A method for strengthening the species of supersaturated sodium aluminate solution

Abstract

The invention discloses a method for reinforcing seed decomposition of a supersaturated sodium aluminate solution. The supersaturated sodium aluminate solution is added to a seed decomposition tank, the initial temperature for seed decomposition is set, a crystal seed fluid is added while stirred, an additive is added, seed decomposition is performed with a cooling system, crystal seed decomposition is started, the end temperature for seed decomposition is controlled, solid-liquid separation is performed, and aluminum hydroxide is obtained; meanwhile, the additive is recovered in the seed decomposition and solid-liquid separation processes. The decomposition rate is high, the circulation efficiency and the equipment productivity are improved, and the circulation volume and the production cost are reduced; the additive is cheap and easy to obtain, and accordingly, the production cost is reduced; the additive is easy to separate in alkali, ammonia gas is easily absorbed by water, later recovery during decomposition is facilitated, on one hand, loss of the additive is reduced, influence on production of aluminum oxide is reduced, on the other hand, influence on the environment is reduced, recycling is facilitated, adding is convenient, the production cost is reduced, and production organization is facilitated; the technology is simple, and industrial implementation is facilitated.

Description

technical field [0001] The invention relates to the technical field of aluminum metallurgy, in particular to a method for strengthening the species of a supersaturated sodium aluminate solution. Background technique [0002] The supersaturated sodium aluminate solution has good metastability, and the addition of seed crystals can destroy its metastability, thereby promoting the precipitation of aluminum hydroxide from the sodium aluminate solution. This process is called seed crystal decomposition, also known as seed separation. The low decomposition rate of seeds has always been the crux of low equipment productivity and high production costs. For this reason, methods such as increasing the amount of seeds, adding organic additives, adding active crystal seeds, reducing the temperature at the end of seed classification, or adding external fields have been proposed successively at home and abroad. Among these methods, although some can increase the seeding rate, the rate of...

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Problems solved by technology

Chinese Patent Publication No. CN 101654272A, published on February 24, 2010, the name of the invention is a new method for the decomposition of sodium aluminate solution, adding 10 to 100% water, although the decomposition rate can be significantly improved, but a large amount of diluted solution will cause steam Consumption is significantly increased, and production organization is difficult; Chinese Patent Publication No. CN101746794A, published on June 23, 2010, the name of the invention is a method for preparing high caustic ratio sodium aluminate solution from a low caustic ratio sodium aluminate solution, Chinese Patent Publication No. CN 101234773A, published on August 6, 2008, the name of the invention is a method for producing aluminum hydroxide using sodium aluminate solution; Alumina methods, these patented technologies are to add a large amount of methanol and other alcohols in the seed separation process to change the solvent properties and significantly increase the decomposition rate, but the separation of methanol and sodium aluminate solution is difficult and costly, and it is also harmful to alumina production. will have a significant impact

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