4.23.2.1 Present State of Production

Ninety per cent of bentonite produced by China is Ca-base bentonite. Mining includes open-pit mining and underground mining. The development haulage of open-pit mining is generally by motorable haul roads, especially for newly built mines; the development haulage of underground mining depends on the types of development openings, and usually development by the inclined shaft is used. The dressing methods include the dry and wet ones. Dry dressing is used to treat good-quality raw bentonite and the procedure includes raw sand drying in the sun, natural air drying or drying on the hot floor, crushing, grinding and gradation.

(1) Main products

According to the processing methods and uses, bentonite may be divided into purified clay, modified clay, organic clay and activated clay.

(2) Production capacity

Now there are more than 100 bentonite productive mines and processing enterprises, but they are generally small in scale. The mining enterprises that produce more than 10,000 tons of bentonite yearly are the Lin'an bentonite mine, Qiushan bentonite mine and Linglong bentonite mine in Zhejiang Province, the Heishan bentonite mine and Lingyuan bentonite mine in Liaoning Province, the Jiutai bentonite mine and Shiping bentonite mine in Jilin Province, the Jinchang bentonite mine in Gansu Province, the No. 184 Regiment bentonite mine in Xinjiang, and the E'zhou bentonite mine and Zaoyang bentonite mine in Hubei Province. China has an annual bentonite production capacity of more than 2 million tons.

(3) Production

More than 40 countries produce bentonite in the world with an average annual production of over 90 million tons. The major producers are the United States, the former USSR, India, Greece and Japan. These countries yield about 3/4 of the world's annual output. Of these countries, the United States is first in the production and the former USSR ranks second. In 1977 China's bentonite production was about 1.60 million tons (the figure comes from the Chinese Nonmetallic Minerals Industry Association), of which bentonite powder was about 1.40 million tons, and modified clay, activated clay and organic clay were about 200,000 tons.

Table 4.23.1 Major bentonite production enterprises in China

4.23.2.2 Distribution of Production

The distribution of major bentonite production enterprises of China is shown in Fig. 4.23.2 and Table 4.23.1. As shown in the map, the producing areas of bentonite in China are concentrated in Zhejiang, Jilin, Liaoning, Hubei, Hebei, Henan and Anhui provinces and the Xinjiang Uygur Autonomous Region.