White latex production process and wastewater treatment method
The white latex production process is simple, and the process is as follows: a predetermined amount of water and polyvinyl alcohol (PVA) are added to the dissolution vessel, and then the mixture is stirred to swell the polyvinyl alcohol, and the solution is heated to obtain a PVA solution having a predetermined concentration. The PVA solution was sent to the polymerization vessel through a filter with compressed air. The polymerization vessel agitator is started, the plasticizer and the antifoaming agent are added to the temperature, and the vinyl acetate (VAc) monomer and the initiator are continuously added to the polymerization vessel at a predetermined temperature to control the reaction temperature until the addition is completed and the reaction is completed. After the product is sampled, it is compressed into the finished tank by compressed air and cooled to below 50 °C. The solid particles are filtered out by the filter to be packaged.
In the process of white latex production, a large amount of milky white wastewater is produced by washing the filter screen, washing the kettle, and the like. The composition of wastewater is complex, including polyvinyl alcohol (PVA), polyvinyl acetate, plasticizer, defoamer, dispersant, antifreeze, starch, talc and unreacted vinyl acetate monomer (VAC). The main components in the wastewater are COD and SS, and the organic content of the wastewater is about 5000 mg/L. About 16,000 tons of white latex, the amount of latex wastewater generated is about 7,000 tons.
The treatment method of white latex production wastewater has been discharged after natural sedimentation for many years. The natural sedimentation method has a long settling time for the latex wastewater, and the wastewater sedimentation tank has a large area. The sedimentation effect is not too good. Only the colloid with larger particles can be treated. The colloid of the fine particles will not settle in the water. The natural sedimentation method is fundamentally The problem of separation of colloidal material from water in wastewater cannot be solved. The COD of wastewater discharged after natural sedimentation is still above 3000 mg/L, and SS is about 500 mg/L, far exceeding the secondary emission standard of the comprehensive wastewater discharge standard (GB8978-1996).
The above is the white latex production process and the wastewater treatment method, and I hope to help everyone.