用废弃物脱硫石膏制备铁酸钙的基础研究
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摘要
结合目前中国大量的废弃脱硫石膏无法被合理利用的情况,讨论了钢厂中脱硫石膏制成铁酸钙回收利用的可能性。通过查询热力学数据进行计算研究,探讨石膏分解所需的气氛条件及相应条件下生成物组成。为达到最佳的分解效果,通过热力学计算调整一氧化碳/二氧化碳混合气体各项参数进而控制实验的进行。相关基础实验在实验室中利用现有管式炉进行烧结还原。通过对XRD数据进行半定量分析来确定石膏在不同条件下分解产物的成分组成。结果表明1 050℃为石膏气固反应和固固反应交界点。同时混合气体中一氧化碳体积分数为5%、100 m L/min的气体流量,可以保证气固反应生成氧化钙的同时,硫化钙的量在合理的范围内。实验进一步利用硫酸钙作为钙源制得铁酸钙,为废弃石膏在钢铁厂回收利用提供理论基础。
Combined with the current situation that a large amount of abandoned FGD gypsum in China can not be rationally utilized,the possibility of recovery and utilization of calcium ferrite from FGD gypsum in steel mills was discussed.The atmospheric conditions required for the decomposition of gypsum and the composition of the resultant product were investigated by thermodynamic calculation.In order to achieve the best decomposition effect,the parameters of the CO/CO_2 mixture were adjusted through thermodynamic calculation to control the experiment.Related basic experiments,such as sintering reduction was carried out by the existing tube furnaces in the laboratory.The ingredients of gypsum decomposition products under different conditions were determined by semi-quantitative analysis according to the XRD data.The results showed that the optimum gypsum decomposition conditions included 1 050 ℃(the junction point of gas-solid reaction and solid-solid reaction of gypsum),5%(volume fraction) CO mixture gas,and 100 mL/min gas flow to generate as much calcium oxide as possible while keeping the amount of calcium sulfide within a reasonable range.In the experiment,calcium ferrite was further prepared by using calcium sulfate as calcium source,which provided the theoretical basis for the recycling of abandoned gypsum in the steel factory.
Combined with the current situation that a large amount of abandoned FGD gypsum in China can not be rationally utilized,the possibility of recovery and utilization of calcium ferrite from FGD gypsum in steel mills was discussed.The atmospheric conditions required for the decomposition of gypsum and the composition of the resultant product were investigated by thermodynamic calculation.In order to achieve the best decomposition effect,the parameters of the CO/CO_2 mixture were adjusted through thermodynamic calculation to control the experiment.Related basic experiments,such as sintering reduction was carried out by the existing tube furnaces in the laboratory.The ingredients of gypsum decomposition products under different conditions were determined by semi-quantitative analysis according to the XRD data.The results showed that the optimum gypsum decomposition conditions included 1 050 ℃(the junction point of gas-solid reaction and solid-solid reaction of gypsum),5%(volume fraction) CO mixture gas,and 100 mL/min gas flow to generate as much calcium oxide as possible while keeping the amount of calcium sulfide within a reasonable range.In the experiment,calcium ferrite was further prepared by using calcium sulfate as calcium source,which provided the theoretical basis for the recycling of abandoned gypsum in the steel factory.
引文
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[12]罗蜀峰,付全军,马先林,等.硫铁矿还原磷石膏反应热力学分析[J].无机盐工业,2016,48(4):57-60.
[13]郭兴敏,杜鹤桂.Ca O-Fe2O3混合层内反应初期铁酸钙生成的动力学研究[J].北京科技大学学报,1998,20(3):247-251.
[14]肖海平,周俊虎,曹欣玉.Ca SO4在CO气氛下的平行竞争反应实验与模型研究[J].燃料化学学报,2005,33(2):151-154.
[2]刘涛,薛建明,王小明,等.湿法烟气脱硫石膏资源化深度利用[J].中国电力,2009,42(8):65-69.
[3]范红宇.不同气氛下高温固硫产物硫酸钙和硫化钙相互转化机理研究[D].杭州:浙江大学,2004.
[4]吉忠海,陈津,郭宇,等.微波加热分解脱硫石膏生产烧结矿研究[J].化工进展,2016,35(7):2251-2257.
[5] Yan B,Ma L P,Ma J,et al.Mechanism analysis of Ca,S transformation in phosphogypsum decomposition with Fe catalyst[J].Industrial&Engineering Chemistry Research,2014,53(18):7648-7654.
[6]邓少刚,王俊哲,黄鹏辉,等.FeS还原Ca SO4的热分解动力学研究[J].磷肥与复肥,2015,30(3):5-10.
[7] Mihara N,Kuchar D,Kojima Y,et al.Reductive decomposition of waste gypsum with SiO2,Al2O3,and Fe2O3additives[J].Journal of Material Cycles and Waste Management,2007,9(1):21-26.
[8] van der Merwe E M,Strydom C A,Potgieter J H.Thermogravimetric analysis of the reaction between carbon and Ca SO4·2H2O,gypsum and phosphogypsum in an inert atmosphere[J].Thermochimica Acta,1999,340:431-437.
[9]郑绍聪,马丽萍,宁平,等.高硫煤还原磷石膏的热分解动力学[J].武汉理工大学学报,2010(5):109-112.
[10] Zhang X M,Xu R W,Sun S Y,et al.Study on the character of calcium sulfate reducing decomposition[J].Environmental Science&Technology,2010(S2):144-148.
[11]马林转,宁平,卿山.高硫煤分解磷石膏影响因素研究[J].中山大学学报:自然科学版,2009,48(2):85-88.
[12]罗蜀峰,付全军,马先林,等.硫铁矿还原磷石膏反应热力学分析[J].无机盐工业,2016,48(4):57-60.
[13]郭兴敏,杜鹤桂.Ca O-Fe2O3混合层内反应初期铁酸钙生成的动力学研究[J].北京科技大学学报,1998,20(3):247-251.
[14]肖海平,周俊虎,曹欣玉.Ca SO4在CO气氛下的平行竞争反应实验与模型研究[J].燃料化学学报,2005,33(2):151-154.