| Ca(H2PO4)2-H3PO4-K2SO4体系中石膏晶型及形貌调控 |
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| 引用本文： | 吴钦,杨林,易芸,耿平兰,曹建新.Ca(H2PO4)2-H3PO4-K2SO4体系中石膏晶型及形貌调控[J].人工晶体学报,2021,50(6):1104-1111. |
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| 作者姓名： | 吴钦 杨林 易芸 耿平兰 曹建新 |
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| 作者单位： | 1.贵州大学化学与化工学院,贵阳 550025; 2.贵州大学,贵州省绿色化工与清洁能源技术重点实验室,贵阳 550025; 3.贵州大学,贵州省工业废弃物高效利用工程研究中心,贵阳 550025; 4.贵州省产品质量检验检测院,贵阳 550016 |
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| 基金项目： | 国家重点研发计划(2018YFC1900202);贵州省科技计划(黔科合服企[2018]4011) |
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| 摘 要： | 为将Ca(H2PO4)2制备KH2PO4过程中的石膏资源化利用,以H3PO4与CaCO3反应制备Ca(H2PO4)2溶液,并与K2SO4溶液反应,进行Ca(H2PO4)2-H3PO4-K2SO4体系中石膏晶型和形貌调控研究。结果表明:通过改变反应时间、反应温度、SO2-4过量系数和CaO含量等参数可对Ca(H2PO4)2-H3PO4-K2SO4体系中石膏晶型和形貌进行调控,制得短柱状α-CaSO4·0.5H2O。体系在温度高于95 ℃和CaO含量为3.0%~5.0%(质量分数,下同)时形成α-CaSO4·0.5H2O,在CaO含量为5.5%主要形成CaSO4·2H2O;反应时间长于20 min和SO2-4过量系数大于1.4将形成K2SO4(CaSO4)5·H2O,导致石膏晶体表面缺陷增加。本实验条件下,适宜反应条件为:反应时间10 min、反应温度95 ℃、SO2-4过量系数1.2和CaO含量5.0%,此条件下可制得长度42~70 μm、直径13~24 μm的短柱状α-CaSO4·0.5H2O,其抗折和抗压强度分别可达5.61 MPa和33.74 MPa,滤液中钾收率和脱钙率分别可达94.23%和83.80%。
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| 关 键 词： | α-CaSO4·0.5H2O Ca(H2PO4)2-H3PO4-K2SO4体系 石膏 晶型 形貌 调控 |
| 收稿时间： | 2021-03-09 |
Regulation of Gypsum Crystalline and Morphology in Ca(H2PO4)2-H3PO4-K2SO4 System |
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| WU Qin,YANG Lin,YI Yun,GENG Pinglan,CAO Jianxin.Regulation of Gypsum Crystalline and Morphology in Ca(H2PO4)2-H3PO4-K2SO4 System[J].Journal of Synthetic Crystals,2021,50(6):1104-1111. |
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| Authors: | WU Qin YANG Lin YI Yun GENG Pinglan CAO Jianxin |
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| Affiliation: | 1. School of Chemistry and Chemical Engineering, Guizhou University, Guiyang 550025, China; 2. Key Laboratory of Guizhou Province for Green Chemical Industry and Clean Energy Technology, Guizhou University, Guiyang 550025, China; 3. Engineering Research Center of Efficient Utilization for Industrial Waste, Guizhou University, Guiyang 550025, China; 4. Guizhou Institute of Products Quality Inspection & Testing, Guiyang 550016, China |
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| Abstract: | In order to make the resource utilization of gypsum in the process of preparing KH2PO4 from Ca(H2PO4)2, the Ca(H2PO4)2 solution prepared by the reaction of H3PO4 and CaCO3 was mixed with K2SO4 solution. Then the regulation of gypsum crystalline and morphology in Ca(H2PO4)2-H3PO4-K2SO4 system was studied. The results show that the short columnar α-CaSO4·0.5H2O can be obtained from Ca(H2PO4)2-H3PO4-K2SO4 system by changing the reaction condition,including reaction time, reaction temperature, SO2-4 excess coefficient (ξ) and CaO content. The α-CaSO4·0.5H2O is formed at temperatures above 95 ℃ and CaO content of 3.0% to 5.0%(mass fraction, the same below), while CaSO4·2H2O is formed at low temperatures and CaO content of 5.5%. Meanwhile, with the increase of CaO content in the range of 3.0% to 5.0%, the aspect ratio of α-CaSO4·0.5H2O decreases. As the reaction time is longer than 20 min and the SO2-4 excess coefficient is greater than 1.4, K2SO4(CaSO4)5·H2O is easily formed, resulting in the increase of surface defects of gypsum crystals. Under the conditions of reaction time of 5 min, reaction temperature of 95 ℃, SO2-4 excess coefficient of 1.2 and CaO content of 5.0%, a short columnar α-CaSO4·0.5H2O crystals with length of 42 μm to 70 μm and diameter of 13 μm to 24 μm are prepared, the flexural strength and compressive strength of which are 5.61 MPa and 33.74 MPa, respectively. The yield of potassium and decalcification rate of the filtrate are 94.23% and 83.80%, respectively. |
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| Keywords: | α-CaSO4·0 5H2O Ca(H2PO4)2-H3PO4-K2SO4 system gypsum crystalline morphology regulation |
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