Crystal production process will produce a lot of waste water and waste residue, if not directly discharged by the filter press, will cause great pollution to the environment. In the production process should be the characteristics of its waste water discharge, should take a scientific and reasonable waste water treatment process, construction of the corresponding waste water treatment project, so that the treated water quality to meet the national provisions of the discharge or recycling standards, waste recycling, so as to save precious water resources, to achieve the purpose of effective control and radical treatment of pollution.

one The properties of crystal processing wastewater and its harm to human body, soil and water

1. Properties and hazards of wastewater

The wastewater produced in the crystal processing process mainly includes three categories: ordinary crystal processing wastewater, acidic wastewater and wastewater containing heavy metals.

Common crystal processing wastewater is mainly milky white, and the main component is silica. This kind of waste water is easy to destroy the ecological environment of the water body and reduce the self-purification ability of the water body. It causes the soil to harden and plants to die.

Acid wastewater refers to the heavy metal strongly acidic wastewater produced by the use of hydrofluoric acid, nitric acid, hydrochloric acid or hydrofluoric acid in the sanding process of the grinding disc and the electroplating process in the fixed emery process. In particular, crystal pickling and grinding disc sanding, production personnel often take night field flow operations, pour strong acidic waste liquid at will, which will cause the surrounding crops to wither and yellow, but also cause serious pollution to the environment that cannot be ignored. Sewage from crystal grinding

The wastewater containing heavy metals refers to the electroplating process used in the sanding and fixing emery processes in the crystal mill processing process, which will produce wastewater containing heavy metals such as nickel.

2. Properties and hazards of waste residue

The solid waste generated in the crystal processing process mainly has two categories: general solid waste and dangerous solid waste. General solid waste by wastewater precipitation sludge and waste slag, waste, waste waste composed of crystal industrial solid waste, piled up at will seriously affect the village appearance, destroy the soil ecology, easy to cause secondary pollution. Hazardous solid waste refers to high-concentration waste acid after pickling and polishing of crystal, solid waste from processing of crystal materials with high lead content, residue after sanding of crystal mill with cyanide, and sludge from processing wastewater of crystal mill. Because of its corrosive, explosive, toxic, flammable, reactivity and other hazardous characteristics, the improper disposal of hazardous solid waste will inevitably cause serious environmental pollution and pose a threat to the human living environment, so the disorderly dumping of waste residue must be implemented as one of the contents of pollution control.

In the process of crystal processing, the waste water residue produced contains lead oxide, which has certain leaching toxicity; In the polishing powder used, some heavy metals are also added to achieve the purpose of presenting a variety of colors, and there is also a certain leaching toxicity. If no effective treatment is carried out, the waste residue will flow into the surrounding environment along with the wastewater, which will directly affect the surface water quality. Crystal waste is highly permeable, which can easily cause soil compaction, crop hypoxia death, ecological environment deterioration, and directly affect human health.

two Characteristics of pollution sources in different sections of crystal processing

1, the largest pollution of crystal processing technology from automatic polishing equipment, some equipment mechanical design is unreasonable, polishing is not separated, polished glass powder and polishing water mixed together, resulting in some not good treatment of wastewater and residue. If the new processing equipment that is separated by polishing is selected, the polished water and the glass powder and the polished water are completely separated, and the polished water passes through the precipitation cycle with zero discharge. The polished water has been recycled on the side of the polishing process, and there is no discharge at all, which will greatly reduce the total amount of sewage discharge and reduce the difficulty of sewage treatment.

2, the second largest source of crystal pollution is crystal grinding processing, this process in the grinding process needs to add a lot of emery, the water is black, and this part of the process water consumption is relatively large, the need for a large sedimentation tank or wastewater treatment, so that the water grinding processing can be recycled after filtration, to achieve zero pollution and zero emissions.

3, the third largest process of crystal pollution is saw material and rolling material, the two processes are mainly produced by glass powder waste slag and water, these two processes need a large precipitation site, with rapid pressure filtration equipment, after treatment, waste dehydration recovery, waste water essence recycling, to achieve zero discharge of waste water rolling material process.

4, crystal production of other processes as well as digging, punching, concave, face, round, these processes are basically some smaller equipment, polishing all are separate, the waste waste water generated are easier to deal with, can be introduced into the automatic polishing wastewater unified treatment.

Three. Crystal processing wastewater waste residue treatment technology

1. Design basis: The main pollutants in the wastewater of crystal processing are crystal powder and grinding wheel abrasive particles, which are mainly inorganic pollution factors such as SiO2 and SS. The wastewater is acidic when discharged from the workshop, and does not contain organic compounds, but the concentration of pollutants is high, if not treated in time, it will cause certain pollution to the surrounding environment.

Therefore, the treatment process of this kind of wastewater is mainly physical and chemical, and the process of medicated coagulation + precipitation is selected. Because the purpose of wastewater treatment is to remove acid, SiO2 and suspended solids, COD and BOD are no longer the main treatment targets. Therefore, it is determined that the treatment process of the wastewater is mostly neutralization precipitation and rapid pressurized sludge dewatering.

In view of the nature of crystal production water and discharge wastewater, combined with the experience of international wastewater treatment and domestic crystal wastewater reuse technology, our company provides a set of solutions for the treatment and reuse of wastewater in the crystal processing industry, the specific process is as follows:

Production wastewater → Regulating tank → Settling tank → Online flocculation dosing → Crystal wastewater filter → Clean water cycle (waste residue recovery)