Difference between Rod mill and Ball mill

The mill can be divided into ball mill and rod mill according to different purposes. Fodamon engineers share the differences between ball mill and rod mill as follows:

1. Appearance and structure
The shape ratio of the barrels of the two mills is different. The ratio of the length and diameter of the rod mill barrel is generally 1.5-2, and the inner surface of the liner on the end cover is a vertical plane. There are various ratios of the length and diameter of the ball mill, such as those below 2, about 3, and above 4.
In addition, the rotating speed of the barrel of the rod mill is lower than the working speed of the ball mill of the same specification, so that the medium in the rod mill can work in the dump state.

2. Ore discharge mode
Among the ball mills, grid ball mills and overflow ball mills are commonly used (the names come from different structures of the ore discharge department). The rod mill does not use grid plate to discharge ore. There are only two types of overflow type and open type. The diameter of the hollow shaft at the discharge end is generally larger than the ball mill of the same specification.

3. Grinding media
Rod mills usually use steel rods with a diameter of 50mm-100mm as grinding media, while ball mills use steel balls as grinding media. The main difference between the two is the difference in grinding bodies.
The ball of ball mill is in point contact with each other, and the rod of rod mill is in line contact with each other, so their working characteristics are obviously different.

4. Media filling rate
The medium filling rate refers to the percentage of the grinding media in the volume of the mill. For different grinding methods, mill structure, operating conditions and medium shape, the medium filling rate has a suitable range, too high or too low will affect the grinding effect. Usually the filling rate of ball mill is 40% -50%, and that of rod mill is 35% -45%.

In the next section, we will continue to share the differences between ball mill and rod mill.

Main factors affecting production capacity of Raymond Mill

Fodamon engineers share the factors that affect production capacity of Raymond Mill as follows:

1. The hardness of the material. The harder the material, the more difficult the Raymond mill is to grind, and the more severe the equipment wear. Raymond milling‘s speed is slow, so milling of raymond mill ability is small.

2. Humidity of the material. When the moisture content in the material is large, the material is easy to adhere in the Raymond mill, and it is also easy to block in the process of feeding and conveying, resulting in the reduction of the grinding capacity of Raymond mill.

3. Fineness of product materials. The finer the finished material milled, the smaller the capacity of the Raymond mill.

4. Composition of materials. The more fine powders in the material before the Raymond milling, the more it affects the Raymond milling, because these fine powders are easy to adhere and affect the transportation. For the large content of fine powder should be sieved in advance.

5. Viscosity of the material. The higher the viscosity of the material, the easier it will adhere.

6. The better the wear resistance of the wearing parts of Raymond Mill, the better the production capacity of Raymond Mill. If it is not wear-resistant, it will affect the ability of Raymond grinding.

Three gravity separation methods of gold ore dressing

Gravity separation is one of the common methods of gold ore beneficiation. It uses different specific gravity of materials and different settling speeds in the medium for layer separation. Generally in placer gold mines, gold mostly exists in the form of single natural gold, which has a large density difference from gangue, and the effect of using gravity separation for gold is very good, and the economic benefit is relatively high.

There are various gravity separation methods, such as jigging gravity separation, shaking table gravity separation, spiral chute, spiral gravity separation, centrifugal gravity separation and wind gravity separation. In gold ore beneficiation, the commonly used methods of gravity separation gold selection are jigging gold selection, shaking table gold selection and spiral chute gold selection. Fodamon engineers’s explaination as below:

1. Gold selection by Jigging

The main equipment of jigging and gold separation is jigger. The process of jigging is to mix the mineral particles with different specific gravity. In the vertical movement of variable speed medium flow, the minerals with small specific gravity are located in the upper layer and the minerals with larger specific gravity are located in the lower layer. Then, the mechanical and water flow are used to discharge the layered materials respectively.
Jigging is suitable for the separation of coarse-grained mineral particles (mineral raw materials with any particle size except fine materials). The particle size range of metal minerals is 50mm-0.074mm. For placer gold, the lower limit particle size can reach 0.04mm on the premise that the specific gravity difference is ≥ 1.25 and the ore monomer is separated. The process is simple and the equipment processing capacity is large, so the application effect in coarse-grained gold separation is very good.

