New models for the development of the recycled lead industry

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New models for the development of the recycled lead industry. As a major metal raw material, lead is widely used in various sectors of the economy. China has seen the fastest growth in lead production and consumption since the 1990s; however, most of this growth has involved primary lead, while the growth rate of recycled lead production has been quite slow. Although China ranks among the top countries in terms of lead resource reserves, excessive mining and lagging exploration have led to an increasingly severe shortage of lead ore resources. The issue of ensuring resource security has thus become a problem that needs to be addressed urgently. Developing the recycled lead industry allows for the full utilization of lead waste, reduces the need to extract primary lead ore, extends the period during which it can be mined, and minimizes environmental pollution caused by lead waste as well as resource waste. It enables lead metal to enter a sustainable cycle of production-consumption-recycling, making it an essential component for China to implement a strategy for the sustainable development of its lead industry and to foster a circular economy. With the rapid development of China’s automotive, communications, and chemical industries, the recycled lead industry has access to more raw material sources, and it is currently in a very favorable period of growth. The current status of the recycled lead industry: China’s recycled lead industry has made significant progress over the past 10 years and has begun to develop into an independent industry. However, overall, there are nearly 300 plants in the country that recycle lead from used batteries, with production capacities ranging from dozens of tons to several thousand tons; very few of these plants have a capacity of over 10,000 tons. The processing techniques primarily involve traditional methods such as small reverberatory furnaces, blast furnaces, and cupolas, with the grid and lead sludge being mixed together without any prior treatment processes ； Some small businesses and individual entrepreneurs even use primitive earthen kilns for smelting ； There are issues such as a large number of enterprises, small scale, high energy consumption, severe pollution, backward industrial technology, and low rates of metal recovery and comprehensive utilization: The lead recovery rate is low – the recovery rate at most domestic production facilities is generally 80%–85% (while the average level abroad is 95%) ； Low comprehensive utilization rate: Due to the lack of sorting, the grid metal and lead paste are mixed together, resulting in the alloy components not being utilized effectively ； High energy consumption: The average level in China is 500–600 kilograms of standard coal per ton of lead, while the average level abroad is 150–200 kilograms of standard coal per ton of lead ； Severe environmental pollution: Due to outdated technology, the levels of lead vapor, lead dust, and sulfur dioxide emitted during the smelting process are far above the allowed limits, reaching dozens of times the standard values. At present, apart from factors such as policy and market, backward technology and low level of intensification are the key issues restricting the development of the recycled lead industry. The vast majority of individual lead recycling enterprises are small in scale due to constraints imposed by the market and recycling channels; as a result, their technical equipment is outdated, leading to serious problems related to environmental protection and resource waste. Even those few manufacturers that adopt advanced foreign technologies face operational difficulties owing to issues related to supporting environmental protection facilities and the costs associated with processing intermediate products. The new process introduced in this article combines the production of primary lead with that of recycled lead, and utilizes a novel process route to develop recycled lead, achieving good economic, environmental, and social benefits. New processes and their practical results: After pretreatment, lead-acid batteries are broken down into plastics, grids, lead paste, separators, etc. The waste liquids generated during this process are recycled and neutralized; the metallic components in the form of grids are directly melted at low temperatures to produce alloy lead required by battery factories, or used to add antimony in electrolysis processes ； The lead sludge, along with lead concentrate and other lead-containing materials, is fed directly into the bottom-blown furnace and blast furnace smelting systems to produce crude lead, which is then sent for refining into electrical lead; the sulfur contained in it is recovered to produce sulfuric acid. The plastic and partition parts are sold or remelted into plastic pellets for sale. This process generates little pollution, has low energy consumption, a high lead recovery rate, and excellent comprehensive utilization efficiency. At present, a certain company uses this process to recycle and process approximately 50,000 tons of recycled lead per year; lead sludge and recycled materials account for around 10% of the total amount of concentrate used. According to practices in other countries, the proportion of recycled lead sludge that can be used can reach up to 44%. Currently, the achieved performance indicators are: lead recovery rate > 98%, and sulfur recovery rate of over 97%. All environmental protection indicators meet or exceed the ** standards; wastewater is discharged in compliance with regulations, and the levels of dust and lead dust in the workshops are below the ** specified limits. In particular, the SO2 content in the exhaust gases is only 14 MG/M3, which is far lower than the ** standard of 960 MG/M3. In order to improve the utilization rate of recycled resources, expand the scale of the recycled lead industry, increase the level of automation, and promote healthy development of this industry, it plans to cooperate with the Italian company Angitec to develop and introduce its CX integrated system, utilizing pollution-free pretreatment technology. With the development and introduction of preprocessing facilities, fully enclosed and pollution-free preprocessing will be achieved, along with fully automated production, which will further improve this manufacturing process. Process characteristics and advantages: (1) Low investment cost, 70% of that of traditional processes, and less than 50% of that of imported processes ； The main advantage is that it allows for the rational use of the existing infrastructure from the original lead industry; for example, the acidic waste generated during the disassembly of used batteries can be directly fed into the existing wastewater treatment plants to be processed and discharged in compliance with regulations ； No need to rebuild. In addition, existing smelting equipment and their environmental protection facilities can be used to jointly treat lead sludge, etc.; the technical and equipment level is high, and no separate supporting projects are required. (2) Low comprehensive energy consumption ； Melting lead sludge and other lead waste together with concentrate enables full utilization of the self-heating effect of sulfur in the lead concentrate; it not only improves the grade of the concentrate but also serves to adjust the composition of the material being melted. This represents a beneficial supplement to the original processing method, resulting in reduced overall energy consumption compared to handling these materials separately. (3) Good environmental protection effects (the comprehensive utilization rate of sulfur reaches 99%) ； Thanks to co-smelting, it is possible to make use of the existing exhaust gas acid production systems, waste acid treatment systems, and workshop dust removal systems from the original production facilities. As a result, environmental protection measures are no longer a constraint on the development of recycled lead, and good environmental outcomes have been achieved. Actual measurements show that SO2 emissions are only 14 MG/M3, which is far below the standard (850 MG/M3). < P> (4) The processing cost of recycled lead is low; it is possible to share a large number of public facilities for environmental protection and other purposes, thereby saving on investments ； And it reduces many administrative costs and material consumption, among other things. (5) High resource utilization rate ； Classify after preprocessing to improve resource utilization. The smelting process is advanced, resulting in a high metal recovery rate (of 98% to 98.5%), which improves the recycling efficiency of lead ； Byproducts such as grid structures are directly used to produce lead-zinc alloys and similar products, thereby increasing the added value of these products ； The plastic and partition parts are sold or remelted into plastic pellets for sale, thereby reducing secondary pollution and similar issues. (6) In line with **policies for a circular economy ； For primary lead production, it reduces the pressure associated with raw material procurement, decreases the amount of primary lead ore that needs to be mined, extends the period during which such mining can take place, and thus helps to preserve these valuable natural resources ； It also reduces the environmental pollution caused by lead waste and the waste of resources, enabling lead metal to enter a virtuous cycle of production-consumption-recycling, in line with the policies of a **circular economy. Developing the recycled lead industry using a new technological approach not only helps to address issues such as small scale, high energy consumption, severe pollution, outdated industrial technologies, as well as low metal recovery and comprehensive utilization rates in this industry, but it also helps to solve some of the resource-related problems faced by the primary lead industry. It represents an excellent model for promoting a circular economy in the lead industry.