摘要 |
The invention relates to a combined process for preparing a calcined soda from a natural soda containing sodium chloride, soda and sodium sulphate, which comprises steps: (a) dissolving the natural soda to prepare an aqueous solution; (b) obtaining sodium carbonate decahydrate crystals from the natural soda solution by using a separation method of attaching crystallization; and (c) treating the obtained sodium carbonate decahydrate crystals to obtain the calcined soda. The selection to raw materials in the combined process is widened, and the associated minerals, such as sodium chloride, soda and sodium sulphate, can be separated as simple substances. The species of the obtained calcined soda and anhydrous sodium sulphate are abundant, and their purities are high. Moreover, the entire processes can be recycled, and there is no discharge of smoke, dust, waste liquid and so on.
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