2. Gold selection by Shaking table

The main equipment of gold separation by shaking table is the shaking table, which is used to select other equipment in the horizontal medium flow. The driving mechanism is used to drive the bed surface to do longitudinal reciprocating motion, to do the flushing and bed surface differential motion. In the reciprocating motion, the ore particles are subject to the layering action perpendicular to the bed surface and the separation action parallel to the bed surface, so that the materials with different particle sizes are discharged from different sections of the bed surface to achieve separation.
According to the different particle size of ore, the ore can be divided into three types: coarse sand bed, fine sand bed and slime bed. The coarse sand bed is suitable for the separation of ore particles with the particle size of 2.0mm-0.5mm, the fine sand bed is suitable for the treatment of ore particles with the particle size of 0.5-0.074mm, and the slime bed is suitable for the treatment of ore particles with the particle size of 0.074-0.037mm.

The ore feeding granularity range of the shaking table gold dressing is generally 3mm-0.019mm, the gold dressing is stable and reliable, the ore belt distribution is clearly visible, the rich ore ratio is higher than other ore dressing methods, easy to manage, and the ore required can be separated at one time.

3. Gold selection by Spiral chute

The main equipment of the chute gold separation is the spiral chute, which uses the inclined water flow to separate the materials. With the help of the combined force of water flow, mineral gravity, friction between the ore particles and the bottom of the chute, the ore particles settle in different areas of the chute according to the specific gravity. The ore particles with small specific gravity are taken away by the water flow, leaving the ore particles with significant proportion, that is to say, the separation is completed.
The spiral chute is suitable for the treatment of fine particles with low mud content. The particle size range of the material is 0.6-0.03mm. It has simple structure, large treatment capacity and low comprehensive cost.

The above three gravity separation gold separation methods are only used for monomer dissociated gold mines (grit gold mines). For vein gold minerals, the gravity separation process is rarely used alone. Generally, it will form a joint process with other processes, such as the gravity separation-flotation combined gold extraction process, gravity separation to assist gold extraction, use of jigs, spiral chutes and shakers in the grinding and grading circuit, first recovery is easy to solve The separated coarse-grained gold creates better separation conditions for the subsequent flotation and cyanidation processes, which can effectively improve the gold ore index and the total gold recovery rate.

In gold ore beneficiation, the selection of gravity separation depends on the nature of the gold ore. It is recommended to conduct a beneficiation test before the process selection, analyze the properties of the gold ore, and determine whether it is suitable to select the gravity separation process through the test and obtain the ideal gold selection process.

Solutions for high temperature oil shutdown of cone crusher

The multi-cylinder cone crusher is equipped in the fine crushing section of a mine crushing operation area, which has the advantages of easy operation, high efficiency and low failure rate. However, the phenomenon of excessively high lubricating oil temperature during the production process, even when the fan cooler is running In the case, the temperature is still greater than 50 ° C, which causes the viscosity of the lubricating oil to decrease, and the pressure of the lubricating oil to be less than 140kPa, which causes the equipment to stop, which not only affects the operation rate, but also affects the production schedule. In this article, Fodamon engineers shared 7 reasons and solutions for the abnormally high cone oil breakage temperature and abnormal shutdown.

1. The lubricating oil in the oil tank is too dirty and the service time is too long.
The cone crusher generally uses Mobil super gear oil (600xp150) as the lubricating oil, and the lubricating oil change cycle is 2000h. If it exceeds 2000h, the viscosity and other indexes of the lubricating oil will be seriously reduced, too many impurities in the oil will cause the decline of the lubricating quality, and the internal wear of the crusher, which will cause the crusher to overheat, and the return oil temperature of the lubricating oil is too high.
In this regard, the lubricating oil and lubricating oil filter element shall be replaced immediately, the oil tank shall be cleaned, the service cycle of lubricating oil shall be formulated, and the lubricating oil shall be replaced at the same time when the lining plate is replaced.
In addition, the impurities on the filter screen in the lubricating oil tank shall be checked and cleaned frequently, and further maintenance shall be determined according to the impurities of the filter screen.

