Method of fabrication of tantalum powder

FIELD: metallurgy.

SUBSTANCE: method includes reduction of fluorine tantalite of potassium with liquid sodium in medium of melted saline bath of halogenides of alkali metals by means of alternate portioned dozing of sodium, and further - of fluorine tantalite of potassium. Fluorine tantalite of potassium is introduced into mixtures with part of the charge of halogenides of alkali metals, used for making of a saline bath. Amount of halogenides of alkali metals in the mixture introduced into melt with fluorine tantalite of potassium constitutes from 60 to 125% (wt) from weight of fluorine tantalite of potassium.

EFFECT: dimension in size of powder particles, reduction of duration of reduction process, decreasing of power consumption for melting of saline charge and forced cooling of reaction vessel.

1 tbl, 1 ex

 

The invention relates to powder metallurgy and, in particular relates to a method of obtaining the primary capacitor tantalum powder by nitratereductor recovery of fortuntate potassium in the environment of molten halides of alkali metals. The powder can be used for the production of radio condensers.

The most popular currently is the method of obtaining the primary tantalum capacitor powders by recovery of tantalum from fortuntate liquid sodium potassium reaction

To2TaF7+5Na→TA+5NaF+2KF+Q

where Q≈1250 kJ/kg mixture of stoichiometric composition (Zelikman A.N. and other Niobium and tantalum. Metallurgy, 1990).

thermal effect of the reaction is sufficient to melt the products of the reaction and heating the melt to a temperature of more than 1200°C.

The recovery process is carried out in an environment of molten halides of alkali metals in a crucible made of corrosion-resistant heat-resistant alloy of the type "Inconel" in an atmosphere of purified inert gas under stirring.

Known the following method of obtaining the primary capacitor tantalum powder, which is considered a classic (United States Patent 4149876. Process for producing tantalum and columbium powder / Rerat. 1979, IPC B22F 009/00). In the crucible is loaded charge of portantly potassium and calcined sodium chloride and potassium chloride. The ratio of the giving Sol/tortontilt 0.25...1 (wt.), the increase in the ratio salt/tortontilt contributes to a more fine powder. The crucible with the charge lid, sealed, evacuated, filled with argon and placed in a furnace and heated to a temperature sufficient to melt the components of the salt system. At a temperature of ≤660°C and stirring in the melt begin to dose sodium speed ≥0.2 kg per 1 kg of fortuntate per hour. Due to the heat released in the reaction, the temperature in the crucible is raised to 760...1000°With a speed of 10...20°C/min, Upon reaching the predetermined temperature, the speed of the dosing of sodium is reduced to 0.1 kg per 1 kg of portantly per hour and continue the dosage until complete consumption of fortuntate potassium. The process at a temperature in the range of 760...850°With a finer powder, while at a temperature in the range of 850...1000°C is larger. Temperature recovery control with precision ±10°by forced cooling of the crucible by the gas flow. The use of forced cooling allows to reduce the duration of the recovery process and helps to ensure a more fine powder. Stirring is continued during the entire process. During the recovery process stirrer gradually lifted the AK, to be above the level of the powder settling on the bottom of the crucible. After the restore process is complete, the melt is maintained at a temperature of 900...1000°about 2 hours. This method allows to obtain a powder with an average grain size Fisher from 2.3 to 7.2 μm.

Closest to the invention is the following method (United States Patent 4684399. Tantalum powder process / Bergman, et al. 1987, IPC SW 034/20). Tortontilt potassium by continuous or batch dosing is introduced into the reactor. As the environment in which the reaction takes place recovery, uses molten salt systems KCl-NaCl or KF-KCl at a ratio of 1:1 (mol). Speed continuous dosing or the value of a single loading unit introduction portantly can be changed depending on the desired properties of the powder. The reducing agent can be introduced into the bath of molten salt at a time to download portantly, boot portions or continuously dosed simultaneously with tortenelem potassium. The temperature of reaction is from 600 to 950°C. This method is adopted for the prototype.

This method allows you to obtain powders with a lower average grain size, because the reagents interact at lower concentrations, local heating decreases, stopping the growth of grain. However, the total amount subject to withdrawal of heat is the power is not reduced. This method according to the source allows to obtain a powder with an average grain size Fisher from 0.48 to 1.0 μm.

