A production process for preparing polyaluminum chloride from strong acid aluminum-containing wastewater

Abstract

This patent discloses a production process for preparing polyaluminum chloride from strong acid aluminum-containing wastewater, including: (1) adding the strongly acidic aluminum chloride-containing wastewater to the reactor, adding sodium hydroxide solution, and stirring for reaction; (2) (3) Concentrate the obtained product to a certain mass ratio, and separate the liquid and solid A; (4) Dry the liquid to obtain a polyaluminum chloride product; (5) Add the solid A to the sodium hydroxide aqueous solution to adjust the pH, and filter Separating the liquid and aluminum hydroxide precipitation; (6) Drying the liquid in step (5) to obtain solid sodium chloride, dissolving the precipitate in step (5) with hydrochloric acid and recycling to step (1). This process features high raw material utilization rate, can effectively deal with the problem of strong acid aluminum-containing wastewater, reduce costs, and improve resource utilization efficiency; the product has high alumina content, which solves the problem of low alumina content in the preparation of polyaluminium chloride by adding alkali; production side effects The product is high-purity sodium chloride, no waste residue in the whole process, and no subsequent treatment is required.

Description

technical field [0001] The invention belongs to the technical field of water treatment, and relates to a preparation method of a polyaluminum chloride water treatment agent using strong acidic low-concentration aluminum chloride industrial wastewater as a raw material, which is characterized in that industrial aluminum-containing wastewater is added with alkali to prepare high salinity High-purity polyaluminum chloride. Background technique [0002] A large amount of wastewater is often produced in industrial production. The wastewater contains various metal ions, organic waste and is often accompanied by strong acid or strong alkali. With the gradual upgrading of national environmental protection policies, the requirements for the treatment of three wastes are becoming more and more stringent. Due to its large amount of treatment, industrial wastewater often costs a lot and causes waste of resources. Therefore, the efficient utilization and recycling of substances containe...

AI Technical Summary

Problems solved by technology

In the CN106186020A published patent, aluminum-containing raw materials are added to hydrochloric acid to obtain a polyaluminum chloride liquid with a basicity of 30-45% and a concentration of aluminum oxide of 10-14%, and then by adding calcium aluminate powder, chlorine Sodium acid and temperature and pressure to adjust the basicity method to obtain high basicity and high concentration of polyaluminum chloride, this method adjusts the aluminum concentration twice and needs to be heated and pressurized, the process is complicated, and the equipment and reaction conditions are proposed higher requirements

This process utilizes hydrogen chloride waste gas and aluminum brine waste liquid in the process of synthesizing anthraquinone, which saves capital investment in sewage treatment and achieves resource utilization. However, calcium aluminate powder is used as an alkaline regulator in this process, resulting in relatively high cost. High cost, dust pollution, and no quality control of calcium aluminate powder, resulting in the formation of calcium aluminate powder residue, resulting in secondary waste, and the utilization rate of waste needs to be improved

[0008] CN109678232A abandons calcium aluminate powder on the basis of previously disclosed patents, and proposes to use industrial waste alkali instead of calcium aluminate powder as a polymerization degree regulator, and uses a high-speed dispersion mechanism to homogenize the aluminum-containing mother liquor and adjust the polymerization degree to produce high aluminum High-basic polyaluminum chloride process, the high-speed homogeneous dispersion method invented by this process can effectively break and homogenize the aluminum slag when preparing the aluminum-containing mother liquor, and promote the white hydrogen generated by local over-alkali solidification The dissolution and polymerization of alumina precipitates in the solution can well control the precipitation during the polymerization process and take into account the dispersion strength. However, the high-speed homogeneous dispersion method used in this process has high requirements for equipment and energy consumption, and is aimed at If the processing volume is large, the corresponding dispersion time will be extended, and because high-strength dispersion has the ability to degrade and destroy polyaluminum chloride polymers, the requirements for specific high-speed dispersion speed and dispersion time are more stringent