Charge for production of niobium-bearing material and a method of its preparation

FIELD: metallurgy; methods of preparation of charges for production of niobium-bearing material.

SUBSTANCE: the invention is dealt with production of niobium-bearing materials used for production of special steels. The technical result is an increased degree of transition of niobium into an alloy, decreased share of impurities in the alloy, decreased production costs. For this purpose the charge for production of a niobium-bearing material contains the raw material containing niobium pentaoxide, a nickel-bearing material, aluminum, calcium oxide, calcium fluoride and an exothermic oxidative additive. At that in the capacity of the exothermic oxidative additive it contains potassium chlorate with moisture of 2-12% at the following ratio in shares in respect to the total weight of the charge: niobium pentaoxide - 0.470-0.520, nickel - 0.190-0.270, aluminum - 0.180-0.200, calcium oxide - 0.030-0.040, calcium fluoride - 0.003-0.004, potassium chlorate with moisture of 2-12% - 0.043-0.049. At preparation of the charge after mixing of components it is exposed to compaction in the crucible up to the value of the plastic strength of 0.4-10.0 MPa.

EFFECT: the invention ensures an increased degree of niobium transition into an alloy, decreased share of impurities in the alloy, decreased production costs.

2 cl, 1 tbl, 3ex

 

The invention relates to metallurgy, namely to obtain NB materials used for special steels.

As the closest analogue to the mixture to obtain NB material and method of preparation of this mixture is taken (1)in which there is a charge to obtain NB material, including raw materials containing niobium pentoxide, niobium, Nickel-containing material, aluminum, calcium oxide, calcium fluoride and exothermic oxidation additive, and a method of preparation of the mixture to obtain NB material, comprising mixing raw materials containing niobium pentoxide, niobium, aluminum, Nickel-containing material, calcium oxide, calcium fluoride and oxidative exothermic additive for download in a metal crucible for ignition.

The disadvantage of this mixture is not sufficiently high degree of extraction of niobium in the alloy (92,5%), lack of purity of the final alloy of aluminium and nitrogen (more than 1.0 and 0.04%, respectively), the need for multi-stage energy-consuming and rather time-consuming process in high temperature furnaces. In addition, the process of this charge is fraught with the following unwanted phenomenon: in the hot condition often ignite (and vzryvoobrazno) sublimates.

For what Ajami, which is aimed at solving this invention is the achievement of a technical result: increase of the transition of niobium in the alloy, the reduced content of impurities, in particular, Al and N in the final alloy, the reduction in the explosion process, and improving economic performance by reducing energy consumption and time of melting.

The technical result is achieved in that the mixture to obtain NB material, including raw materials containing niobium pentoxide, niobium, Nickel-containing material, aluminum, calcium oxide, calcium fluoride and exothermic oxidation additive, characterized in that the exothermic oxidation additives it contains potassium chlorate humidity 2-12% in the following ratio, in percentage, of the total weight of the mixture:

the niobium pentoxide, niobium 0,470-0,520

Nickel 0,190-0,270

aluminum 0,180-0,200

calcium oxide 0,030-0,040

calcium fluoride 0,003-0,004

the potassium chlorate with humidity 2-12% 0,043-0,049

And the fact that the method of preparation of the mixture to obtain NB material, comprising mixing raw materials containing niobium pentoxide, niobium, aluminum, Nickel-containing material, calcium oxide, calcium fluoride and oxidative exothermic additive for download in a metal crucible for ignition, according to the invention, as exothermic additive used is tons of potassium chlorate with humidity 2-12% and after mixing the mixture is compacted in the crucible to the size of the plastic strength of 0.4-10.0 MPa.

Use as exothermic oxidation additives wet (2-12% N2A) potassium chlorate will allow the first wave of thermal energy, which is extremely intense is formed by the reaction of potassium chlorate and aluminum, to send the water evaporation and hardening of low-melting eutectics of micropores formed as a result of evaporation in a compact to the plastic strength of 0.4-10.0 MPa material, which from the zone of active oxidation-reduction reactions gases are released to the surface. This prevents the threat of gas concentration inside the charge mass with a further explosion or ejection charge. On the other hand, the pressure of exhaust gases prevents contact of molten metal with the atmosphere, from which the melt enters the nitrogen. The use of chlorate calcium instead of nitrate eliminates an additional source of nitrogen pollution. The seal of the charge leads to a closer contact of the oxidant with aluminum, which is more fully and with greater speed becomes oxidized state, is not able to dissolve in the formed metal melt. In addition, potassium chlorate, together with slag-forming reagents increases legkopodwijnaya slag, after which the active gas in the micropores, has preliminarily formed in the compacted charge easily reaches the molten metal and will protect the ingot from unwanted contact with the atmosphere during solidification and cooling.

The ranges of the contents are explained as follows.

For Nb O less than 0.47 content of niobium in the final alloy will be less than 55%;

more than 0.52 content of niobium in the final alloy will be more than 65%.

For Ni of less than 0.19, the Nickel content in the final alloy will be less than 35%;

more than 0.27 content of niobium in the final alloy will be more than 45%.

For Al less than 0.18 is not achieved the necessary degree of recovery of niobium;

more than 0.20 - excess aluminum can go into the alloy, polluting it.

Calcium oxide less than 0.03 - due to insufficient output from the reaction zone of the aluminum oxide will decrease the degree of extraction of niobium in the alloy;

more than 0.04 - excess will increase the viscosity of the slag without improvements to the main index, will increase the output of slag, which lost the alloy.

