PAC Flocculant is a chemical with excellent performance, which is widely used in water treatment, such as drinking water treatment, paper making industry, wastewater treatment and so on. Do you know how the PAC is obtained? In this article, we will talk about this issue.
For the application of PAC, refer to: Poly Aluminum Chloride: A Great Option for Water Treatment
Polyaluminum Chloride, also known as PAC, is an important inorganic polymer flocculant. Its raw material sources are wide and diversified, mainly including aluminum-bearing minerals and industrial waste. The following is a detailed explanation of the sources of these two types of raw materials:
Aluminum-bearing minerals
Aluminum-bearing minerals are one of the main raw materials for PAC production, and these minerals are rich in aluminum, which can be converted into PAC by proper process treatment. Common aluminum-bearing minerals include:
- Bauxite: This is an earth-like mineral containing aluminum hydrate, the main minerals of which are gibbsite, boehmite, diaspore or a mixture of these hydrates, and is one of the important raw materials for the PAC production.
| Substance | Distribution in China | Feature |
| Gibbsite | Fujian, Hainan Island, Taiwan | The method is characterized by short flow and low energy consumption |
| Boehmite | Guangyuan City, Sichuan | It is an excellent raw material for the production of PAC and aluminum sulfate |
| Diaspore | Widely distributed | Due to its complex process flow, it cannot be directly used for PAC production at present. It is mainly used in the production of alumina, cement and refractory materials |
- Clay and kaolin: Clay and kaolin deposits are abundant in almost all of China. Clay and kaolin generally have less than 80% alumina dissolution rate after roasting in the acid, although the alumina content is not high, it is still a good raw material for producing PAC.
- Alunite: There are rich alunite resources in China, such as in Zhejiang, Anhui, Fujian and other places. Alunite is a mineral with high utilization value, which can be synthesized into PAC while extracting alumina, sulfuric acid and potassium salt.
- Nepheline: The Al2O3 content of nepheline is about 30%. PAC can be produced by sintering method, and its byproducts are soda ash or potassium alkali.
- Other substances containing aluminum: Artificially produced aluminum-containing raw materials are also a source of PAC, including aluminum hydroxide and calcium aluminate. Aluminum hydroxide is prepared from bauxite by the Bayer process or sintering process. While, the process of calcium aluminate powder is mainly made of high bauxite and limestone after crushing and drying, ball grinding, and sintering under the action of high temperature in rotary kiln. Aluminum hydroxide and calcium aluminate with high purity are used to produce PAC for drinking water treatment and daily chemical use.
Industrial waste
The use of industrial waste as raw materials for PAC not only realizes the recycling of resources, but also reduces environmental pollution. Common raw materials for industrial waste include:
- Aluminum ash: Aluminum ash is the slag produced when electrolytic aluminum, aluminum and aluminum alloys are dissolved and aluminum scrap is refined and recovered. Among them, the aluminum ash produced by industrial pure aluminum is pure aluminum ash, and the content of other metals is extremely small, which is the main raw material for the PAC production. The aluminum ash produced by aluminum alloy containing small amounts of beryllium should be prohibited because of its high toxicity.
- Coal gangue and flyash: Coal gangue is the waste from the coal mining process, and flyash is the ember of the coal containing aluminum minerals. The content of Al2O3 in both varies with the source of the mine, generally between 10%-30%. The Al2O3 content of coal gangue clinker in some areas is more than 40%, which is suitable for comprehensive utilization to produce PAC.
- In addition, there are many sources of PAC production, such as alumina waste from aluminum oxide plants and electrolytic aluminum plants, chemical metallurgical products, aluminum trichloride and aluminum sulfate.
It should be noted that industrial waste is only used to produce industrial grade PAC, mainly for wastewater treatment.
It can be seen that the raw materials of PAC are widely and diversified, including natural resources such as bauxite, clay, kaolin, alunite and nepheline, as well as industrial wastes such as aluminum ash, coal gangue and flyash. The full use of these raw materials not only reduces the production cost, but also realizes the recycling of resources and environmental protection. If you are interested in polyaluminum chloride, please feel free to contact us.