect of cyanide on plants

When the concentration of cyanide in irrigation water is below 1 mg/L, the growth and development of wheat and rice are normal; When the concentration was 10 mg/L, rice began to suffer, the yield was 78% of that of the control group, and wheat did not suffer significantly; When the concentration was 50 mg/L, both rice and wheat were obviously injured, but rice was more seriously injured, the yield was only 34.7% of the control group, and wheat was 63% of the control group. When the cyanide content was 1 mg/L in water culture, the growth and development of rice began to be affected; When the concentration was 10 mg/L, the growth of rice was obviously inhibited, and the yield was 50% lower than that of the control group; At 50 mg/L, most of the plants were killed, and a few of the remaining plants could no longer bear fruit. In the land seriously polluted by cyanide containing wastewater, the yield of fruit trees decreases and the fruit becomes smaller. In addition, when cyanide containing wastewater is used to irrigate rice, wheat and fruit trees, the fruits will contain a certain amount of cyanide.

2 Study on process mineralogy of cyanide tailings

Cyanide tailing is the tailing obtained from flotation gold concentrate after cyanidation operation and pressure filtration. Due to different ore properties and gold extraction processes, the properties, types and contents of valuable metals and minerals in the tailing are different. The main metal minerals in the cyanide tailings are sulfides: pyrite, chalcopyrite, galena, sphalerite, etc; Gangue minerals are mainly quartz, a small amount of chlorite, mica, feldspar, kaolinite, etc.

The main copper mineral in cyanide tailings is chalcopyrite, so copper can be recovered by conventional flotation method. As sphalerite and galena have less content and pyrite has the largest content, copper and sulfur can be recovered.

Cyanide tailings have some common features: fine mineral particle size and serious argillization; The mineral composition is relatively complex; It contains a certain amount of CN – and some residual reagents. Due to the influence of the above factors, the floatability of some minerals in the cyanide tailings is greatly reduced, and it is difficult to recover valuable elements.

The recovery of metal from cyanide tailings is different from that from raw ore, mainly because:

1) After regrinding and long-time aerated stirring of gold concentrate, the mineral particle size is very fine (- 0.045mm particle size content reaches 95%, or even finer, the specific surface is increased, and the colloidal dispersion system appears, which makes flotation separation difficult.

2) The metal minerals are seriously overworn, and some of them are strongly inhibited due to excessive oxidation in the cyanidation process, so they are difficult to activate.

3) A large amount of argillaceous silicate minerals and cyanide in the pulp will deteriorate the flotation process and affect the grade and recovery of the concentrate.

3 Cyanide treatment

There are many methods to treat cyanide containing wastewater, including alkali chlorination method, acidification recovery method, sulfur dioxide air oxidation method, electrochemical method, activated carbon adsorption catalytic oxidation method, peroxide oxidation method, ferrous sulfide method, biochemical method, ion exchange method, natural purification method, ozone oxidation method, emulsion liquid membrane method and pressurized hydrolysis method. The main treatment methods of cyanide and cyanide tailings are summarized as follows.

3.1 Chemical treatment alkali chlorination

Alkali chlorination method is very effective in treating high concentration cyanide, and the treatment equipment is simple and easy to operate. Both small batch processing and large-scale processing can achieve good results. This method has been applied in the treatment of waste cyanide for enterprises and institutions, and achieved very good results.

The reaction principle is as follows: under alkaline conditions, CN – in the solution is oxidized to extremely weak toxic CNO – with bleaching powder [the main component is calcium hypochlorite Ca (ClO) 2], and CNO – is further oxidized to non-toxic carbon dioxide and nitrogen. The reaction formula is:

ClO- + CN- + H2O → ClCN + 2OH-

ClCN + 2OH → NCO-+ Cl- + H2O

2NCO- + 3ClO- + H2O → 3Cl- + N2↑+ 2CO2↑+ 2OH-

First, add sodium hydroxide into the container containing water, adjust the pH of the aqueous solution to 11~12, and then add the waste cyanide into the aqueous solution with the pH adjusted, gently stir to make it completely dissolved. Then add industrial bleaching powder and continue to stir gently to facilitate the reaction. During the reaction, cyanide is first oxidized to cyanate, and the toxicity of cyanate is only 1 ‰ of that of cyanide. Cyanate continues to be oxidized and finally completely oxidized to carbon dioxide and nitrogen.

