Method of preparing low-calcium polymeric aluminum chloride water purifier from aluminum ash, hydrochloric acid, and optical red mud

Abstract

The invention provides a method of preparing a low-calcium polymeric aluminum chloride water purifier from aluminum ash, hydrochloric acid, and optical red mud. The preparation method comprises following steps: burning aluminum ash, calcium carbonate, and/or calcium oxide in an oxidative atmosphere; burning the obtained material, reacting the burned material with hydrochloric acid and optical redmud to prepare slurry containing polymeric aluminum chloride, adding sodium sulfate to carry out reactions; filtering the slurry, wherein the filtrate is the water purifier, washing the filter residues by water, and utilizing the obtained solid slag or stacking /burying the solid slag. A problem that when aluminum is hydrolyzed or acid-hydrolyzed, hydrogen is generated and the hydrogen is combustible and explosive is solved. A problem that when aluminum nitride is hydrolyzed, ammonia is generated and the water purified by the water purifier is polluted by ammonia nitrogen is solved. The low activity alumina, which comprises alpha-alumina, can be activated. The fluorine containing aluminum ash is stabilized and detoxicated. Moreover, a low-calcium polymeric aluminum chloride water purifierand a low-calcium polymeric ferric aluminum chloride water purifier are prepared, and the hardness of the processed water is barely increased, during the application process of the water purifier. Thetechnology is simple, the investment and operation cost is low, and the obtained solid slag is common solid wastes.

Description

Technical field [0001] The invention belongs to the technical field of non-ferrous metallurgy and environmental protection, and specifically relates to a method for preparing a polyaluminum chloride-containing low-calcium water purifier from aluminum ash, hydrochloric acid and optional red mud. Background technique [0002] Aluminum ash is an important solid waste in the aluminum industry. According to the source and the content of metal aluminum, it is generally divided into primary aluminum ash and secondary aluminum ash; in addition to metal aluminum, aluminum ash generally also contains sodium chloride, potassium chloride, Fluoride salts, alumina, aluminum nitride. The primary aluminum ash has a relatively high content of metallic aluminum, and the metallic aluminum is usually recovered by methods such as salt bath treatment. Secondary aluminum ash includes the residue after the metal aluminum is recovered from the primary aluminum ash, and its metal aluminum content is lowe...

AI Technical Summary

Problems solved by technology

Secondary aluminum ash has complex components and many impurities, so it is difficult to return to use after simple purification or treatment

[0008] 1. The hydrolysis of the contained metal aluminum or the reaction with hydrochloric acid to produce hydrogen gas requires higher requirements on the flame-proof and explosion-proof conditions of the equipment. Sometimes the combustion of hydrogen gas can be seen in the open reaction pool, and some often produce explosion sounds, which is a safety hazard. Hidden dangers, it is not easy to use low-cost FRP reaction vessels or reaction pools lined with FRP coatings; some aluminum ash also contains a small amount of cyanide, which may release extremely poisonous hydrogen cyanide gas in the early and middle stages of the reaction with hydrochloric acid , causing hidden dangers to the health and safety of operators, and when entering the water purifier product, it may cause the cyanide content of the purified water to exceed the standard;

[0009] 2. If the contained aluminum nitride is hydrolyzed to produce ammonia gas and ammonia water, it needs to be useful or can be sold. If the reservoir is blocked, it will affect the production of water purifiers. The preparation of ammonium chloride by hydrochloric acid absorption requires equipment investment and operating costs ; If it reacts with hydrochloric acid to generate ammonium chloride, it will not be easy to separate, and it will enter the water purifying agent to cause ammonium nitrogen problems, limiting the use of polyaluminum chloride water purifying agent;

[0010] 3. After water washing or pickling, the roasting of filter residue with calcium oxide and calcium carbonate activated alumina generally adopts a relatively high temperature of 1200-1400 ° C, and the equipment cost and energy consumption are high;

[0011] 4. The existing process usually requires two slurry reaction processes, two filtration and washing processes and a high-temperature roasting process for wet materials. In the two filtration and washing processes, the filter residue contains very fine solids, which are difficult to clean, and the filtration and washing are relatively slow. Difficult, consumes more fresh water, lower efficiency, needs to use leaf filter or plate-frame filter with higher pressure, cannot use high efficiency, fast speed, more fresh water consumption, less manual labor, less labor Vacuum belt filter with low strength and low operating cost; when the filter residue is sprayed with water, the finer parts are easy to lose and cause environmental pollution;

[0012] 5. The overall process is relatively complicated, the operating cost is high, the equipment investment is high, and the site and workshop area are large