酸对捕收剂在胶磷矿和白云石表面吸附的影响

Effects of Acid on Adsorption of Collector on Collophane and Dolomite Surface

浮选过程中抑制剂会使矿物表面亲水,还可能与捕收剂存在竞争吸附.硫酸和磷酸是钙(镁)质磷矿石反浮选工艺常用的抑制剂.通过单矿物和人工混合矿浮选试验及吸附量测定,研究了胶磷矿-白云石反浮选体系中,抑制剂硫酸或磷酸浓度对捕收剂GJBW在矿物表面吸附量的影响.结果表明,酸浓度对矿物上浮率影响较大,但对捕收剂在胶磷矿和白云石表面吸附量影响均较小,说明该体系中抑制剂和捕收剂在矿物表面不是竞争吸附而是共同吸附,综合决定表面亲/疏水性,进而影响其上浮率.于是建立了两者在矿物表面共同吸附的双电层模型,其中不溶油酸分子(HOl)作为主要捕收剂组分在白云石-水界面起主导作用使表面疏水,而胶磷矿酸溶释放出的或磷酸电离出的H_2PO_4^-做为主要抑制组分在胶磷矿-水界面起主导作用使表面亲水.

Depressants could make mineral surface hydrophilic，and there may be a competitive adsorptionbetween depressants and collectors in the progress of flotation. Sulfuric acids and phosphoric acids arecommonly used as depressants in reverse flotation of calcareous - dolomitic phosphate ores. This paperinvestigated the effects of the concentrations of depressants（H 2 SO 4 or H 3 PO 4 ）on the adsorption capacity ofcollector GJBW at mineral surfaces in reverse flotation of collophane and dolomite by micro - flotation andmeasurement. The results indicated that the acid concentration greatly affected the flotation recovery ofminerals，but it slightly affected the adsorbing capacity of collectors on collophane and dolomite surfaces，whichindicated that depressants and collectors in the system were synergistic adsorption rather than competitiveadsorption at the mineral surfaces. Depressants and collectors collaboratively decided the surface properties ofhydrophilicity or hydrophobicity，thereby affecting the flotation recovery of minerals. Moreover，the doubleelectric - layer models of synergistic adsorption between depressants and collectors at the mineral surfaces weredeveloped. In the models，the insoluble oleic acid molecule（HOl）acted as the main collector component at thedolomite - water interface to make the surface hydrophobic，and the H 2 PO 4 - ions from the release of collophanedissolution or ionization of phosphoric acid functioned as the main inhibitory component in the phosphate - waterinterface to dominate the surface hydrophilic.