硫化碱浸工艺处理文丘里泥回收碲、硒

Recovering tellurium and selenium by sulfuric-alkaline leaching in Venturi sludge

文丘里泥中含有金、银、铅、铋、砷、硒及碲等有价元素,返回卡尔多炉熔炼时,碲与金、银会生成化合物进入熔炼渣,造成损失;如果在返回卡尔多炉熔炼之前除碲,则不但回收利用碲资源,还增加了金银回收率。本文以某稀贵车间文丘里泥为原料,利用硫化钠对铅的抑制浸出作用,进行了NaOH-Na2S浸出及制备二氧化碲和粗硒的试验,实现了文丘里泥中碲和硒的回收。试验结论如下:在氢氧化钠浓度100 g/L、硫化钠加入量4%、反应温度80℃、碱浸2 h的优化条件下,碲、硒浸出率分别可达到90.06%、30.58%;加入与未加硫化钠工艺相比,粗二氧化碲品质可从80%提升至90%以上;动力学分析结果表明,文丘里泥硫化碱浸阶段碲的浸出受扩散模型控制。采用该工艺不但能提升金银回收率、回收碲资源,而且还提高了生产效率,所产出的二氧化碲纯度达到99%以上,副产粗硒纯度达到90%以上,经济效益显著。

There are valuable elements such as gold,silver,lead,bismuth,arsenic,selenium and tellurium in Venturi sludge.When it is returned to Kaldor furnace for smelting,tellurium forms compounds with gold and silver in Venturi sludge,and enter smelting slag,resulting in loss.If tellurium is removed before Venturi sludge returning to Kaldo furnace,not only the tellurium resource is recycled,but also the gold and silver recovery rate is increased.In this paper,by using the inhibition of lead leaching by sodium sulfide,the experiment of NaOH-Na2S leaching Venturi sludge and preparation of tellurium dioxide and crude selenium was carried out.The following conclusions are obtained.The leaching rate of tellurium and selenium can reach 90.06%and 30.58%respectively under the optimum conditions of sodium hydroxide concentration of 100 g/L,sodium sulfide addition of 4%,reaction temperature of 80℃and alkali leaching for 2 h.Compared with the process without sodium sulfide,the quality of crude tellurium dioxide can be increased from 80%to more than 90%.The results of kinetic analysis show that the leaching of tellurium in the sulfide alkali leaching stage of Venturi sludge is controlled by the diffusion model.This process can not only improve the recovery rate of gold and silver,recover tellurium resources,but also improve the production efficiency.The purity of tellurium dioxide produced is more than 99%,and the purity of crude selenium by-product is more than 90%.The economic benefit is remarkable.