低品位镍磁黄铁矿镍浸出特性及回收方法

Leaching characteristics and recovery method of nickel from low-grade nickel-pyrrhotite

对我国某高硅低品位镍磁黄铁矿进行直接酸浸、焙烧--酸浸和细菌浸出比较,并考察硫酸用量及氧化亚铁硫杆菌对浸出率的影响.以稻壳为硫酸盐还原菌固定化载体构建连续上升流固定填充床反应器,以连续上升流方式处理浸出液.结果表明：焙烧使矿物发生烧结,镍被包裹,不利于浸出;细菌浸出Ni2＋浸出率为92.16%,质量浓度可达973.22 mg·L-1·T·f.菌在矿物表面形成生物膜,直接与矿物发生作用使矿物溶解,将浸液中Fe2＋氧化为Fe3＋,Fe3＋进一步溶解矿物·浸出液以2200~3600 mL·L-1·d-1的速率经过反应器,Ni2＋以NiS的形式吸附于稻壳上,回收率在98%以上,使原矿中NiO质量分数由1.69%上升至稻壳中的11.84%.浸液中98%的Mg2＋留在溶液中,利于金属分离.

In order to leach and recover nickel from high-silicon low-grade nickel-pyrrhotite, some factors were determined, including roasting pretreatment control, sulfuric acid use ratio, inoculated ThiobaciUus. ferrooxidans or uninoculated. Then sulfate-reducing bacteria （SRB） were immobilized by intact rice chaff in an up-flow anaerobic bed reactor. The leach liquor was treated by the reactor. It is shown that roasting results in the sintering of minerals and makes nickel wrapped, which is not conducive to the leaching of nickel. Thiobacillus ferrooxidans form a biofilm on the mineral surface, which plays a key role in the dissolution of minerals, and oxidizes Fe^2＋ to be Fe^3＋ , which does a further dissolution of minerals. The leaching rate of nickel reaches to 92.16% and the concentration of Ni2. is 973.22 mg· L^-1. When the influent passes through the reactor at a speed of 2 200 to 3 600 mL·L^-1· d^- 1, the recovery of Ni^2＋ , which adsorbs on the rice chaff in the form of NiS, is above 98% , and 98% of magnesium exists in the solution in the form of ions. The NiO content increases from 1.69% of the crude ore to 11.84% of the rice chaff .