低品位钼矿制备钼酸盐的研究

Research on the Preparation of Anmonium Molybdate from Low Grade Molybdenum Ore

研究了在氧化焙烧过程中温度、时间、通氧气次数、不同助熔剂对低品位钼精矿中钼得率的影响,优化了氧化焙烧、氨浸、酸沉的条件,确定了制备钼酸盐的最佳条件。当氧化焙烧温度为625℃,焙烧2h,物质的量比为摩尔比n(Na2CO3)∶n(NaNO3)∶n(Mo)=2∶0.5∶1,焙烧含钼为8.37%的低品位钼精矿粉时,钼的收率为96.76%。焙烧物用1∶1氨水,温度60℃,浸出2h,氨浸率为78.1%。氨浸液用硝酸调节pH=2.0-2.5时,得到的结晶产物是不溶于水的四钼酸铵,母液中钼含量为8.67g/L,产品纯度为93.83%,不含硫酸盐,含有少量氯化物。ICP-MS测定不含Ca、Fe,含有的杂质为:P=0.038mg/g、Na=0.40mg/g、Cu=8.57×10-3mg/g、Pb=0.81×10-3mg/g。

The effects of temperature, time, air frequency and different fluxes on the yield rate of molybdenum in the process of oxidation roasting at low grade molybdenum ore and the best condition for ammonium molybdate production by means of optimization of conditions for oxidation roasting, ammonia soaking and acid precipitation are discussed. The experimental results show that when the temperature of oxidation roasting is 625℃ and the roasting time is 2h, the ratio of the substances is molar ratio： Na2CO3： NaNO3∶Mo=2∶0.5∶1 and the yield rate of molybdenum is 96.76% if the low grade molybdenum concentrate containing 8.37% molybdenum is roasted. When the roasting substances are soaked in 60℃ ammonia water （1∶1） for 2h, the leaching rate of ammonia is 78.1%. When the PH of the leaching liquid is adjusted to 2.0-2.5 using nitric acid, the product is anmonium molybdate which can not be dissolved in the water containing 8.67g/L of molybdenum with a purity of 93.83%. An ICP-MS test shows that it contains a small amount of chloride, however, it does not contain Ca, Fe and sulfate. In addition, its P is 0.038 mg/g, Na is 0.40mg/g, Cu is 8.57×10^-3mg/g, and Pb is 0.81 ×10^-3 mg/g.