3.15.2.1 Production

At the beginning of the 1950s, China's mercury industry focused on the taking-over of some mercury mines left over by China before 1949 and the restoration and expansion of their production. From 1950 to 1952, some concerned departments took over the Wanshan, Dadongci, Danzhai and Wuchuan mercury mines in Guizhou and the Huangxian mercury mine in Hunan, and resumed the production of and renovated and extended the mines. The country's total mercury production was only 3 tons in 1950, rapidly increased to 52 tons in 1951, and hit 108 tons in 1952 when 5 mercury producers (the Wanshan, Tongren, Danzhai, Wuchuan and Huangxian mines) were put into operation. Thereafter, on the basis of large-scale geological prospecting in Guizhou, Yunnan, Sichuan, Shaanxi, Guangxi and Guangdong, the above-mentioned mines were expanded or renovated, a series of pitheads, ore dressing and smelting plants newly constructed, and some new mines were built in certain provinces or autonomous regions, causing a fast growth in the mercury production of China. From the end of the 1950s to the mid-1960s, China's mercury industry reached its acme. The country's mercury production hit 2,684 tons in 1959, a record high, and stood at 2,362 tons in 1960. In this period, the production of the mercury mines in Wanshan, Guizhou increased to 1,260 tons, accounting for 40£¥~60% of the country's total for a long time, while that of the mercury mines in Danzhai of the same province made up about 30% of the total. From the late 1950s to the early 1960s, China's mercury production constituted about 35% of the world's total. In 1959~1961, its mercury production stayed at more than 2,000 tons. Since 1964, due to the constraints of the market conditions, the country's production fell a bit but still remained at about 1,000 tons. The mercury production of the mines in Wanshan, Guizhan, although relatively low during the chaotic years (1966~1976), was basically stabilized at about 450 tons in other years; that of the mercury mines at Tongren and Danzhai was annually kept at around 150 tons. The annual production of the Xinhuang mercury mine (i.e. the Huangxian mercury mine called before 1958) stood at over 100 tons before 1973, gradually dropped since 1974, and was only 30 tons in 1981; that of the Wuchuan mercury mine stayed at around 50 tons; and that of the other small and local people-mined mercury deposits totalled about 100 tons.

As for cinnabar, in 1950, only one mercury mine in Guizhou produced it (over 8 tons per year). In 1952 the Huangxian and Tongren mines of the same province became the cinnabar producers, and in 1955 the Dazhai mercury mine joined them in producing the material. Their total annual production exceeded 100 tons in 1958. In the year 1962, the country's cinnabar production began to drop. This production stood at 40~80 tons during the period 1962~1970, picked up to 109 tons in 1971, rose again to 141 ton in 1972, but slightly declined in 1974. The cinnabar production of the mercury mines in Guizhou started to increase in 1978, causing a steady growth of the country's total in three consecutive years. In 1980, the country's total cinnabar production reached 246 tons, a historical peak. Since then, it has been stabilized at 130~260 tons.

In recent years, China's mercury production has had a tendency to decline. The reasons are as follows. Firstly, because of the serious environmental pollution caused by the mercury ore mining, dressing and smelting, many countries tightened their production and use of mercury, leading to a drastic drop in mercury demand and a decline in mercury price on the international market. Therefore it was unsuitable to export the substance in large quantities. Secondly, China's mercury mines, mostly constructed and put into operation in the 1950s~1960s, have now entered their late stage of mining, and some have even been closed or stopped their production because of the difficulty in selling their products, thus resulting in the year-by-year decrease in the productive capacity and production. For instance, the comprehensive ore mining-dressing-smelting capacity was 930 tons in 1990, 760 tons in 1991, and dropped to 600 tons in 1996; while the mercury production stood at 930 tons in 1990, 768 tons in 1991, and decreased to 508 tons in 1996 but somewhat rose again in 1997. Tables 3.15.2 and 3.15.3 show the mercury metal production and the technical economic criteria, respectively.

3.15.2.2 Distribution of Production

As of the 1990s, China has had a total of 11 major Hg-producing enterprises (excluding township enterprises), of which 1 produces by-product mercury and 2 recover waste mercury. The country's integrated mercury ore mining-dressing-smelting capacity has been at 900 t/a, its ore mining-dressing capacity at 1,200 t/a (mercury metal), and its ore smelting capacity at 860 t/a (primary mercury). Enterprises annually producing over 100 tons of mercury have been the Guizhou, Wuchuan and Tongren mercury mines.

According to the mercury resources distribution and constructional conditions of China, the 11 State-owned mercury-producing enterprises are sited mainly in the southwest, northwest and south-central parts of the country. Their names and locations are as follows: in the southwest part are the Guizhou Hg mine (in the Wanshan Special Economic Zone of Guizhou Province), the Wuchuan Hg mine (in the Daping area, Wuchuan County, Guizhou Province), the Tongren Hg mine (in Tongren County, Guizhou Province), the Danzhai Hg mine (dealing chiefly with the recovery of waste mercury; in Danzhai County, Guizhou Province), the Huangping Hg mine (in Huangping County, Guizhou Province), the Xikou Hg mine (in Xiushan County, Sichuan Province), and the Youyang Hg mine (in Youyang County, Sichuan Province); in the northwest part are the Xunyang Hg mine (in Xunyang County, Shaanxi Province) and the Tongde Hg mine (in Tongde County, Qinghai Province); in the south-central part are the Xinhuang Hg mine (dealing mainly with the recovery of recycled mercury; at Jiudiantang, Xinhuang County, Hunan Province) and the by-product enterprise of the Shaoguan smelter (in Shaoguan City, Guangdong Province).

Table 3.15.2 Mercury metal production of the whole country and its major Hg-producing provinces(t)

Table 3.15.3 Major technical economic criteria of mercury ore mining and dressing in the whole country

Since the 1980s, China has attached importance to the readjustment of the structure of mercury products. In the 1970s, its mercury products were confined to metal mercury and cinnabar, while now nearly 20 mercury products are being produced. Furthermore, some of its intensively processed products such as cinnabar, red mercury oxide, red mercury bromide and mercury chloride are being exported.