Molybdenite-limestone oxidizing roasting followed by calcine leaching with ammonium carbonate solution

辉钼矿-碳酸钙氧化焙烧及熟料在碳酸铵溶液中的浸出（英文）

Oxidizing roasting of molybdenite with lime can significantly reduce SO2pollution compared with the traditional roastingwithout lime.However,the calcine is subsequently leached by sulfuric acid,resulting in serious equipment corrosion and abundantnon-recyclable CaSO4slag.In this work,a novel process,in which the molybdenite was roasted with CaCO3followed by(NH4)2CO3solution leaching,was proposed to improve the art of lime roasting-sulfuric acid leaching.Oxidizing roasting of molybdenite withCaCO3was investigated through thermodynamic calculation,thermogravimetric analysis and roasting experiments.The results showthat the products of the oxidizing reaction of MoS2in the presence of CaCO3and O2are CaSO4,CaMoO4and CO2at573-1000K.The MoS2conversion rate achieves approximately99%and the sulfur-retained rate attains approximately95%with aCaCO3-to-MoS2molar ratio of3.6at500°C for1h by adding5%mineralizer A(mass fraction).The leaching results show that theleaching rate of Mo reaches98.2%at85°C for7h with a(NH4)2CO3concentration of600g/L and a liquid-solid ratio of10mL/g.The results presented are potential to develop a novel cleaner technique for ammonium molybdate production.

石灰焙烧-硫酸浸出法可大大降低传统氧化焙烧-氨浸工艺处理辉钼矿的含硫烟气污染,但存在设备腐蚀严重、渣量大等缺点。基于石灰焙烧工艺研究,本文作者提出"碳酸钙氧化焙烧-碳酸铵浸出"新工艺来处理辉钼矿。通过热力学计算、热重分析以及焙烧试验等对辉钼矿-碳酸钙氧化焙烧过程进行详细研究。结果表明,MoS_2与CaCO_3和O_2在573~1000K下反应的主要产物是CaSO_4、CaMoO_4和CO_2;当CaCO_3和MoS_2的摩尔比为3.6并加入5%矿化剂A在500°C下焙烧1h时,钼精矿中的MoS_2的分解率达到约99%,固硫率达到约95%。用碳酸铵溶液浸出焙烧后熟料,控制碳酸铵浓度为600g/L、液固比为10mL/g,在85°C下浸出7h,Mo浸出率可达98.2%。该研究结果将有助于钼酸铵清洁生产新技术的开发。