When flotating fluorite, oleic acid, alkyl sulfates, sulfonates, etc., can be used as collectors. Modifiers can include water glass, sodium metaphosphate, lignin sulfonate, dextrin, etc.
The main problem in fluorite flotation is the separation from quartz, calcite, barite, and sulfide minerals. The separation methods are as follows:
(1) Separation of fluorite from quartz. Adjust the pH of the pulp to 8-9 using sodium carbonate. Use water glass to suppress quartz; the amount of water glass must be carefully controlled, as excessive amounts will also suppress fluorite. Use fatty acids to collect fluorite. To improve the selectivity of water glass and enhance its suppressive power, polyvalent metal ions (such as Al³⁺, Fe²⁺, etc.) are often added.
(2) Separation of fluorite from barite and calcite. Generally, oleic acid is used to float fluorite. When floating fluorite, a small amount of aluminum salt can be added to activate it, and dextrin can be added to suppress barite and calcite. For complex fluorite deposits containing significant amounts of calcite, limestone, and dolomite, tannin and lignin sulfonates can be used to suppress gangue minerals with good results.
(3) Separation of fluorite and barite. Generally, fluorite and barite are first mixed and floated, then separated. Two methods can be used for separating the mixed concentrate: one is to use dextrin or tannins and iron salts to suppress barite, and oleic acid to float fluorite; the other is to use hydrocarbon sulfates to float barite, leaving fluorite in the floater.
(4) Fluorite deposits containing sulfide minerals. Generally, xanthate collectors are first used to float the sulfide minerals, and then fatty acids are added to float the fluorite. If the sulfide minerals are not completely floated, a small amount of sulfide mineral inhibitor can be added to suppress the remaining sulfide minerals during fluorite floatation to prevent them from being incorporated into the fluorite concentrate.