硝酸体系镍电解除铁渣氨浸脱硫新工艺试验研究

Experimental research on the new process of ammonia leaching desulfurization for iron residue from nickel electrolysis in nitric acid system

镍电解过程需要除铁,当采用硫酸体系进行镍电解时,一般采用黄钠铁矾法除铁,存在碱量消耗量大、产出的铁渣含镍高、进入铁渣中的镍和铁资源回收困难等问题。金川实验室尝试采用硝酸体系进行镍电解,此时铁以硝酸铁的形式存在于电解液中,可利用硝酸铁低温易分解的特点除去,但生成的铁渣含硫较高,铁资源无法直接回用。本文针对硝酸体系产出的铁渣提出了一种氨浸脱硫的新工艺,对影响脱硫效果的因素进行了单一因子试验,并进行了扩大实验和工业试验,试验结果表明,在氨水用量3.0倍、反应时间1 h、反应温度85℃、液固比6∶1、搅拌速度180~200 r/min的条件下,可产出含铁>58%,含硫<0.3%的铁精矿。该工艺浸出过程中的浸出剂可实现循环利用,生成的硫酸钙渣可销往水泥厂,生成的硝酸钙溶液用于回收硝酸,是一条清洁脱硫的新工艺。

The nickel electrolysis process needs to remove iron.When the sulfuric acid system is used for nickel electrolysis,the yellow sodium iron vitriol method is generally used to remove iron.There are some problems such as a large amount of alkali consumption,the produced iron slag containing high nickel,and the nickel and iron that enter the iron slag difficult recovery.In the treatment of materials containing nickel with nitric acid,a kind of iron slag containing sulfur is produced.In order to recover iron resources from iron slag,this paper analyzes the properties of iron slag.The method of ammonia leaching is proposed for desulfurization,and the ammonia dosage,reaction time and reaction temperature on desulfurization effect are studied.The results show that when the amount of ammonia is 3.0 times,the reaction time is 1 h,and the reaction temperature is 85℃,the iron concentrate containing more than 58%iron and less than 0.3%sulfur can be produced.The leaching agent can be recycled in the leaching process,which is a new clean desulphurization technology.