钛白废酸深度脱铁净化工艺研究
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摘要
硫酸法钛白粉生产中产生的废硫酸铁含量高,需要除铁后方能实现循环利用。工业上采用废酸增浓、析出硫酸亚铁的方式来脱除铁,但此工艺得到的硫酸亚铁颗粒小,晶体团聚严重,不易过滤,挟带的游离酸含量很高。采用先除钛后脱铁的工艺方法以改善硫酸亚铁晶型和粒度分布,实现废酸的深度脱铁:先以磷酸氢二铵与钛白废酸反应生成磷酸钛,通过除钛来降低酸中铁的溶解度;然后将除钛酸与浓硫酸直接配酸至酸质量分数为53%进行深度脱铁。实验研究得到了优化的除钛操作参数:反应时间为60 min、反应温度为100℃、n(五氧化二磷)/n(二氧化钛)=0.9。与原工艺相比较,脱铁净化酸中的铁质量分数由直接配酸工艺的0.4%~0.5%降低至现工艺的0.2%左右。同时,所得硫酸亚铁颗粒大,分布均匀,挟带的游离酸质量分数由原工艺15%降至10%左右,表明该改进工艺具有良好的工业应用价值。
Titanium waste vitriolic acid produced during the production of TiO_2 can be used in the production of wet-process phosphoric acid after the removal of the iron.In industry,the iron is removed by increasing the concentration of sulfuric acid to precipitate ferrous sulfate.However,the removed ferrous sulfate by this method is in the form of small particles.The aggregationof ferrous sulfate crystal leads to bad filterability,leaving large amount of free sulfuric acid in the filtercake.To improve the morphology and particle size of ferrous sulfate crystal,a method called ‘two-step' was adopted:Firstly,titanium phosphate was precipitated by the reaction of(NH4)2 HPO_4 and titanium white waste acid to reduce the solubility of ferrous sulfate in the sulfuric acid.Second,the waste sulfuric acid,after the removal of titanium,was mixed with concentrated sulfuric acid until the acid′ s mass fraction reaching 53% to deeply precipitate ferrous sulfate.The above process resulted in an optimized parameter:reaction time was 60 min,reaction temperature was 100 ℃,and amount-of-substance ratio of P2 O5 to TiO_2 was 0.9.Compared to the original method,the new method reduced the iron mass fraction from the range of 0.4%~0.5%to 0.2% in the purified titanium white waste acid.Meanwhile,the particle size of ferrous sulfate crystal was increased,the particle size distribution of ferrous sulfate was also more homogeneous,and the quantity of free sulfuric acid in ferrous sulfate filtercake was reduced from 15% to about 10%.The above results showed that the new method had very powerful industrial application value.
Titanium waste vitriolic acid produced during the production of TiO_2 can be used in the production of wet-process phosphoric acid after the removal of the iron.In industry,the iron is removed by increasing the concentration of sulfuric acid to precipitate ferrous sulfate.However,the removed ferrous sulfate by this method is in the form of small particles.The aggregationof ferrous sulfate crystal leads to bad filterability,leaving large amount of free sulfuric acid in the filtercake.To improve the morphology and particle size of ferrous sulfate crystal,a method called ‘two-step' was adopted:Firstly,titanium phosphate was precipitated by the reaction of(NH4)2 HPO_4 and titanium white waste acid to reduce the solubility of ferrous sulfate in the sulfuric acid.Second,the waste sulfuric acid,after the removal of titanium,was mixed with concentrated sulfuric acid until the acid′ s mass fraction reaching 53% to deeply precipitate ferrous sulfate.The above process resulted in an optimized parameter:reaction time was 60 min,reaction temperature was 100 ℃,and amount-of-substance ratio of P2 O5 to TiO_2 was 0.9.Compared to the original method,the new method reduced the iron mass fraction from the range of 0.4%~0.5%to 0.2% in the purified titanium white waste acid.Meanwhile,the particle size of ferrous sulfate crystal was increased,the particle size distribution of ferrous sulfate was also more homogeneous,and the quantity of free sulfuric acid in ferrous sulfate filtercake was reduced from 15% to about 10%.The above results showed that the new method had very powerful industrial application value.
引文
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[12]陈玲.钛白粉生产硫酸废液中铁的脱除过程研究[D].上海:华东理工大学,2015.
[13]蒋永金,崔庆雄,毛禹平.磷酸氢二铵分离-电感耦合等离子体原子发射光谱法测定钛白粉中痕量铜和钒[J].冶金分析,2015,35(6):40-43.
[14]卜凡晴,张旭东,何文,等.磷酸钛的研究进展[J].齐鲁工业大学学报,2010,24(1):28-32.
[15]朱涤尘.焦磷酸钛的合成、性能及其在金属离子分离中的作用[J].淮海工学院学报,1999(1):38-41.
[2]崔佳娜,任慧莉.我国钛白粉生产工艺技术的发展及比较[J].稀有金属与硬质合金,2013,41(4):14-17.
[3]范兵,李志广,李昭,等.硫酸法钛白废酸的处理[J].河南化工,2013,30(6):12-15.
[4]魏绍东,冯圣君,魏艳.钛白废酸的治理与浓缩综述[J].无机盐工业,2007,39(2):15-17.
[5]龚家竹,江秀英,袁丰波.硫酸法钛白废酸浓缩技术研究现状及发展方向[J].无机盐工业,2008,40(8):1-3.
[6]刘国燕,吴汝范.硫酸法钛白水解废酸的浓缩[J].矿冶工程,1998(1):53-56.
[7]唐文骞,王效英.硫酸法钛白废酸浓缩技术介绍及评述[J].化工设计,2010,20(2):3-8.
[8] Agrawal A,Kumari S,Shu K K.Liquid-liquid extraction of sulphuric acid from zinc bleed stream[J].Hydrometallurgy,2008,92(1):42-47.
[9] Lin S H,Mu C L.Recovery of sulfuric acid from waste aluminum surface processing solution by diffusion dialysis[J].Journal of Hazardous Materials,1998,60(3):247-257.
[10]高英卓.磷酸钛的制备[J].河北化工,2001(4):31-32.
[11]刘向云.钛白废酸液制磷酸钛和氧化铁黑的研究[J].商丘师范学院学报,2001,17(6):82-85.
[12]陈玲.钛白粉生产硫酸废液中铁的脱除过程研究[D].上海:华东理工大学,2015.
[13]蒋永金,崔庆雄,毛禹平.磷酸氢二铵分离-电感耦合等离子体原子发射光谱法测定钛白粉中痕量铜和钒[J].冶金分析,2015,35(6):40-43.
[14]卜凡晴,张旭东,何文,等.磷酸钛的研究进展[J].齐鲁工业大学学报,2010,24(1):28-32.
[15]朱涤尘.焦磷酸钛的合成、性能及其在金属离子分离中的作用[J].淮海工学院学报,1999(1):38-41.