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Vsesojuzny Nauchno-issledovatelsky I Proektny Institut Aljuminievoi,

Vsesojuzny Nauchno-issledovatelsky I Proektny Institut Aljuminievo

Leningradsky Tekhnologichesky Institut Imeni Lensoveta

Isaak A Zatulovsky

Ivan M Kostin

Khoren A Badaliants

Nikolai A Kaluzhsky

Nikolai S Shmorgunenko

Viktor M Sizyakov

Alexei I Alexeev

Nikolai A Novikov

Alexandr V Eljutin

Raisa V Ivanova

Alexandr V Peredereev

Leonid I Finkelshtein

Arkady I Zazubin

Leonid M Butorin

Elena L Shalavina

Tatyana D Ostapenko

Valentin I Korneev

Vladimir V Andreev

Evgeny A Isakov

Anna E Danilina

Arkady A Belsky

Nikolai Ivanovich Eremin

Askar M Kunaev

Georgy P Tkachenko

Pavel S Vladimirov

Mikhail Ivanovich Zaitsev

Garegin A Peikarov

Gennady A Romanov

Ioan V Davydov

Anatolia T Simanova

Gennady A Panasko

Natalya V Tishevetskaya

Ljubov B Samaryanova

Avgusta I Samoilova

Zarya N Alexandrova

Evgeny M Steshenko

Alexandr G Zhukov

Larisa I Sinelnikova

Valentin N Afanasiev

Greogy I Lazarev

Viktor S Kutsenko

Petr V Fedorin

Evgenia S Ostrovlyanchik

Vladimir V Krasavin

Khoren A Badaiants

Galina M Vysotskaya

Leonid I Finkelshtein, Deceased

Vinetsy I Chernov

Evgeny I Mironov

Julia L Finkelshtein, Administrator

Anatolia I Simanova

Nina J Finkelshtein, Administrator

Boris A Kuzmin

Vladislav A Krochevsky

Petr F Minin

Jury N Evseev

Teodor G Milberger

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

The starting aluminate-alkaline solutions are subjected to two-stage carbonization with stirring and the production of hydrate of aluminum oxide, a gallium-containing precipitate, and solutions containing caustic and bicarbonate alkali, thereafter the produced gallium-containing precipitate is mixed with a solution containing caustic alkali to achieve a content of gallium in the solution of 0.05 to 1 g/l, the precipitate thus formed is separated and the solution enriched with gallium is mixed with a solution containing bicarbonate alkali, the produced mixture is evaporated to separate compounds of alkali metals, and the evaporated solution is carbonized to produce a solution containing alkali metal salts, and a gallium concentrate from which gallium is produced by transforming it into alkaline solution and subsequently reducing electrochemically. The proposed method makes it possible to extract gallium at a comparatively low cost from solutions in the processing, for example, of nephelines containing it in amounts which do not exceed 0.02 to 0.03 g/l. Owing to the proposed method it has become possible in the processes of concentration of gallium to produce a number of valuable components such as alkali metal salts contained in the starting ore.

Method for extraction of gallium from aluminate-alkaline solutions in

A process for recovering gallium from alkali aluminate solutions which consists in that the starting alkali aluminate solution is neutralized to a concentration of the caustic alkali of from 0.1 to 10 g/l, whereafter the neutralized liquor is evaporated to a concentration of the caustic alkali therein of from 30 to 150 g/l. Then the evaporated solution is corrected to obtain the ratio between the alkali metal oxide and alumina of above 2.0. The corrected solution is treated with a liquid alloy of gallium containing an element possessing an oxidizing potential exceeding that of gallium to give a concentrate containing more than 90% of gallium by mass, wherafter gallium of a higher purity grade is recovered from the resulting concentrate by the electrochemical method. The process according to the present invention makes it possible to recover gallium from alkali solutions resulting from the treatment of nephelines with the production of a 90% gallium concentrate, wherefrom gallium of an increased purity is obtained at relatively low cost. Processing of the concentrate with the production of gallium is simple, it is not encountered with any additional expenses and requires no additional equipment. Another advantage of the process resides in a more comprehensive utilization of low-grade aluminum-containing ores.

Process for recovering gallium from alkali aluminate solutions resulting

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Isaak A Zatulovsky