废轮胎热解炭黑灰渣中锌提取工艺

Extraction technology of zinc from pyrolysis carbon black ash residue of waste tires

废轮胎经煤油预处理后,经热解生成炭黑,之后煅烧生成灰渣,针对废轮胎热解炭黑煅烧后灰渣中锌的提取进行了相关研究,采用酸溶-分步沉淀法,最终锌以氧化锌产品回收。分别采用4种无机酸(HCl、HNO3、H2SO4及醋酸)对灰渣进行酸溶处理,得出盐酸对灰渣酸溶效果最佳;在此基础上,考察了酸浓度、液固比(酸体积/炭黑质量)、浸出时间、酸解温度等因素对锌离子浸出效果的影响,得到锌浸出的优化工艺条件为:酸浓度2 mo1/L、温度20℃、浸出时间60 min和液固比6∶1(mL/g),在此条件下浸出锌离子的浸出率约为91.4%。经分步沉淀法对滤液进行沉淀、煅烧后,得到纯度约为98.2%氧化锌产品,灰渣中锌提取率达到81.4%左右。

Waste tires were pretreated with kerosene,then pyrolyzed to form carbon black,and then calcined to form ash.The extraction of zinc from ash after calcination of waste tires pyrolyzed carbon black was studied.The zinc was finally recovered as zinc oxide by acid dissolution-step precipitation method.Four kinds of inorganic acids(HCl,HNO3,H2 SO4 and acetic acid)were used to acid dissolve the ash,and it was found that hydrochloric acid had the best acid dissolution effect on the ash.On this basis,the effects of acid concentration,liquid-solid ratio(acid volume/carbon black mass),leaching time,acidolysis temperature and other factors on the leaching effect of zinc ions were investigated.The optimal technological conditions for zinc leaching were as follows:acid concentration 2 mo1/L,temperature 20℃,leaching time 60 min and liquid-solid ratio 6∶1 mL/g.Under these conditions,the leaching rate of zinc ions was about 91.4%.After precipitation and calcination of filtrate by step precipitation method,zinc oxide product with purity of about98.2%was obtained,and the extraction rate of zinc from ash was about 81.4%.