(一)引言过去十多年来,随着全世界食盐生产的不断增长,国外主要井矿盐生产国家在发展钻井水溶法的同时;井下旱采岩盐,仍获得一定的发展,产量也有较大的增长。岩盐井下旱采获得一定发展的主要原因,除了工业上对高质量的固体岩盐的需要不断增加,以及一些岩盐矿床具有含盐品位高,埋藏浅,交通便利等适于干式作业的良好条件外,还由于北美、北欧等冬季严寒地区,近十多年来,每年耗用大量食盐溶化道路积雪和防冻。而此项用盐,几乎全部取之于岩盐,因而促使一些国家的岩盐产量急剧上升。如美国全国消耗于道路溶雪用盐,自1940年至1971年约30年间,每五年翻一番,1971年达7.9百万吨。加拿大在1954年耗用于此项用盐,不到10万吨,而1971年达2.2百万吨。英国帝国化学公司扩 (1) Introduction Over the past decade, with the continuous growth of salt production in the world, major well and salt producing countries in foreign countries have not only developed the water-soluble drilling law, but also have made some progress in the production of rock salt in underground dry mining, growth of. In addition to the increasing demand for high quality solid rock salt in industry, some rock salt deposits have good conditions for dry operation such as high salt content, shallow burial, and convenient transportation. , But also because of North America, northern Europe and other winter cold areas, the past 10 years, each year consume a large amount of salt melting road snow and frost. The use of salt, almost exclusively from rock salt, led to a sharp rise in rock salt production in some countries. For example, the United States consumes salt for road melting snow throughout the country, doubling every five years from 1940 to 1971 and 7.9 million tons in 1971. Canada consumed the salt in 1954, less than 100,000 tons, compared with 2.2 million tons in 1971. British Imperial Chemical Company expansion