Development of a process for producing high‐purity calcium carbonate (CaCO3) from waste cement using pressurized CO2
Development of a process for producing high‐purity calcium carbonate (CaCO3) from waste cement using pressurized CO2
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DOI：
10.1002/ep.10080
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发表时间：
2005-07
期刊：
影响因子：
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通讯作者：
Y. Katsuyama;A. Yamasaki;A. Iizuka;M. Fujii;K. Kumagai;Y. Yanagisawa
中科院分区：
文献类型：
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作者：
Y. Katsuyama;A. Yamasaki;A. Iizuka;M. Fujii;K. Kumagai;Y. Yanagisawa
开发了一种利用废水泥粉生产高纯碳酸钙的新工艺。该工艺包括两个主要反应：通过加压CO2（通常在几MPa下）从水浆中的废水泥粉中以钙离子形式提取钙，以及通过降低CO2压力从提取溶液中沉淀碳酸钙（CaCO3）。该过程也可以被认为是CO2的减排过程。对萃取反应和沉淀反应进行了实验室规模的实验研究，以考察该工艺的可行性。提取过程中发现进行在一个相对较高的速率，特别是在最初的10分钟。钙离子的浓度超过了热力学溶解度的碳酸钙（过饱和）时，丰富的废水泥。过滤残余物后，通过将CO2减压获得纯度>98%的CaCO3颗粒。反应速率对操作条件的依赖性，如废水泥与水的比例，CO2压力，和废水泥颗粒的粒径，进行了研究。在此基础上，提出了一种适用于烟气脱硫和超高纯碳酸钙生产两种碳酸钙生产工艺的工艺设计方案。每公吨CaCO3的估计成本为脱硫136美元，高纯度CaCO3为323美元。© 2005年美国化学工程师协会环境规划，2005年
A new type of process for producing high-purity calcium carbonate from waste cement powder was developed. The process consists of two main reactions; extraction of calcium in the form of calcium ions from waste cement powder in a water slurry by pressurized CO2 (typically at several MPa), and precipitation of calcium carbonate (CaCO3) from the extracted solution by reduction of the CO2 pressure. The process can be recognized as the emission reduction process of CO2 as well. Laboratory-scale experimental studies were conducted for both the extraction reaction and the precipitation reaction, to examine the feasibility of the process. The extraction process was found to proceed at a relatively high rate, especially during the initial 10 min. The concentration of calcium ions exceeded the thermodynamic solubility of CaCO3 (supersaturation) when abundant waste cement was available. After filtration of the residues, CaCO3 particles with >98% purity were obtained by depressurizing the CO2. The dependency of the reaction rates on the operating conditions, such as the ratio of waste cement to water, CO2 pressure, and particle size of waste cement particles, was investigated. A process design was carried out based on the experimental results, assuming that the present process is applied to two types of CaCO3 production process: flue gas desulfurization and production of ultrahigh-purity CaCO3. The estimated costs per 1 metric ton of CaCO3 were USD 136 for desulfurization and USD 323 for high-purity CaCO3. © 2005 American Institute of Chemical Engineers Environ Prog, 2005