Electrochemical chemical polishing waste acid resource utilization

Chemical polishing process waste acid 
Chemical polishing solutions are divided into chemical polishing solutions and electrochemical polishing solutions. They are generally classified into two-acid polishing (phosphoric acid, sulfuric acid) and three-acid polishing (phosphoric acid, sulfuric acid, nitric acid). Usually, organic solvents are added. 
Question:
The common methods for treatment are direct evaporation or resin recovery. The former cannot achieve the separation of aluminum ions from the acid, while the latter has problems such as poor separation effect of aluminum ions, large amount of regeneration water, rapid performance decline, and cumbersome operation. Solution:

Acid recovery using diffusion dialysis: Recovers 50% - 65% of phosphoric acid; Significantly reduces aluminum ion concentration; The comprehensive economic benefits are much higher than the current disposal methods. 
The feed conditions for the diffusion dialysis equipment require pre-treatment of the materials: filtration to ensure that the SDI of the liquid is less than 5.
Control the content of the oxidant (residual chlorine < 0.2 mg/L, ozone < 0.1 mg/L, hydrogen peroxide < 0.1 mg/L).
Specific gravity ≤ 1.4.
Operating temperature: ≤ 40℃; Optimal operating temperature: 30 - 35 degrees Celsius.
The chemical liquid parameters that affect the economic value of diffusion dialysis: the phosphorus-sulfur ratio. The higher the phosphorus-sulfur ratio, the more recoverable phosphoric acid, and the greater the economic value.
Aluminum ion concentration: The lower the aluminum ion concentration, the more free phosphoric acid, and the greater the economic value.
Specific gravity: The optimal specific gravity is 1.35 - 1.4. The closer the specific gravity is to 1.4, the less the processing volume and the smaller the equipment scale.
Performance indicators of the diffusion dialysis equipment
Phosphoric acid recovery rate.
Aluminum ion retention rate.
Residual liquid treatment methods: neutralization, dilution, evaporation, resin.