Calcium fluoride less than 0,003 - toxins are not flexible enough, the difficulty in separating it from the alloy will reduce the yield of the latter;

0.004 - excess reagent, not leading to improved performance, will increase the amount of waste slag.

Potassium chlorate is less 0,043 - deficiency obtained by the decomposition of salt heat will deteriorate the oxidation-reduction reactions and reduce the article the stump transition of niobium in the melt;

more 0,049 - excess of salt will lead to local overheating and change the direction of the reactions that will affect the process performance.

The humidity of potassium chlorate: less than 2%, there is a tendency to emissions charge;

increased content of aluminum and nitrogen in the alloy;

more than 12% - increased content of nitrogen and aluminum in the alloy, drop all the process indicators, as heat is spent for evaporation of moisture.

The range of the given values of plastic strength is explained as follows.

Plastic strength: less than 0.4 MPa is observed microfibres charge, increased aluminum content in the alloy;

more than 10 MPa is getting worse all the technological parameters of the process, including the degree of contamination of the alloy of aluminum and nitrogen. In the more dense the material begin to appear the phenomenon of microvibration.

As the Nickel-containing materials can be recycled NiNb-ligatures.

Examples 1-3

Preparation of the mixture was carried out as follows.

The original niobium pentoxide, niobium (Nb25) was mixed with wet potassium chlorate (2-12% H2O), the resulting mixture of niobium pentoxide, niobium and potassium chlorate mixed with aluminum powder PA-4, the mixture of niobium pentoxide, niobium, potassium chlorate and aluminum powder was mixed with Nickel or mixture of waste from production nominitive ligatures, calcium fluoride (Caf2) and calcium oxide (Cao). The resulting mixture was placed in a copper (or iron) the crucible and condensed before reaching the plastic strength of 0.4-10.0 MPa, which is measured using the methods specified in lit. source (2). The mixture was lit from the surface using a heated nichrome spiral. Melting of the charge flowed within 1.0 to 1.5 minutes

Examples of compositions and plastic strength of the blends are listed in table 1.

Table 1
№ p/pThe content in the charge, in increments of ObsesThe formation. strength, MPaThe content in the alloy, wt%Retrieve s in the alloy Nb, % of Ref.
Nb2O5NiAlCaOCaF2lO3waste NiNbNbNiAIN
10,470,270,180,030,0030,0430,090,4of 60.539,50,580,01295,5
20,490,190,190,0350,00350,046 0,0455,055,044,20,380,01295,0
30,520,200,200,040,0040,049010,064,235,00,330,01294,9

Thus, embodiments of the invention (table. 1) demonstrate the following technical result from the introduction of damp within the specified limits of potassium chlorate, along with the seal of the mixed charge in the crucible to achieve quantities of plastic strength of 0.4-10.0 MPa: prevents the explosion process: the degree of transition of niobium in the alloy is of 94.9 95.5 per cent, the contents of aluminum and nitrogen in the alloy does not exceed 1.0 and 0.02%, respectively, there are no energy costs of running the melting unit, reduced time actually melting to 1.0 to 1.4 minutes

In summary, we can conclude: with the help of the claimed invention, it becomes possible to achieve a technical result: vzravobezopasna, economically, with a high degree of extraction of the base metal (of 94.9 95.5 per cent) get in the open crucible, without heating and protect the surface of the inert gas is expensive and in short supply for high-tech (aviation, space technology, scuba sudos the building, petrochemicals and other) industries especially clean of unwanted impurities (Al and N, respectively, not more than 1.0 and 0.02 wt.%) the alloy. Comparison of compositions of similar alloys produced by the firms of the world's leading producers of special steels and using the invention, confirms these findings.

The list of references

1. The patent of Russian Federation № 2007486, CL 22 With 1/02, With 22 1/03 "Method of obtaining nominitive ligatures in the electric furnace”announced. Chernega NI and others, Klyuchevsky Ferroalloy plant, Institute of metallurgy, publ. 15.02.94.

2. Pavlasek, Iggeres “basic techniques of granulation”, M, “Chemistry”, 1982, p.27-33.

1. Charge to obtain NB material, including raw materials containing niobium pentoxide, niobium, Nickel-containing material, aluminum, calcium oxide, calcium fluoride and exothermic oxidation additive, characterized in that the exothermic oxidation additives it contains potassium chlorate humidity 2-12% in the following ratio, in percentage, of the total weight of the mixture:

the niobium pentoxide, niobium 0,470-0,520

Nickel 0,190-0,270

aluminum 0,180-0,200

calcium oxide 0,030-0,040

calcium fluoride 0,003-0,004

the potassium chlorate with humidity 2-12% 0,043-0,049.

2. The method of preparation of the mixture to obtain NB material, comprising mixing the materials is, containing niobium pentoxide, niobium, aluminum, Nickel-containing material, calcium oxide, calcium fluoride and oxidative exothermic additive for download in a metal crucible for ignition, characterized in that the exothermic additive use potassium chlorate with humidity 2-12% and after mixing the mixture is compacted in the crucible to the size of the plastic strength of 0.4-10.0 MPa.



 

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2 cl, 4 ex, 3 tbl

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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.

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2 cl, 1 tbl

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EFFECT: enhanced efficiency of process, lowered cost price of high-purity niobium ingots.

2 tbl, 2 ex

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