Na_(2)CO_(3)-Na_(2)SO_(4)复盐熔炼法从碱溶渣中高效分离钨的工艺研究

Process study on efficient separation of tungsten from alkali molten slag by Na_(2)CO_(3)-Na_(2)SO_(4) compound salt melting

钨合金废料资源化利用过程中容易产生含钨碱溶渣,且该部分含钨碱溶渣中钨品位较高。本文开发了一种复盐(Na_(2)CO_(3)-Na_(2)SO_(4))熔炼工艺,以对含钨碱溶渣中的钨进行高效分离;探究Na_(2)CO_(3)和Na_(2)SO_(4)的添加量、复盐熔炼温度、熔炼时间以及水浸液固比、水浸温度对钨回收率的影响。结果表明:从含钨碱溶渣中高效分离钨的最优条件为n(W)∶n(Na_(2)CO_(3))∶n(Na_(2)SO_(4))=1∶1.25∶0.54,复盐熔炼温度为800℃,熔炼时间为3 h,水浸液固比为2.5,水浸温度为75℃,在该最优条件下可将含钨碱溶渣中99.93%的钨分离出来。同时,本文通过XRD分析以及热力学分析对复盐熔炼的反应机理进行了探讨,复盐体系的构建有助于降低体系共熔点,降低能耗,同时有助于促进碱溶渣与反应介质的充分接触,提高反应效率。

The resource utilization of tungsten alloy waste is prone to produce tungsten-containing alkaline residue,and the tungsten content in this part of tungsten-containing alkaline residue is high.In this paper,a compound salt(Na_(2)CO_(3)-Na_(2)SO_(4))melting process was developed for the efficient separation of tungsten.The effects of the addition amount of Na_(2)CO_(3) and Na_(2)SO_(4),the melting temperature of the compound salt,the melting time as well as the water leaching liquid-solid ratio and the water leaching temperature on the recovery of tungsten were investigated.The results show that the optimal conditions of separating tungsten from alkali molten slag are n(W)∶n(Na_(2)CO_(3))∶n(Na_(2)SO_(4))=1∶1.25∶0.54,the melting temperature of the compound salt is 800℃,the melting time is 3 h,the water leaching liquid-solid ratio is 2.5,the water leaching temperature is 75℃,and 99.93%of the tungsten metal in the tungsten-bearing alkali residue can be optimally separated out.Meanwhile,the reaction mechanism of compound salt melting was discussed in this paper based on XRD analysis and thermodynamic analysis.The construction of compound salt system helps to reduce the eutectic point of the system save energy consumption,and also helps to promote the full contact between alkali-soluble slag and reaction medium to improve the reaction efficiency.