With the rapid development of new energy, what should I do with lithium battery waste residue? New research by experts from the Academy of Communications Sciences: when building roads, it is used as a roadbed

Chengdu Business Daily Red Star News

2024-06-28 06:18Chengdu Business Daily Red Star News official account

With the vigorous development of the new energy industry, the discussion on the environmental protection of waste lithium batteries has been concerned. In fact, a large amount of lithium slag will be produced in the production of lithium carbonate, the raw material of lithium batteries, which will also have an impact on the environment, and the problem of lithium slag treatment has also become one of the troubles that plague the development of the lithium battery industry.

In the pilot work of building a transportation power, the Academy of Science of the Ministry of Transport (hereinafter referred to as the Academy of Communications Sciences) has undertaken such a pilot task: the research and development and industrial application of solid waste resource utilization technology, including the research on the use of waste lithium slag for road construction. Dr. Cheng Yin of the Engineering Technology and Materials Research Center of the Academy of Communications told Red Star News that this research has been applied in Jiangxi Province, and local standards have also been introduced, and the future prospects are very good.

▲ Lithium slag roadbed application test section in Jiangxi Courtesy of the Academy of Communications Sciences

Recently, the Red Star News reporter participated in the theme interview activity of "Accelerating the Construction of a Transportation Power", and walked into the Research Institute of the Ministry of Transport to understand the progress of the pilot work of building a transportation power.

Solid waste is increasing

It is a win-win situation for building roadbeds

Zhou Xiaohang, President of the Academy of Communications Sciences, introduced that in July 2021, the Ministry of Transport agreed that the Academy of Transportation Sciences would carry out the pilot work of building a transportation power, including 7 pilot tasks, and the R&D and industrial application of solid waste resource utilization technology is one of them. At present, solid waste materials have been successfully applied in the construction of highway projects in more than 10 provinces and autonomous regions across the country, with a cumulative mileage of more than 100 kilometers of highways, a total of 4.8 million tons of industrial solid waste, and 11,000 tons of carbon emission reduction.

Cheng Yin told Red Star News that cement building materials were originally the largest path for solid waste utilization, accounting for about 70%. However, the high energy consumption and high carbon emissions of the cement industry, coupled with the restrictions of the new national standard, are reducing the use of solid waste, while the amount of industrial solid waste has been increasing, and the stock is increasing. On the other hand, transportation construction uses a large amount of earthwork and river sand, and in recent years, environmental protection requirements have become more and more stringent, resulting in higher and higher costs of river sand and earthwork. "If something is used in the wrong place, it is waste, and if it is used well, it is a resource, and this principle is very appropriate for our solid waste research."

▲Schematic diagram of lithium slag roadbed project

Cheng Yin introduced that solid waste is used as roadbed materials, which reduces the cost of ordinary materials by 30%~50%, and the cost of pile foundations, high-grade concrete and other materials by 70%~80%. Although it accounts for less than 1% of the roadbed use now, it will definitely increase in the future.

In industrial solid waste, lithium slag is a special existence. With the development of the new energy industry in recent years, the amount of lithium slag produced by the manufacture of new energy batteries has also increased significantly. According to the data, in Yichun, Jiangxi, the "lithium capital of Asia", it is estimated that the future mining scale of china clay (containing lithium) will be 75 million tons, and the annual production of lithium slag is expected to exceed 10 million tons. Cheng Yin said that for each lithium battery produced, the amount of slag produced is 200 to 500 times that of lithium electricity, and the number of these toxic lithium slags is very large, if it cannot be solved, it will restrict the development of the lithium battery industry. After being used as a road subgrade through harmless treatment, it is a suitable path with good effect and large consumption.

Waste residue is used as a roadbed

Can environmental protection be met?

In May this year, Jiangxi issued the "Technical Specifications for the Utilization of Lithium Slag in Highway Subgrade Engineering (Trial)", and the Academy of Communications Science and Technology was one of the drafting units.

In this local standard, there is a lot of space to regulate environmental standards. For example, it is stipulated that "lithium slag that has been identified as hazardous waste is strictly prohibited from being used for roadbed filling." Lithium slag belonging to general industrial solid waste can only be used for highway embankment filling after modification, and shall not be used for highway bed filling. It also requires that modified lithium slag roadbed sections shall not be selected in ecological protection red line areas, permanent basic farmland concentration areas and other areas that need special protection, and also stipulates detailed standards and requirements for testing groundwater, surface water and soil in road sections.

Cheng Yin said that environmental issues have been on their minds, and solid waste will be treated harmlessly before being used on the road. The Chinese Academy of Communications Sciences, together with the Solid Waste Center of the Ministry of Ecology and Environment and the Chinese Academy of Environmental Sciences, completed the long-term monitoring and evaluation of the land, water bodies and rivers around the relevant roads.

"We have paved a test section of the lithium slag road subgrade in Jiangxi, which has been running for more than two years, and there are no problems in terms of performance and environment. This year, Jiangxi also issued local standards, hoping to provide a solution to the stockpiled lithium slag. Cheng Yin said.

Jiangxi Yichun release

Development plan for the comprehensive utilization of lithium slag building materials

According to public data, Yichun, Jiangxi, known as the "lithium capital of Asia", has proven available lithium oxide reserves of 2.58 million tons, accounting for 23.8% of the country's lithium resources; The proven mineable lithium oxide reserves are 1.1 million tons, accounting for 31% of the country and 12% of the world. CATL and Guoxuan Hi-Tech, two leading power battery companies, have settled here.

Yichun mentioned in the "Development Plan for the Comprehensive Utilization of Lithium Slag Building Materials (2024~2030)" released this year that it is expected that about 10 million tons of lithium slag will be produced in the city in 2024 and about 13.5 million tons of lithium slag in 2025. "In 2023, Yichun will produce about 7 million tons of lithium slag, with a stockpile of more than 5 million tons, with lithium slag stockpiling accounting for 71.4% and a comprehensive utilization rate of less than 30%.

In 2023, the Yichun Municipal Bureau of Industry and Information Technology replied to the suggestions of the National People's Congress, mentioning that "in conjunction with the Research Institute of the Ministry of Transport and Tongji University, we have developed the application technology of lithium slag to directly replace earthwork filling roadbed and apply large amount to pavement base." ”

The experimental road mentioned by Cheng Yin is also highly valued in the local area, and the relevant person in charge has visited it many times. At the end of 2022, Yu Xiuming, then secretary of the Yichun Municipal Party Committee, went to the site to investigate and asked to ensure that safety and environmental protection requirements were met. He also pointed out in the subsequent discussion that "the pace of consumption and treatment in the city has not kept up with the rapid growth of tailings lithium slag production, and great efforts must be made to promote it." ”

In addition, the "Development Plan for the Comprehensive Utilization of Lithium Slag Building Materials (2024~2030)" mentioned in the key development direction part that it is necessary to make every effort to promote the large-scale application of lithium slag in municipal, water conservancy, road and other engineering fields. 

Red Star News reporter Fu Yao and intern reporter Liu Yaya

Editor: Zhang Li, Editor: Feng Lingling

View original image 759K

• 

•