Method of producing metal tantalum

 

(57) Abstract:

The invention relates to metallurgy tantalum production for structural products and tantalum capacitors. A method of producing tantalum is to restore his zincatura of the blend containing pentachloride tantalum and potassium chloride in a ratio of 1:(0,51,0) by weight with increasing temperature from 370 to 720oAnd the extraction of tantalum from the product recovery vacuumforming processing the resulting reaction mass. The recovery process is carried out by feeding a metal reducing agent is zinc on the surface of the mixture continuously during the process or in portions. When the rationed supply the quantity of reducing agent when the temperature on every 40-60oin the interval 370-720oC is 12-17% of the total amount of the reducing agent. Before surgery vacuumforming processing of the reaction mass is then cooled and vacuumforming processing carried out at the initial temperature of the reaction mass 500-510oC and initial pressure 110-1-110-2mm RT. Art. the rise of temperature up to 1000-1010oC and a pressure not exceeding 110-3mm RT. Art. Also offered the option vacuumforming overtime is m by lowering the pressure from atmospheric up to 110-3mm RT. V. Technical result is that the obtained powdered tantalum fractional and chemical composition meets the requirements for tantalum materials used for the production of tantalum structural products and tantalum capacitors. The method is environmentally friendly technologies. 4 C.p. f-crystals, 1 table.

The invention relates to the field of metallurgy of refractory rare metals, namely metallurgy tantalum, and can be used to obtain tantalum for the production of structural tantalum products and tantalum capacitors. Fractional and chemical composition of tantalum obtained by the proposed method meets the requirements for tantalum materials in both areas of its use.

A known method of producing tantalum nitratereductor restoration of its fluoride complex salts with subsequent hydrometallurgical processing of the reaction mass. This method is only used in industrial practice. (See Zelikman A. N. and other Niobium and tantalum. M.: Metallurgy, 1990. 126-130). The resulting tantalum powder can be used in the production design and the d material weaknesses, the main of which are: the need to create a redistribution of complex fluoride of potassium - K2TaF7low quality product for a range of major impurities, such as Nb, Fe, O2the presence of the operation technology of hydrometallurgical processing of the reaction mass with discharge in the environment fluoride salts or disposed of slabokontsentrirovannye fluorine-containing solutions.

A method of obtaining metal tantalum recovery pentachloride tantalum magnesium, sodium, potassium. The recovery process is carried out in a steel crucible, where to download the charge consisting of tantalum chloride, magnesium turnings and chlorides of potassium and sodium, employees flux. The restoration carried out in an atmosphere of dried argon, slowly lowering the crucible in a furnace, heated to 750oC. the Reaction mass is washed salt products and excess magnesium water and a mild hydrochloric acid. Product recovery process is powdered tantalum. (See Rozhkov centuries "Production of metallic niobium and tantalum." The overview. Issue 2(146): Cniiatominform, 1994. 34-41 C.). The method adopted for the prototype.

The main weaknesses of the method include neizbegnost the political ungovernability of the process since its initiation, significant loss of tantalum in the hydrometallurgical processing of the reaction mass, the need for disposal of waste.

The technical result of the claimed method is to obtain tantalum, satisfying in its fractional and chemical composition requirements of materials for the production of tantalum structural products and tantalum capacitors and the creation of environmentally friendly technologies.

The technical result is achieved in that in the method of producing tantalum, including metallothermic recovery of tantalum from a mixture containing pentachloride tantalum and potassium chloride with subsequent extraction of tantalum from the products of recovery, according to the invention the recovery of tantalum spend zincatura of the blend containing pentachloride tantalum chloride and potassium in the ratio of 1:(0,51,0) by weight with increasing temperature from 370 to 720oC, and the extraction of tantalum from the product recovery exercise vacuummetrice processing of the reaction mass.

The metal is the reducing agent is zinc serves on the surface of the mixture continuously during the process with an excess of 15-20% of the stoichiometric required.

Who is on every 40-60oin the interval 370-720oC is 12-17% of the total amount of the reducing agent.

At the end of the recovery process before the operation vacuumforming processing of the reaction mass is then cooled and vacuumforming processing carried out at the initial temperature of the reaction mass 500-510oC and initial pressure 110-1-110-2mm RT. Art. with increasing temperature up to 1000-1010oC and a pressure not exceeding 110-3mm RT. Art.

Or vacuumforming processing of the reaction mass are directly after a restore operation when the temperature of the reaction mass 720oAnd atmospheric pressure uniform temperature rise to 1000-1010oWith simultaneous uniform pressure drops to 110-3mm RT. Art.

The essence of the claimed invention consists in the following. Use as a charge for recovery of a mixture of TaCl and KCl at a ratio of 1:(0,51,0) mass provides education at the initial stage of the process of low-melting (melting point 370oC) and thermally stable (the onset temperature of thermal decomposition with release of gaseous TaCl5- 540o(C) salt water, close the soft reductant as metallic zinc, leads to the restoration of pentachloride tantalum to the connection of its lower valences: l4and l3and the simultaneous binding of their excess KCl in thermally much more durable than KTaCl6complex salts of K2TaCl6and K2TaCl5and formed ZnCl2- K2ZnCl4. This allows heating of the melt without evaporation and loss pentachloride tantalum to a temperature that provides a favorable kinetic conditions for the recovery of tantalum chlorides to metal.

