关键词: 钙离子, 碳酸钠, }溶液化学, 白钨矿, 纳米碳酸钙

Abstract: The surface properties and flotation behaviors of scheelite are affected by metal ions in the pulp. In order to investigate the effect of calcium ions on scheelite flotation and its regulation methods,flotation tests of scheelite and calcite in the presence of calcium ions with different pH adjusters were carried out,and the mechanism was analyzed by XRD,particle size analysis,infrared spectroscopy,and adsorption amount tests. The results showed that when the pH was adjusted to 10 by sodium carbonate in calcium ions slurry,the flotation recovery of scheelite was only 11. 40%,which was 46. 73 percentage points lower than the flotation recovery when sodium hydroxide was utilized. The addition of sodium fluoride boosted the flotation recovery of scheelite from 20. 46% to 76. 01% when pH was adjusted to 9. 50 with sodium carbonate for scheelite flotation. The mechanism studies showed that when sodium carbonate was used to adjust the pH of calcium ions slurry,a large amount of calcium carbonate nanoparticles was generated in the slurry,and the Pb-BHA collectors chemisorbed on their surfaces with a higher adsorption amount than that of scheelite. After the addition of sodium fluoride,the nano-calcium carbonate surface was transformed to generate calcium fluoride,and the adsorption amount of the collectors on its surface was significantly reduced. The nano-calcium carbonate generated when sodium carbonate was used in high-calcium ions slurry competed with scheelite surface for adsorption of collectors in flotation,which made the flotation of scheelite worse. Sodium fluoride promoted the surface conversion of calcium carbonate nanoparticles to calcium fluoride and reduced the adsorption of collectors on their surfaces,thus eliminating their unfavorable effect on scheelite flotation.

Key words: calcium ions,sodium carbonate,solution chemistry,scheelite,nano-calcium carbonate