Bauxite actually refers to the ores that can be used in industry and are composed of gibbsite, boehmite or diaspore as the main minerals. In this article, Fodamon engineer will briefly introduce the main beneficiation process of bauxite.
Bauxite, also known as bauxite, is generally a fine dispersed colloidal mixture composed of diaspore, boehmite and gibbsite in various proportions. Bauxite often coexists with iron oxides and hydroxides, anatase, kaolinite, chlorite and other clay minerals. Sometimes it also contains calcium, magnesium, sulfur and other minerals. Bauxite can be divided into high alkali bauxite, high titanium bauxite and high iron bauxite according to its impurities.
The process of separating bauxite concentrate from bauxite ore is actually a process of removing gangue minerals and harmful impurities, separating high aluminum minerals and low aluminum minerals, so as to obtain a concentrate with high aluminum silicon ratio.
The main beneficiation methods of bauxite include ore washing, flotation, magnetic separation, chemical beneficiation, etc. Ore washing is the simplest and effective method to improve the aluminum silicon ratio of bauxite. Generally, the aluminum silicon ratio of ore can be increased by about 2 times through ore washing, which is more effective for the separation of loose ores. Ore washing is often combined with other separation methods to form a ore washing (screening washing) – Classification – manual separation process.
Flotation method can be used to separate boehmite and kaolinite in alkaline medium with oxidized paraffin soap and tar oil as collectors. Magnetic separation is used to separate iron bearing minerals. Chemical beneficiation mainly includes roasting desilication, which is based on the fact that the main silicon bearing mineral in the ore is aqueous aluminosilicate. After roasting, part of Si () Z is transformed into amorphous silicon oxide particles that are easily soluble in alkali, which improves the aluminum silicon ratio of the material.
Generally speaking, the main beneficiation process of bauxite will adopt different beneficiation process according to different types of ore. For example, in the beneficiation process of gibbsite kaolinite bauxite, it is often used to separate mud and sand first, remove iron by magnetic separation after coarse grinding, and flotation after slime grinding. The flotation reagent is prepared with oleic acid, tar oil and engine oil in a ratio of 1:1:1.
The bauxite flotation concentrate contains 49.65% alumina and the recovery rate is 45.3%. A1203/sio2 is 12.3. The desilication and beneficiation process of high silicon bauxite is more effective by flotation method. Aluminum mineral collectors include fatty acids and sulfonates, and regulators include sodium hexametaphosphate, tannic acid, sodium pyrophosphate, soda and sodium carbonate. The beneficiation process of high iron bauxite will adopt different iron removal methods according to the content, type and distribution characteristics of iron minerals. The common ones are magnetic separation, roasting magnetic separation and carrier flotation iron removal.
In general, the beneficiation methods of bauxite are complex, and the corresponding beneficiation process should be selected according to the type and characteristics of the ore in the beneficiation process. At present, bauxite in China is mostly separated by flotation.