Bentonite, a naturally occurring clay mineral, has become an essential material in various industries, particularly in construction and environmental protection. According to recent data, China is home to over 200 domestic bentonite processing companies, most of which are small or medium-sized enterprises. There are more than 20 mining operations that produce over 10,000 tons annually, with total output reaching approximately 200–210 million tons. The industry has a production capacity exceeding 3 million tons, primarily focused on basic processing products. Provinces such as Liaoning, Hebei, and Zhejiang have the largest production capacities.
In terms of output, China produces about 1.6–1.7 million tons of raw bentonite ore or coarse powder each year. Meanwhile, deep-processed products—such as synthetic sodium-calcium bentonite, activated clay, and organic bentonite—account for around 300,000 to 400,000 tons. Major production centers include Zhejiang, Jilin, Liaoning, Xinjiang, Hebei, Henan, Hubei, and Anhui.
Traditionally, waterproofing methods in China have not been very effective. Although developed countries use high-performance bentonite-based waterproof materials, these are rarely adopted in China due to their high cost. In recent years, they have only been used in a few foreign-invested projects. However, with the localization of bentonite waterproof blankets, prices have dropped to about one-third of imported alternatives, leading to increased adoption across many Chinese projects.
Bentonite waterproof blankets are now widely used in municipal, environmental, water, road, railway, landfill, and hydraulic engineering projects. They also play a key role in underground structures, such as landfills, sewage treatment plants, and industrial and civil buildings. Their excellent anti-seepage and reinforcement properties make them ideal for applications like irrigation channels, dam reinforcement, and subway waterproofing.
Despite the growing demand, China lacks a specific standard for bentonite waterproof blankets. Most manufacturers follow American ASTM or Korean standards. For example, some Sino-Korean joint ventures adhere strictly to Korean specifications, requiring natural sodium-based bentonite. The ASTM D5890 standard requires a swelling index of over 24, but no clear guidelines exist for raw materials in China. Key technical parameters should include the type of bentonite, montmorillonite content, water absorption rate, and swelling index.
Geotextiles used in bentonite waterproof blankets are subject to various international standards, and China has issued several related regulations in recent years. However, there are still gaps in the requirements for raw materials. Domestic manufacturers often use either natural or artificially sodium-treated calcium-based bentonite. While artificial sodium treatment is simple—adding sodium carbonate and mixing with water—it can result in shorter service life. Some experts warn that such materials may not pass long-term aging tests.
Many natural sodium-based bentonites in China do not meet the required expansion index of over 24. To improve quality, high-grade ore must be selected, impurities removed, and re-sodium treatment applied if possible. Adding organic polymers can enhance the expansion coefficient, though it increases costs. Some research institutes, like the Xianyang Non-Metallic Research and Design Institute, have successfully boosted the expansion ratio beyond 100 times, though this is more suitable for specialized applications.
The production process of bentonite waterproof blankets is relatively straightforward, but it requires specialized equipment, especially for raw material treatment. Currently, no dedicated production lines exist in China, so most manufacturers import fully automated systems from abroad. Some have developed their own, and auxiliary materials like waterproof powder, slurry bentonite, and waterproof strips are also produced alongside the main product.
China’s bentonite resources are abundant, with a wide variety and several high-quality types. It does not need to rely heavily on imports. For instance, the bentonite from Xiazi Street in Xinjiang is comparable to Wyoming soil in the U.S. However, the gap in product quality compared to foreign counterparts remains significant, mainly due to limitations in purification and deep-processing technology. As new applications continue to emerge, the market potential for bentonite waterproof blankets is vast. With growing awareness and technological advancements, the usage of these materials is expected to expand significantly in the future.
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