Environmental pollution in the cable manufacturing process

In the process of rapid industrial development, if environmental pollution is not strictly controlled, it will cause devastating ecological problems. In the 80s of the 20th century, when we criticized the environmental pollution of industrially developed countries, it was our country's industry The period of development is also the time when industrially developed countries are considering transferring pollution to developing countries. For more than 20 years, while our country's industry has developed rapidly, it has also caused more and more serious pollution.

We have been saying that the cable industry is an industry that does not produce environmental pollution, and each factory has been recognized by the Environmental Protection Bureau, and many factories have also obtained ISO14001 environmental protection certification. However, according to the in-depth care In cable manufacturing plants, there is environmental pollution in almost every process, but the form, path and severity of pollution are different. The factory area is greened, tree planted, grass planted, flower grown, rockery, bonsai are built, and built The "garden-style factory" can only give people a visual experience, but it is not helpful for the treatment of the "three wastes" generated by the production process, and can only be a kind of appearance decoration. In recent years, some experts and scholars have been interested in the cable industry Environmental pollution has been discussed, but it is still limited to the composition of cable materials, and does not involve environmental pollution caused by the cable manufacturing process.

The following discusses the environmental pollution of several major processes in the cable manufacturing process.

Copper rod manufacturing:

Copper is a trace element necessary for life, but excess copper is harmful to people, animals and plants. During the process of copper smelting and processing, if appropriate smoke and dust removal measures are not taken, black smoke will occur and serious pollution will occur. Copper and The soot of the compound enters the atmosphere and causes air pollution. During copper smelting and processing, copper acidic wastewater is produced, with a maximum copper content of tens to hundreds of milligrams per liter of wastewater. Soil near copper smelters with high concentrations of copper, This wastewater is discharged without treatment and will affect the quality of the water.

It is understood that some small copper rod factories are thick with smoke and stench, and a large amount of sewage and exhaust gas are directly discharged without any treatment, seriously polluting water quality, crops are seriously damaged, and some are even cut off.

The exhaust gas produced is mainly flue gas produced by melting furnace, copper particles and SO2 gas produced in gas furnaces, etc., which should be discharged to meet the standards after dust removal by the tandem baghouse. The process wastewater generated in the continuous casting and rolling process should be cooled and circulated. Both the used oil and waste emulsion of the mill lubrication system should be properly disposed of.

In our country, the maximum allowable discharge concentration of copper and its compounds in industrial wastewater is 1 mg/L (in terms of copper). Some factories still use the technologically backward fire copper smelting process, and there are countless earth copper smelters, causing serious problems environmental pollution. The state is intensifying its efforts to inspect copper processing plants with serious pollution in order to control the use of substances and pollution emissions from the production process, reduce pollution from the source, and reduce waste, wastewater and waste heat generated in the production process Comprehensive utilization or recycling to improve resource utilization efficiency and reduce or eliminate hazards to human health and the environment.

Aluminum rod manufacturing:

Many cable factories have their own aluminum rod processing capabilities. There are two main types of molten aluminum heat source fuels: furnace gas and heavy oil. If the heavy oil is not atomized well and the combustion is incomplete, black smoke will be generated. If the gas generator furnace is not properly configured or If it is in disrepair, CO gas leakage will occur and poison the environment. During the melting process, the solvents used also produce large amounts of harmful fly dust. If the smoke and dust removal measures are not effective, thick smoke will be produced and the atmosphere will be polluted. It should be non-polluting and toxic auxiliary materials, the generated flue gas is treated by dry flue gas purification technology and discharged at high altitude. The coolant of aluminum rod continuous casting and rolling needs to be carefully treated before it can be discharged, and the pH value of the waste emulsion should be adjusted first (to 6.5-7.5), and then Add 2~5% of the total amount of sodium chloride of the waste liquid for stirring, dissolve for two hours, then add 1~3% potassium aluminum sulfate according to the amount of waste oil, stir slightly, and then stand still for 24 hours, after its condensation and stratification, separate the upper float material, drain the lower part of the wastewater. Some small factories use earth-based equipment to manufacture aluminum rods, and there are no flue gas, flying dust and wastewater treatment measures at all, and the environmental pollution is quite serious.

Rubber processing:

Cable manufacturing plants generally use small and medium-sized mixers, due to cost problems, generally use manual batching, manual feeding, manual operation of rubber mixing, workers labor intensity, serious pollution to the workshop and the surrounding environment.

Henan Medical University and other units have investigated and studied the skin diseases of rubber mixing workers in cable factories, and found that the prevalence of skin diseases among rubber mixing workers was 68.7%; Eight ingredients, antioxidant (DNP and D), accelerator (DM, M, CZ, DPTT), antioxidant 1246 and lightfast crimson, showed different degrees of positive reactions. After diagnosis and investigation, it was proved that the skins of rubber processing workers Skin diseases are mainly caused by dust pollution.