2. The blower does not operate normally and the air filter element is not replaced in time.
The function of the blower is to introduce air into the crusher, keep the pressure inside the crusher, and reduce the dust entering the bearing and lubricating oil inside the crusher.
The blower of the cone crusher is started at the same time as the lubricating oil pump, i.e. when the lubricating pump is started, the blower starts automatically. If the blower is not started, relevant technicians shall be arranged immediately for handling.
In actual operation, when the blower of the cone crusher is started, it will display green in the corresponding computer operation interface, and red when it stops. The operator can determine the operation of the blower according to this, so as to arrange maintenance in time.

3. The counterweight guard is seriously worn.
The crushed ore particles will wear the U-shaped oil seal and T-shaped oil seal of the main frame of the crusher. The damage of the two oil seals will first lead to the leakage of lubricating oil, and then lead to the entry of ore powder particles into the lubricating system, making the lubricating oil dirty. The long time will cause the wear of various parts inside the crusher, resulting in the abnormal temperature rise of the crusher.
In this regard, each time the lining plate is replaced, the T-shaped oil seal of the moving cone shall be checked, and the damaged one shall be replaced in time. Every month, relevant technicians shall be arranged to enter the lower part of the cone crusher to check the counterweight guard plate. If the counterweight guard plate is found to be seriously worn, the cone shall be disassembled. When replacing the counterweight guard plate, the wear of the U-shaped oil seal of the main frame shall be checked at the same time, and the oil seal shall be replaced if necessary.

4. The running current setting of crusher is unreasonable.
The running current of the cone crusher is set at 30-35a. If the current is too high, the cone load will be too high, which will cause the temperature of the cone and the lubricating oil to rise; if the current is too low, and the clearance of the ore discharge port is too large, the crushing efficiency will be low.
In this regard, the gap of crusher should be adjusted properly according to the load of crusher, the material level should be controlled at 300 mm above the distributing plate, and the operating current should be controlled at 30-35 a, so as to give full play to the working efficiency of crusher and not cause overload operation of crusher.

5. Insufficient cooling strength.
The original configuration of the cone crusher is air cooling. In practical application, especially when the temperature is high in summer, the cooling strength is insufficient.
Through analysis, in addition to regularly cleaning the dust and other impurities on the air-cooled radiator to ensure that the air-cooled radiator can play its role to the maximum extent, the technicians control the temperature of the lubricating oil by adding a water-cooled radiator between the oil outlet pipe of the lubricating oil pump and the air-cooled radiator, which is far greater than the specific heat capacity of the lubricating oil.

6. The contact surface between the spherical surface of the moving cone and the spherical bush, the upper and lower bushes of the moving cone and the eccentric shaft bushes are seriously worn.

The contact surface between the moving cone sphere and the spherical bush, the upper and lower bushes of the moving cone, and the eccentric shaft bushes are severely worn. In addition, the upper and lower bushes of the moving cone are respectively matched with the bowl shaped Bush bracket and the eccentric shaft bush, and the eccentric shaft bush is matched with the main shaft. If there is point contact, the contact surface is irregular, and the wear is serious, it is easy to cause the crusher to overheat, resulting in the increase of the oil temperature, and even the burning of the copper bush To spindle wear and other accidents.
Therefore, when the upper and lower bushings of the moving cone or the eccentric shaft bushings are in failure, they must be ground. If they are seriously worn, they should be replaced in time.
The upper thrust bearing is made of copper, and the original oil groove depth is 11mm. When the oil groove depth is less than 9.7mm due to wear, the lubricating oil will be insufficient. The main function of lubricating oil is cooling, and the secondary function is lubrication. The insufficient oil will weaken the cooling bearing function, causing the crusher to overheat and the oil temperature to rise.
Therefore, when checking the upper thrust bearing, vernier caliper can be used to measure the depth of oil groove, when the depth of oil groove is less than 9.7mm The upper thrust bearing must be replaced. The lower thrust bearing is made of steel with relatively small wear.

7. The axial clearance of horizontal shaft is too small or the inner and outer bushings of transmission shaft are worn, resulting in irregular contact surface.
According to relevant regulations, the axial clearance of the cone crusher is 0.8-1.5mm. If it is too small, the lubricating oil temperature will be too high. At this time, it is difficult to change the axial clearance until the copper sleeve of the standard horizontal shaft is worn. If it is determined that the copper sleeve inside and outside the horizontal shaft is worn after a series of inspections, the horizontal shaft shall be removed and the copper sleeve shall be replaced. As shown in below image.