3.2 Biological treatment

There are four main biochemical processes of cyanide degradation by microorganisms: hydrolysis, oxidation, reduction and substitution. Among them, hydrolysis and oxidation are dominant.

One of the most important methods of flotation operation technology is to observe the foam in the flotation machine and judge the flotation effect according to the change of foam. Based on years of experience, Fodamon engineers would like to share with you the following:

Experienced flotation machine operators can judge the causes of changes from observing various changes in the apparent phenomenon of foam, so as to adjust in time to ensure that the flotation process is carried out under optimal conditions.

Whether the floater can correctly adjust the flotation reagent addition, concentrate scraping and middling circulation depends on the correctness of his judgment on the appearance of flotation foam, and the ability to observe and judge is mainly obtained from continuous and careful summary of operating experience. The appearance of flotation foam includes the virtual and solid, size, color, luster, shape, thickness, strength, fluidity, sound and other phenomena of foam, which are mainly determined by the type, quantity, particle size, color, luster, density, and amount of foaming agent of minerals attached to the surface of foam.

1. The Virtual and Real of foam

The mineral particles attached to the surface of the bubble are many and dense, while the foam is solid. The mineral particles attached to the bubble surface are few and thin, and the foam is empty. The raw ore grade is high, the dosage of reagent is appropriate, and the foam is solid. The foam will become empty if the inhibitor is excessive and the collector is too little.

2. The size of foam

The size of bubbles on the surface of foam layer often varies with ore properties, reagent system and flotation area.

3. Color

The darker the color of the floating minerals in the scavenging area, the greater the metal loss. The darker the color of the floating minerals in the coarse and fine concentration areas, the better the concentrate quality.

4. Gloss

For the rough flotation of sulfide minerals, the foam mineralization in the concentration area is good, so its metallic luster is strong, while the foam mineralization in the sweep area is poor, showing the glassy luster of water film. If the scanning foam shows semi metallic luster, it indicates that the metal loss is large.

5. Contour

When the foam mineralized by moderately hydrophobic mineral particles is formed on the pulp surface, it has sufficient water, and the contour of each bubble is relatively bright. The foam stays on the pulp surface for a long time, and the mineral is hydrophobic. When the bubble wall is dry and incomplete, the bubble contour is blurred.

6. Thick and thin

The thickness of the foam layer is mainly related to the amount of foaming agent and the degree of bubble mineralization. There are many foaming agents, high grade of raw ore, high concentration, and good degree of mineralization. The foam layer is generally thick, on the contrary, it is relatively thin. The floating ore particles are too thick, and it is difficult to form a thick foam layer. The slurry surface in the cleaning area is low, the foam layer is thick, and the concentrate grade is high. The cleaning area maintains a high slurry surface, and the floating minerals can be scraped out in time. The foam layer is thin, and the recovery rate is high.

7. Brittleness and viscosity

The foam is too brittle, poor stability, easy to break, and sometimes cannot be scraped out. On the contrary, the foam is too viscous and stable, which will cause the flotation machine to “run off”, damage the normal flotation process, cause difficulty in concentrate transportation, excessive foaming agent, and a large amount of soluble salts such as slime and lead sulfate falling into the oil or ore, all of which can make the foam too stable.

8. Audio

When the foam is scraped into the foam tank by the scraper, it makes a sound of “rustling”. It is often because foam contains a large number of minerals with large proportion and coarse particle size.

The above eight points are the flotation operation technology to judge the flotation effect. The appearance of foam varies with different flotation areas, but specific areas often have specific phenomena. To observe the foam situation, we should focus on several flotation cells that have obvious characteristics and have a major impact on the concentrate grade and recovery rate, mainly including: final concentrate flotation cells, several flotation cells before operation, flotation cells with flotation reagents and flotation cells at the end of scavenging.

According to the different compositions of nickel ores, the selected process methods are also different. Fodamon engineers will share the following nickel ores based on years of experience.

Beneficiation of copper nickel sulfide ore

This type of ore is mostly magmatic molten copper nickel ore, in which the rich ore containing more than 3% nickel can be directly smelted; Ore containing less than 3% nickel shall be beneficiated.

