从石煤中提取五氧化二钒的工艺研究

根据陕西某石煤矿的特点，采用“氧化焙烧-硫酸浸出-P204萃取-硫酸反萃-氨水沉钒-煅烧”的工艺流程，进行了从石煤中提取V2q的试验研究，结果表明，石煤矿样于850℃焙烧2h后，在液固比1：1，浸出温度103℃的条件下，采用二段浸出方式，焙烧矿样用二次浸出的溶液补加少量硫酸进行一次浸出，一次浸出渣用在较高酸度下二次浸出，钒的总浸出率可达84％。浸出液经预处理后用氨水调节pH值至2．0左右，用P204萃取，经水洗后硫酸反萃，可得到较为纯净的钒溶液，再将其氧化后，经氨水沉钒、煅烧得到纯度大于98％的V2O5产品，全流程钒总回收率可达80％以上。     

Ni-Cr alloy electrodepositing technology on Fe substrate and coating performance

The Ni-Cr alloy electrodepositing technology on iron substrate in the chlorid-sulfate solution and the impacts of main processing parameters on coating composition were studied. The optimal Ni-Cr alloy electrodepositing conditions are that the cathode current density is 16 A/dm^2, the plating solution temperature is 30 ℃ and the pH value is 2.5. The bright, compact coating gained under the optimal conditions has good cohesion and 24.1% Cr content. The results show that the coating is composed of crystalline, the average grain size is 82 nm and the higher the Cr content of coating, the larger the rigidity, and the higher the corrosion resistance. The rigidity of coating reaches 78.6（HR30T） and the passivation area broadens to 1.4 V when the Cr content of coating is 24.1%.