盐介质对磷石膏常压盐溶液法制备α半水石膏的影响研究

发布时间：2018-03-01 22:20

本文关键词： 磷石膏常压盐溶液法 α半水石膏盐介质　出处：《矿产保护与利用》2017年06期 　论文类型：期刊论文

【摘要】：磷石膏是湿法磷酸生产过程中用硫酸分解磷矿石排放的固体废弃物,采用常压盐溶液法制备α半水石膏是磷石膏资源化的新途径,其中盐介质的选择是常压盐溶液法的关键。研究了NaCl、NaNO_3、MgCl_2、CaCl_2和Ca(NO_3)2五种盐介质对磷石膏制备α半水石膏转化速率、物相组成和形貌的影响。研究结果表明:随着NaCl、NaNO_3和MgCl_2浓度的增加,磷石膏转化为α半水石膏的速率加快,结晶诱导时间和晶体生长时间缩短;反应产物中α半水石膏的含量在95%以上,显微形貌均为六方长柱状,但端面形貌不同。在NaCl和NaNO_3溶液中,α半水石膏存在多个锥面且晶面完整,长径比约为14∶1;在MgCl_2溶液中端面呈空心层状包裹,长径比为11∶1,粒度均匀,但晶体缺陷较大。NaCl与NaNO_3、MgCl_2相比,具有用量低、磷石膏转化速率快的优点,可作为常压盐溶液制备α半水石膏的盐介质;由于同离子效应的影响,磷石膏在Ca Cl_2和Ca(NO_3)2溶液中未发生转变,不宜作为盐介质。
[Abstract]:Phosphogypsum is a kind of solid waste from phosphorous rock decomposed by sulfuric acid in the process of wet phosphoric acid production. The preparation of 伪 -hemihydrate gypsum by normal pressure salt solution is a new way for the utilization of phosphogypsum. The influence of five salt mediums, NaCl-NaNO3MgCl2CaCl2 and Ca(NO_3)2, on the conversion rate, phase composition and morphology of phosphogypsum to 伪 -hemihydrate gypsum were studied. The results showed that with the increase of NaCl-NaNO3-MgCl2CaCl2 and MgCl_2 concentration, the conversion rate, phase composition and morphology of 伪 -hemihydrate gypsum from phosphogypsum were increased with the increase of NaCl-NaNO3-MgCl2CaCl2 and Ca(NO_3)2. The conversion rate of phosphogypsum to 伪 -hemihydrate gypsum was accelerated, the crystallization induction time and crystal growth time were shortened, the content of 伪 -hemihydrate gypsum in the reaction product was more than 95%, and the microstructure was hexagonal column shape. In NaCl and NaNO_3 solution, 伪 -hemihydrate gypsum has several conical surfaces and complete crystal face, the aspect ratio is about 14: 1. In MgCl_2 solution, the end face is covered with hollow layer, the aspect ratio is 11: 1, and the particle size is uniform. However, the crystal defect is larger than that of NaNO3 / MgCl _ 2, but the crystal defect of 伪 -hemihydrate gypsum is larger than that of NaNO3 / MgCl _ 2. It has the advantages of low dosage and fast conversion rate of phosphogypsum, which can be used as salt medium for the preparation of 伪 -hemihydrate gypsum in normal pressure salt solution. Due to the effect of the same ion effect, phosphogypsum does not change in Ca Cl_2 and Ca(NO_3)2 solution, so it is not suitable as salt medium.
【作者单位】：贵州大学材料与冶金学院;贵州大学矿业学院;喀斯特地区优势矿产资源高效利用国家地方联合工程实验室;贵州省非金属矿产资源综合利用重点实验室;
【基金】：贵州省重大专项(黔科合重大专项字[20116023] 贵州省科学技术基金(黔科合JZ字[2014]2009号)
【分类号】：TQ177.373

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