The parts of cone crusher are expensive, the purchase cycle and repair time of parts are long. In case of major accidents, it not only costs a lot of maintenance costs, but also seriously affects the mine production. Knowing the possible conditions, causes and corresponding treatment measures of the equipment in advance can ensure the safe and stable operation of the equipment more effectively.

Difference between fixed crushing and mobile crushing

According to the degree of fixation of crushing equipment and foundation, mine crushing equipment can be roughly divided into two categories, mobile crusher and fixed crushing station, both of which have advantages and disadvantages. Understanding the advantages and disadvantages of these equipment in detail will greatly benefit your choice of equipment . Fodamon engineers analyze for you as follows:

◆  Mobile crushing station

Fodamon mobile crushing station integrates feeding, crushing and conveying, and adopts track or tire for walking. It can adjust its position at any time along with the movement of working face in the stope or construction site.

1. Advantages
1.1 The length of the mobile crushing station is short. On the independent movable chassis installed by different crushing equipment, the wheelbase is short and the turning radius is small, which can be flexibly driven in the ordinary highway and operation area.
1.2 Equipped with main equipment with excellent performance, it has large crushing ratio, high efficiency, larger output and excellent effect. It is an ideal crushing pioneer.
1.3 Mature design scheme creates a green and pollution-free broken environment.
1.4 The centralized lubrication system is adopted to make the maintenance and repair more convenient, which can save a lot of labor and time costs.

2. Disadvantages
The use of updated technology and better manufacturing process leads to higher equipment costs.

◆  Fixed crushing equipment

1. Advantages
The fixed crushing station is connected to the ground with a permanent fixed foundation, and the equipment has a stable foundation for operation. It can be permanently used after completion.

2. Disadvantages
Its disadvantages mainly lie in the complexity of design and installation, and the long construction period of the project, which should not be adjusted after completion.

In general, the mobile crushing station is self-driving in terms of its own walking ability. The typical walking mode is tire type and crawler type. It can flexibly move at the production site, which is its unique advantage. The fixed crushing equipment can be used for a long time and stable outside the stope because of its solid foundation, but it is also inconvenient because it is not suitable for adjustment in the later period.

Beneficiation process of lead zinc oxide ore (Ⅱ)

Fodamon engineers continue to share the other four flotation methods of beneficiation process of lead zinc oxide ore in this article.

1.2. Sulfuration amine flotation method
The sulfurization amine flotation method, also called Rey method, was first discovered by Maurice Rey and his assistant, and proved that the primary amine collectors were the most effective. At present, sulfide amine flotation has become the main method of flotation of lead-zinc oxide. Most of the domestic lead-zinc oxide concentrators adopt sulfide ammonium flotation. The process does not need to be heated and sulfurized, and excessive sodium sulfide will not significantly inhibit the subsequent flotation. Chen Jinquan et al. Carried out sulfurization amine salt flotation test on a high-speed iron slime lead-zinc oxide mine. Using sodium sulfide as sulfurizer and mixed amines (dodecylamine, cetylamine and octadecylamine) as collector, under the conditions of lead-zinc feed grade of 3.54% and 5.86%, the flotation indexes of lead concentrate grade of 45.23%, recovery rate of 73.51%, zinc concentrate grade of 40.56% and recovery rate of 76.21% were obtained. Li Yuqiong et al. Recovered zinc oxide from a zinc oxide ore in Pu’er of Yunnan Province by sulfurization amine flotation method after pre desliming before grinding. With sodium sulfide as sulfurizer and octadecylamine as collector, the grade of original zinc ore was 6.08%. After one roughing, three cleaning and three scavenging, the grade of zinc concentrate was 37.21% and the recovery rate was 64.97%. Amine collectors have good selectivity to lead and zinc, and their separation index is better than sulfurization xanthate method. However, there are some shortcomings in sulfurization amine salt flotation: it is sensitive to slime and soluble salt, poor selectivity to gangue minerals with easy sliming in raw ore, and large dosage of reagents. The actual production needs desliming and sulfuric acid cleaning and activation, which will make a lot of zinc metal loss and process complexity.