(1) Mineral Composition and Beneficiation Method of Copper Nickel Sulfide Ore

The common metal minerals in this type of ore are: pyrrhotite, pentlandite and chalcopyrite, as well as magnetite, pyrite, ilmenite, chromite, chalcopyrite, copper blue, chalcocite, bornite and platinum group minerals; Gangue minerals include olivine, pyroxene, plagioclase, talc, serpentine, chlorite, actinolite, mica, and sometimes quartz and carbonate.

Copper in copper nickel ore mainly exists in the form of chalcopyrite; Nickel mainly exists in the form of free nickel sulfide, such as pentlandite, goethite and violarite. A considerable part of nickel occurs in pyrrhotite in isomorphism, and there is a small amount of nickel silicate.

The main beneficiation method of copper nickel sulfide ore is flotation, while magnetic separation and gravity separation are usually auxiliary beneficiation methods.

(2) Floatability of main nickel minerals and flotation characteristics of copper nickel ores

Pyrrhotite, goethite and nickel bearing pyrrhotite can be effectively floated with butyl or amyl and other high-grade xanthates. The floatability of pentlandite and goethite is between chalcopyrite and pyrrhotite. Pyrrhotite can be flotation well in weak acidic, weak alkaline or neutral media; Nickel goethite can also be better flotation with butyl xanthate in weak acidic, neutral or weak alkaline medium; Nickel bearing pyrrhotite is suitable for flotation in acidic or weak acidic medium, but the flotation speed is slow.

Pyrrhotite, goethite and nickel bearing pyrrhotite can all be inhibited by lime, but their degree is different. Pyrrhotite is easier to inhibit, while pentlandite and goethite require excessive lime. Unlike pyrrhotite and pyrite, other alkalis do not inhibit pentlandite and goethite. The effect of separating pentlandite and chalcopyrite with lime alone is not good enough, and a small amount of cyanide is usually added to inhibit pentlandite. Pyrrhotite can be quickly oxidized by oxygen in the air, forming an iron hydroxide film on its surface, which reduces its floatability. Pyrrhotite is oxidized faster in the air than pentlandite. Copper sulfate is the activator of pentlandite, especially pyrrhotite. Nickel minerals can be reactivated with copper sulfate after being inhibited by lime (rather than oxide). In order to improve the activation of nickel minerals by copper sulfate, it is sometimes necessary to add a small amount of sodium sulfide in advance.

At present, nickel silicate minerals cannot be separated by industrial flotation, so the nickel silicate content in ores is an important factor affecting the nickel recovery.

Based on the properties of copper nickel ore, its flotation process has the following characteristics: simple flotation process, long flotation time, less times of concentration, multiple points of decentralized concentration, and early recovery of nickel mineral; The grade of nickel concentrate is generally 4~8%, and the higher one can reach 13~15%. Removal of pyrrhotite, talc, chlorite, actinolite, serpentine, mica and other easy floating gangue is the key to improve the quality of nickel concentrate; In order to strengthen nickel mineral flotation, mixed collectors are often used; The combined flowsheet of flotation and magnetic separation is often used to remove pyrrhotite.

(3) Flotation process of copper nickel ore

When flotation copper nickel sulfide ore, the collector and frother of flotation copper sulfide ore are often used. A basic principle for determining the flotation process is that it is better to let copper enter the nickel concentrate than to avoid nickel entering the copper concentrate as much as possible. Because the nickel in the copper concentrate loses a lot in the smelting process, the copper in the nickel concentrate can be completely recovered. Copper nickel ore flotation has the following four basic processes:

(4) Direct preferential flotation or partial preferential flotation process

When the copper content in the ore is much higher than the nickel content, this process can be used to separate the copper into a separate concentrate. The advantage of this process is that copper concentrate with low nickel content can be obtained directly.

(5) Mixed flotation process

It is used to separate ores with copper content lower than nickel, and the obtained copper nickel mixed concentrate is directly smelted into high nickel matte.

(6) Copper and nickel are mixed flotation from ores, and then copper concentrate containing low nickel and copper nickel concentrate are separated from mixed concentrate. After smelting the nickel concentrate, high nickel matte is obtained, and then the high nickel matte is separated by flotation.

