明确制盐企业存在的职业病危害因素，为制盐企业提供职业病防制对策。

To define the occupational hazards which exist in salt-producing enterprise and to offer occupational diseases preventing countermeasure to them.

卤水净化是真空制盐的一个重要生产环节。

Brine purifying is very important to productions of the vacuum salt.

利用自制的新型离子交换剂从制盐母液中直接提取铯和铷。

A new method for direct extracting ce and Ru from mother liquor of bittern by ion exchange is introduced.

本文应用传热学的理论知识，分析了真空蒸发制盐的加热室的传热机理。

This paper analyzed the mechanism of heat transferring with applications of the calorifics.

历史：自贡的历史和盐业密不可分。自贡也因其1900年的制盐历史而成为历史名城。

History: the history of Zigong is tightly connected with salt industry and the city is well-known for its 1,900 years of salt manufacturing history.