微波加热低品位稀土精矿酸浸实验研究  

Acid Leaching of Low Grade Rare Earth Concentrate by Microwave Heating

作　　者：李解[1] 李成元[1] 李保卫[1] 王少炳 韩继铖[1] 王介良[1] 

机构地区：[1]内蒙古科技大学白云鄂博矿多金属资源综合利用国家重点实验室,内蒙古包头014010

出　　处：《稀有金属》2014年第5期839-845,共7页Chinese Journal of Rare Metals

基　　金：内蒙古自然科学基金项目(2012MS0714);内蒙古科技大学创新基金项目(2011NCL064);白云鄂博矿多金属资源综合利用国家重点实验室资助项目(BO-13-001)资助

摘　　要：针对稀土精矿高温酸浸焙烧钍难回收、成本高而低温酸浸焙烧又效率低的问题,采用"微波加热低温酸浸"新工艺,研究了低品位稀土精矿硫酸焙烧浸出的过程。实验首先考察了微波加热稀土精矿硫酸焙烧的升温特性,重点探讨了微波加热的焙烧温度、酸矿比、焙烧时间对酸浸矿稀土浸出率的影响,同时考察了不同焙烧温度下水浸渣中钍的残留率。实验结果表明:稀土精矿微波酸浸焙烧的升温速率随着酸矿比和微波功率的增加而加快;而且随着温度的升高、酸矿比和焙烧时间的增加,微波加热酸浸稀土精矿的浸出率提高,其浸出的最佳条件为:焙烧温度220℃,酸矿比1.5,焙烧时间8 min;此条件下的稀土浸出率为92.55%,且水浸渣中的钍未生成焦磷酸钍,可用于下一步提取。与现行的稀土精矿硫酸高温焙烧生产工艺和常规的低温酸浸焙烧工艺相比,微波焙烧低温酸浸工艺更具优势,在保证稀土较高浸出率和后续工艺能回收钍的基础上,将焙烧时间缩短为常规低温酸浸工艺浸出时间的1/15,从而提高了浸出效率。Owing to the disadvantages of difficult recovery,and high cost for acidic leaching calcination of Th at high temperature and low recovery rate for that at low temperatures,the new process of sulfuric acid leaching of low grade rare earth concentrate by microwave heating at low temperature was studied. Temperature rise properties were firstly investigated,and the effects of roasting temperature,the rate of acid to ore,roasting time of rare earth concentrate treated with microwave heating and sulfuric acid on the leaching rates of rare earth were mainly discussed,and the residual rates of thorium under different roasting temperatures were investigated. The results showed that the rates of temperature rise of acid leaching of rare earth concentrate by microwave heating were accelerated with the increase of the ratio of acid to ore and microwave power; the leaching rates of rare earth increased with the increase of temperature,the ratio of acid to ore and roasting time,and the optimum conditions of acid leaching of rare earth concentrate were as follows： roasting temperature of 220 ℃,the ratio of acid to ore of 1. 5,roasting time of 8 min. Under the optimum conditions,the leaching rate of rare earths was 92. 55%,and there was no thorium phosphate in water leaching residue,which could be used in the next extraction of thorium. Compared with the current productive process of acid leaching at high temperature and the conventional acid leaching process of rare earth concentrate at low temperature,the acid leaching process by microwave heating had obvious advantages. On the basis of keeping relatively high leaching rate of rare earth and recycling of thorium for the next process,the roasting time of acid leaching by microwave heating was shortened to one-fifteenth of that of the conventional acid leaching and thereby the acid leaching efficiency increased.

关 键 词：微波加热 稀土精矿 酸浸 

分 类 号：TQ110.6[化学工程—无机化工]