Vsesojuzny Nauchno-issledovatelsky I Proektny Institut Aljuminievoi,

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Vsesojuzny Nauchno-issledovatelsky I Proektny Institut Aljuminievo

Leningradsky Tekhnologichesky Institut Imeni Lensoveta

Alexei I Alexeev

Ivan M Kostin

Viktor M Sizyakov

Nikolai A Kaluzhsky

Isaak A Zatulovsky

Nikolai S Shmorgunenko

Khoren A Badaliants

Pavel S Vladimirov

Valentin I Korneev

Vladimir V Andreev

Leonid I Finkelshtein

Evgeny A Isakov

Georgy P Tkachenko

Alexandr G Zhukov

Viktor S Kutsenko

Evgenia S Ostrovlyanchik

Leonid F Bilenko

Khoren A Badaiants

Galina M Vysotskaya

Oleg V Alexeev

Leonid I Finkelshtein, Deceased

Vinetsy I Chernov

Vitaly L Aronzon

Evgeny I Mironov

Julia L Finkelshtein, Administrator

Nina J Finkelshtein, Administrator

Boris A Kuzmin

Zarya N Alexandrova

Vladislav A Krochevsky

Valentin N Afanasiev

The cement of the invention comprises chemically combined oxides, percent by mass: CaO, 50 to 60; Al.sub.2 O.sub.3, 28 to 37; Fe.sub.2 O.sub.3, 0.01 to 1; SiO.sub.2, 0.1 to 8; Na.sub.2 O, 0.1 to 1; K.sub.2 O, 0.1 to 0.5; H.sub.2 O, 3 to 12; and incorporates 85 to 99% by mass of a fraction with a particle size of below 80 .mu.m and 1 to 15% by mass of a fraction with a particle size of from 80 to 200 .mu.m. The cement can also contain one or more additives: calcium oxide or calcium hydroxide, calcium carbonate, calcium carboaluminate. The method according to the invention for preparing said cement comprises a heat-treatment of calcium hydroalumosilicate containing SiO.sub.2 in an amount of not more than 8% by mass at a temperature of from 250.degree. to 600.degree. C. The heat-treated product is disintegrated to produce 85 to 99% by mass of a fraction with a particle size of below 80 .mu.m and 1 to 15% of a fraction with a particle size of from 80 to 200 .mu.m. During the heat-treatment of the hydroalumosilicate at least one component can be added calcium oxide or calcium hydroxide, calcium carbonate, calcium carboaluminate. The cement is useful in foundry engineering for the manufacture of articles from ferrous and non-ferrous metals.

Cement for the manufacture of cores and moulds and method for preparing

The process consists of two desilication stages. In the first stage the aluminate liquor resulting from digestion of the sinter is subjected to an autoclave treatment to remove the major portion of impurities of SiO.sub.2 and Fe.sub.2 O.sub.3. In the second stage the aluminate liquor is treated with a desilication agent comprising a lime pulp containing oxides CaO, Al.sub.2 O.sub.3, SiO.sub.2, Fe.sub.2 O.sub.3, Na.sub.2 O in a mass ratio of CaO:(SiO.sub.2 +Fe.sub.2 O.sub.3)=1,000 to 5,000:1 and Na.sub.2 Al.sub.2 O.sub.3 =0.25-0.60:1, wherein CaO is active, Na.sub.2 O--in the carbonate form. This lime pulp is employed in such an amount as to ensure the content of active CaO in the aluminate liquor within the range of from 5 to 10 g/l . The impurities of SiO.sub.2 and Fe.sub.2 O.sub.3 present in the liquor pass into the solid phase with the formation of calcium hydrogarnets of the formula 3 CaO(Al,Fe).sub.2 O.sub.3 mSiO.sub.2 (6-2m)H.sub.2 O, wherein m=0.01-0.5 which are separated as a mud.

Process for desilication of aluminate liquors in the production of

The present invention relates to the production of alumina and, more specifically, to a process for desilication of aluminate solutions. The process of desilication according to the present invention comprises treatment of the aluminate solution first with a calcium-containing reagent 'a' which is a product of the reaction of desilication of the aluminate solution; reagent 'a' contains mainly calcium hydrogarnet of the formula:

Process for desilication of aluminate solution

An improved method for recovering aluminum values from alkaline aluminosilicate raw material by sintering a comminuted aqueous mixture of the alkaline aluminosilicate material, limestone and soda solution wherein the alumino-silicate material is first comminuted with the soda solution to form a mixture with a fraction of particles larger than 0.08 mm greater than 20 percent by weight, mixing limestone with the mixture and comminuting until the fraction of particles larger than 0.08 mm is between 2 and 15 percent by weight.

Method for the production of alumina

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Saint-Petersburg, Russia

Alexei I Alexeev