Battery industry water quality testing solutions

Industry background

There are many types of batteries, and the commonly used batteries are mainly dry batteries, accumulators, and small miniature batteries. In addition, there are metal-air batteries, fuel cells, and other energy conversion batteries, such as solar cells, thermoelectric batteries, nuclear batteries, etc.

Alkaline zinc-manganese battery (commonly known as alkaline manganese battery or alkaline battery), nickel-cadmium battery, nickel-metal hydride battery, etc. Acid batteries, mainly using sulfuric acid aqueous solution as the medium, such as zinc-manganese dry batteries (some consumers also call them acid batteries), seawater batteries, etc.; Organic electrolyte batteries, mainly batteries with organic solution as the medium, such as lithium batteries, lithium-ion batteries, etc.

The urgent demand of the market has led to the emergence of new secondary batteries. Among them, new secondary batteries such as high-energy nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, maintenance-free lead-acid batteries, lead-cloth batteries, lithium-ion batteries, and lithium-polymer batteries are favored. It has been widely used in CHINA, forming an industry and developing rapidly.

Sources and hazards of lead

The pollution of lead-acid batteries is important in the production process, in the process of coating and battery cleaning, there are heavy metal wastewater containing lead, and in the process of grid casting, alloy preparation, lead parts and aluminum powder manufacturing, a variety of lead-containing smoke and lead dust appear. The pollutant of lead-acid batteries is lead, so what is the harm of lead pollution?

1) Effects of lead on the nervous system

The central nervous system of the human body is the main organ of vital activities, and its functional state plays a leading role in the course of lead poisoning. Language and spatial abstraction ability, sensory and behavioral ability changes, fatigue, insomnia, irritability, headache and hyperactivity and other symptoms, moderate or above lead poisoning, polyneuritis can occur, severe cases even damage the tip nerve or spinal cord anterior horn cells, resulting in lead paralysis, advanced lead poisoning can cause toxic encephalopathy due to organic lesions of the central nervous system, such as intracranial vasospasm to promote early sclerosis of cerebral blood vessels

2) The effect of lead on the hematopoietic system

Lead can affect the metabolism of phyllotin, phylloline is the intermediate product of the hemoglobin synthesis process, when the body is exposed to lead poisoning, it affects the conversion of 6-aminolevulinic acid (6-ALA) into phyllogen, fecal phylline into protoporphyrin and protoporphyrin and ferrous synthesis of orthoherubin, etc., resulting in hemoglobin formation disorders, causing lead-induced anemiaLead-induced anemia is common in lead workers and children, especially children, in addition, lead also inhibits Na+-K+-ATPase on the red blood cell membrane and inhibits the pentose phosphate bypass pathway, resulting in hemolysis.

3) Effects of lead on the digestive system

Under the use of lead poisoning, a series of changes in gastrointestinal function may occur, lead can inhibit pancreatic function, increase the secretion of salivary glands and gastric glands; At the same time, lead will bind to hydrogen sulfide in the intestine, so that the hydrogen can no longer promote intestinal motility, resulting in intractable constipation.

4) The effects of lead on other organ systems

Lead can damage the proximal tubules and glomerular cells of the kidney, increase the glomerular filtration rate, renal tubular reabsorption disorder, and in severe cases, lead toxic nephropathy can occur, such as nephrogenic hypertension, lead can inhibit the synthesis of hepatic mixed function oxidase, resulting in liver biotransformation use is impaired, reduce liver detoxification function Lead can also affect human reproductive function, make sperm aberration, maternal lead can affect fetal development through the placenta, resulting in fetal malformations, causing serious harm to human reproduction.

Wastewater from the battery manufacturing industry

Wastewater from battery production:

The main sources are wastewater from cleaning slurry in battery production lines; Preparation of spilled chemical wastewater in the slurry; Cleaning of waste water from production floors. Wastewater from battery production contains a large number of heavy metal ions such as Zn2+, Mn2+, and Hg2+, which will cause pollution to the environment if discharged without treatment.

In the production process, raw materials containing mercury, zinc, manganese and starch are used, and the concentration of heavy metal pollutants in the wastewater discharged in the production process of electro-hydraulic preparation, gelatinization, and carbon washing rod head is 0.08mg/L of mercury, 315mg/L of zinc, and 73mg/L of manganese, which is directly discharged, causing serious pollution to the environment.

Through the analysis of the water quality and wastewater discharge characteristics of battery wastewater, the following process flow is determined: the wastewater flows from the regulating tank to the reaction tank, three groups of agents are added to the inlet and outlet of the reaction tank, and then the wastewater after coagulation reaction is pumped into the purifier by the inlet pump, the treated clean water flows out from the top, and the sludge is discharged into the sludge thickening tank from the bottom, and is dehydrated and transported away after being concentrated by the sludge thickening tank and the sludge storage tank.

Products: zinc-manganese dry batteries, alkaline zinc-manganese dry batteries and other batteries;

Wastewater mainly includes: domestic wastewater, mercury-containing wastewater, zinc-containing wastewater, and other wastewater;

After treatment, the water quality standard should meet the maximum allowable discharge concentration of Class I pollutants and the Class I discharge standard of Class II pollutants in GB8978 1996.

Table 1 Influent water quality and discharge standards

TABLE 2 OPTIMAL PH RANGE FOR THE PRECIPITATION OF VARIOUS METAL IONS

Cadmium-nickel battery plant discharges wastewater: In the process of battery production, impregnation, formation, etc., metal cadmium and nickel ions are discharged from the wastewater.

Cadmium-containing wastewater: mainly from the anode workshop, Cd2+ concentration 0.5~3 mg/ L pH=11~14.

Nickel-containing wastewater: mainly from impregnation and formation workshops, Ni2+ concentration 0.5~40 mg/L pH=10~14.

Cadmium and nickel ions are the first category of pollutants prohibited from random discharge in the national sewage discharge standards, because it can accumulate in the environment and animals and plants, and have long-term adverse effects on human health, so the sewage containing such substances, regardless of industry and discharge mode, and the function and category of the receiving water body, its maximum allowable discharge concentration Cd2+<0.1mg/L Ni2+<1.0 mg/L.

However, cadmium and nickel are relatively expensive metals, and reasonable recycling can greatly reduce the cost of sewage treatment, so it is necessary to develop a set of efficient and economical wastewater treatment solutions for the above situations.

Workshop wastewater from lead-acid battery plants:

Its main components are lead sulfate and iron ions, and it also contains small amounts of suspended solids and oils. The pH value of the water is between 1~2, the total lead concentration is 2.2~7.0mg/L, the total iron concentration is 3.1~7.5mg/L and the SO2 4 concentration is 150~4000mg/L.

The test items are: total lead, total iron, pH (7-9), SS, sulfate, chloride ion, nitrate, sludge concentration, all of which must meet the sewage discharge standard before discharge.

Lead-acid battery plant wastewater discharge: lead-containing acid wastewater discharge index

Before treatment: pH: 1.6-2.1, SS: 208-297mg/L; Lead ion: 2.32-6mg/L; Oil 5-13mg/L;

After treatment: pH: 6-9; SS：707mg/L； Lead ion: 1mg/L; Oil: 10mg/L;

Battery production wastewater testing solutions