研究煤在铁闪锌矿氧压酸浸中的应用。实验发现,含碳量高于70%的煤无助于铁闪锌矿浸出。在温度为423K时,低碳煤(褐煤)可以用作铁闪锌矿氧压酸浸中优良的硫分散剂,其用量选定1.O%(相对于精矿质量)为宜,在98%以上精矿粒度小于43)am,液固比为4.5:1mL/g,浸出剂中初始硫酸浓度为1.43mol/L,锌浓度为0.62mol/L,浸出温度为423K,氧分压为0.5MPa,搅拌转速为800r/min,浸出1.5h条件下,添加1.0%褐煤后,锌浸出率达到96%,上述工艺运行高效、稳定。褐煤具有比木质素磺酸钠更强的分散单质硫的能力,并能基本消除单质硫对浸出残余硫化矿的沾染。
Oxidative pressure leaching of marmatite concentrates with adding coal as elemental-sulfur disperser was investigated. The experimental results show that the coal with carbon content higher than 70% can not improve the leaching of zinc. The coal with low carbon content (lignite coal) can act as excellent elemental-sulfur disperser in the pressure leaching of marmatite concentrates at 423 K. The appropriate dosage of lignite coal is further determined as 1.0% of the mass of concentrates. The leaching rate of zinc is achieved as high as 96% in the following conditions: the particle size of concentrates of 98% less than 43 gm, the lignite coal dosage of 1.0% of the mass of concentrates, the liquid to solid ratio of 4.5:1 mL/g, the initial sulfuric acid concentration of 1.43 mol/L, the initial zinc concentration of 0.62 mol/L, the leaching temperature of 423 K, the oxygen partial pressure of 0.5 MPa, the agitation speed of 800 r/min, the leaching time of 1.5 h. This pressure leaching technique is proved to be effective and stable. The sulfur-dispersing capability of lignite coal is further proved to be much higher than that of sodium lignosulphonate. The adherence of elemental sulfur to residual sulfide ores in the slag is nearly eliminated with lignite coal as elemental-sulfur disperser.