There are two main types of raw materials for the production of polyaluminium chloride(PAC): one is aluminous minerals, including bauxite (gibbsite, boehmite and diaspore), clay, kaolin and alunite; The other is other aluminum containing raw materials, including metal aluminum, scrap aluminum, ash aluminum, aluminum hydroxide, aluminum trichloride, coal gangue, fly ash, etc. Only with aluminum ingot, aluminum scrap and aluminum hydroxide as raw materials and aluminum sulfate and aluminum dichloride as raw materials can pure polyaluminium chloride products be produced.
The raw materials used in the production of polyaluminium chloride in China are mainly the development and utilization of their own mineral resources according to local conditions. The production of polyaluminium chloride in China started with aluminum ash as raw material. Due to the low cost of aluminum ash raw materials and simple production process, its production process was rapidly popularized in China in the 1970s. However, polyaluminium chloride produced by aluminum ash has many impurities, and it is no longer used for the purification of tap water after the 1980s. In the early 1980s, the raw materials for the production of polyaluminium chloride were mainly polyaluminium chloride products produced from clay ore, kaolin ore and bauxite. Except iron, other indicators could reach the advanced level abroad. However, due to the large amount of slag, poor appearance and the rapid development of China’s aluminum industry, the raw materials used in the production of polyaluminium chloride in China have gradually turned to aluminum hydroxide in the early 1990s. In addition, some production plants use aluminum chloride and metal aluminum as raw materials.
Because the iron content of domestic synthetic hydrochloric acid is higher than that of Japan and other countries, the appearance and color of polyaluminium chloride produced is yellow.