RU2764445C2 - Method for obtaining metallic scandium - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to the metallurgy of rare metals, in particular to the technology of obtaining metallic scandium. Scandium chloride is mixed with a reducing agent, sodium hydride, the charge is heated in vacuum at 100-15°C, then heated in an argon atmosphere from a temperature of 200° to 450°C, then the mixture is heated in vacuum to a temperature of 600°C. The resulting cake is treated with 1-2% acetic acid solution and washed with ethyl alcohol. After that, it is dried to obtain a powder, which is pressed into briquettes when reheated in vacuum up to 1100°C.

EFFECT: method makes it possible to obtain metallic scandium using a cheaper reagent to ensure its optimal consumption.

1 cl, 1 dwg, 1 ex, 1 tbl

Description

The invention relates to the metallurgy of rare metals, and in particular to the technology of obtaining metallic scandium.

A known method [1] for the production of yttrium and scandium metals, including heat treatment of metal chlorides at 800-900 ° C in vacuum, characterized in that the heat treatment is carried out in the presence of lithium hydride or calcium hydride and before heating in vacuum, the reaction mass is subjected to hydrometallurgical processing by leaching water at room temperature, followed by drying the resulting metal hydride powder.

The disadvantage of the method is that the reaction mixture was subjected to heat treatment immediately at a temperature of 800-900°C, which created an increased consumption of lithium hydride. This is explained by the fact that at a temperature of 700°C, instead of interacting with scandium chloride, lithium hydride evaporates with decomposition.

Known adopted for the prototype method [2] for obtaining metallic scandium, including mixing scandium chloride with a reducing agent, heating the mixture in vacuum, subsequent heating to obtain a reaction mass, characterized in that the mixing of scandium chloride is carried out with lithium hydride, heating in vacuum is carried out at 200 -300°C, then heating is carried out in an argon atmosphere at 500-680°C, followed by washing the reaction mass with water and a weak acid solution, grinding it, drying the resulting powder, briquetting it and heating in vacuum to 650-900°C.

The disadvantage of this method, revealed when it was used at the Novosibirsk Tin Plant, is its high cost of using an increased consumption of expensive lithium hydride.

The aim of the invention is to obtain metallic scandium with the replacement of lithium hydride with cheaper sodium hydride.

This goal is achieved in that scandium chloride is mixed with sodium hydride with heating in vacuum at 100-150°C, then heated in an argon atmosphere from a temperature of 200 to 450°C, then the mixture is heated in vacuum to a temperature of 500-600°C, the resulting cake treated with a 1-2% solution of acetic acid, washing with ethyl alcohol, and after drying, the scandium hydride powder is pressed with reheating of the briquettes in a vacuum to 1100°C.

The essence of the method lies in the fact that scandium chloride is mixed with sodium hydride at a flow rate of 110-120% of the required amount and heated in vacuum, first at 100-150°C to remove adsorbed gases from the surface of the powders, but preventing the reagent from evaporating.

Then the mixture is heated in an argon atmosphere, gradually increasing the temperature from 200 to 450°C to ensure the passage of the hydrogenation reaction even before its decomposition at 425°C, ensuring optimal consumption of the reagent.

ScCl3 + 6NaH \u003d 2ScH ₂ + 6NaCl + H ₂

Then a vacuum is created over the mixture with a temperature rise to 500-600°C to remove reaction products and the temperature is maintained for 2 hours.

Speck is unloaded and washed with a 1-2% solution of acetic acid to dissolve the reaction products (NaCl, Na), then washed from moisture with ethyl alcohol. The absence of scandium in industrial water indicates the completeness of the reaction. After drying, the scandium hydride powder is pressed into briquettes.

The briquettes are heated under a vacuum of 10 ^{^-2} mm Hg. with an increase in temperature to 1100°C for an hour.

ScH ₂ \u003d Sc + H ₂

In this case, scandium hydride decomposes and traces of decomposition products (H ₂ , NaCl) and sintering into dense briquettes evaporate.

