Ca/Al/La LDH对磷石膏可溶性磷的固化研究  

Study on solidification of soluble phosphorus in phosphogypsum by Ca/Al/La LDH

作　　者：杨雨晴 罗爱文 王杰 吴晨捷[1,2] 瞿军 徐志高 杜冬云 曹艳敏[1,2] YANG Yuqing;LUO Aiwen;WANG Jie;WU Chenjie;QU Jun;XU Zhigao;DU Dongyun;CAO Yanmin(Engineering and Technology Research Center for Heavy Metal Pollution Prevention and Control,College of Resources andE nvironment,South-Central Minzu University,Wuhan 430074,China;Key Laboratory of Catalytic Transformation and Energy Materials Chemistry,Ministry of Education,South-Central Minzu University,Wuhan 430074,China)

机构地区：[1]中南民族大学资源与环境学院,湖北省重金属污染防治工程技术研究中心,湖北武汉430074 [2]中南民族大学催化转化与能源材料化学教育部重点实验室,湖北武汉430074

出　　处：《无机盐工业》2024年第12期134-141,共8页Inorganic Chemicals Industry

基　　金：湖北省科技计划重大项目“磷石膏污染防治与综合利用相关技术研究与示范”(2022CA004);湖北省自然科学基金宜昌创新发展联合基金(2024AFD136)。

摘　　要：磷石膏是湿法磷酸工艺的副产物,含有质量分数为1%~2%的水溶性磷,其大量堆存对环境造成了严重危害。通过采用机械化学法合成Ca/Al/La水滑石(LDH)材料固化磷石膏中的可溶性磷,考察合成条件对产品磷吸附容量的影响,研究对比原始磷石膏和处理后磷石膏制备建筑石膏粉的理化性质差异。通过X射线衍射仪(XRD)、傅里叶红外光谱仪(FT-IR)、扫描电子显微镜(SEM)和粒度分析仪对固化前后的磷石膏进行表征,探究固化剂用量对可溶磷固化率和微观结构的影响。结果表明,在n[Ca(OH)_(2)]∶n[Al(OH)_(3)]∶n[La_(2)(CO_(3))_(3)·x H_(2)O]=12∶6∶1、球磨转速为600 r/min、球磨时间为1 h的条件下,加6%(体积分数)的乙醇作分散剂所得产品Ca/Al/La LDH(乙醇)磷吸附固化性能较优。Ca/Al/La LDH(乙醇)的添加量为1 g/L时,磷石膏中可溶磷固化率达到89.95%,优于Ca/Al LDH(78.70%)和Ca/Al/La LDH(80.86%)。乙醇能够使固化剂在磷石膏中分散均匀,与可溶性磷结合更充分,从而提高固化性能。处理后磷石膏制备建筑石膏粉,其抗折和抗压强度分别为6.60 MPa和9.30 MPa,符合建筑石膏2.0级质量标准。该研究结果为磷石膏的无害化与资源化提供了可行思路。Phosphogypsum(PG)is a byproduct of the wet phosphoric acid process which contains soluble phosphorous with a mass fraction of 1%to 2%.Stockpiling of large amount of PG will cause serious environmental issues.In this study,Ca/Al/La hydrotalcite(LDH)materials were synthesized by using mechanochemical method and then applied for the solidification of the soluble phosphorus in PG.The effects of synthesis condition on solidification capacity were analyzed and the physiochemical characteristics of gypsum blocks using PG before and after treatment were compared.X-ray diffractometer(XRD),Fourier infrared spectrometer(FT-IR),scanning electron microscope(SEM)and particle size analyzer were applied to explore the effects of the LDH-material dosage on soluble phosphorus solidification efficiency and PG microstructure.The results showed that the optimal synthesis conditions were using 6%(volume fraction)ethanol as the dispersant with a molar ratio of n[Ca(OH)_(2)]∶n[Al(OH)_(3)]∶n[La_(2)(CO_(3))_(3)·xH_(2)O]=12∶6∶1,ball milling speed of 600 r/min,and ball milling time of 1 h,which showed best solidification effects on soluble phosphorus.With addition of 1 g/L of LDH materials,the solidification efficiency of soluble phosphorus in PG was up to 89.95%for Ca/Al/La LDH(ethanol),superior than Ca/Al LDH(78.70%)and Ca/Al/La LDH(80.86%).Ethanol enabled the LDH materials to be uniformly dispersed in PG and therefore could more effectively combine with soluble phosphorus,improving the solidification performance.The flexural and compressive strengths of gypsum blocks prepared using treated PG reached 6.60 MPa and 9.30 MPa,respectively,which were in accordance with the standard of construction gypsum(level 2),and thus provided a feasible approach towards the harmlessness and resourcefulness of PG.

关 键 词：磷石膏 水滑石 可溶性磷固化 β-半水石膏 

分 类 号：TQ132.32[化学工程—无机化工]