(7) Mixed preferential flotation and partial nickel recovery from mixed flotation tailings

When the floatability of various nickel minerals in ore is greatly different, nickel containing minerals with poor floatability can be further recovered from its tailings after copper nickel mixed flotation.

(8) Cu Ni separation

Copper is a harmful impurity in nickel smelting, and copper grade in copper nickel ore has industrial recovery value, so copper nickel separation technology is an important subject in copper nickel ore dressing. Copper nickel separation technology includes copper nickel mixed concentrate separation and high nickel matte separation. Generally, the mixed concentrate separation method is adopted for the ores with coarse grain size of copper nickel minerals and not closely embedded with each other; However, for copper nickel minerals with fine particle size and very dense distribution, high nickel matte separation process is often used.

(9) Separation process of copper nickel mixed concentrate

At present, the most commonly used separation methods of this process are lime cyanide method and lime sodium sulfide method. Sometimes, slurry heating measures can improve the separation effect. In addition, there is bisulfite method.

(10) Separation process of high nickel matte mixed concentrate

This process has better technical and economic effects than separation smelting and hydrometallurgy, so it is widely used.

High nickel matte mainly consists of copper sulfide (Cu2S) and nickel sulfide (Ni3S2), followed by Cu Ni alloy, cobalt, platinum group metals and some iron impurities. The composition of high nickel matte can be controlled artificially during smelting. Iron content and cooling rate are two main factors for high nickel matte flotation separation. They not only affect the material composition of high nickel matte, but also affect its crystal structure.

Iron is a harmful impurity in the separation and flotation of high nickel matte, which can lead to the complexity of the composition of high nickel matte. When the iron content is less than 1%, there will be compounds similar to bornite and pentlandite, which is not conducive to flotation and affects the recovery of cobalt; When the iron content is more than 4%, not only the composition of high nickel matte becomes more complex, but also the crystal structure becomes finer, which is not conducive to flotation. The production experience shows that the iron content in high nickel matte should be controlled within the range of 2~4%.

The high cooling rate of nickel matte also has a great influence on its separation. When it is slowly cooled from 800 ℃ to 200 ℃, the crystal grain size of copper and nickel minerals becomes coarser. Especially when the slow cooling temperature drops to 510~520 ℃, nickel sulfide undergoes crystal transformation, and changes from NiS2 to a-Ni3S2, which makes copper sulfide dissolved in nickel sulfide separate out, thus helping to reduce the copper content in nickel sulfide ore. Therefore, ensuring the slow cooling rate of high nickel matte can improve the separation effect of high nickel matte flotation.

Nickel oxide ore treatment

Nickel laterite in nickel oxide ore has high iron content, low silicon and magnesium content, and nickel content is 1-2%; However, nickel silicate ore has low iron content and high silicon magnesium content, with nickel content of 1.6~4.0%. At present, nickel oxide ore is mainly exploited by nickel laterite. Because nickel in nickel oxide ore is often dispersed in gangue minerals in the same way as the other minerals, and the particle size is very fine, it is difficult to obtain good results by directly treating it with mechanical beneficiation method. After the ore is calcined to change the mineral structure, although better technical indicators can be obtained, the cost is high and it has not been used in industrial production.

At present, crushing, screening and other processes are often used for nickel oxide ore treatment to remove large bedrock ore blocks with weak weathering degree and low nickel content in advance, so the enrichment is relatively low.

In recent years, due to the continuous development of nickel smelting technology, the increase of nickel consumption and the continuous reduction of nickel sulfide rich ore resources, the development and utilization of nickel oxide ore has been paid more and more attention. Nickel oxide deposits are generally shallow, suitable for large-scale open-pit mining, but also for selective mining. Due to the low mining cost, it has certain competitiveness compared with nickel sulfide ore.

The smelting and enrichment methods of nickel oxide ores can be divided into two categories: pyrometallurgy and hydrometallurgy. Pyro smelting can also be divided into matte smelting, ferronickel process and granular iron process. Hydrometallurgy also includes reduction roasting atmospheric ammonia leaching and high pressure acid leaching.