The disadvantage of this method of recovery is that the heat released during the reaction, is removed from the reaction zone on the principle of heat transfer through the layer of melt on the force of gas-cooled wall reactor, which causes performance degradation due to internal limitations of the speed of loading the reagents into the reactor to negotiate the amount of heat produced by its diversion, and increase energy by pre-melting the entire mixture and cooling the melt.

The objective of the invention is to substitute a known method of heat removal from the reaction zone to a more efficient, allowing more accurate to maintain the temperature in the reactor regardless of the number of reactive products.

The technical result of the invention is to improve the quality of the powder, increasing productivity and reducing energy consumption.

The invention consists in the fact that in contrast to the known method of producing tantalum powder, which consists in the fact that the liquid sodium, and then tortontilt potassium portions metered into the reactor, where tortontilt potassium recovers the liquid sodium in the environment of the molten halide salts saloon the x metals the proposed method simultaneously with tortenelem potassium was charged to the reactor part of the charge halide salts of alkali metals, which were used to create the salt bath in the reactor, in an amount of from 60 to 125% (wt.) from the mass of fortuntate potassium.

When carrying out the recovery process according to the invention the heat released by the reaction is absorbed by the heating and melting loaded simultaneously with tortenelem mixture of potassium halide salts of alkali metals.

The download speed or the amount of the lump sum portion of the coolant salt mixture is selected in accordance with the magnitude of simultaneous upload and speed dispensing of fortuntate potassium, temperature and composition of the cooling material and the speed of cooling of the reactor thereby to prevent undesirable increase or decrease in melt temperature. Cooling effect when loading the coolant salt mixture in a quantity less than 60% (wt.) from the mass of fortuntate potassium did not significantly affect the reduction of the temperature in the reaction zone, when the loading of the salt mixture from 60 to 125% (wt.) from the mass of fortuntate the cooling effect is quite sufficient. Loading coolant salt mixture in more than 125% (wt.) from the mass of fortuntate potassium can lead to crystallization of the salt bath.

With irenie mass of the primary molten salt does not affect the quality of the powder, since the beginning of the process reactant concentrations in portions of their introduction may be regulated by the size of portions, and the end of the process the originally planned volume of molten salt is restored.

The recovery process in accordance with the invention is carried out as follows. Part of the mixture of salts is loaded into the reactor. The reactor is sealed, the air inside the reactor was replaced with argon. The salt system is melted, homogenized and lead to a given temperature. The recovery process is carried out by portions alternating injection into the reactor of sodium, and then fortuntate potassium. Simultaneously with tortenelem potassium metered into the reactor remaining salt mixture. After the restore process is complete, the reactor is cooled, the recovered product is recovered and crushed. The powder is separated from the reaction products and salts by dissolving them in water.

The invention result in a more rigid and reliable control of temperature molten salt allows ceteris paribus get smaller and therefore more quality powder. Due to the fact that the melt is subject to only part of the salt mixture used to create the original bath salt melt, reduced energy consumption for melting salts. The invention eliminates prinuditelnoj the cooling of the crucible wall and therefore be excluded from the design of the facility site forced cooling, and also to eliminate the energy consumption for forced cooling.

Example

The tantalum powder obtained in the following way. In a tantalum crucible volume of 10 liters downloaded 4,25 kg equimolar mixture of KCl-NaCl. The crucible was placed in a retort made of stainless steel. The retort was sealed, evacuated, filled with argon and was heated up to 850°C. At this temperature, the retort has stood for 30 minutes. After the salt had melted, the crucible is lowered stirrer and stirring the melt was cooled to 660°C. Upon reaching temperature the set temperature in the crucible sequentially downloaded 97 g of sodium preheated to 180°C, and 650 g of a mixture consisting of 300 g of fortuntate potassium, 196 g of KCl and 154 g of NaCl. The length of boot portions of sodium and the mixture of fortuntate and potassium salts was 3 and 2.5 minutes, respectively. The boot routine reagents repeated five times. Only in the crucible was loaded with 485 g of sodium, 1500 g of fortuntate potassium, 980 g of KCl and 770 g of NaCl. The temperature variation of the melt from the set - 660°With registered no. At the end of the recovery process, the retort was heated up to 700°and kept at this temperature for 30 minutes without stirring. Then the retort was removed from the furnace and cooled to room temperature. The recovered mass was knocked out of the crucible and broke. The powder was separated from the products implement the tion by dissolving them in distilled water and treated in a 5% solution of hydrochloric acid within one hour. The parameters of the recovery process and the particle size of the obtained powder is shown in table 1.

