Research On The Separation Of Scheelite From Calcareous Gangue Minerals By Flotation With Cationic Collectors

Based on the different surface electrical properties of three calcareous minerals, including scheelite, calcite and fluorite,the cationic collectors were adopted to separate scheelite from calcareous gangue minerals by flotation.The flotation behaviors of alkylamine acetates (dodecylamine, tetradecylamine and octadecylamine) and quaternary ammonium salts (dodecyltrimethylammonium chloride, octadecyltrimethyl ammonium chloride,didodecyldimethyl ammonium chloride, dioctadecyldimethyl ammonium chloride, and dodecyldimethylbenzyl ammonium chloride) for three calcareous minerals, including scheelite, calcite and fluorite were studied by single mineral flotation tests.The results show that the collective capacity of alkyl amine for calcium-containing minerals decrease with the increase of carbon chain length in alkaline medium, i.e. dodecylamine>tetradecylamine>octadecylamine, and in strong acidic and strong alkaline medium, the collective capacities of three alkyl amines become weak, but there is a large flotability difference between scheelite and calcite and fluorite in acidic medium. On the whole, for the same series of quaternary ammonium salt, the collective capacities of reagents for calcium-containing minerals increase with the increase of carbon atoms of hydrocarbon chain, i.e.1831>1231,1821>1221.And for the same length of the hydrocarbon chain, the series 21 is better than series 31,i.e.1221>1231,1821>1831.The weak acidic and weak alkaline medium is the effective pH range for flotation separation scheelite from calcite and fluorite.The collective capacities of quaternary ammonium salts for scheelite, calcite and fluorite are different while increasing the quaternary ammonium salt concentration. Therefore, an appropriate concentration range should be controlled for flotation separation scheelite from calcite and fluorite by quaternary ammonium salt. The results show that the collective capacity difference of 1221 for scheelite, calcite and fluorite is the largest in the pH range of 7.5～8.0 at reagent concentration of 1.6×10-4mol·L-1.At this time,the differences of flotation recovery between scheelite and calcite and fluorite are 62% and 47%,respectively. The flotation separation of artificial mixed minerals has been achieved good index. Under the conditions of pH=7.5～8.0 and 4.0×10-4mol·L-1 of 1221,the concentrate with the grade of 38.40% WO3 and the recovery of 92.92% has been yielded from the feed containing 23.22% WO3.The analysis of Zeta potential and adsorption quantities shows that the effect of cationic collector on the mineral surface is mainly electrostatic actions,as well as dispersion force and hydrophobic association between hydrocarbon chain, etc.Solution chemical analysis shows that there is ionic and molecular dissociation equilibrium in alkyl amine solution. When pH increases to a certain value, amine molecular deposition will emerge, and amine ions and molecules can form ionic molecules associating content, and it is the same between amino ions; quaternary ammonium salts can ionize completely in the whole pH range. The calculating results of CMC and HLB show that with increasing of carbon chain length, CMC value and HLB value decrease and hydrophobicity of reagent increase in homologues, but the reduction of solubility also affect its dissolvability and dispersity.