Method for separatingcalcium chloride and sodium chloride in ammonia distillation waste clear solution with nanofiltration technology and application of production by the method

Abstract

The invention discloses a method for separating calcium chloride and sodium chloride in ammonia distillation waste clear liquid by using nanofiltration membrane technology and application of product thereof, relating to a chemical field of preparing calcined soda by using an ammonia-soda process or a union alkali method; the method comprises that the ammonia distillation waste clear liquid is separated through a nanofiltration membrane filtering equipment to obtain concentrated solution mainly containing calcium chloride solution and penetrant mainly containing sodium chloride solution. The penetrant can be recycled for salt dissolving technology. The concentrated solution containing high-concentration calcium chloride can be used for producing calcium chloride product by adopting methods of evaporation and crystallization. The method leaves out processes of repeated sunning, heating and vacuum pumping, and most moisture can be reused; the invention reduces energy consumption and area occupation, saves a large amount of water resource, which create good condition for technology of subsequent salt dissolving and the calcium chloride production.

Description

technical field [0001] The invention relates to the field of chemical industry for preparing soda ash by an ammonia-soda method or combined alkali method, in particular to a method for separating calcium chloride and sodium chloride in ammonia distillation waste liquid by nanofiltration membrane technology and an application of the product of the method. Background technique [0002] In recent years, membrane technology has made great progress in the field of material separation, among which nanofiltration membranes have been widely used in the separation of special materials. Nanofiltration (NF, Nanofiltration) is a pressure-driven membrane separation process between reverse osmosis and ultrafiltration. The pore size of the nanofiltration membrane ranges from 1 to 10 nanometers. Nanofiltration separation is a new type of membrane separation technology, and its technical principle is similar to mechanical sieving. By recombining positive charges on the surface of the nanofi...

AI Technical Summary

Problems solved by technology

[0005] From the traditional treatment process, we can see that, first, the waste liquid after settlement and clarification needs to be re-dried, and it usually takes a long time to re-dry to achieve the desired effect, which brings the area occupied by the re-dried field. Larger, and re-drying is bound to be restricted by sunshine conditions, affecting re-drying and concentration effects

Moreover, the concentration rate of re-drying to the waste clear liquid is only 1.5 to 2 times, and to reach the concentration for salt separation, it needs to be concentrated more than twice, and this concentration can only be achieved by strong means such as heating or vacuum suction.

2. A large amount of water will be lost by concentrating the waste liquid by re-drying, heating, vacuum suction and other means, so the traditional process has the disadvantages of high energy consumption, high water consumption, large floor area and low treatment efficiency.