For comparison conducted the restoration of the prototype. In a tantalum crucible volume of 10 liters downloaded 6 kg of an equimolar mixture of KCl-NaCl. The crucible was placed in a retort made of stainless steel with a shirt air cooling. The retort was sealed, evacuated, filled with argon and was heated up to 850°C. At this temperature, the retort has stood for 40 minutes. After the salt had melted, the crucible is lowered stirrer and stirring the melt was cooled to 660°C. Upon reaching temperature the set temperature in the crucible sequentially downloaded 97 g of sodium preheated to 180°S, and 300 g of fortuntate potassium. The length of boot portions of sodium and fortuntate potassium was 3 and 2.5 minutes, respectively. The boot routine reagents repeated five times. Only in the crucible was loaded with 485 g of sodium and 1500 g of fortuntate potassium. After downloading portions of fortuntate potassium temperature in the crucible due to thermal effect of the reaction was increased to 690°C. Another portion of fortuntate potassium loaded into the crucible after cooling to 660°C. the duration of the cooling ranged from 15 to 17 minutes. At the end of the recovery process, the retort was heated up to 700°and kept at this temperature the ones who begins 30 minutes without stirring. Then the retort was removed from the furnace and cooled to room temperature. The recovered mass was knocked out of the crucible and broke. The powder was separated from the reaction products by dissolving them in distilled water and treated in a 5% solution of hydrochloric acid within one hour. The parameters of the recovery process and the particle size of the obtained powder is shown in table 1.

As can be seen from the table, the proposed method can significantly reduce the duration of the recovery process and improve the quality of the powder, to abandon the use of air cooling to reduce energy consumption including by melting more than a quarter of the mass of the salt bath heat of the exothermic effect of the reaction.

Table 1
The placeholderThe present invention
1. Weight charge (kg)
1.1 total recovery66
1.2 on the creation of primary melt64,25
1.3 loading during recoveryno1,75
2. The number of podrouzek reagents55
3. Duration is hladiny after loading fortuntate potassium, min15...17no
4. The total duration of loading of reagents, min2828
5. The total duration of the recovery process (without taking into account the time of heating, melting salts and extracts the recovered mass), min.10528
6. The increase of technological the duration of the recovery process by cooling, min77no
7. The average grain size (FSSS), microns0,240,20
8. Full specific surface area, m2/g5,737,98

A method of producing tantalum powder recovery of fortuntate potassium liquid sodium in the environment of the molten salt bath of halides of alkali metals by portions of alternate dosing of sodium, and then fortuntate potassium mixed with part of the mixture of halides of alkali metals used to create the salt bath, wherein the amount of alkali metal halides in a mixture, are introduced into the melt with tortenelem potassium ranges from 60 to 125 wt.% from the mass of fortuntate potassium.



 

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FIELD: chemistry.

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2 cl, 1 dwg, 3 ex

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FIELD: hydrometallurgy; ore concentrates processing.

SUBSTANCE: the invention is pertaining to the field of hydrometallurgy, in particular, to processing of the loparite concentrate. The method includes a decomposing of the loparite concentrate at the temperatures of 103-105°C and the concentration of hydrofluoric acid of 38-42 mass % with production of the pulp containing fluorides of titanium, rare earth elements (REE), niobium, tantalum and sodium. The pulp is filtered at the temperature of 90-95°C with extraction into the fluorotitanium solution of fluorides of niobium and tantalum and no less than 58 % of sodium in terms ofNa2O and separation of the sediment containing fluorides of rare earth elements (REE) and a residual sodium. The produced solution is cooled down to 18-24°C with separation of the second sediment of sodium fluorotitanate. After that they extract niobium and a tantalum from the solution by octanol-1 extraction at a ratio of the organic and water phases as 1.1 : 1. The sediment of REE fluorides is washed from fluorotitanate by sodium water in a single phase at the temperature of 90-95°C and at the solid :liquid ratio = 1:2-2.5. The cleansing solution is separated and evaporated with extraction of the additional sediment of sodium fluorotitanate. After extraction of niobium and tantalum the fluorotitanium solution is evaporated and filtered with separation of the first sediment of sodium fluorotitanate from the concentrated solution of fluorotitanium acid, which is directed to extraction of titanium. The gained first, second and additional sediments of sodium fluorotitanate are combined and subjected to conversion with production of sodium fluorosilicate and the conversional fluorotitanium acid added to fluorotitanium solution before its evaporation. The technical result of the invention is a decrease in 2.0-2.5 times of the volume of the cleansing solutions at provision of a high degree of extraction of compounds of titanium and other target products. The produced sodium fluorotitanate contains the decreased amount of the impurity ingredients of calcium and strontium.