Although the current internal mixer adopts the feeding system of the upper auxiliary machine, which realizes mechanization and automation, compared with manual batching and feeding, it does reduce the labor intensity and environmental pollution, but because the raw materials have to be unpacked and put into storage bucket, automatic weighing according to the requirements of the formula, put into the intermediate hopper and other processes. In these processes, dust is flying. After the workers who unpacked and poured carbon black, the rest of their bodies were black except for their eyes and teeth, which were white.

In addition, if the waste water and waste oil discharged from the rubber processing process are discharged into the sewer without treatment, it will also cause serious public pollution.

Drawing:

Copper drawing oil is formulated from base lubricants, emulsifiers and stabilizers, among others. The main source of pollution in the wire drawing process is the drawing oil. The treatment of copper drawing oil waste liquid mainly includes two steps: demulsification and water purification. Demulsification is mainly will The principle of two-phase separation of oil and water is to add salt compounds containing metal ions such as Ca2+, Na+, Al3+ to the emulsion, so that the surfactant in the emulsion and it form insoluble soap, thus producing coagulation Assemble.

When formulating brushed oils, certain chemicals are added, such as sodium tripolyphosphate or sodium ethylenediaminetetraacetic acid. The drawing oil will foam during use, and a defoamer needs to be added. Due to the fact that there are many oils and fats in the emulsion It is easy to produce bacteria, so it is necessary to add the right amount of antioxidants and fungicides. Emulsions are affected by microorganisms (such as bacteria, mold and algae) After erosion, the unsaturated fatty acids and other compounds in the emulsion are decomposed by microorganisms, which destroys the balance of the emulsion, resulting in oil separation, soap separation and increased acid value, causing the emulsion to spoil and produce odor. All of these factors, all It is decided that the drawing oil cannot be discharged casually, and it is best to recycle it after filtration. It is best to use deionized water to reduce the effect of water hardness on the drawing oil, as well as the corrosion of the copper wire by Cl- in the water, and the pH value should not be lower 6.5。 Proper control of the emulsion temperature. The system should be equipped with a filtration device to filter out copper powder and copper mud in time to keep the drawing oil clean. When replacing the waste oil, it is necessary to entrust a special recycling company to take the waste oil away. Some cable factories have rings The use of drawing oil and improper disposal of waste liquid and waste residue are also an important reason.

Some small wire drawing factories scattered in towns and villages still use the old water tank wire drawing machine, which uses soapy water for stand-alone dead water lubrication, which does not have the ability to treat wastewater at all, and is discharged at will, resulting in water quality around the factory Contaminate. Waste drawing lubricants usually contain more than 90% water, and the rest is copper soap, fat, and oil. This waste contains a lot of copper and, like pesticides, cannot be discharged into sewers.

　　镀锡：

　　镀锡是被公认的环境污染行当之一。目前，电线电缆行业广泛使用的铜线镀锡方法仍然是热镀锡和电镀锡。传统的开放式热镀锡方法仍然在许多中小企业中使 用。热镀锡工序的主要污染源是铜线清洗剂酸、镀锡锅散发出的酸汽以及工艺废水。传统高温热浸锡工艺成本高，能源和锡的消耗浪费大且不安全，对环境和操作工 人的身体健康有极大危害。车间的通风、排气、地面污染、废水排放、工人劳保等都应加以关注。经改进的热镀锡设备和工艺，虽然对环境污染有所改善，甚至被称 为“无污染镀锡”，但需要对车间通风和废水排放严格控制。

　　电镀锡通常被认为是无污染的镀锡工艺。其实，电镀锡工艺的污染主要取决与电镀液的成分和工艺控制。我国电线电缆行业有一些进口的金属丝电镀锡机组。这 些进口电镀锡机有些在正常运转，据说不产生污染；有些则被环保部门查处水质污染问题而被禁止使用。即使有的正常使用的工厂，也是把电镀废液、淤泥偷偷地运 到偏僻地带扔掉，而不敢乱排乱放。

　　事实证明，不论是热镀锡还是电镀锡，虽然在设备本身、镀锡液和添加剂等方面已经有很大改进，但是人们只能尽量减少它们对环境的污染，而完全消除污染是不可能的。镀锡工序仍然是环保部门高度关注的工序。

　　涂漆：

　　早在20年前，美国就列出了一个“烟囱工业”黑名单，其中电磁线工业单上有名，引起各国的关注。

　　尤其是开始使用清漆制造漆包线以来，这一行业便带来了令人烦恼的环境污染控制问题。在制造漆包线时，通常使用酚、芳香烃和甲酚作为漆的溶剂载体。这些 材料燃烧时所产生的有害气体排放到大气中去，会严重污染空气，危害人身健康。为了消除污染、改善环境，后来在漆包炉上加装了催化燃烧和焚化燃烧装置。旧式 漆包炉都有焚化装置，有些使用催化剂，有些装有内部燃烧焚化装置。实践证明，热焚化燃烧装置的效率可达90－99％，而催化剂的效率开始时是 90－95％，但其效率随着装置变脏而下降。据外国资料称，催化剂在漆包炉中的有效期最多大约1万小时，而新型陶瓷催化剂的有效期可达1年以上。至于漆包 炉散发出的废气，现在正在使用高固体含量漆和水溶性漆加以解决。

