Method for simultaneously producing sodium aluminofluoride and silica white

Abstract

The method for producing ice spar and coproducing white carbon black includes the following steps: (1) adding ice mother and ammonia water in water to prepare dilute ammonia water, making fluorosilicic acid solution react with dilute ammonia water to obtain white carbon black crystal seed, controlling pH value of white carbon black in 6-8 and reaction temp. at 30-40 deg.C; (2). adding a certain quantity of white carbon black crystal seed into ammonolysis cell, in which the added quantity of crystal seed can be regulated according to the requirements, adding proper quantity of ice mother, in the presence of crystal seed making sodium fluorosilicate and ammonia water implement ammonolysis reaction at about 60 deg.C to obtain white carbon black slurry, filtering and washing to obtain white carbon black ointment, drying to obtain its finished product; (3). providing the steps for obtain ice spar product.

Description

technical field [0001] The invention relates to a method for producing cryolite and co-producing white carbon black. Background technique [0002] The chemical name of cryolite is sodium fluoroaluminate, and the molecular formula is Na 3 AlF 6 , It is mainly used in industry as a flux for aluminum smelting, in the silicate industry as an opalescent agent for glass and enamel, and in agriculture as a pesticide. The main raw material used in the aluminum smelting industry in the world is cryolite . The traditional production process of cryolite is the soda ash-fluoroaluminic acid method. First, hydrofluoric acid and aluminum hydroxide react to form fluoroaluminic acid, and then react with soda ash to form cryolite. The chemical reaction formula is as follows: [0003] <chemistry num="001"> <chem file="03118447_cml001.xml" / > < / chemistry> [0004] <chemistry num="002"> <chem file="03118447_cml002.xml" / > < / chemistry> [0005] The o...

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Problems solved by technology

The disadvantages of this process are: due to the high temperature required for the reaction, the reaction of synthesizing fluoroaluminic acid is violent, the operation is not easy to control, and accidents of leaking tanks and hurting people are prone to occur; and because the entire production is carried out under acidic conditions, and The temperature is high, the equipment is severely corroded, and acid waste residue is produced, polluting the environment

[0011] The disadvantages of this process are: (1) using sodium fluorosilicate and dilute ammonia water to react white carbon black seed crystals, since sodium fluorosilicate is a solid phase, the reaction is not complete, and the content of sodium ions in the prepared seed crystals Larger, poor seed crystal quality, and there are solid particles, poor transparency, whitish color

(2) The white carbon black slurry obtained by using sodium fluorosilicate to make seed crystals has more crystals of sodium fluoride, which is inconvenient for washing and separation, which greatly affects the purity of white carbon black

(3) The prepared cryolite molecules are relatively high, generally above 2.8, and cannot be adjusted downwards, so they can only be used in the slotting stage of electrolytic aluminum production

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