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INVENTION
Russian Federation Patent RU2025525

Method of extracting tungsten from tungsten MATERIAL

Method of extracting tungsten from tungsten MATERIAL

Name of the inventor: Chub AV .; Gorshkov AV .; AI Dobrynin .; Shchelkonogov MA .; Melnikov LV .; Krivoruchko SL
The name of the patentee: Open Joint Stock Company "Solikamsk Magnesium Plant"
Address for correspondence:
Starting date of the patent: 1992.06.04

Usage: As for the processing of natural or recycled raw materials volfamsoderzhaschego. The bottom line: raw autopsy produce sodium (potassium) containing reactants + by self-propagating high-temperature synthesis (SHS). SHS method is based on the strongly exothermic reaction of carbonaceous materials with the sodium (potassium) nitrate. As used retarder endothermic reaction of oxide materials and soda. Operation batch preparation for SHS process involves mixing and grinding the components in the following proportions: - tungsten carbonized material and / or carbonaceous reactant with the degree of oxidation of carbon (2) to (4) nitrate and sodium or potassium in a weight ratio 1: (0.6-2) - exothermic part of the charge; oxidized tungsten material and / or reagent containing metal oxides, and soda in a ratio 1 :( 0.4-1.4) - moderator; offset the charge and the exothermic part retarder are in a weight ratio of 1 :( 0.3-1). Removing the tungsten in the application of this method is 90-98%.

DESCRIPTION OF THE INVENTION

The invention relates to ferrous metallurgy and can be used in the production of rare refractory metals and alloys.

The method for extracting tungsten from tungsten carbide wastes comprising grinding the alloys to a particle size of 10-100 mm, the melting of the ash in the mixture of ammonium nitrate and in excess of 100% at 650 ~ C for 2 h and leaching in water at 80-100 C. . Further processing of the products carried by the classical scheme.

A disadvantage of the method is an increased consumption of reagents. In addition, the aggressiveness of the environment creates a difficulty in the selection of materials for the lining of melting furnace.

is close and tungsten scrap recycling method comprising subjecting the scrap in a salt bath followed by chemical extraction of tungsten compounds. The optimum temperature of the melt of sodium nitrate and sodium nitrate is 680-750 ° C. The amount of nitrate should be in accordance with the stoichiometry of the amount of tungsten. The melt after cooling is dissolved in water, followed by separation in a classic case of tungsten.

The disadvantage of this method is the difficulty in hardware design. Large selection of nitric oxide require the creation of the gas cleaning system.

The closest to the technical nature and the results obtained is the method of extraction of tungsten from tungsten waste by sintering it with sodium nitrite or nitrate with the addition of coal. Coal added for the formation of nitrite from nitrate. Tungsten nitrite oxidation occurs at an elevated temperature. An external heating of the mixture, so the sintering is carried out in a flame annealing furnaces.

The aim of the invention to provide a universal method for processing different kinds of raw materials of the tungsten, including trudnovskryvaemogo carbide.

Separation of tungsten and tantalum (or) other refractory metals entering into the composition of recyclable materials is carried out by transferring them to sodium-form, which is soluble in the case of an insoluble tungsten and - in the case of tantalum and other metals. This makes it possible to remove the tungsten in the form of commercial products (chloride, tungsten (VI), tungsten oxide (VI), ammonium paratungstate, etc.) and concentrate the tantalum, niobium, titanium in forms convenient for further processing. This ensures the greatest possible complexity of the use of raw materials.

In connection with sodium refractory metals transferred using the method SHS (SHS), which is based on the exothermic oxidation reaction of carbon-containing components of the burden of sodium nitrate. As moderator of the reaction is a mixture of oxygen-containing materials or carbide raw material pre-oxidized with soda. The ratio of the exothermic portion, that is, the mass of carbide scrap or other carbonaceous material with a retarder nitrate is about 1: 1 and is adjusted depending on the volume of a single processing.

In the case of carbide raw material synthesis preferably takes place according to the reactions:

WC + 2 NaNO 3 = 4 of Na 2 NO + N 2 + CO 2 10 18 TaC + NaNO 3 = 10 NaTaO 3 + 9 + 10 N 2 CO 2

MeO + Na 2 CO 3 = Na 2 MeO 4 + CO 2

The resulting melt had a porosity of 50%, so easily is crushed and leached with water. The resulting solution containing sodium tungstate, is subject to processing by the classical scheme.