　　漆包线厂产生的废弃物包括拉丝润滑剂、废漆、废溶剂、废水和废气，这些废物对环境都有害，不能随便排放。

　　挤塑：

　　PVC和PE在火灾中分解、氧化和燃烧时可以产生氯甲烷、氯化氢、苯、一氧化碳、二氧化碳等多种有毒或腐蚀性产物，对人造成伤害。

　　在PVC挤出阶段的环境污染是PVC热分解作用引起的。PVC热分解时首先散发出HCL，还有一些铅、铬等重金属元素。PVC电缆料正常的挤出温度 （160－180℃）下，便开始发生热分解，生成刺激性很强的白色烟雾（图5）。在PVC电线电缆挤出车间里，充满了这种很有害的气体味道，挤出机旁边的 控制仪表外壳受到HCL气体的腐蚀而发黑生锈。长期与PVC挤出工作环境接触的人，会发生恶心、头晕、神经麻木等症状，并且会引发其他疾病。有些工厂在 PVC挤出机头上方安装了吸风排气装置，有些工厂则没有安装，任凭有害气体散发，对操作工人的身体健康极为有害。排放出的气体对大气造成严重污染。挤出生 产线上的冷却水槽里的水，由于PVC分解出HCL的缘故，其酸性PH值高于正常自来水，不能任意排放，应循环使用。

　　挤橡硫化：

Rubber raw materials can only be turned into rubber with different functions after adding appropriate compounds, mixing thoroughly and undergoing vulcanization reactions. When the compounded compound is extruded, whether it is hot or cold, it will be dissipated Strong smell. In addition to the rubber itself, these odors are mainly from various compounds. Some of these odors can be eliminated, while others cannot be eliminated. As mentioned above, the dust from these compounds is harmful to the operator They are very harmful, and their decomposition products at extrusion temperature are harmful to human health in the form of gases. The gases that occur during rubber extrusion and vulcanization are discharged into the atmosphere and pollute the air. Residents living around rubber products factories are all inhabited Complain about this. In addition, the wastewater generated during the vulcanization process of rubber cables contains rubber and various decomposed ionic harmful substances, which cannot be discharged into the sewer without treatment.

Crosslinking:

People always think that XLPE is a non-toxic and harmless material, and in the project proposal and feasibility report, the chemical cross-linked cable project is also described as a project without environmental pollution. In fact, it is not.

XLPE material is made of polyethylene with crosslinking agents, antioxidants and voltage stabilizers, etc., which are used to manufacture medium and high voltage cross-linked cables on CCV and VCV production lines. XLPE undergoes chemical crosslinking reaction at high temperatures When it is timely, it will also decompose to form by-products such as dehydroxy alcohol, acetyl benzene, and methane. Especially when manufacturing cross-linked cables with CCV production lines, the cross-linked pipes must be cleaned every 3 months to remove the accumulated cross-linking by-products in the tubes Dirt. According to on-site observations, these by-product dirt are as sticky as asphalt and have a foul smell. Some cross-linked by-products exist in liquid form. After they are discharged from the cross-linked pipe, they should be collected and disposed of properly, and cannot be followed Intentional emissions. According to British experts, some of the by-products of polyethylene chemical cross-linking are extremely toxic and even carcinogenic substances (extremely toxic and carcinogenic）。 There are 235 CCV cross-linked cable production lines distributed throughout the country in our country, and if the discharge of cross-linking process wastewater is not strictly controlled, the consequences can be imagined.

Environmental protection measures at cable manufacturing plants

From the above description of environmental pollution in cable factories, it can be seen that the cable industry is not an industry without pollution, but an industry with serious pollution. Appropriate countermeasures should be taken and implemented in detail.

(1) Factory operators should effectively improve their awareness of environmental protection, understand national environmental protection laws and regulations, and make factory construction and human society and ecological harmonious development.

(2) Increase investment in environmental protection, eliminate old equipment with high pollution and high energy consumption, try to adopt new technologies, new equipment and new processes, reduce pollution generated by the production process, strengthen the treatment of waste gas, wastewater and waste residue, and control waste emissions to the minimum level allowed by the state.

(3) Strengthen the environmental supervision of major pollution processes such as wire drawing, tin plating, enameling, extrusion, mixed rubber, extrusion, vulcanization, and cross-linking, and implement ISO14001 system certification.

(4) People-oriented, care about the health of workers, and improve the working environment and labor protection conditions.