4.19.3.1 Availability and Consumption

On the whole, limestone resources of China can meet the needs of production. Some areas, however, are deficient in limestone resources, including coastal areas such as the Bohai Bay area, coastal area of Jiangsu, southeastern Zhejiang, southeastern Fujian, eastern Guangdong and southeastern Hainan; and inland areas such as central Inner Mongolia, eastern Jilin, western Jiangxi and northern Shaanxi. Consequently, some old cement plants in these areas are in bad need of limestone resources, for example the Jiangshan Cement Plant of Zhejiang and Mudanjiang Cement Plant of Heilongjiang.

Limestone ores produced in China are mainly supplied to internal markets. Only minor amounts of them are exported and the exports have been fluctuated and even decreased in recent years. The export of 1996 was 31.53% lower than that of 1995 and the export of 1997 was 41.87% lower than that of 1996. Table 4.19.2 shows the import and export of limestone ores from 1994 to 1997.

4.19.3.2 Trends

Limestone is one of the superior mineral resources of China and has abundant retained reserves, which can fully satisfy the needs of national production and construction until 2010. With the development of the cement industry, iron and steel industry, light industry and architectural engineering, limestone will become more and more important. Because high-grade limestone is necessary for some industrial sectors but may not be necessary for others, the production of limestone mines of China has to be planned rationally to make full use of limestone resources, so that the utilization ratio of resources and economic benefit of mines can be further increased.     

Controlling pollution and improving environment are arduous tasks to be completed in the sustainable development of the Chinese cement industry. The cement industry has now become one of the major pollution sources in China and it may discharge more than 10 million tons of smokes and dusts every year. To solve this problem, restructuring should be implemented to eliminate a group of small enterprises that employ backward technologies, waste resources and pollute environment and have dim prospects.     

With the rapid development of the new-type dry cement-producing technology, inclu-ding mainly the suspension type preheating and precalcining technology, more and more up-to-date high technologies will be lent to the entire cement production to save energy, lower costs and yield high-grade products, and meanwhile cement production will become a "clean process" by using the bag filter installation and electrical dust collection. Moreover, the pre-cal-

Table 4.19.1 Major limestone mines and enterprise in China

Table 4.19.2 Import and export trade of limestone in China (1994~1997)

cining technology will lessen the content of harmful gases, such as nitrogen oxides (NO_x) and sulfur dioxide (SO₂), and make use of wastes of other industrial production. Moreover, the precalcining kiln is an ideal device for disinfecting wastes of chemical and medical industries. The new-type cement industry, with the dry production technology as a representative, will cooperate most likely with other industrial sectors to solve problems aroused from social environment and ecological balance in order to accomplish the sustainable development of economy.