低浓度铁尾矿酸浸出液选择性沉铁及制备LiFePO_4的研究

以低浓度铁尾矿酸浸出液为原料,通过控制溶液pH值进行选择性沉铁,制备出多元金属掺杂的FePO_4·xH_2O。并以其为前驱体,通过固相-碳热还原法成功地制备出LiFePO_4。利用化学滴定法、SEM、XRD和充放电测试等方法对样品进行了分析。结果表明:所制备的LiFePO_4结晶良好,为单一的橄榄石结构。在0.1C、1C、2C和5C倍率下首次放电比容量分别为144.9mAh·g^(-1)、132.07mAh·g^(-1)、122.6mAh·g^(-1)和115.6mAh·g^(-1)。这种以铁尾矿为主要原料制备锂离子电池正极材料LiFePO_4的方法,为铁尾矿的综合利用提供了一条新途径。

Separation of macro amounts of tungsten and molybdenum by precipitation with ferrous salt

In order to develop a low-cost approach for separating macro amounts of Mo and W, the effects of parameters on the separation using FeSO4 as precipitation reagent were studied. The results show that the optimum reaction temperature is 10 °C, and the separation factor does not further improve after a reaction time of 7 h. Moreover, slow dropping speed of the precipitation reagent is beneficial for improving the separation efficiency. When the H＋/W molar ratio is below 1/1, the addition of acid to a neutral solution is favorable to the separation. For the solution with an ammonium concentration below 3 mol/L, the separation factor is high due to the high W-precipitation rate. Furthermore, the method is also effective when it is applied to industrial solution containing some other impurities. All these indicate the ferrous salts have great potential for removing W from Mo on a commercial scale.

利用锌浸出渣制备铊吸附剂

火法冶金工序中,含铊物料易挥发进入烟气洗涤工序,从而产生了大量含铊废水,带来环境污染风险;同时,铅锌行业每年产出总量达数百万吨以ZnFe2O4为主要成分的浸出渣废料,需要妥善处置。基于此,本文提出以锌浸出渣为原料,通过酸浸法提取其中的有价值元素锌和铁,通过氨络合选择性沉铁工艺实现锌铁分离,最后将沉铁产物经过冷冻干燥处理,制得铁基铊吸附剂。稀硫酸逆流浸出法处理锌浸出渣可实现较高的锌、铁浸出效率,分别达到97.05%、99.31%,得到的浸出液中锌、铁浓度分别为86.54 g/L、77.86 g/L;采用本研究提出的络合沉淀法选择性沉铁工艺可以将浸出液中99.78%的铁沉淀分离,且锌损失率控制在0.5%;冻干处理后的沉铁产物是优秀的铁基铊吸附剂,3 g/L铊的水溶液中铊去除率为98.9%,采用pH值1.5的稀盐酸可以洗脱95%的吸附铊,为铊的进一步回收和资源化利用提供了有利条件。该工艺不仅实现了对锌浸出渣的绿色、高值化回收利用,而且成功制备出性能优异的铊吸附剂。