(北京有色金屬研究總院 生物冶金國家工程實(shí)驗(yàn)室，北京 100088)
摘 要: 堿性硫脲浸金需要用氧化劑來調(diào)節(jié)溶液的氧化電勢，氧化劑的氧化電勢既要大于金溶解形成Au[CS(NH2)2]2+的電勢(0.38 V)，由于電勢太高硫脲易被氧化而失效，故氧化劑的氧化電熱不能太高。在堿性溶液中，氧的標(biāo)準(zhǔn)電極電勢為0.40 V，因此，理論上空氣中氧是理想而經(jīng)濟(jì)的氧化劑。然而，水的飽和溶氧量小，自然溶氧速度慢，從而使氧用作氧化劑受到限制。通過在攪拌浸出槽底部接入螺旋空氣管、微孔材料的方法改變發(fā)泡方式，進(jìn)而在持續(xù)增氧(空氣中氧作氧化劑)的條件下對堿性硫脲浸出低品位金礦石進(jìn)行具體地研究。發(fā)泡方式的改變既增大空氣中氧向水中傳遞的速率，又改善攪拌效果。結(jié)果表明：增氧條件下浸出體系的充氧能力越強(qiáng)，堿性硫脲浸金效果則越好。在相同充氣量條件下，微孔材料發(fā)泡增氧的效果最好，浸出率最高。而且在一定范圍內(nèi)，金浸出率隨著充氣量的增加而增大，而充氣量過大時則會降低金浸出率。
關(guān)鍵字: 增氧；堿性；硫脲；浸金
（National Engineering Laboratory of Biohydrometallurgy, General Research Institute of Nonferrous Metals, Beijing 100088, China）
Abstract:During alkali thiourea Au-leaching process, the oxidation potential of the solution is needed to be adjusted by oxidation reagents. The oxidation potential should be higher than 0.38 V, which is the potential for gold to dissolve, and to form Au[CS(NH2)2]2+. However, the thiourea will be decomposed rapidly if the oxidation potential level is too high. In alkaline solution, the standard electrode potential of oxygen is 0.40V, which indicates that theoretically oxygen in the air is an economical oxidant for alkali thiourea Au-leaching system. The use of oxygen as oxidant is negatively impacted due to the low saturation and the slow natural dissolution rate of oxygen in water. The bubble generation type was changed by adding spiral air ducts or microporous material at the bottom of agitating leaching tank, and then the alkali thiourea Au-leaching system for low grade gold ore was studied under the condition of continuous oxygen supplementation (oxygen used as oxidant in the air). The change of bubble generation not only increases the oxygen transfer rate from air to water, but also improves the mixing effect. The test results show that the stronger the oxygenation capacity of the leaching system is, the better the leaching effect of gold with alkaline thiourea will be. Under condition of the same aeration rate, the foaming efficiency of microporous material with the highest leaching rate is the best. Within a certain range, the gold leaching rate increase with the aeration rate increasing, but an extremely high aeration rate will decrease the gold leaching rate.
Key words: oxygen supplementation; alkaline; thiourea; gold leaching
