New method and apparatus of membrane-method calcium chloride mother liquid concentration

Abstract

The invention relates to a new method and an apparatus of membrane-method calcium chloride mother liquid concentration. The method includes the following particular steps: (1) regulating the pH of a to-be-concentrated low-concentration calcium chloride mother liquid to 6.0-6.5 with hydrochloric acid; (2) adding 0.01-0.5% of a chelating agent R; (3) in a liquid storage tank 1, performing temperature-constant treatment to the to-be-concentrated low-concentration calcium chloride mother liquid to 65 +/- 2 DEG C; (4) pumping the material liquid through a liquid transportation pump 2, enabling the material liquid to flow through a membrane core of a hydrophobic membrane assembly 7, feeding the material liquid to a pump body, and finally enabling the material liquid to flow through a rotor flow meter 3, a pressure meter 4 and a temperature meter 5 and then feeding the material liquid back to the liquid storage tank 1 for further circulation; (5) when a vacuum pump 9 is started, pumping one part of evaporated material liquid into a condenser 8 through the vacuum pump 9 through micropores on the hydrophobic membrane assembly 7, and cooling the evaporated material liquid and feeding the evaporated material liquid into a collection bottle 6; and (6) enabling the other part of the material liquid to flow out through the hydrophobic membrane assembly 7 back into the liquid storage tank 1, thereby concentrating the material liquid in the liquid storage tank 1 and finally reaching the concentration of not less than 30%.

Description

technical field [0001] The invention relates to the field of concentrating industrial calcium chloride mother liquor, in particular to a new method and device for concentrating calcium chloride by membrane method. Background technique [0002] For the concentration of low-concentration calcium chloride mother liquor, simple evaporation, multi-effect evaporation and other evaporation methods are usually used to recover calcium chloride, but the lower the concentration, the greater the energy consumption. It must be concentrated to more than 30% before multi-effect evaporation Only then is it economically feasible. [0003] At present, there are many technologies that can be used to concentrate salt solution, such as electrodialysis, reverse osmosis, nanofiltration, ion exchange, and heat pump technology, pervaporation, and membrane distillation technology developed in recent years. Different methods have different energy consumption and concentration efficiencies. [0004] ...

AI Technical Summary

Problems solved by technology

[0004] Electrodialysis, reverse osmosis, nanofiltration, and ion exchange processes have strict requirements on the salt concentration of the raw solution, and are only suitable for concentration treatment of solutions with low salt concentrations, otherwise concentration polarization will occur to form membrane fouling, which will affect the performance of the membrane

Electrodialysis technology generally requires that the salt content of the original solution is less than 5000ppm, which is more economical; reverse osmosis requires that the salt content of the original solution is less than 1500ppm, which is more economical; for the treatment of the original solution with a salt content far exceeding 5000ppm, it is often necessary to use multi-effect evaporation technology. Efficient evaporation technology needs to vaporize a large amount of water during the treatment process, resulting in high energy consumption, high treatment cost and poor economy

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