Carrying out the process of sintering SHS is possible with the following ratio of the components of the charge:

- Carbonized tungsten-containing material and / or carbonaceous reactant with the degree of oxidation of carbon (2) to (4) nitrate and sodium or potassium salts in a weight ratio of 1 :( 0.6-2) - exothermic part of the charge;

- Oxidized tungsten material and / or reagent containing metal oxides, and soda in a ratio 1 :( 0.4-1.4) - moderator;

- The ratio of the exothermic charge and moderator of 1: (0.3-1).

This ratio of components in the mixture is an essential feature of the invention.

As the carbonaceous reactant materials may be used such as carbides of metals and silicon, any modification of the carbon black, coke, graphite dust, etc., that agents capable of maintaining the combustion of the chemical reaction when combined with nitrogen-acid salts. In the case of processing carbide raw starting material contains carbon itself. Additionally, enter the carbonaceous reactant is necessary in the case of processing of raw materials containing no carbon in its composition, such as an oxide or containing it in insufficient quantities.

Oxidation of tungsten carbide and other metal sodium (potassium) nitrate in which the refractory metals pass into compounds with sodium (potassium) has the explosive. Some of the released energy is spent on heating (up to about 900-1000 ° C) and melting of components and part remains free. This energy can be used for the reaction or interaction waste concentrate containing tungsten oxides. Calculating the energy balance reactions and comparing it correctly, you can create the conditions for the SHS process.

The temperature achieved during synthesis (900-1000 ° C), facilitates the rapid transition metals in the sodium-form. Terms of the process ensure the completeness of the reaction.

Pre-mixing and grinding for maximum contact area of ​​the reactants and thus a fairly complete process flow. Removing the tungsten is 90-98%.

The evolved gases during synthesis porous facilitate obtaining the reaction product, which significantly improves the leaching process.

Method is as follows

Received concentrate chemical composition of which is presented in Table. 1, is pre-milled in a rod mill to a particle size less than 0.5 mm. grinding time depends on the load.

Classification is carried out in the shaker.

Part milled concentrate (approximately two fifths) pre-oxidized for 30-40 minutes in a rotary kiln at 600 ° C. The oxidized product was cooled in air.

Mixing is carried out in mixers or rod mills. Composition of charge as follows: 24 kg of raw carbide chemical composition is presented in Table 1, 30 kg of sodium nitrate, 30 kg of raw oxidised, 20 kg of soda.

The sintering process is carried out in a metal box made of sheet steel. Loading is 30-50 kg. Initiate reactions produce spark pulse supplied remotely. The time required for the burn-mixture is less than 30 minutes. Speck has a gray color permeated the pores of frozen gas inclusions, easily breaks into pieces.

sinter grinding is performed in wet grinding mill of 400 mm diameter at a liquid to solid ratio of 1: 4. Drum speed 60 rev / min, 0.5 h duration of grinding.

The pulp is discharged through a chute into the receptacle for the sludge.

The washing is carried out by decantation pulp sludge, which is carried out in the rubberized tank. Sodium tungstate solution is removed by vacuum suction. After repeated washing the precipitate was dried and sent for further recycling.

The results of this experiment are presented in Table 2. The table shows that the extraction of tungsten on the experience of 94.3%, 98.5% for tantalum.

To illustrate the application of the above method of extracting tungsten oxide materials presents the results of the following experiment (see. Table. 3). Composition of charge in this case: 750 g of the oxide feed containing 19% tungsten oxide (VI) oxide and 20% tantalum, 52 g of coal dust, 190 g of sodium nitrate and 66 g of soda.

The table shows that the extraction of tungsten on in this experiment was 95.1% in tantalum - 98.7%.

CLAIM

METHOD FOR EXTRACTION OF TUNGSTEN tungsten material include batch mixing and sintering, characterized in that the batch is prepared by mixing tungsten carbonized material and / or carbonaceous reactant with the degree of oxidation of carbon (2) to (4) nitrogen and sodium or potassium salts at a weight component ratio 1: (0,6 ÷ 2) to obtain the first part of the charge, an oxidized tungsten material and / or reagent containing metal oxides and ash components in a weight ratio 1: (0,4 ÷ 1,4) to form a second portion batch and then mixing the first and second portions in a weight ratio of 1: (0,3 ÷ 1).

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Publication date 16.03.2007gg