The rotary kiln grain milling method in pyrometallurgy belongs to an ancient method. Its disadvantages are that the process is complex, the nickel content of grain iron is low, the nickel recovery rate is low, and cobalt cannot be recovered; Electric furnace smelting is characterized by high nickel recovery rate. Part of the nickel is drilled into ferronickel, which can be recovered in the refining process. This method is suitable for the treatment of silicon magnesium nickel ore. When it is used in laterite ore with high iron content, the iron recovery rate is low and the power consumption is large.

The atmospheric ammonia leaching method in hydrometallurgy has the disadvantage of low cobalt recovery; The high-pressure acid leaching method is suitable for treating nickel oxide ores with low magnesium silicate content.

At present, nickel oxide is mostly treated by smelting ice nickel in electric furnace; However, the rotary kiln granulation iron process is rare. Hydrometallurgical methods, such as ammonia leaching and acid leaching, have been applied in industry. Other new nickel oxide smelting methods, such as high-temperature chlorination, sulfuric acid roasting and other extraction processes, are still in the research stage and have made some progress.

Tantalite niobate is mainly composed of tantalum, niobium tin, tungsten, lithium, beryllium and other polymetallic ores. It has the characteristics of low grade of raw ore, complex mineral composition, high mineral density and brittle property. After years of experience, Fodamon engineers have concluded that the mineral processing methods mainly include gravity separation, magnetic separation, electrical separation, floating gravity separation, flotation and chemical treatment. The beneficiation process is generally divided into two parts: roughing and cleaning.

a. Tantalite niobate roughing

The gravity separation process is mainly used for the roughing of tantalite niobate, but gravity separation flotation gravity separation is also used; Gravity separation flotation or gravity separation magnetic separation gravity separation.

(1) Reselection process

The primary tantalum niobium ore is mainly subject to stage grinding and multi-stage gravity separation. Separation equipment is usually added in the grinding circuit to recover monomer minerals in advance. Tantalum niobium placer generally does not need to be broken and ground due to good dissociation of mineral monomer. Screening shall be carried out before being selected to remove block stones and pebbles, and then rough separation shall be carried out. Coarse grained tantalum niobium iron ore is roughened by jigging machine or spiral concentrator (including rotary spiral chute), and the roughing concentrate is cleaned by shaking table; Fine grained tantalum niobium iron ore is roughened by spiral chute or shaking table, and the roughing concentrate is cleaned by shaking table; The tantalum niobium slime is roughed by centrifugal concentrator or multi-layer turning bed, and the roughing concentrate is cleaned by belt chute or trough flow belt chute combined with slime shaker. This process is characterized by less investment, fast start-up, low cost and less environmental pollution. But the efficiency of slime separation is low.

Gravity separation – flotation – gravity separation or gravity separation – flotation process: gravity separation is adopted for coarse and fine-grained materials and flotation is adopted for slime. Before flotation, small-diameter cyclone or centrifugal concentrator is generally used for desliming, and then alkylsulfonated succinate is used as collector, sodium silicate and oxalic acid are used as adjusters for flotation under the condition of pH 2-3. The flotation concentrate is cleaned by Holman slime shaker cross flow belt chute; Alternatively, styrene phosphonic acid is used as collector, sodium fluosilicate and lead nitrate are used as adjusters, and flotation is carried out at ph6. The flotation concentrate is cleaned by vibrating belt chute or cross flow belt chute, or hydroxamic acid and transformer oil (2:1) are used as collector, sodium hydroxide and sodium silicate are used as adjusters, and flotation is carried out at ph8-8.5. Hydroxamic acid and transformer oil are added to the flotation concentrate, and oxalic acid is used as inhibitor, Under the condition of pH 2.5-3. Tantalum iron ore or niobium iron ore concentrate can be obtained by the above methods. This process is characterized by high separation index, but the content of tantalum and niobium in the removed fine mud is close to the grade of raw ore, large reagent consumption and high production cost.

(2) Gravity separation magnetic separation gravity separation process

Gravity separation is adopted for coarse-grained materials. The combination of magnetic separation and gravity separation is adopted for fine particle and slime. This process is characterized by high separation efficiency for fine-grained tantalum iron ore and niobium iron ore, but the tantalum niobium minerals in the ore must have weak magnetism.

b. Cleaning of tantalite niobate coarse concentrate

Tantalite niobate coarse concentrate is generally complex in composition and difficult to separate. It is often necessary to adopt one or two or more methods of magnetic separation, gravity separation, floating gravity separation, flotation, electrical separation, chemical treatment and other methods. In particular, the separation of tantalite and niobate from some difficult minerals requires a combination of multiple separation methods. For example, tantalite niobate is separated from garnet and tourmaline by magnetic separation, electrical separation or flotation.

