高钙低品位硫氧混合锌矿氧化焙烧矿相的转变规律

Mineral Phase Transformation during Oxidation Roasting of Low-grade Sulfide and Oxide Mixed Zinc Ore with High Calcium

针对低品位硫氧混合锌矿含钙高的特点,在低温下对其进行氧化焙烧,通过控制气相中的硫势和氧势,使矿石的矿相发生转变,促进锌在氨性体系中溶解;同时利用矿石中钙的固硫作用,使硫转化成CaSO_4,有效避免SO_2对环境的污染.结果表明,锌品位为5.45%的硫氧混合锌矿在300℃下焙烧3h,矿石中的异极矿和闪锌矿转化成了易溶出的ZnO,方铅矿和黄铁矿分别转化成了PbSO_4和Fe_2O_3,方解石转化成了CaSO_4,所得焙砂在NH_3-(NH_4)_2SO_4-H_2O体系中45℃下浸出,锌浸出率可达73.27%;焙烧温度大于300℃时,焙砂中会产生大量铁酸锌,使锌浸出率下降.

Based on the characteristics of high calcium content,the low-grade sulfide and oxide mixed zinc ore was treated via an oxidation roasting at low temperatures by controlling the sulfur and oxygen potentials in the gas phase to make the transformation of zinc-bearing mineral phases and promote the dissolution of zinc in the ammonia system.At the same time,sulfur in the ore could be transformed into CaSO_4 in the presence of CaCO_3 and the pollution of SO_2 to environment could be effectively avoid.The results showed that when the mixed zinc ore with a Zn content of 5.45% roasting at 300 for 3 h,℃ the hemimorphite and sphalerite in the ore were transformed into easily soluble ZnO,while the galena,pyrite and calcite were transformed into PbSO_4,Fe_2O_3 and CaSO_4,respectively.The obtained calcine was leached with NH_3-（NH_4）_2SO_4-H_2O system at 45 ℃ and the zinc leaching rate was up to 73.27%.When the temperature was higher than 300 ℃,however,a large amount of franklinite would be produced in the calcine,resulting in a decrease in the leaching rate of zinc.