含锗锌浸出渣强化解离及有价金属浸出行为

Enhanced dissociation and valuable metal leaching behavior of germanium-zinc leaching residue

针对含锗锌浸出渣处理过程中存在有价金属回收率低、工艺复杂等问题,本文提出了Ⅰ段控铁低酸加压浸出-Ⅱ段深度高酸加压浸出的两段逆流加压酸浸工艺。深入研究了Ⅱ段深度高酸加压浸出过程中载锌、锗复杂物相解离机理以及锌、锗、铁等有价金属的深度浸出行为。结果表明:升高反应温度、延长反应时间、增加氧分压不仅能促进载锌、锗铁酸盐(MeFe_(2)O_(4),Me=Zn,Ge)复杂物相的高效解离,也有利于Fe(Ⅲ)水解沉淀反应的发生,浸出渣物相组成由以铁酸盐为主逐步演变为以铁矾为主;酸度是影响铁酸盐热力学优势区的重要因素,其热力学稳定性随体系酸度的升高而逐渐降低,酸度过高时铁的溶解速率大于其沉淀速率,同时因H+活性增强抑制了Fe(Ⅲ)水解生成黄钾铁矾反应的发生。在反应温度150℃、初始酸度100 g/L、反应时间180 min、氧分压0.4 MPa、搅拌转速500 r/min的优化技术条件下,锌、锗的浸出率分别为92.47%、61.33%,获得的浸出终渣中主要物相为铁矾、硫酸钙,其含锌、锗、铅、银、硫分别为1.41%、370.00 g/t、3.52%、150 g/t、12.88%。含锗锌浸出渣的两段逆流加压酸浸工艺可同时实现锌、铁高效分离以及锌、锗等有价金属的高效浸出。

Aiming at the problems of low recovery rate of valuable metals and complicated process in the treatment of germanium-zinc leaching residue,this paper proposed a two-stage countercurrent pressurized acid leaching technique,which consisted of stage Ⅰ iron-controlled low-acid pressure leaching and stage Ⅱ deep highacid pressure leaching.The phase dissociation mechanism of zinc-loaded and germanium complexes and the deep leaching behavior of valuable metals such as zinc,germanium and iron during the deep high-acid pressure leaching process of stage Ⅱ were deeply studied.The results show that increasing the reaction temperature,prolonging the reaction time and increasing the oxygen partial pressure can not only promote the efficient dissociation of zinc-loaded and germanium ferrite(MeFe_(2)O_(4)) complex phases,but also facilitate the occurrence of Fe(Ⅲ) hydrolysis and precipitation.The phase composition of the leaching residue gradually evolves from ferrite to jarosite;the acidity is an important factor affecting the thermodynamically dominant region of ferrite,and its thermodynamic stability gradually decreases with the increase of the acidity of the system.When the acidity is too high,the dissolution rate of iron is greater than its precipitation rate,and the hydrolysis of Fe( Ⅲ) to jarosite is inhibited due to the enhanced H+ activity.Under the optimized technical conditions of reaction temperature of 150 ℃,initial acidity of 100 g/L,reaction time of 180 min,oxygen partial pressure of 0.4 MPa,and stirring speed of 500 r/min,the leaching rates of zinc and germanium are 92.47% and 61.33%,respectively.The main phases are jarosite and calcium sulfate,and the contents of zinc,germanium,lead,silver and sulfur are 1.41%,370.00 g/t,3.52%,150 g/t,and 12.88%,respectively.The two-stage countercurrent pressurized acid leaching process of germanium-zinc leaching residue can simultaneously realize the efficient separation of zinc and iron and the efficient leaching of valuable metals such as zinc and germanium.