SU802188A1

SU802188A1 - Method of producing mixed chromium and aluminium oxides

Info

Publication number: SU802188A1
Application number: SU772496333A
Authority: SU
Inventors: Борис Андреевич Пахомов; Борис Алексеевич Попов; Анфия Александровна Ваулина; Дуниса Хакимовна Саляхова; Людмила Андреевна Колесникова
Original assignee: Предприятие П/Я Г-4427
Priority date: 1977-06-13
Filing date: 1977-06-13
Publication date: 1981-02-07

Description

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Изобретение относитс к получению смешанных кислородных соединений хрома и других металлов, которые могут быть использованы как катализаторы , пигменты, абразивные материалыThe invention relates to the preparation of mixed oxygen compounds of chromium and other metals, which can be used as catalysts, pigments, abrasive materials.

Известен способ получени смешанных окислов на основе хрома, включающий восстановительное осаждение гидроокисей из раствора бихромата натри в присутствии соли или гидроокиси соответствующего металла и соли .сульфидного р да в две стадии: сначала соли сульфидного р да окисл ют до тиосульфата в щелочной среде а затем - до сульфата в кислотной среде 1 .A known method for producing chromium-based mixed oxides involves reducing the precipitation of hydroxides from a solution of sodium dichromate in the presence of a salt or hydroxide of the corresponding metal and salt of the sulfide series in two stages: first the salts of the sulfide series are oxidized to thiosulfate in an alkaline medium and then to sulphate in acidic medium 1.

Недостатком известного способа вл етс сложность процесса из-за многостадийности.The disadvantage of this method is the complexity of the process due to the multistage.

Известен также способ получени смешанных окислов хрома и алюмини путем совместного осаждени гидроокисей этих металлов из сульфата хрома, в частности из натриевой сол хромисульфатсерной кигдоты, и раствора алюмината натри при кип чении с последующим отделением осадка, ег термической обработкой, промывкой и сушкой продукта .There is also known a method of obtaining mixed oxides of chromium and aluminum by co-precipitating the hydroxides of these metals from chromium sulfate, in particular from sodium salt and chromium sulfate cygdotes, and sodium aluminate solution at boiling, followed by separation of the precipitate by thermal treatment, washing and drying of the product.

Недостатком известного способа вл ютс невысокие абразивные свойства целевого продукта. Так, выход годных шаров О степени точности при применении продукта, полученного по известному способу, составл ет 6%. Съем металла при использовании абразивного материала - 0,10 ,3 мг/минм .The disadvantage of this method is the low abrasive properties of the target product. Thus, the yield of balloons on the degree of accuracy in the application of the product obtained by a known method is 6%. Removal of metal using abrasive material - 0.10, 3 mg / min.

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Целью изобретени вл етс повышение абразивных свойств продукта.The aim of the invention is to increase the abrasive properties of the product.

Поставленна цель достигаетс способом получени смешанных окислов хрома и алюмини путем совместного The goal is achieved by the method of obtaining mixed oxides of chromium and aluminum by joint

5 осаждени гидроокисей этих металлов из сульфата хрома и сернокислого алюмини при кип чении с последующим отделением осадка, его термической обработкой, промывкой и сушкой продукта.5 precipitating the hydroxides of these metals from chromium sulfate and aluminum sulphate at boiling with subsequent separation of the precipitate, its thermal treatment, washing and drying of the product.

Отличительным признаком способа вл етс использование в качестве соли алюмини сернокислого алюмини .A distinctive feature of the method is the use of aluminum sulphate as an aluminum salt.

Технологи способа состоит в сле5 дующем.The technology of the method is as follows.

Claims

The precipitation of hydroxides is carried out from a solution containing soluble sulfuric salts of chromium and aluminum at a weight ratio of: Cr, A1 0 0 1: 1, pH of 6-10 and the boiling point of the reaction mixture. The precipitated hydroxide mixture is filtered and subjected to heat treatment with gradual heating to 1200 ° C for 2 h and boiled at this temperature for 0.5-1 h. The sintered mixed oxides of chromium and aluminum are leached with a condenser in a wet grinding mill and are classified by the method grinding in order to obtain a fine fraction of the abrasive product. Sweeping is carried out at a ratio T: / K 1: (6T10) - the limits are chosen with regard to the required quality of tarring and the optimum performance. A suspension of mixed oxides in the condensate is prepared with the addition of liquid, glass in the amount of 0.2-0.3% to the weight of the precipitate of oxides, calculated on S i 0 /. Suspe sia is settled for 10-30 minutes. A slurry containing a fine fraction, drain into a tank neutralizer, where it is treated with a strong electrolyte, such as strong sulfuric acid, to remove the electric charge from the product particles. The precipitate of the fine fraction is separated from the solution by filtration and dried at a temperature of 100-110 ° C. The coarse fraction is returned to ground. Nitsu wet grinding. Example. With the mixer in operation, 20 l of a solution of chlorine sulphate with a content of 3.94 kg Cr, (50) s and 20 l of a solution of aluminum sulphate with a content of 7/84 kg 1 g (504) 3 1 bNCO are introduced into the tank reactor. The mixture is adjusted to pH 8.5 with NaOH solution and boiled for 1 hour. The precipitate of mixed chromium and aluminum hydroxides is separated from the mother liquor by filtration and subjected to heat treatment with gradual heating to 2 hours and aging at this temperature. 1h The precipitate after leaching in a wet-grinding mill in the amount of 2.4 kg is washed in a condenser at a T: W ratio with the addition of liquid glass in the amount of gg in terms of SL. Suspension defended within 20 minutes A suspension of the fine fraction of mixed oxides of chromium and aluminum is poured into a neutralizing tank, to which 36 g of sulfuric acid (beats, weight 1.84 g / cm) are added. A fine precipitate of mixed oxides in the amount of 1.2 kg is filtered off and dried at a temperature of 110 ° C to obtain a product with a weight ratio of C o O ,,: A 1;

2. About 3 particle size of not more than bk. Using the proposed method allows to obtain a product with improved abrasive properties due to a more perfect crystalline structure of the product. When using mixed oxides of chromium and aluminum, obtained by the proposed method, for final finishing of bearing balls. On the degree of accuracy, the yield of suitable balls increases to 40-45% and the removal of metal from polished samples - to 0.30, 6 MG / MINSM -. The microstructure of the surface of the layer of polished specimens is preserved. In addition, the washing time of the product from sodium sulfate is reduced by eliminating the sodium-containing raw material. The method of obtaining mixed oxides of chromium and aluminum by co-precipitating the hydroxides of these metals from chromium sulfate and aluminum salt at boiling with the subsequent separation of the precipitate, its thermal treatment, washing and drying of the product, characterized in that, in order to improve the abrasive properties of the product, Aluminum sulphate is used as an aluminum salt. Sources of information taken into account during examination 1, USSR Author's Certificate No. 31553, class, C 01 G 37/02, 15.05.70, 2, USSR Author's certificate No. 4 26969, class C 01 G 37/02, 23,02,72 (prototype),