Method of electrochemical processing refractory nickel alloy wastes bearing rhenium, tungsten, tantalum and other valuable metals

FIELD: metallurgy.

SUBSTANCE: proposed method comprises anodic oxidation of melt in acid electrolyte at application of electric current. Note here that said anodic oxidation is carried out in acid electrolyte containing 150 g/l of H2SO4+50 g/l HCl. Applied direct electric current features density of 250-300 mA/cm2. Application of said current is conducted at 20-40°C.

EFFECT: notable increase in anodic oxidation rate.

3 tbl, 2 ex

 

The invention relates to the recycling of metallic materials, in particular the recycling of waste heat-resistant Nickel alloys containing rhenium, tungsten, tantalum and other precious metals.

In modern conditions in Russia there is no reliable and Mature raw sources of rhenium that defines an acute need to make maximum use of different types of secondary raw materials containing the metal (waste metal rhenium, rhenium waste catalysts and others).

One of the most popular types of secondary registertimer raw materials are waste heat-resistant Nickel alloys brand LGL-32. Their typical composition shown in table 1.

Table 1
Typical waste composition alloys brand LGL-32
ComponentContent, %ComponentContent, %
Nickel~60Chrome4,7-5,0
Rhenium3,6-4,0Niobium1,3-1,5
Wolfram8,0-8,5Aluminum5,1-5,3
Molybdenum1,0-1,2Siliconof 0.7-0.9
Tantalum3,3-3,5Cobalt7,0-7,5

In industrial conditions, metal waste Nickel and cobalt are usually podsalivayut when pyrometallurgical processing of ore and secondary raw materials [Khudyakov IVAN Tikhonov, A.I. and other metallurgy of copper, Nickel and cobalt, M.: metallurgy, 1976, 230 S.]. Rhenium and other metals in these conditions completely lost with different products (flue gases, slag and the like).

The known method (similar) decomposition HRSA brand LGL-32 mineral acid (H2SO4, HNO3in oxidative conditions with the translation of the main part of rhenium in the solution [of the Caciques A.G., Petrova A. M. Recycling of rhenium from waste heat resistant steels and special alloys. Technology of metals, 2010, No. 2, pp.2-12]. The limiting factor of this process is the need for pre-shredding recyclable products.

The closest technical solution (prototype) is a "Method for electrochemical processing of metallicheskih waste heat-resistant Nickel alloys containing rhenium [RF patent №2401312 from 09.04.2009]. The process involves anodic oxidation (dissolution) of the waste heat resistant alloy in acidic electrolytes (200-250 g/l HNO3or 150-200 g/l H2SO4) at a temperature of 20-40°C and amperage of at least 1 kA.

Processing is carried out in the mode of the asymmetric half-wave alternating current of industrial frequency. The disadvantage of this method is the limited speed of oxidation (dissolution) of the alloy, which in the proposed mode is only 50-56 mg/HR·cm2.

The problem to which the present invention is directed, is to create a method for electrochemical processing of heat-resistant Nickel alloys containing rhenium, tungsten, tantalum and other precious metals, using acidic electrolyte when applying electric current to the intensification of redistribution.

The technical result of the invention is a significant increase in the speed of the process of anodic oxidation to 250-313 mg/cm2·h.

This technical result is achieved by the fact that during electrochemical processing of waste heat-resistant Nickel alloys containing rhenium, tungsten, tantalum and other precious metals, includes anodic oxidation in acidic electrolyte upon application of a constant electric current, and according to the invention the oxidation of the alloy wire is t in acidic solution with a content of H 2SO4150 g/l HCl and 50 g/l at a current density of 250 to 300 mA/cm2and a temperature of 20-40°C.

The invention consists in that the waste heat-resistant Nickel alloys containing rhenium, tungsten, tantalum and other precious metals, carried out by anodic oxidation under the application of a constant electric current in an acid electrolyte. The electrolyte composition: 150 g/l H2SO4+50 g/l HCl; mode process: density constant electric current 250-300 mA/cm2temperature of 20-40°C.

In these conditions, the rate of anodic oxidation of the alloy is 250-315 mg/cm2·hour, which is considerably higher than in the prototype. Table 2 presents the composition of the products of the processing of the alloy LGL-32.