Operations vacuumforming processing of the reaction mass is cooled to a temperature of not more than 500-510oTo prevent boiling volatile components of the molten ZnCl2, Zn and release products recovery in the condenser during subsequent vacuum to a residual pressure of 110-1-110-2mm RT. century Heating the reaction mass with 500-510oTo 1000-1010oWith continuous vacuum and pressure not exceeding 110-3mm RT. Art. allows you to completely drive away from the products of recovering volatile components chlorides of zinc, potassium and excess reducing agent.

Vacuumforming processing can be poplava provide uniform pressure drop in the reactor is proportional to the uniform increase in the temperature of the reaction mass.

The rationale of the proposed methods and process parameters.

Metallothermic ways of getting powdered tantalum traditionally involve two operations: metallothermic recovery of tantalum from its compounds are strong reducing agents (sodium, magnesium, potassium) and the subsequent hydrometallurgical processing of products recovery. The use of relatively mild reducing agent is zinc, in contrast to the use of strong reducing agents, allows to speed recovery through the chloride compounds of tantalum lower valences. The process in this case takes place in the molten salt containing dissolved tantalum compounds. The kinetics of recovery of zinc significantly better than when using the above strong reducing agents, because its density is higher than the density of molten salt. Applied to the surface of the charge zinc drowning in the melt, which provides mixing of the melt and more effective contact of the reacting phases than in the case of the interaction of the melt with floating on its surface by the reducing agent.

The maximum temperature cincturing recovery (720o(C) limited to biostructure process, as well as the low efficiency of zinc as the reducing agent, do not provide full recovery of tantalum from salt water, as is the case when using a strong reducing agents and high process temperatures (850oC). Consequently, at the completion of the process in the melt remains of 0.4-0.5% nedoustanovlennoy (dissolved) tantalum. Holding hydrometallurgical processing of products in these conditions was not feasible due to the inevitable loss of tantalum, which have not undergone restoration. In addition, the products of hydrolysis nedoustanovlennoy salts of tantalum is extremely difficult to filter working solutions.

Removing the tantalum vacuumforming processing products recovery eliminates these drawbacks. Heating products provides evaporation of excess reductant (boiling point 906oC) located at the bottom of the melt, break it bubbles through the layer of melt, perfect mixing and full dopostavleno tantalum salts to metal. Thus, the operation vacuumforming processing of the reaction mass does in this process two functions: dopostavleno dissolved in the molten salt tantalum lower valences on the initial replication of the AI.

The essential feature of the claimed method is the ratio TaCl5and Kl in charge equal to 1:(0,51,0) by weight. The bottom of the stated limit ratio of 1: 0.5 to match the amount of potassium chloride, sufficient to bind all of tantalum, regardless of its valence forms a complex salt KTaCl6, K2l6and K2TaCl5. The upper limit of the ratio 1:1.0 equals excess KCl to reduce the melting of the charge in the beginning of the process with a temperature of 430oWith (delectica KTaCl6) to 370oC (eutectic KCl-KTaCl6and to restore in a wider temperature range, which determines the possibility of practical realization of the invention. Increasing the amount of potassium chloride in the mixture in excess of match 1:1,0 in addition to the undesirable increase of the melting temperature of the charge, leads to the destruction of the cleaning mechanism from a number of impurities having a relatively low strength of the complex with KCl.

The presence in the mixture of strong complexing agents - potassium chloride defines education in the melt chloride complex salts of tantalum, zinc, as well as some impurity elements such as niobium and iron. thermal stability of the complex half-life is 4. In the initial stage of the process, the excess potassium sufficient for the formation of complex salts of tantalum, as well as all impurities. However, when the feed to the reactor zinc is formed ZnCl2and another complex salt - K2ZnCl4. As this accumulation of salt in the melt occurs deficit KCl, which leads to the destruction of the less durable than the K2ZnCl4complexes of impurities KNbCl6and KFeCl4. Released during the chlorides of iron and niobium - FeCl3and NbCl5evaporate and are carried from the melt into the cold zone of the reactor. In the case of excess Kl in the melt above the ratio of 1:1,0 required deficit does not occur and the mechanism of purification of the melt is not included.

Temperature limit cooling of the products after the restoration process, 720oWith up to 500oWith due to the need of exception ejection of the melt in the condenser under vacuum heated the reaction mass to 110-1-110-2mm RT. Art. including volatile products - ZnCl2and Zn.

The beginning of the process vacuumforming food processing can be carried out without cooling the reaction mass after completion of the recovery process. This requires adjustable uniform lowering of the pressure is LASS="ptx2">

Examples of the method cincturing getting powdered tantalum.

