Leaching of a limonitic laterite in ammoniacal solutions with metallic iron

The leaching of a limonitic laterite (containing approximately 1% Ni, 0.1% Co and 50% Fe) was studied in ammoniacal solution. The laterite was leached in the presence of metallic iron which acted as a reductant. The kinetic parameters studied included the effect of temperature, metallic iron concentration, total ammonia concentration and ammonium sulphate to ammonium hydroxide ratios. Tests were performed in a batch cell with temperature ranging from 50 to 80 °C at atmospheric pressure. The kinetic behavior for nickel and cobalt extraction was observed to be different. Cobalt extraction was initially faster than nickel and it showed good extractions at lower temperatures, however, after reaching a maximum value of approximately 80%, extraction decayed by as much as 50%. This was likely due to cobalt co-precipitation and/or adsorption into iron and/or manganese oxides and hydroxides which could form during the process. Cobalt losses tended to increase with temperature, total ammonia concentration, ammonium hydroxide to ammonium sulphate ratio and metallic iron concentration. Nickel extraction was increased by higher temperature, total ammonia concentration and metallic iron concentration up to a maximum of roughly 70% after 48 h at 80 °C.Through feed and solid residue analysis, by X-ray diffraction and SEM, it was possible to characterize and understand how the feed mineral reduction occurred. The main phases present in the feed and residue were goethite and magnetite, respectively. Results suggest that the reduction occurs through two main reactions. First, the reaction between goethite and metallic iron produced Fe(II) ammines. The Fe(II) ammines are capable of reducing goethite and producing magnetite. The Fe(II) ammines play an important role because they accelerate the reduction and favor the extraction kinetics of nickel. The main advantage of using metallic iron as a reducing agent is the possibility of generating an autocatalytic system.     

石煤钒矿焙砂加压碱浸试验

针对目前采用"焙烧—碱浸提钒"工艺从石煤钒矿中提取钒存在碱消耗大、浸出时间长和浸出液杂质含量高等问题,研究采用高压碱浸法浸出石煤钒矿焙砂。试验考察碱用量、液固比、浸出时间、循环浸出等因素对钒浸出率的影响。结果表明,在NaOH用量为矿重的3.5%,液固比为1.5∶1,180℃下,2 h浸出,钒的浸出率达到86%,浸出液中钒硅质量浓度比为0.65,浸出液pH值约为12.1。高压碱性浸出具有钒浸出率高,杂质浸出率低等优点,为石煤提钒提供了一个新的途径。     

采用磁场强化浸出提高某含铜难浸金矿浸出率的试验研究

某含铜难浸金精矿常规硫脲浸出率仅48.71%,采用细菌预处理及磁场强化浸出后金浸出率可达92.86%。在常规硫脲浸出、低氧细菌预处理及氧化渣浸金试验中添加磁场可明显促进金的浸出,提高浸出率。     

锌加压浸出渣浮选硫磺精矿的干燥试验研究

针对锌加压浸出渣浮选硫磺精矿的物料特点, 通过探索及连续试验, 对双桨叶螺旋干燥机干燥浮选硫磺精矿的可行性进行了研究。结果表明, 双桨叶螺旋干燥机干燥硫磺精矿可行, 适宜的蒸汽控制温度约120 ℃, 出料含水以7%~8%为宜, 平均传热系数约为50 W/(m²·℃)。     

生物质还原浸锰液净化制备硫酸锰工艺研究

使用植物副产生物质对锰银多金属矿还原浸出, 得到浸出锰液。采用一类价廉、具有吸附功能的天然硅酸盐矿物处理生物质浸出锰液, 净化后制得硫酸锰。该方法具有工艺简单、吸附剂添加量少、除杂效率高、处理成本低的特点, 解决了生物质浸锰工艺长期存在的所制硫酸锰产品档次低的难题, 制备的硫酸锰可以同时达到HG/T2962-1999工业硫酸锰和HG/T2936-1999饲料硫酸锰标准; 研究技术具有较好的推广应用前景。     

青海某难选半氧化金矿选矿试验研究

为了提高青海某难选半氧化金矿的选矿回收率,在原矿工艺矿物学研究的基础上,开展了原矿浸出、浮选和浮选尾矿CIL浸出试验,并进行了环保提金剂和NaCN浸出对比试验研究。结果表明,在磨矿细度（-74 μm含量）为91.81%条件下,分别采用1#、2#环保提金剂和NaCN堤金,金的浸出率分别为80.07%、79.71%和80.80%;在磨矿细度（-74 μm含量）为83.64%条件下,采用浮选和浮选尾矿CIL浸出,获得浮选金精矿品位为125.94×10-6,浮选回收率为73.72%,浮选尾矿采用1#、2#环保提金剂和NaCN,选矿总回收率分别达到92.67%、93.62%和94.99%。     

常压盐酸浸出红土镍矿的研究

为有效提取红土矿中镍钴资源,研究了常压盐酸浸出工艺提取红土矿中的镍钴。结果表明,矿料粒度为-0.15 mm,初始酸浓度8 mol/L,浸出温度353 K,固液比S/L=1:4,搅拌速度300 r/min,反应时间2 h,镍、钴、锰、铁、镁的浸出率分别达到93.94%、60.5%、94%、56%9、4%。     

某含钼钨矿石选矿试验研究

某含钼白钨矿采用依次浮钼、硫、钨的优先浮选工艺流程,浮选钨精矿再酸浸脱磷,最终获得了WO3品位为79.14%、回收率为77.56%的合格白钨精矿,并综合回收钼、硫。     

红土矿还原焙砂常压酸浸液用SO2/O2氧化除铁的研究

在实验室条件下采用SO2和O2混合气体为氧化剂,开展了从预还原焙烧红土矿常压酸浸液中氧化、除铁的研究.模拟浸出液中Fe2+的质量浓度为10.2 g/L,实验温度分别为60、70、80和90℃.氧化后的Fe(Ⅲ)基本以针铁矿的形式沉淀除去,沉淀过程中加入碱式碳酸镁为中和剂以维持溶液pH值恒定.氧化、沉淀除铁的pH值控制范围为1.7至3.2.实验结果表明,SO2和O2混合气体可加速Fe2+的氧化,且SO2的优化配比取决于混合气体的流量.在优化配比情况下,混合气体中SO2的利用率在97%左右.SO2含量超过最优配比时,过量的SO2则会被溶液中的Fe3+氧化.除铁沉淀渣中的镍含量(质量分数)不超过0.05%,镍仅有少量损失于除铁渣中.     

从锌阳极泥中综合回收锌锰并富集铅银的研究

主要以锌电积过程中产生的锌阳极泥为原料,采用全湿法工艺流程,开展对锌阳极泥综合回收处理,先经酸洗,然后在硫酸介质中进行还原浸出,浸出液经净化、合成等工序,生产出更具应用与市场前景的锰产品。试验结果表明：锌阳极泥通过酸洗,锌的脱除率达90％以上,再经还原浸出,锰的浸出率超过92％,合成得到的锰产品符合国家标准要求,锰回收率在90％以上。浸出渣为铅银渣,渣中铅、银含量较锌阳极泥富集了3～4倍,利于后续铅银等贵金属的回收利用。