The process is carried out in the reactor shown in FIG. The reactor 1 is a cylindrical vessel made of stainless steel with a water-cooled flange 4 with a lid 8 to be closed on a hermetic sealant VGO-1, which can withstand a temperature of 800°C. Fitting 6 is hermetically connected to flange 4 - connection to the vacuum pump. Fittings 7 for supplying and discharging argon are welded to cover 8. The vessel 1 reactor is placed in the furnace 5. The tantalum crucible 2 is placed in the reactor 1, in which the charge or rods are placed.

The peculiarity of the reactor is that the fitting 7, supplying argon, is hermetically connected to the tube 3, immersed to the bottom of the crucible 2 to displace gaseous products.

The crucible 2 with scandium chloride and sodium hydride is placed on the bottom of the vessel of the reactor 1 (Fig), cover 8 is closed and air is evacuated from the system with heating in vacuum at 100-150°C. After that, the system is filled with argon 7 and furnace 5 is turned on and slowly raised from a temperature of 200 to 450°C, then the vacuum mixture is heated to a temperature of 600°C, held for 2 hours.

After cooling to 80°C, the resulting cake is treated with a 12% solution of acetic acid, washed with ethyl alcohol. After drying, the powder is pressed with repeated heating of the briquettes in vacuum up to 1100°C.

Example: A tantalum crucible is charged with 20 g of scandium chloride (obtained from the extraction of associated processing of wolframite-tin slag [3]) and 11 g of sodium hydride and placed in a heated reactor (previously used for hydrogenation [2]). The reactor is evacuated, heated to 150°C, and purged with argon for 30 min. Shut off the vacuum line and argon supply and gradually increase the temperature to 450°C. After an hour, connect the vacuum line and gradually reduce the pressure and turn on the heating. The reactor is heated within an hour to 600°C. The heating is turned off and the reactor is cooled to 200°C, the vacuum line is disconnected, argon is supplied, cooled to 80°C, and the reactor is opened. The crucible with the sinter is treated three times in 50 ml of 1% acetic acid solution, and then washed twice with ethyl alcohol and dried under an infrared lamp. Industrial waters are analyzed for scandium content. The powder is pressed in a mold with a diameter of 1 cm under a pressure of 100 atm, and the resulting briquette is loaded into the reactor. The reactor is evacuated and the temperature is gradually raised to 1100°C. After an hour, cool, unload the reactor. Get a briquette of metallic scandium weighing 6 g with a yield of 92%. Similar swimming trunks are shown in the table.

The technical result consists in obtaining metallic scandium using a cheaper reagent.

Used Books:

1. Pat RF 2013460 - Method for obtaining rare earth metals yttrium and scandium - Kamarzin A.A., Sokolov V.V., Trushnikova L.N., Savelyeva M.V., Stonoga Yu.A., applicant Institute of Chemistry of the Siberian Branch of the Russian Academy of Sciences \\ С22В 59/00; Application: 925059367 dated 08/21/1992.

2. Pat RF 2102513 - Method for obtaining metallic scandium - Dyakov V.E., \\ C22b 59 \ 00, App. 93014720 from 22.03.93 publ. 20.01.98; Bee No. 2 - 1998 - p. 290.

3. RF patent 1450389 - Method for processing tin-tungsten concentrates - Dyakov V.E., Rozlovsky A.A., Dulepov E.V., Mikhalev V.V., Dugelny A.P., Maslov V.I., Kleshchenko I.N., Koryukov Yu.S., Semenov A.E. - Applicants: Novosibirsk Tin Plant, Gidrotsvetmet \\ С22В 25/00; Application: 4164146 dated 12/18/1986; Published 07/10/2012; No. 19-12-509.

Claims (1)

A method for obtaining metallic scandium, including mixing scandium chloride with a reducing agent, heating the mixture in a vacuum, followed by washing the obtained sinter with a weak acid solution, drying the obtained powder and pressing it into briquettes, characterized in that to reduce the cost of the process, scandium chloride is mixed with sodium hydride and heated in vacuum at 100-150°C, then heated in an argon atmosphere from a temperature of 200° to 450°C, then the mixture is heated in vacuum to a temperature of 600°C, the resulting cake is treated with 1-2% acetic acid solution, washed with ethyl alcohol and dried, after which the resulting powder is pressed into briquettes by reheating in vacuum to 1100°C.

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