Process for preparing calcium chloride solution by utilizing ammonia soda filtration mother liquor

Abstract

The invention discloses a process for preparing a calcium chloride solution by utilizing ammonia soda filtration mother liquor and relates to the field of the production method of calcium chloride. The process comprises the following steps: distilling the filtration mother liquor to obtain mother liquor without ammonia, performing triple effect evaporation and separation to the obtained mother liquor to obtain an ammonium chloride saturated solution, then using the ammonium chloride saturated solution to react with lime powder in a reactor and generate a calcium chloride solution, and finally purifying the calcium chloride solution to prepare the finished product-calcium chloride solution. By adopting the process, the soda-calcium production can be realized under the premise of ensuring the recovery and recycling of ammonia and carbon dioxide and the content of the calcium chloride solution is more than 30wt%.

Description

technical field [0001] The invention relates to the field of production methods of calcium chloride, in particular to a method for preparing calcium chloride by filtering mother liquor in ammonia-alkali alkali production, that is, a process for preparing calcium chloride solution by using ammonia-alkali to filter mother liquor. Background technique [0002] As the largest producer of soda ash in the world, my country has implemented three production methods of ammonia-soda method, combined soda method and trona method, and a strategy of joint development of various technologies, which has promoted the transformation from a country with a large output to a country with a strong technology. The production of soda ash by the combined soda method occupies a large proportion in my country. Its advantage is that the waste liquid discharge problem of the ammonia-soda method is solved through the co-production of ammonium chloride. With the increase of production, it became increasin...

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Problems solved by technology

[0011] The second idea of ​​technicians for waste liquid treatment is to recycle the waste liquid to its own alkali-making system for use. Although the problem of waste liquid utilization has been solved, calcium chloride cannot be prepared. Therefore, the ammonia-alkali waste in the existing process is The preparation of calcium chloride by liquid recovery method is the main process for preparing calcium chloride

However, the method for preparing calcium chloride is to directly evaporate the distillation waste liquid after purification, because its calcium chloride concentration is low, the steam consumption is large, and the cost is high; the distillation waste liquid can increase the concentration of calcium chloride to 20% through beach drying. %, but it requires a large beach drying site and the round-trip transportation of waste liquid. With the increasing shortage of land, it is becoming more and more difficult to obtain high-concentration calcium liquid raw materials after beach drying

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