(1) Magnetic separation

Their specific magnetization coefficient: tantalite is 2.4 × 10-5 cm3 / g, niobium ore is 2.5 × 10-5 cm3 / g, 5.8 × 10-5cm3 / g, garnet and tourmaline change with their iron content. When the Fe2O3 content of garnet increases from 7% to 25%, its specific magnetization coefficient increases from 11 × 10-6 cm3 / g, increased to 124 × 10-6 cm3 / g (11 times increase). When the Fe2O3 content of tourmaline increases from 0.3% to 13.8%, its specific magnetic coefficient increases from 1.1 × 10-6 cm3 / g, increased to 30 × 10-6 cm3 / g (30 fold increase). In order to improve the separation selectivity of minerals in the magnetic field, acid (solid: liquid = 1:5) is generally used for a short time (5-15 minutes) to remove the iron on the surface of minerals, and then garnet and tourmaline are separated in the magnetic field of different strength to obtain tantalum niobium concentrate.

(2) Electric separation

The materials shall be screened and graded in narrow grades, and then heated separately for electric separation in a composite electric field: the particles larger than 0.2 mm are generally selected with low voltage (20-35 kV), large polar distance (80-100 mm), slow speed (low centrifugal force) (the number of rotations of the roller or drum is 33-38 RPM) Generally, high voltage (35-45 kV), small polar distance (50-80 mm) and high rotational speed (high centrifugal force) are used for 0.2 ～ + 0.08 mm particle size fraction (the rotation speed of the roller is 70-118 RPM). Tantalite niobate can be separated from garnet.

(3) Flotation separation

Niobate and garnet can be separated by using sodium cetylsulfonate as collector and fluorine compound as regulator.

Separation of tantalum niobate from monazite

Electric separation is usually used for coarse grain size; For the fine particle (－ 0.075mm), oleic acid or rice bran oil is used as a collector, sodium carbonate (Na2CO3) is used as a regulator, sodium silicate (Na2SiO3) and sodium sulfide (Na2S) are used as inhibitors (Na2SiO3 ∶ Na2S = 3:1). Monazite can be floated under the condition of PH9 to separate iron tantalite (niobate) from monazite.

(4) Separation of fine crystal and cassiterite

Electrostatic separation (voltage: 16 kV) is usually adopted for coarse particle grade; The fine particle is treated with 2% hydrochloric acid for 15 minutes, then sodium alkyl sulfate (600g / T) is used as a collector, and sodium fluorosilicate (Na2SiF6) is used as an inhibitor to float cassiterite under the condition of pH 2-2.3 to separate the fine crystal from cassiterite.

(5) Separation of tantalum niobate and magnetic CASSITERITE

The coarse particle is generally separated by wind shaking table; In the fine-grained grade, Guangzhou Nonferrous Metals Research Institute of China has developed a new magnetic separation process of oxidation roasting (800-900 ℃), which can well separate tantalum niobate, tantalum rutile and cassiterite.

(6) Separation of tantalum niobate and wolframite

Hydrometallurgy is usually adopted. First, grind the material to – 0.04 mm, add sodium carbonate (Na2CO3) for roasting (800 ℃), or boil it with concentrated alkali under normal pressure, and then decompose the filtered residue with HCl (5%) to obtain artificial tantalum niobium concentrate. The filtrate is sodium tungstate solution, and the tungsten oxide (WO3) product can be obtained by adjusting the acid (pH 2-2.5), extracting, neutralizing and crystallizing.

(7) Separation of niobate and zircon

Magnetic separation or flotation can be used. Sodium oleate can be used as collector in flotation, lead chloride, water vitrification or lead chloride and oxalic acid can be used as adjusters to separate niobate from zircon.

First of all, quartz ore is abundantly divided into three categories: quartz, tridymite, and white silica. The quartz ore beneficiation process is often used in the industry to purify and process it.

