The application of water treatment technology in the production of enameled wire

The quality of enameled wire is determined not only by the main raw materials of copper and paint, but also by the process. The process equipment has also received sufficient attention, but in the production process, the indispensable auxiliary material - water - is often overlooked. Mainly due to insufficient understanding of the role of water in production processes and insufficient knowledge of water quality itself.

One water and water quality

As an industrial raw material, process water, and production process water, the quality of water directly affects product quality and yield. Therefore, the preparation of pure water has become a topic of industrial production.

During the natural and social cycles of water, various impurities are always mixed in. There is no truly pure water in nature, it always exists in a certain solution or turbid state, containing various impurities. This impurity is divided into five categories.

1. Electrolyte: It refers to a substance that exists in an ionic state in water. Including soluble inorganic substances, organic substances, and charged colloidal ions, it has conductivity, so the relative content of such impurities can be reflected by measuring the conductivity or resistivity of water.

2. Organic matter: It refers to natural or artificially synthesized organic matter. Such as organic acids, organometallic compounds, etc.

3. Particle matter: including sediment, dust, and organic matter. Microorganisms and colloidal particles.

4. Bacteria and microorganisms: Bacteria and microorganisms in water include plankton and algae.

5. Dissolved gas: It includes N2, CL2, H2S, CO, CO2, CH4, etc.

The commonly used water is surface water and groundwater. They all contain impurities and dissolved substances mentioned above, and even tap water cannot be directly used in the production of enameled wire because tap water contains chlorine (bleach, chlorine gas), which is a strong oxidant and has a direct oxidizing and corrosive effect on metals. We use activated carbon filters to remove impurities in water treatment.

2、 The impact of water quality on the production of enameled wire

The water used in the production of enameled wire also has various uses, and there are different requirements for water quality. According to the requirements for water quality according to the purpose of use, it can be divided into: annealing furnace water sealing water, equipment cooling water, lubricant preparation water, etc.

1. The impact on the quality of enameled wire.

In the production process of enameled wire, if particles in the water remain on the copper wire, it will cause uneven oxidation surface of the copper wire and create small holes; The pollution of ionic impurities can increase the surface charge density of copper wires, causing a decrease in the electrochemical performance of the oxide layer and affecting its parameters. During the wire drawing process, these impurities adsorb onto the copper wire and can diffuse into the interior, affecting the smoothness of the copper wire surface, causing uneven local resistance, easy breakdown and other defects. Also, due to oil stains or organic substances in the water, the painting effect is affected, and the adhesion of the paint film is poor, resulting in pores and a decrease in its insulation parameters. Especially the pollution of CL can cause deliquescence, resulting in black spots in humid climates. This is the reason for the formation of black spots on enameled wires, leading to perforation of the paint film and further invasion of moisture, resulting in a decrease in the quality parameters of enameled wires. This is also the cause of voltage drop.

2. Impact on mechanical components.

We know that in the transmission process of mechanical equipment, in order to ensure continuous operation of the equipment under high-speed and metal friction conditions, it is necessary to cool the equipment. If the cooling water contains a large amount of impurities, it can cause equipment pollution, corrosion, scaling, salt formation, sludge accumulation in pipelines, and blockage of scale deposits. The cooling effect of the equipment has decreased. The rapid damage to facilities, increased maintenance pressure, and decreased mechanical lifespan will greatly affect both production efficiency and economic benefits.

The blockage of annealing furnace annealing tubes and surface fouling of water ingress guide wheels encountered during the production process of enameled wire are all related to the deposition of calcium and magnesium ions in hard water.

3. Impact on wire drawing lubricant

Due to the chemical reaction between impurities, especially hardness components, in water and alkaline lubricants, a large amount of lubricant is consumed, resulting in a decrease in its effectiveness and accelerated deterioration. Therefore, many manufacturers use pure water when preparing lubricants, resulting in much better results.

In short, the water quality of the washing solution and cooling water (directly in contact with the product) involved in the product must be strictly controlled, and the finer the wire diameter, the higher the requirement. Roughly controlled within the following ranges:

(1) Enamel wire, copper wire annealing water seal: meets the standard of primary distilled water, with a conductivity of<10/CM, no CL detection, and no hardness.

(2) Mechanical cooling water: standard for softened water.

(3) Lubricant: Softened water standard.

3、 Water quality treatment methods

At present, in the enameled wire industry, the three processing methods are generally adopted.

1. Membrane separation technology

That is to use the currently popular membrane separation technology in the world - reverse osmosis method for water quality treatment. The desalination rate reaches about 98%, and its distinctive feature compared to traditional electrodialysis and ion exchange technologies is the significant savings in acid and alkali. However, strict requirements are placed on the quality of incoming water. If the incoming water quality is too poor and the effluent does not meet the standards, secondary treatment is required.

Process flow:

Raw water - sand filter - activated carbon filter - softener - precision filter - reverse osmosis machine.

(2) Electrodialysis - Ion Exchange Technology

The process involves adding pre desalination equipment electrodialysis before ion exchange (cation bed anion bed mixed bed). First, 80% of the salt is removed by electrodialysis, and the remaining 20% is removed by ion exchange process. This process has high water quality. Up to 0. Below 5/CM, stable and not affected by water temperature, but the disadvantage is also obvious, mainly due to a large consumption of acid and alkali, which affects environmental protection.

Process flow:

Raw water - precision filter - electrodialysis - water tank - cation bed - anion bed - mixed bed

(3) Softening water technology

This process is the simplest and only requires water to pass through a sodium ion exchanger. Meet the softened water standard. Scaling sodium salts can be reduced in the cooling system. But this process has the worst effluent quality and cannot remove CL.

Process flow:

Raw water - precision filter - softener.

The process equipment for water treatment is not complicated and the operation is convenient. But its industry is more biased and it is an auxiliary equipment in the industry. Generally, people do not attach enough importance to it, manage it casually, and have more part-time management. They do not attach importance to spare parts and regular maintenance. So there are not many companies that use it well.

The quality of products is the lifeline of enterprises. All factors that affect product quality should be taken seriously, otherwise they will suffer incalculable losses and consequences. Such examples are countless in our enameled wire production industry, which is also the reason why water quality treatment is widely valued today.

Test the water in the cooling water tank twice a week using silver nitrate. If the water turns white, it is necessary to replace the water in the sink. Not only do we use deionized water, but we also need to regularly replace the isolation water in the sink with new water every day to ensure that the water in the isolation sink does not contain too many impurities