Method for removing sulfate ions by high-temperature membrane method

Abstract

The invention discloses a method for removing sulfate ions by a high-temperature membrane method. The method comprises the following steps: pretreating high-temperature electrolyzed light salt brine;performing dechlorination treatment on the high-temperature electrolyzed light salt brine in the pretreatment process; adjusting the pH value of the high-temperature electrolyzed light salt brine; finely adjusting the temperature of the high-temperature electrolyzed light salt brine to slightly reduce the temperature of the high-temperature electrolyzed light salt brine; and then carrying out membrane separation treatment, crystallizing and separating the saline water with high sulfate ion concentration after membrane separation, and concentrating the saline water with low sulfate ion concentration after membrane separation or returning the saline water with low sulfate ion concentration to a saline water process for salt melting. According to the method, sulfate radicals in the electrolyzed light salt brine are removed through a high-temperature nanofiltration process, the treatment temperature of the light salt brine treated by the system is high, desulfurization acid radical treatment can be carried out without cooling to 45 DEG C or below, and the use amount of cooling water is remarkably reduced; and in addition, the temperature of filtrate obtained after membrane filtration is high, heat consumption during MVR evaporation or salt melting is reduced, energy consumption is reduced in the MVR concentration process, and energy is saved.

Description

technical field [0001] The invention relates to a desulfation radical treatment system and method, in particular to a brine desulfation radical treatment system and method, and belongs to the technical field of chlor-alkali equipment. Background technique [0002] Chlor-alkali industry refers to the industrial production of caustic soda, chlorine and hydrogen by electrolysis of saturated NaCl solution, and is one of the important basic chemical industries. The electrolysis is carried out in a vertical diaphragm electrolyzer, which divides the electrolyzer into an anode chamber and a cathode chamber. When the power is turned on, under the action of the electric field, the negatively charged Cl - moving towards the anode, the positively charged H + Moving to the cathode, under these conditions, the following reaction occurs on the electrode: [0003] Anode: 2Cl - -2e=Cl 2 ↑ [0004] Cathode: 2H + +2e=H 2 ↑ [0005] That is, Cl is released in the anode chamber 2 , the...

AI Technical Summary

Problems solved by technology

[0009] There are two methods for removing sulfate ions in the existing chlor-alkali industry. One uses the barium chloride method to remove sulfate ions. The disadvantage is that the cost is high. Barium chloride is a highly toxic chemical that is harmful to humans and animals; the other uses the membrane method. Treatment, below 45°C, the disadvantage of this process is that the temperature must be lowered before the membrane treatment, and the temperature must be reheated after treatment, and the energy consumption is too high

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