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7 cl, 1 dwg, 1 tbl, 3 ex

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5 tbl, 5 ex

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2 cl, 1 tbl, 3ex

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2 tbl, 2 ex

FIELD: production of pure niobium.

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EFFECT: production of pure niobium with increased effectiveness without deterioration of refined niobium quality.

2 cl, 1 tbl

The invention relates to pyrometallurgy, in particular the production of niobium from its oxide, and can be used for the production of ferroniobium

The invention relates to the field of hydrometallurgical processing of tantalum raw materials and are aimed at achieving its complex use

FIELD: metallurgy.

SUBSTANCE: invention pertains to procurement of metallic device; in particular, parts for gas turbines of the flying constructions made from titanium alloys. To produce such metallic devices, the following range of procedures must be brought into action. Firstly, one or several non-metallic junction-predecessors should be made ready, each containing metallic composition element therein. These need to be chemically restored to procure a multitude of initial metallic particles, preferably those whose size varies between 0.0254 mm to approximately 13 mm, which do not have to be melted down. After having been fused at a later stage, they will solidify. The melted and solidified metal can be used either as a casting metal product or can be transferred into a partially finished product (billet) to be processed additionally until it is ultimately ready. The invention permits to substantially reduce the frequency of chemical faults in a metal product.

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19 cl, 4 dwg

FIELD: nonferrous metallurgy.

SUBSTANCE: invention relates to manufacturing zirconium powder for making pyrotechnic articles, in particular explosive and inflammable mixtures. By-layers prepared powered mixture of potassium fluorocirconate and alkali metal chloride, preferably sodium chloride, at ratio 1:(0.15-0.6) and sodium metal in amount exceeding its stoichiometrically required amount by 10-20%. Preparation involves grinding of potassium fluorocirconate and alkali metal chloride to fineness below 50 μm as well as preliminary recrystallization of potassium fluorocirconate. Charge is heated to temperature 450-600°C, at which reduction reaction starts and during this reaction reaction mixture heats to 700-800°C and reduction of potassium fluorocirconate takes place. Reaction products are cooled to 400-650°C and freed of sodium through vacuum distillation at residual pressure 1.3-13.3 Pa for 0.5-2.0 h, after which they are discharged from reaction vessel and ground. Zirconium powder is washed with water to remove fluoride and chloride salts and then dried. Zirconium powder contains 95-98% of fine fractions, including fraction below 10 μm in amount 45-55%.

EFFECT: enhanced fineness of prepared zirconium powder end assured fire safety of the process.

8 cl, 3 ex

FIELD: treatment of powdered, especially metal containing initial material introduced together with treating gas such as reducing gas for creating fluidized bed in fluidized bed chamber, for example in fluidized-bed reactor.

SUBSTANCE: treating gas at least after partial conversion in fluidized bed is removed out of fluidized bed and then outside fluidized bed it is partially recovered, preferably oxidized due to performing chemical, namely exothermal reaction with gaseous and(or) liquid oxidizer. Heat energy of such reaction at least partially is fed to fluidized-bed chamber, especially to fluidized bed or it is taken out of it. Cyclone is arranged over fluidized bed in fluidized-bed chamber. Powdered initial material is heated or cooled in zone of cyclone, namely near inlet opening of cyclone due to using treating gas at least partially recovered over fluidized bed in fluidized-bed chamber, possibly heated or cooled, and(or) due to using system for recovering treating gas.

EFFECT: possibility for decreasing caking on distributing collector of fluidized-bed reactor, lowered slagging in zone of fluidized bed.

10 cl, 1 dwg

FIELD: powder metallurgy, possibly production of finely dispersed powder of molybdenum, its composites with tungsten, namely for producing hard alloy materials on base of molybdenum and tungsten.

SUBSTANCE: method provides production of molybdenum and its composites with tungsten at temperature no more than 900°C and also production of materials in the form of finely dispersed powders. Method comprises steps of reducing compounds of molybdenum and tungsten (MoO3 and WO3) by metallic magnesium in medium of melt chlorides such NaCl, KCl or carbonates such as Na2CO3, K2CO3 or their binary mixtures such as NaCl - KCl, Na2CO3 - K2CO3, NaCl - Na2CO3, KCl - K2CO3 at temperature 770 -890°C. According to results of fineness analysis produced powder of molybdenum represents homogenous material having 80% of particles with fraction size 2.2 - 3 micrometers. Composition material depending upon Mo content includes particles with fraction size 5 - 15 micrometers.

