SU933639A1 - Process for producing calcium hydroaluminate - Google Patents

Description

{

The invention relates to methods for producing calcium hydroaluminates obtained from aluminate solutions in the complex processing of nepheline ores and bauxites.

A known method for the preparation of calcium hydroaluminates by reacting an alumina gel with calcium hydroxide Ll.

The closest to the invention in its technical essence and the achieved result is a method for producing calcium hydroaluminate, including treating the aluminate solution with a reagent containing calcium oxide, followed by slurry separation, washing and heat treatment of the fZ precipitate.

The disadvantage of this method is that it does not provide a high yield of half-sodium calcium hydroaluminate containing 9.8-99% of the main product.

The purpose of the invention is the generation of calcium hydroaluminate.

The goal is achieved by the fact that in the method of producing calcium hydroaliminate, including C) processing a solution of an agadash solution with calcium oxide with a subsequent pulp separation, washing and heat treatment of the precipitate, the solution is calcium sucrose solution, which is treated with a weight solution the ratios of saharat calcium to aluminate oxide, equal to 0.75-0.8, and also the fact that the solution of saharaty calcium is obtained by treating calcium oxide with a solution of sucrose with a weight ratio of enii calcium oxide to sucrose, equal to 1.031, and a temperature of 1 25-9 C, followed by exposure and separation of the pulp to obtain a clarified solution.

The essence of the invention is as follows.

High silica limes are calcined at 900–1100 ° C. After calcining, lime is treated with a 10-60% sucrose solution, having a composition with a weight ratio of 1.031, 1. The study established that sucrose interacts only with calcium oxide by the reaction

(V,

with the formation of an aqueous solution of calcium saharat and a solid precipitate containing products of incomplete decomposition of limestone. The impurities are separated from the sucrose solution by settling or filtration and sent to the turnover for calcining. The clarification solution containing calcium sucrose is a calcium reagent for preparing calcium aluminate calcium by the reaction | (C H, A1., Oz + 6H O.

four

3 CaO-A1.0z 6H (H, (Ma. ,,

The obtained tricalcium hydroaluminate is then subjected to heat treatment at 250-4 ° C to obtain the dehydrated TCAO-Al O 1 compound.

The resulting half-water hydra & Calcium luminate contains 95-98% of the main product.

It should be noted that the weight ratio of Calcium Sugar to Alumina, equal to 0.75-0.8, ensures complete binding of calcium ions to tricalcium hydroaluminate; a weight ratio of calcium oxide to sucrose equal to 1.03-1.1 and a temperature limit of 25-95 ° C provides a pure solution of calcium sucrose, and at a temperature less than 25 ° C the yield of the latter decreases, and at a temperature greater than economy is impractical.

Example. One hundred grams of limestone, containing,%:, 35, CaO 53.05; , 0.55; 0.15, HgO 0.5; the remaining 42.1 is fired at for I h. As a result of firing, active lime is obtained in the amount of 57.9 g. In the firing process, SiO is bound to CaO, forming ZCdOS 0 (, 2CaO FO-3CaO and Ca004141.4 "Obtained lime is treated with a 15% strength sucrose C Ei solution at a weight ratio of .CaO "1.0 at 40 s for bO min.

As a result, hydrochemical processing of CaO-. | it reacts with sucrose and an aqueous solution of calcium saharat is obtained, and in the solid phase it is found with inert materials.

After the hydrochemical treatment of the lime, the pulp is separated and an aqueous solution of calcium sugar is obtained, which is introduced into the aluminate solution containing too g / l at a weight ratio of calcium saccharide to 0.75. The resulting pulp is kept for three hours, after which calcium hydroaluminum is filtered off from the L solution of the sugar, washed with hot water and subjected to heat treatment for 1 hour.

As a result of this technological sequence, a precipitate is obtained containing 95–98% of half-aqueous calcium hydroaluminate. With this, the yield of the useful product from CaCOj is 84%. Comparative data yield of the product, the proposed and known methods are summarized in table.

Famous Water

1.03

C H 0 ,. -P 1.08 1.1

60

0.78

90 95 98

Claims (2)

80 98 98 0.78 0.78 The developed method allows to produce a high-quality product. This ensures a reduction in its input into the molding and core mixtures, which increases the gas permeability and the gas-resistance mixture. The introduction of the proposed & south way will allow to obtain an annual economic effect of 30 thousand rubles. Claim 1. Method for the absorption of calcium hydrochloride aluminate, which includes treating the aluminate solution with a reagent containing calcium oxide, followed by separation of the pulp of the pulp and heat treatment of the precipitate, characterized in that, in order to increase the output of calcium hydroaluminum, the sugar solution is used as a reagent calcium, which is treated with an aluminate solution at the rate of obtaining a weight ratio of calcium sucrose to alumina, equal to 0.75-0.80. 2. The method according to p. 1, - distinguishes between t and and tvm that the calcium sugar solution is produced by treating the oxide with a succinic solution with a weight ratio of calcium oxide: sucrose, 1 avy 1.03-1.10, and a temperature of 25-9 C followed by exposure and separation of the pulp to obtain a clarified solution. The sources of information taken into account in the examination of the USSR Copyright Certificate of the USSR 704019, cl. C 01 F 7/16, 1975, 2. USSR author's certificate in application for Р 2592242, cl. C 01 F 7/16, 1978.