1.3. Flotation of fatty acid collectors
Fatty acid collectors are widely used in the flotation of silicate minerals, phosphate minerals and other oxidized ores, which can be directly used in the flotation of zinc oxide, can also be used in reverse flotation to remove carbonate and sulfate from concentrate, and improve concentrate grade.
French j.m.cases and others first applied the fatty acid process to the flotation of lead-zinc oxide ore containing silicate gangue, and used this process to treat sanguinide (sanguinete) lead-zinc oxide ore, through sulfide xanthate flotation of white lead ore, using Na2CO3 and Na2SiO3 to inhibit the silicate gangue mineral, using oleic acid to directly flotation of smithsonite, and finally obtained the grade of 44.60% zinc concentrate, recovery The rate is 84.50%. Ye Junjian et al. Used the combination collector of fatty acid collector FA-1 and GA-1 when butyl xanthate or amine collector GA-1 had no effect on the collection of smithsonite in the ore. when the zinc grade of the ore was 8.90%, the zinc concentrate grade was 22.59% and the zinc recovery rate was 74.03% after one roughing.
Although the research on the flotation of oxidized lead-zinc ores by fatty acids began in the 1920s, the selectivity of fatty acid collectors to gangue minerals is poor, and the separation effect of oxidized lead-zinc ores containing carbonate and sulfate gangue minerals is very poor, especially the high iron oxide lead-zinc ores is more difficult, so far it is not widely used in industry.

1.4. Chelating agent flotation method
Chelating agent collector has been paid more attention because of its high selectivity and strong collection ability. Wang Lun et al. Used the zinc oxide ore of Pu’er county to carry out the flotation test of SALICYLALDOXIME, an organic chelating agent, and used a flotation process to obtain the zinc concentrate with a grade of 37.07% and a recovery rate of 73.92%.
Tan Xin et al. Studied the collection performance of CF collector for smithsonite, white lead mine, calcite, dolomite, quartz and limonite, and found that CF has good collection performance for smithsonite and white lead mine, while the effect of calcite, dolomite, quartz and limonite is weak. When CF is used as collector, sodium hexametaphosphate and zinc sulfate sodium silicate can effectively inhibit the flotation of gangue minerals such as calcite.
In the pulp with normal temperature and natural pH value, smithsonite, galena and gangue minerals can be effectively separated without the alkaline environment like xanthate and amine collectors, and the reduced sulfuration process improves the operability, saves a lot of energy consumption and sodium sulfide agents. The disadvantages of low flotation index, high reagent consumption and high operation cost due to the poor selectivity of xanthate and amine collectors are avoided. Due to the high price and relatively short development time of chelating agent collector, the stability and theoretical research still need to be further improved, which has not been widely used in production.

1.5. Flocculation flotation method
The main reason for the low flotation index of lead-zinc oxide ore is that the loss of lead-zinc oxide ore in fine particles and slimes is more. After adding the selective flocculant, the fine-grained lead-zinc oxide minerals agglomerate into larger particles, which improves the floatability and realizes the separation of fine-grained gangue minerals, and effectively improves the recovery rate of lead-zinc metals.
Ms. Han has carried out a study on the medium scale flocculation flotation of a deep oxidized lead zinc ore in Henan Province. The zinc oxidation rate of raw ore is 92.3%, the lead oxidation rate is 90.4%, and the primary slime is 16.8%. With carboxymethylcellulose as flocculant, the flotation principle of lead first and zinc second was adopted. Finally, lead-zinc concentrate with grades of 49.83% and 40.75% was obtained, and the recovery of lead-zinc was 42.26% and 81.64%, respectively. The grade of zinc concentrate is more than 30% and the recovery of zinc is 64%.

Beneficiation process of lead zinc oxide ore (Ⅰ)

Lead and zinc are important non-ferrous metals and have an irreplaceable role in the development of the national economy and industry. 80% of the world’s lead and zinc are obtained by smelting lead sulfide ore. However, with years of mining, the easy-to-select sulfide ore resources are increasingly depleted, and the lead-zinc ore resources are being continuously developed. However, due to the complex mineral composition of lead-zinc oxide ore, many associated minerals, fine particle size of embedding, serious sludge phenomenon, and high soluble salt content, various unavoidable ions have a great influence on the lead-zinc floatability. Therefore, at present, only a small part of high-grade lead-zinc oxide mines have mining value, and it is difficult to recover low-grade lead-zinc oxide mines using conventional beneficiation processes.