As can be seen from table 2, when implementing the process of anodic oxidation of waste in this mode, the main part of rhenium (>80%), as well as tungsten, tantalum and niobium (~99%) is transferred into the solid phase (anode KEK). While Nickel, cobalt and other non-ferrous metals (aluminum, chromium) accumulate in acidic electrolyte solution (90% or more).

/table>

Typical balanced distribution of metals in the products of electrochemical recycling of alloy LGL-32 in acidic electrolyte (H2SO4+HCl) are presented in table 3.

Table 2
The metal content in products of processing when the electrochemical oxidation of the alloy LGL-32 in a solution of 150 g/l H2SO4+50 g/l is CL under the action of a constant electric current
MetalNiCoWAlCrReTaNbMo
The solid phase (KEK), %0,85-0,880,15-0,29of 24.3 and 24.52,2-4,61,0-1,45,8-7,4by 12.4 and 12.64,8-5,32,7-2,8
Electrolyte (acid solution), g/l60-805,5 - 6,40,02-0,052,2-4,65,2-7,40,6-0,8<0,01<0,010,27-0,42
Of located, g/la 13.3-13,71.1 to 1.40,051,2-1,70,9-1,40,3-0,4<0,01<0,010,02-0,04
Table 3
Extraction of metals in the products of electrochemical oxidation (dissolution) waste alloy LGL-32 in acidic electrolyte, % of baseline
ComponentNiCoWAlCrReTaNbMo
Removing at KEK, %0,600,92104,27,07,272,7107,5101,292,4
Removing the electrolyte, %74,856,00,075,976,712,2 0,00,09,1
Removing the located, %29,5of 40.90,020,923,015,00,00,02,9
Debalance+a 4.9-3,1+4,2+3,9+6,9-0,1+7,5+1,2+3,4

Processing of these precursors with obtaining the appropriate commercial products is carried out by known methods, leaching, precipitation of low-solubility compounds, etc.

Example 1

For processing received lump waste heat-resistant Nickel alloy grades LGL-32. This product is a unground fragments and fragments of blades aviation gas turbines, up to 7.5 cm and a width of up to 4.5 refer to the Chemical composition of raw materials the following (in %): W 8,50; Mo 1,15; Re 3,60; Si 0,75; Ta 3,20; Nb To 1.35; 4,75 Cr; Al 5,15; C 0,15; Co 7,0, the rest is Nickel.

Mode anodic oxidation of waste: temperature 20-25°C, the density is constant e is aktionscode current 250 mA/cm 2. The composition of the original acid solution: 250 g/l H2SO4+50 g/l HCl.

Only in this mode was oxidized of 50.9 g of the original alloy. The mass obtained solid product (anode slime) amounted to 12.7 g, dissolved - 38,2, Unbalance was <1%. The rate of oxidation (dissolution) of the original alloy in this mode reaches 254 mg/cm2·the hour. In the anode product (KEK 1) moved up to 80% of rhenium and more than 99% of tungsten, tantalum and niobium.

The typical composition of the oxidation products and the extraction of metals in the products are presented in table 2 and 3, respectively.

Example 2

For processing received lump waste heat-resistant Nickel alloy grades LGL-32, similar to example 1. Chemical composition of raw materials (%) : W 8,50; Mo 1,15; Re 3,60; Si 0,75; Ta 3,20; Nb To 1.35; 4,75 Cr; Al 5,15; C 0,15; Co 7,50, the rest is Nickel.

Mode anodic oxidation (dissolution): temperature of 35-40°C, density DC 300 mA/cm2. The composition of the original acid solution: 250 g/l H2SO4+50 g/l HCl.

Only in this mode was oxidized 103,7 g of the original alloy. The mass of solid product (anode sludge) was 27.8, Dissolved 67,7, the eccentric weight of ~4%.

The rate of oxidation of the alloy under these conditions amounted to 315 mg/cm2·the hour. The distribution of metals in products similar to example 1.

These examples suggest on stijene declared effect of increasing the rate of anodic oxidation of the alloy when using this electrolyte and the application of a constant current.

Method for electrochemical processing of waste heat-resistant Nickel alloys containing rhenium, tungsten, tantalum and other precious metals that are included in the processed alloy comprising anodic oxidation of the alloy in acidic electrolyte when applying an electric current, characterized in that the anodic oxidation of the alloy is carried out in acidic electrolyte containing 150 g/l H2SO4+50 g/l HCl with the application of a constant current density of 250-300 mA/cm2and a temperature of 20-40°C.



 

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