Example 1. In the retort stainless steel with a diameter of 200 mm and a height of 900 mm establish a quartz reactor with a diameter of 160 mm and a height of 850 mm, which loads powder charge, consisting of 8,0 kg l5and 6.4 kg KCl, pre-mixed in the atmosphere of dried nitrogen. The retort is closed by a cover, the reactor was placed in an electric furnace of the resistance. The recovery process is carried out in an atmosphere of dried argon.

The heating apparatus is carried out with a speed of 6-8oa minute.

Portional supply of reductant begin when reaching into the reactor temperature 370oC. Just serves 8 portions zinc 525 g (14% of the total quantity of reducing agent) each. The next portion is served after increasing the temperature to 50oC. the Total amount of reducing agent - 4.2 kg, which corresponds to 115% of the stoichiometric amount.

After the last portion of zinc for 720oWith time and exposure of the reactor is removed from the furnace and cooled to 500oC. the Cover on the socket evacuation of the gaseous products replace fusible plug from the zinc plate. On recorreremos 500-550oC. Include a heating furnace (the speed of 6-8oper minute) and start the vacuum capacitor, the retort and gas space contrajournal furnace. 3-5 minutes is the penetration of zinc caps on the pipe in the gas space of the retort and condenser are reported. The pressure in the retort is reduced to 110-1-110-2mm RT. senior Process vacuumforming distillation salts and excess reductant continues until it reaches the temperature on the surface of the retort 1000oWith residual pressure in the condenser - 110-3mm RT. Art. and in the retort - not more 0,510-3mm RT. p.. After cooling and removal retort process product - tantalum powder poured from a quartz reactor.

Example 2. The blending process and its holding up to the stage of completion of the exposure after recovery is similar to example 1.

Preheated 720oWith the retort set in contractorsnow furnace heated to a temperature of 720-750oC. After installation, fusible plugs and condenser switch on the furnace. During vacuumforming separation in the condenser support the following gauge mode depending on the temperature on the surface

850oS - 200 mm RT. Art.,

900oWith 10 mm RT. Art.,

950oC - 10-3mm RT. Art.,

1000oC - 10-3mm RT. Art.

After cooling and removal retort process product-tantalum powder as in example 1 is poured out of the quartz reactor.

Characteristics obtained by the method cincturing recovery of tantalum powder in examples 1 and 2 given in the table.

Data presented in table indicate that received on the proposed technology powdered tantalum satisfies the requirements of THE 95205-82 on tantalum materials for the production of ingots of the highest grade. High recovery of tantalum, the reliability of the technology, allowing to automate the process, the application utilized in industry the main equipment indicate favorable prospects for large-scale development of the invention.

Easy grindability get Malaspina agglomerates to a particle size consistent with the requirements of tantalum capacitor powders, the adequacy of the chemical composition of the powders characteristics capacitor powders open prospects for their use in electronics.

1. holding pentachloride tantalum and potassium chloride, with the subsequent extraction of tantalum from product recovery, characterized in that the recovery of tantalum spend zincatura of the blend containing pentachloride tantalum and potassium chloride in a ratio of 1:(0,51,0) by weight, with increasing temperature from 370 to 720C, and extraction of tantalum from the product recovery carry out the vacuum-thermal treatment of the resulting reaction mass.

2. The method according to p. 1, wherein the metal reducing agent is zinc serves on the surface of the mixture continuously during the process when the total number 115-120% of stoichiometry.

3. The method according to p. 1, wherein the metal reducing agent is zinc serves on the surface of the charge portions, and the quantity of reducing agent when the temperature on every 40-60C in the interval 370-720C is 12-17% of the total amount of the reducing agent.

4. The method according to any of paragraphs.1-3, characterized in that at the end of the recovery process before the operation of the vacuum heat treatment of the reaction mass is then cooled and vacuum heat treatment is carried out at the initial temperature of the reaction mass 500-510C and initial pressure 110-1-110-2mm RT. Art. with increasing temperature up to 1000-1010C O vacuum heat treatment of the reaction mass are directly after a restore operation when the temperature of the reaction mass 720C and atmospheric pressure uniform temperature rise to 1000-1010C and simultaneous uniform pressure drops to 110-3mm RT. Art.

 

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FIELD: production of pure niobium.

SUBSTANCE: method includes reducing fusion of niobium pentoxide with aluminum and calcium to provide crude ingots followed by heat treatment and multiple electron beam refining. As an additional raw material in step of reducing fusion sublimates (preferably in non-oxidized form) from second and subsequent electron beam refining are used. Such sublimates are obtained by subsequent cooling of furnace smelting chamber under residual pressure of 10-2-10-4 mmHg for 1.0-3.0 h, letting-to-helium under 1-3 mmHg for 1.0-3.0 h, and letting-to-air for 20-40 min. Sublimates are added in amount of 4.5 % based to feeding niobium pentoxide. Claimed method affords the ability to increase niobium pentoxide consumption by 73 kg in respect to 1000 kg of pure niobium in crude ingots.

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

2 cl, 1 tbl

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