At present, lead-zinc oxide ores with industrial value mainly include white lead ore (PbCO3), lead alum (PbSO4), smithsonite (ZnCO3), heteropolar ore, etc. as a large country of lead-zinc oxide ore resources, China’s current domestic lead-zinc concentrate output can not meet the demand, and still relies heavily on imports, strengthening the research on the recovery and utilization of lead-zinc oxide ore is of great practical significance to alleviate the contradiction between supply and demand. On the basis of practice and theory for many years, fodamon engineers summarized the methods of treating oxidized lead-zinc ore from flotation process, leaching process and combined process of concentration and metallurgy as follows.

1. Flotation process

At present, the flotation process is usually used in lead-zinc concentrators. A single oxidized lead-zinc deposit is relatively rare. The oxidized lead-zinc ore mainly comes from the oxidized zone of sulfide ore, containing both oxidized ore and sulfide ore. There are two main flotation principles for lead-zinc oxide ores: one is “sulfur before oxygen”, i.e. flotation in the order of galena sphalerite lead oxide zinc oxide ore; the other is “lead before zinc”, i.e. flotation in the order of galena lead oxide sphalerite zinc oxide ore. At present, the flotation technology of lead-zinc oxide ore mainly includes sulfide flotation, fatty acid collector flotation, chelator flotation and flocculation flotation.

1.1 sulfuration xanthate flotation method

Sulfide xanthate method is an effective way to recover lead-zinc oxide. A lot of researches have been made on it by domestic and foreign concentrators. The mechanism of sulfurization xanthate method is to sulfurize the surface of lead-zinc oxide in advance, so that the surface of lead-zinc oxide is covered with a strong hydrophobic sulfide film, and then the xanthate collector is used for flotation. It was found in the early research that when the pulp temperature was increased to 50-60 ℃, it would be beneficial to the sulfidation of zinc oxide minerals and the adsorption of reagents, but the excessive amount of sulfidizer would inhibit the interaction between xanthate and mineral surface, and zinc oxide minerals need to be activated by adding copper sulfate after sulfidation before being collected by xanthate. In gorno concentrator in northern Italy, the lead tailings were flotation by heating sulfuration flotation method. The pH value of pulp was adjusted to 11, and the heated pulp was sulfurized at 45 ~ 50 ℃. After being activated by copper sulfate, the grade of zinc concentrate was up to 38% , zinc recovery 76.4% 。 Sun Wei et al. Studied the flotation process of a lead-zinc oxide ore in Cangyuan, Yunnan Province, by using sulfide xanthate flotation and sulfide thiophenol flotation. Using Na2S as sulfurizer, xanthate as lead collector, thiophene as zinc collector and oil No.2 as foaming agent, lead grade was obtained 53.93% , zinc 13.13% Lead concentrate, zinc grade 31.82% With lead 2.75% Of zinc concentrate and lead grade of 33.38% , zinc grade 19.10% The comprehensive recovery of lead and zinc is over 98%.

Sulfur xanthate method is widely used in lead oxide recovery, but its selectivity is generally poor, so it is difficult to obtain better beneficiation indexes for complex low-grade lead-zinc oxide ore. In addition, heating process and activation process are also needed, which are more complex and costly.

In the next part, Fodamon engineers continue to share the other four flotation methods.

Methods to increase the capacity of cone crusher (Ⅱ)

Fodamon engineers continue to share six other operation skills to improve production capacity of cone crusher.

1. Minimize the stagnation of the buffer silo, improve the efficiency of the production line
As the “enemy of output”, the buffer bin of cone crusher and other related equipment also need to be carefully arranged.
It is recommended that the rational use of buffer bins or hoppers and variable-speed feeding devices (conveyor belts, plate-type vibrating feeders) can enable the operating operator to maintain the cone broken “full cavity” for a long time, and easily increase the cone bankruptcy by 10%.
2. Accurately grasp the three upper design limits of cone crusher
The cone crusher has three design upper limits: the upper limit of throughput (capacity), the upper limit of power and the upper limit of crushing force.

