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浸出—萃取法综合回收磷尾矿中磷、镁的试验研究
【作者】 杨书怀；
【导师】 李军旗；
【作者基本信息】 贵州大学 ， 有色金属冶金， 2008， 硕士
【摘要】 由于世界磷矿资源的逐渐枯竭,品位趋于贫化,而为了满足湿法磷酸对原料矿石的质量要求,通过各种选矿技术的运用,每年都产生大量的磷尾矿。如果能对磷尾矿进行综合利用,不仅可以减少资源浪费,还能避免尾矿堆积占用土地及对环境的污染。通过对此浮选获得的尾矿进行物相及化学分析后发现该尾矿的主要物相为Ca（CO3）2、Mg（CO3）2及Ca5F（PO4）3,其中P2O5含量7～9%,MgO含量高达16～18%,属高镁磷尾矿。本文初步探索了用盐酸和硫酸混合酸酸浸的方法来分解磷尾矿的工艺,新工艺主要研究了磷矿的酸解工艺条件、浸出液的综合净化,并对萃取分离MgCl2和H3PO4进行了实验研究。在酸解工艺条件优化研究中,通过单因素及正交试验获得实验室条件下的最佳工艺条件:反应时间60min、温度80℃、液固比为5:1、酸的过量系数则取1.05。在此工艺条件下P2O5和MgO都有较高的浸出率,分别为97.2%、98.5%,且各因素对P2O5和MgO的浸出率影响趋势相似。其中反应时间和液固比对二者浸出率的影响最为显著,酸的过量系数对它们浸出率的影响很小,主要是由误差所引起的。在综合净化过程中采用同步脱氟、脱硫、脱重金属,效果理想,达到净化要求。通过萃取实验研究,首先确定了选择正丁醇作为萃取剂,然后在进一步的试验研究中确定了最佳萃取工艺条件和反萃工艺条件,最佳萃取工艺条件:在H3PO4浓度为60%,萃取剂采用正丁醇,萃取相比为1:1,温度为常温,萃取时间为5分钟,在均衡搅拌速度下,P2O5萃取效果最佳,可达68%以上。最佳反萃工艺条件:反萃剂采用水,加入量为反萃前有机相体积的30%,反萃时间为3分钟,常温下进行反萃时,反萃率可达90%。本试验工艺条件易于控制,操作简单,对设备要求低,基本上可以实现循环生产,仅有少量对环境无污染的废渣。上述研究成果对瓮福磷矿浮选尾矿的开发利用具有一定的参考价值。
【Abstract】 For the gradual depletion of the phosphate resources and the tending depleted grade of them,in order to satisfy the wet-process phosphoric acid production（WPA） ore quality requirements of raw materials,it will be a large amount of phosphorus tailings per year through the use of various mineral processing technology.If we can take comprehensive utilization of the phosphorus tailings,that not only can reduce the waste of resources,but also prevent occupied land and environmental pollution which the tailings piled up.Through the chemical analysis of phase from this flotation tailings,we found that the main phases in the tailings are Ca（CO3）2、Mg（CO3）2 and Ca5F（PO4）3,with the content of P2O5 from 7%to 9%,the content of MgO is as high as 16 to 18 per cent,which attach a high magnesium phosphate tailings.This article initially explored the new process which using hydrochloric acid and sulfuric acid leaching mixed to decompose phosphate tailings,this new technology research acid solution process conditions of phosphate,and study MgCl2 and H3PO4 extraction.In the process optimization studies of acid conditions,I got optimum conditions in laboratory conditions through the single-factor orthogonal test.The optimum conditions are 60 min’s reaction time,80℃’s temperature,the 5:1 ratio of liquid to solid,the 1.05 excessive coefficient of acid.In this condition,the extraction rate of P2O5 and MgO are higher,respectively attain 97.2%and 98.5%.And the influence of factors to leaching rate of the P2O5 and the MgO are similar.The two most notable factors are the reaction time and the ratio of liquid and solid leaching rate,the least notable factors is coefficient of excessive acid,which mainly caused by the error.Through the extraction experimental study,I determine the choice of n-butanol as the extraction solvent,and then identified the best extraction conditions and the anti-extraction process in the further pilot study.In the best extraction conditions, the P2O5 extraction is best and attains more than 68%.The best extraction conditions:H3PO4 concentration of 60%,n-butyl alcohol for extraction,extraction compared to 1:1,the room temperature,the extraction time for 5 minutes,churn up with balanced speed..The best anti-extraction process conditions:used water for anti-extraction,the amount is about the volume of 30%of organic phase before anti-extraction anti-extraction time for 3 minutes.At room temperature for anti-extraction, the stripping rate attain 90%.The technological conditions of the test are easy controlled with simple operation and low facility request.It could produce circularly,and only a small quantity of waste slag that is pollution-free to our environment was produced.The research in this paper can provide some valuable reference for exploitation and utilization of Wengfu phosphate floatation tailings.