工业磷酸分解磷矿影响因素及副产物性质研究
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摘要
为改进湿法磷酸生产工艺,提高副产磷石膏的品质,减少湿法磷酸固体副产物堆存产生的经济和环境压力,进行了工业磷酸分解磷矿制磷酸的实验,同时对固体副产物的性质进行了分析。工业磷酸分解磷矿制磷酸的工艺分为两步:第一步,工业磷酸与磷矿反应,得到磷酸二氢钙溶液和酸不溶渣;第二步,浓硫酸与磷酸二氢钙溶液反应,得到磷酸溶液和高纯石膏。采用单因素实验考察了酸比(工业磷酸用量与理论磷酸用量的物质的量的比值)、磷矿粒度、反应温度和反应时间对磷矿中磷浸出率的影响。得到磷矿酸解适宜工艺条件:酸比为6.8,磨矿细度为小于0.074 mm粒级占60%,反应温度为50℃,反应时间为2.5 h。在此条件下,磷矿中磷的浸出率可达87.69%。磷矿酸解制磷酸产生的固体副产物中石膏占35.32%(质量分数)、酸不溶渣占64.68%(质量分数)。制备的高纯石膏的纯度为95.80%,工业利用价值较高,有利于提高湿法磷酸固体副产物的利用率。
In order to improve the wet phosphoric acid process,enhance the quality of by-product phosphogypsum and reduce the economic and environmental pressure caused by the accumulation of solid by-products of wet phosphoric acid,an experiment was carried out to produce phosphoric acid from industrial phosphoric acid decomposing phosphate rock,at the same time,the properties of solid by-products were analyzed.The process of decomposing phosphate rock to phosphoric acid by industrial phosphoric acid was divided into two steps:The first step was the reaction of industrial phosphoric acid with phosphate rock to obtain calcium dihydrogen phosphate solution and acid-insoluble slag.The second step was to the reaction of concentrated sulfuric acid with calcium dihydrogen phosphate solution to obtain phosphoric acid solution and high purity gypsum.The effects of acid ratio(the amount-of-substance ratio of industrial phosphoric acid dosage to theortical phosphoric acid dosage), phosphate rock particle size, reaction temperature and reaction time on leaching rate were investigated by single factor test.The results showed that the suitable technological conditions for acidolysis of phosphate rock were as follows:the acid ratio was 6.8,grinding fineness less than 0.074 mm accounted for 60%,reaction temperature was 50 ℃,reaction time was 2.5 h.The leaching rate of phosphorus in phosphate rock after acid hydrolysis could reach 87.69%.In the solid by-products produced after the reaction,the mass fraction of high-purity gypsum was 35.32%,and the mass fraction of acid-insoluble slag was 64.68%.The purity of CaSO_4·2H_2O in high-purity gypsum was 95.80%,which was of high value for industrial use and was beneficial to increase the utilization of solid by-products of wet-process phosphoric acid.
In order to improve the wet phosphoric acid process,enhance the quality of by-product phosphogypsum and reduce the economic and environmental pressure caused by the accumulation of solid by-products of wet phosphoric acid,an experiment was carried out to produce phosphoric acid from industrial phosphoric acid decomposing phosphate rock,at the same time,the properties of solid by-products were analyzed.The process of decomposing phosphate rock to phosphoric acid by industrial phosphoric acid was divided into two steps:The first step was the reaction of industrial phosphoric acid with phosphate rock to obtain calcium dihydrogen phosphate solution and acid-insoluble slag.The second step was to the reaction of concentrated sulfuric acid with calcium dihydrogen phosphate solution to obtain phosphoric acid solution and high purity gypsum.The effects of acid ratio(the amount-of-substance ratio of industrial phosphoric acid dosage to theortical phosphoric acid dosage), phosphate rock particle size, reaction temperature and reaction time on leaching rate were investigated by single factor test.The results showed that the suitable technological conditions for acidolysis of phosphate rock were as follows:the acid ratio was 6.8,grinding fineness less than 0.074 mm accounted for 60%,reaction temperature was 50 ℃,reaction time was 2.5 h.The leaching rate of phosphorus in phosphate rock after acid hydrolysis could reach 87.69%.In the solid by-products produced after the reaction,the mass fraction of high-purity gypsum was 35.32%,and the mass fraction of acid-insoluble slag was 64.68%.The purity of CaSO_4·2H_2O in high-purity gypsum was 95.80%,which was of high value for industrial use and was beneficial to increase the utilization of solid by-products of wet-process phosphoric acid.
引文
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[2]毛常明,刘晶晶,尹进华,等.湿法磷酸的工艺研究进展[J].河北化工,2005(4):14-16.
[3]邵一鑫,张泽强,孙桦林,等.氢氧化钠分解磷石膏工艺研究[J].无机盐工业,2017,49(9):52-54.
[4]李美.磷石膏品质的影响因素及其建材资源化研究[D].重庆:重庆大学,2012.
[5]李相国,陈嘉懿,马保国,等.粒度分布对磷石膏-石灰-粉煤灰胶结材物理性能的影响[J].化工学报,2012,63(S1):230-234.
[6]高洁,赵国彦.磷石膏再结晶体力学特性试验研究[J].矿冶工程,2013,33(2):18-21.
[7]阮耀阳,罗惠华,张泽强,等.难选硅钙质胶磷矿正反浮选研究[J].矿冶工程,2017,37(6):38-41.
[8]余静.利用低品位磷矿生产湿法磷酸的新工艺及动力学研究[D].成都:四川大学,2005.
[9]刘代俊,钟本和,张允湘.磷酸复杂系统液固相反应动力学(Ⅱ)磷矿颗粒系统酸解动力学实验研究[J].化工学报,2001,52(1):28-34.
[10]马保国,茹晓红,邹开波,等.常压水热Ca-Na-Cl溶液中用磷石膏制备α-半水石膏[J].化工学报,2013,64(7):2701-2707.
[11]高学顺,陈江,陈学玺.一种副产石膏晶须的湿法磷酸新工艺[J].无机盐工业,2011,43(10):51-53.
[12]刘代俊,钟本和.磷酸复杂系统液固相反应动力学(Ⅰ)分形介质中的扩散与反应机理[J].化工学报,2000,61(5):620-625.
[13]吴佩芝.湿法磷酸[M].北京:化学工业出版社,1987.
[14]曾亚平,党亚固,费德君.制备高品质磷石膏的湿法磷酸新工艺的开发[J].化工进展,2015,34(增刊1):167-172.
[15]彭家惠,万体智,汤玲,等.磷石膏中杂质组成、形态、分布及其对性能的影响[J].中国建材科技,2000(6):31-35.