The upper limit of cone crusher capacity refers to the maximum passing capacity of the crusher. A cone crusher running in “full chamber” has reached the maximum passing capacity, and if it exceeds the limit, it will overflow the feed port; when the feeding material increases and the material is broken finer, the actual power of the crusher will rise; the same as the power, the crushing force generated between the bowl shaped tiles and the crushing wall of the cone crusher will also follow When the crushing force exceeds the upper limit, the adjusting ring will bounce and loosen.
When the crusher operates at the maximum throughput, the actual power and crushing rate are still slightly lower than the upper limit. Running in a state beyond the upper limit of rated power and crushing force will cause overload and permanent fatigue damage of cone crusher, which is irreversible and will continue to accumulate, and ultimately shorten the service life of cone crusher.
3. Ensure operation within the upper limit of the crusher design
If the cone crusher operation exceeds the upper limit of crushing force (adjusting ring runout) or exceeds the rated power, you can:

a. Slightly increase the tight side discharge port parameters and try to ensure “full cavity” operation. The advantage of “full cavity” operation is that there will be a stone-rocking process in the crushing cavity, which can keep the product grain shape when the discharge port is slightly larger;
b. Or reduce the feed rate, but it may be difficult to ensure a good particle size.
Generally speaking, the problem of the adjustment ring runout or exceeding the rated power of the cone crusher is caused by material jamming, eccentric feeding, uneven feeding, too much fine material in the feeding, too much mud content, wrong use of the crushing wall and the bowl lining, or simply because the operation personnel set the tight edge discharge port of the cone crusher too small.

4. Monitor and try to ensure proper crusher speed
If the proper drive belt tension is not maintained, incorrect or driver maintenance is ignored, the belt will slip and the speed of crusher will drop during operation. The stone handling capacity of the crusher decreased sharply when the rotating speed decreased, while the power consumption increased sharply, the unit energy consumption increased, and the operation cost increased.

It is suggested that the speed monitoring device can be installed in the intermediate shaft and connected to PLC or alarm device directly. Once the speed drops, the maintenance personnel can be informed to adjust the belt, which can extend the belt life and ensure excellent production capacity and energy consumption.
5. Control the fine material content in the feed
Fine material in the feed: the material that enters the crusher’s stone and has a particle size equal to or less than that set at the tight-side discharge port. According to experience, for the two-stage cone crusher, the fine material content in the feed should not exceed 25%; for the three-stage cone crusher, the fine material content should not exceed 10%.

Excessive fines are usually caused by vibration screen problems. Insufficient screen hole diameter or insufficient screening capacity may cause this problem. Too much fines will cause problems such as insufficient power utilization and abnormal increase in unit energy consumption during crushing.
6. The feeding height should not be too high
For small and medium-sized cone crushers, the maximum suitable height of materials falling from the feeding equipment to the feeding port is Zero point nine About meters. If the feeding height is too high, the stone is easy to “rush” into the crushing chamber at high speed, causing impact load to the crusher, and the crushing force or power exceeds the upper limit of the design.
This problem will cause excessive pressure or tension on the crusher components, resulting in additional maintenance costs and low production.

Methods to increase the capacity of cone crusher (Ⅰ)

Cone crusher is one of the most popular medium and fine crushing equipment, which is suitable for crushing all kinds of medium and hard materials. However, many users find that even though they are in full production, they still feel that the capacity of crusher is not high enough to reach the ideal production state. Engineers of fodamon will share the skills and methods to improve the capacity of cone crusher, hoping to help you.

1. Keep the tight edge discharge port parameters unchanged
If you want to stabilize the output, quality and load of the sandstone products, the first thing to ensure is that the parameters of the discharge port of the tight edge of the cone are unchanged. Otherwise, the particle size of the product will be unexpectedly increased, which will affect the entire production line system and the final output.
For example, the discharge opening of the tight edge of a device is set to 10mm. However, due to negligence of inspection and equipment wear, the parameter has been expanded to 13mm. Then the product with the device less than 10mm will be reduced by 15%, and the target product output will be significantly reduced. A considerable number of sand and stone manufacturers suffered losses in this regard. It is recommended that the parameters of the tight-edge discharge port be recommended to be checked every time the shift is changed.
2. Try to keep “full cavity” operation
If a cone crusher is “full” when it is “hungry” due to unstable feeding and other factors, its product grain type and product rate will also fluctuate. The products of cone crusher with half cavity operation are not ideal in grading, needle slice and other aspects.
It is suggested that the manufacturer of sand and stone should try to ensure the operation of cone crusher full cavity and not overfeeding, so as to obtain better throughput and grain shape. This is particularly important for the production of the third stage cone break (short head cone break) of the final product.