EFFECT: enhanced efficiency of method.

1 tbl, 3 ex

FIELD: non-ferrous metallurgy, possibly production of highly purified powders of tantalum and niobium with large specific surface by metal thermal reduction.

SUBSTANCE: method is realized at using as corrosion protection means layer of halide of alkali metal formed on inner surface of vessel before creating in reaction vessel atmosphere of inert gas. Charge contains valve metal compound and halide of alkali metal. It is loaded into reaction vessel and restricted by protection layer of halide of alkali metal having melting temperature higher than that of charge by 50 - 400°C. Before loading charge, valve metal compound and alkali metal halide may be mixed one with other. Mass of protection layer of alkali metal halide Ml and charge mass Mc are selected in such a way that that to satisfy relation Ml = k Mc where k - empiric coefficient equal to 0.05 - 0.5. Gas atmosphere of reaction vessel contains argon, helium or their mixture. Fluorotantalate and(or) oxyfluorotantalate or fluoroniobate and(or) oxyfluoroniobate of potassium is used as valve metal compound. Sodium, potassium or their mixture is used as alkali metal. Chloride and(or) fluoride is used as alkali metal halide. Valve metal compound and alkali metal halide may contain alloying additives of phosphorus, sulfur, nitrogen at content of each additive in range 0.005 - 0.1% and 0.005 - 0.2% of mass valve metal compound respectively. Invention lowers by 1.3 - 2 times contamination of powder with metallic impurities penetrating from vessel material. Value of specific surface of powder is increased by 1.2 - 1.8 times, its charge is increased by 10 - 30 %, leakage current are reduced by 1.2 - 1.5 times.

EFFECT: improved quality of valve metal powder, enhanced efficiency of process due to using heat separated at process of reducing valve metal for melting protection layer.

9 cl, 1 tbl, 4 ex

The invention relates to the metallurgy of tungsten, in particular the production of metallic tungsten from wolframalpha compounds, in particular SelidovUgol concentrate
The invention relates to powder metallurgy and can be used to obtain powder for capacitor production

The invention relates to ferrous metallurgy and can be used to obtain alloy powders of tantalum or niobium
The invention relates to metallurgy, in particular, to obtain granules and powders of rare and radioactive metals and their alloys

The invention relates to ferrous metallurgy and can be used to obtain high-purity powders of tantalum and niobium with a large specific surface for the production of capacitors

FIELD: non-ferrous metallurgy, possibly production of highly purified powders of tantalum and niobium with large specific surface by metal thermal reduction.

SUBSTANCE: method is realized at using as corrosion protection means layer of halide of alkali metal formed on inner surface of vessel before creating in reaction vessel atmosphere of inert gas. Charge contains valve metal compound and halide of alkali metal. It is loaded into reaction vessel and restricted by protection layer of halide of alkali metal having melting temperature higher than that of charge by 50 - 400°C. Before loading charge, valve metal compound and alkali metal halide may be mixed one with other. Mass of protection layer of alkali metal halide Ml and charge mass Mc are selected in such a way that that to satisfy relation Ml = k Mc where k - empiric coefficient equal to 0.05 - 0.5. Gas atmosphere of reaction vessel contains argon, helium or their mixture. Fluorotantalate and(or) oxyfluorotantalate or fluoroniobate and(or) oxyfluoroniobate of potassium is used as valve metal compound. Sodium, potassium or their mixture is used as alkali metal. Chloride and(or) fluoride is used as alkali metal halide. Valve metal compound and alkali metal halide may contain alloying additives of phosphorus, sulfur, nitrogen at content of each additive in range 0.005 - 0.1% and 0.005 - 0.2% of mass valve metal compound respectively. Invention lowers by 1.3 - 2 times contamination of powder with metallic impurities penetrating from vessel material. Value of specific surface of powder is increased by 1.2 - 1.8 times, its charge is increased by 10 - 30 %, leakage current are reduced by 1.2 - 1.5 times.

EFFECT: improved quality of valve metal powder, enhanced efficiency of process due to using heat separated at process of reducing valve metal for melting protection layer.

9 cl, 1 tbl, 4 ex

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