The quartz ore beneficiation process has the advantages of mass production, high purity and fast efficiency. The following Fodamon engineer will tell you how to reasonably form a quartz stone beneficiation production line.

All the beneficiation processes are first crushed, then ground, then sorted and separated by magnetic separator and flotation machine, and finally concentrated and dried. Although it will vary according to the actual situation, but It comes down to the key beneficiation steps must be crushing, grinding, sorting (purification), and concentration. The quartz stone beneficiation process also revolves around these steps to sort and purify the quartz stone.

a. Crushing process–type of crushing; jaw crusher, cone crusher and other crushing equipment are used to form the crushing production link, and the quartz ore is crushed to a certain particle size, and the quartz ore particle size can reach 25mm, which is exactly the next step. The feed particle size of the quartz ore ball mill for grinding operations (of course, the crushing particle size is better than 25mm, which is more beneficial to the grinding operation).

b. Grinding process–grinding type; use a special grinding ball mill for quartz ore to grind the crushed quartz ore, after grinding, quartz ore powder within the range of 0.074mm-0.89mm can be obtained, which is convenient for the next step of classification, Purification, in order to achieve the expected grinding quartz ore powder more quickly, the personnel operating the quartz ore ball mill are required to strictly implement the feeding requirements (≤25mm).

c. Purification process–purification types; a purification production line composed of classifiers, magnetic separator and flotation machine is used, and the principle of first roughing and then fine selection is followed. The magnetic separator is used for preliminary sorting, and finally the flotation machine is used to further separate the quartz material from the complex minerals.

d. Concentration process–concentration types; the separated quartz material can be concentrated and dried by using a concentrator and a dryer, and dry and high-purity quartz products can be obtained, which can be directly used in the industrial field.

The quartz beneficiation process is to crush the mined quartz ore. The qualified materials crushed by the crusher are evenly sent to the inside of the quartz ore ball mill through the hoist and ore feeding equipment. The quartz ore ball mill will continue to pulverize and grind the material. , the material ground by the ball mill is sent to the spiral classifier for cleaning and classification, then the magnetic separator is used for preliminary sorting and the flotation machine is used to separate the desired minerals from other substances, and finally the concentrator is used to remove the material contained in the material. The moisture and drying equipment are used to dry the materials, and then the quartz stone raw materials required for production can be obtained.

There are many ways to reduce the wear of the fine abrasive liner of the ball mill, that is, to reduce the abrasive particle size, actively adopt the closed grinding technology, reduce the grinding temperature, adopt the fine grinding bin liner activation technology, adopt the rod grinding technology, and follow the ball mill Fodamon manufacturer to learn about these ways in detail.

a. Actively apply closed-circuit grinding technology

Using closed grinding technology and powder separation equipment, the original basic output can be increased by 30%-40%, the grinding current consumption can be reduced by 3-5kwh/t, and the “filling effect” of circuit materials can effectively reduce the wear of lining plates.

b. Lower grinding temperature

Generally, the feeding methods include cold feed grinding, water spray grinding, etc. The latter has a significant cooling effect.

c. Using the activation technology of fine grinding silo lining

The layout of the village plate in the fine grinding silo has an important impact on the production efficiency of the mill. Using the arrangement and combination of new and old lining plates to achieve the purpose of activation can not only improve the throwing height and the throwing times, but also ensure the fineness qualification rate of the finished product, reduce the wear of the lining plate and prolong the service life.

d. Adopt rod grinding technology

The grinding body used by the mill is a steel rod with good “line contact” with the floor material. The bar load has the special function of “selective” grinding for the material range. In the grinding process, there are many forces such as grinding, pressing, rolling, rolling, grinding and so on, so the grinding efficiency is high.

e. Reduce the particle size of grinding materials

If the particle size of the abrasive material is reduced, the average particle size of the abrasive body and the filling rate in the grinding can be reduced accordingly, which is very beneficial to the protection of the lining plate. From the perspective of energy conservation and consumption reduction, the more materials a pair of lining plates grind within the service life, the lower the wear cost. Production practice shows that the grinding performance can be improved by 30% – 50%, and the power consumption can be reduced by 10% – 20%. The particle size after necessary pretreatment can be reduced to less than 4-6mm, The reduction of the particle size has a certain effect on reducing the wear of the lining plate.