3. Don’t feed too little
Giving only a small amount of raw material will not reduce the burden of cone crusher. On the contrary, too little raw material will not only damage the output of the product and have a poor particle size, but also have an adverse effect on the cone broken bearings.
According to the working principle of cone crusher, the actual power of cone crusher should not be lower than 40% of the rated power. In order to obtain proper “load bearing positioning” and maximize productivity, the actual power of cone crusher should be kept between 40% and 100% of rated power. Reaching 75% to 95% of rated power during operation is the best choice. Running beyond the rated power will affect the service life of the cone and cause various problems.

4. The feed drop point needs to be aligned with the center point of the cone crusher feed port
A vertical deflector is recommended to guide the feed drop point in the center of the cone break feed. Once the drop point is eccentric, one side of the crushing chamber is full of material while the other side is free of material or less material, which will result in low throughput of the crusher, increase of needle and sheet products, oversize product particle size and other adverse effects.
Once this happens, the operators tend to reduce the parameters of the tight edge discharge port and try to let the crusher produce the product with the target particle size. However, this is easy to cause overload, adjustment ring runout and other problems on the side with too much feeding. In the long run, it will cause adjustment ring tilt, warping, base damage and other problems, resulting in greater production losses.

5. Ensure uniform feeding
When feeding, it is necessary to avoid the situation where large-diameter stones are concentrated on one side and small-diameter stones are concentrated on the other side, so as to ensure that the stones are mixed evenly.

Once the feeding is not uniform, due to the abnormal increase of bulk density, the compaction and blocking on the side of small-sized stones are easy to occur, resulting in the jumping of the adjusting ring. In the face of the jumping of the adjusting ring caused by blocking, the operators will be forced to increase the discharge port parameters, resulting in the increase of product particle size. In the long run, it will also cause damage to the adjusting ring and other problems, resulting in greater production losses.

Fodamon engineers will continue to share with you the skills and methods to improve the capacity of cone crusher in the next article.

One-time forming without returning material fine crushing equipment

The double stage crusher (also known as the two-stage hammer crusher) is improved on the basis of the old-fashioned hammer crusher. It is a relatively new structure of crusher equipment.

The two stage crusher is equivalent to the combination of two hammer crushers, which is reasonably combined into a whole. Two sets of rotors are used in series and have the following characteristics:

1. Two rotors are crushed up and down in two stages. Two sets of rotors connected in series make the material crushed by the upper rotor be crushed again by the hammer of the lower rotor that rotates rapidly.The materials in the inner cavity collide with each other quickly and crush each other.After the effect of the powder material is reached, it is directly discharged .

2. There is no screen bottom, high humidity materials, never blocking. The traditional crusher with sieve plate is not suitable for raw materials with moisture content higher than 8%. When the moisture content of raw materials is higher than 10%, it is very easy to cause serious blockage, so that the hammer can not rotate, so that the hammer can not rotate, the materials can not be discharged, or even burn the motor, which seriously affects the production. The design of the machine has no screen bottom, no strict requirements on the moisture content of materials, no problem of paste blocking the screen plate, no problem of fine powder not being discharged in time and repeated crushing, so the crushing efficiency is high and there is no invalid wear of hammer head.

3. Unique two-way gap adjustment technology, when the gap between hammer head and lining plate becomes larger and the particle size becomes thicker after wear, the hammer head position can be moved from the center to the outside, and the gap between hammer head and lining plate can be reduced to continue to use. One hammer head can be used to top three hammerheads.

4. Hydraulic electric starter casing. Only one person can easily open and close, which is not only light and fast, safe and reliable, but also easy to maintain.

Fodamon two-stage crusher is applicable to the crushing operation of coal slag, furnace slag, slag, shale, gangue, construction waste, construction waste and other materials in pebble, calcite, limestone and brick factories. It has uniform discharging particles, one-time forming and no return material, which solves the problem of crushing a variety of high humidity materials.

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