废抛光粉中综合回收Ce、La研究

以湖南某企业废抛光粉为研究对象,采用硫酸焙烧-水浸-草酸沉淀-煅烧工艺从废铈抛光粉中回收铈镧,并制备成低级抛光粉。结果表明,在硫酸焙烧温度300℃、浓硫酸用量(mL/g)3∶5、焙烧时间2 h;水浸温度25℃、水浸液固比(mL/g)20∶1、水浸时间2 h;草酸沉淀温度25℃、草酸用量为理论值1倍、沉淀时间1 h;焙烧温度850℃、焙烧时间2 h的条件下,可获得Ce、La品位分别为65.56%和24.12%的稀土氧化物,达到低级Ce稀土抛光粉标准。

废抛光粉中Si、Al杂质脱除技术研究

为高效回收废抛光粉中的稀土元素,需要预先脱除其中的Si、Al杂质。采用NaOH溶液浸出工艺脱除废抛光粉中的Si、Al杂质,研究了碱比(NaOH与抛光粉质量比)、浸出时间、浸出温度和碱浓度对Si、Al脱除率的影响。结果表明:碱比与浸出时间对Si、Al脱除率影响较大;当浸出温度为90℃,碱比为1.0,浸出时间为90 min,NaOH浓度为1.00 mol/L时,Si、Al脱除率分别可达95.37%和97.93%。

稀土抛光粉固体废粉资源特性研究

研究了稀土抛光粉固体废粉资源化利用及污染特性。结果表明,该废粉中主要含有稀土(wREO>80%)、硅、氟等元素;经与包头稀土精矿生产的稀土产品进行工艺比较,认为可利用该废粉生产稀土化合物。测试结果表明,废粉浸出毒性、腐蚀性符合国家标准要求,经实验确定该废粉不具备反应性及易燃性,不含有放射性物质。

废稀土抛光粉盐酸浸出过程研究

采用盐酸直接浸出方式从稀土废抛光粉中回收稀土,考察了盐酸浓度、浸出温度、浸出时间和液固比对稀土和主要杂质元素Al_(2)O_(3)浸出率的影响,并探讨了浸出机理。结果表明,HCl体系单级浸出的优化条件为:HCl浓度8 mol/L、浸出温度80℃、浸出时间3 h、液固比4∶1,此时稀土元素浸出率为90.81%,Al_(2)O_(3)浸出率为43.68%。对比了单级浸出、二级浸出和三级逆流浸出效果,证实三级逆流浸出时稀土浸出率高达98.38%,浸出液中稀土总量增加,有利于稀土元素的下一步萃取回收,大大降低了回收成本。

酸溶法测定稀土抛光粉废粉中的稀土总量

建立了稀土抛光粉废粉中稀土总量的分析方法。通过不同的实验,选择合适的溶样酸及溶样试剂量,并考察硅量、铁和铝对测定的影响。通过精密度实验及溶样方法的比对,证明此方法可以准确测定稀土抛光粉废粉中的稀土总量。测定稀土总量含量范围10%~95%,RSD为0.17%~0.28%。此方法简单、准确、重复性较好,能满足科研生产的技术要求。

Preparation of high performance ceramic tiles using waste tile granules and ceramic polishing powder

This paper presents an innovative approach to reusing waste tile granules(TG) and ceramic polishing powder(PP) to produce high performance ceramic tiles.We studied formulations each with a TG mass fraction of 25.0% and a different PP mass fraction between 1.0% and 7.0%.The formulations included a small amount of borax additive of a mass fracton between 0.2% and 1.2%.The effects of these industrial by-products on compressive strength,water absorption and microstructure of the new ceramic tiles were investigated.The results indicate that the compressive strength decreases and water absorption increases when TG with a mass fraction of 25.0% are added.Improvement of the compressive strength may be achieved when TG(up to 25.0%) and PP(up to 2.0%) are both used at the same time.In particular,the compressive strength improvement can be maximized and water absorption reduced when a borax additive of up to 0.5% is used as a flux.Scanning electron microscopy reveals that a certain amount of fine PP granules and a high content of fluxing oxides from borax avail the formation of glassy phase that fills up the pores in the new ceramic tiles,resulting in a dense product with high compressive strength and low water absorption.