A method for recovering valuable metals from waste tungsten slag

Abstract

The present invention relates to the technical field of industrial waste resource recovery and utilization, and particularly relates to a method for recovering valuable metals from waste tungsten slag, comprising: A) mixing a first part of waste tungsten slag powder with a slag-forming agent, followed by cold isostatic pressing to obtain a mother material blank; the slag-forming agent includes CaCO3 and SiO2; mixing a second part of waste tungsten slag powder, calcium carbonate and a metal assistant, followed by granulation to obtain a spherical blank; B) under an inert atmosphere, heating the mother material blank (or spherical blank) to 1300-1400 °C for melting, adding the spherical blank (or mother material blank) to the melted melt, continuing to heat to 1400-1600 °C for melting, and removing the slag to obtain a stable melt; C) cooling the stable melt to obtain an alloy ingot enriched with valuable metals. The recovery method can adjust the viscosity of the slag phase, which not only promotes the thermal reduction reaction, but also improves the sedimentation rate of metal droplets, reduces the residual valuable metals in the slag phase, and improves the recovery rate of valuable metals.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial waste resource recovery and utilization, and particularly relates to a method for recovering valuable metals from waste tungsten slag. Background Art

[0002] Currently, the processes for recovering valuable metals such as tungsten, tantalum, niobium, cobalt, and nickel from metallurgical solid waste are divided into two processes: pyrometallurgy and hydrometallurgy. The pyrometallurgy process generally uses reduction smelting. In this process, a carbonaceous reducing agent is added at high temperature to reduce the metal oxides in the slag and generate an alloy phase for recovery. This process has the disadvantages of high smelting temperature, high energy consumption, and difficulty in crushing and separating the generated alloy phase, resulting in a large loss of alloy inclusions in the slag. The hydrometallurgy process mainly leaches the metals in the slag with a high-concentration acid solution and then recovers them through purification and separation processes. This process has the disadvantages of high acid consumption, low metal leaching rate, complex process route, and large environmental pollution.

[0003] Patent CN110241311A discloses a recovery method. This patent uses a sulfide reduction process to recover cobalt-nickel-iron alloy from the slag after tungsten extraction. The added sulfiding agent generates a matte phase mainly composed of FeS at the smelting temperature, which can effectively dissolve the reduced cobalt, nickel, and iron from the smelting slag, realizing the separation of the alloy phase and the slag phase, reducing the alloy phase inclusions in the slag phase, and thus improving the metal recovery rate. However, when this method is applied to low-grade tungsten slag materials, the alloy phase has a small specific gravity, the slag phase has a high viscosity, and it is difficult to separate the valuable alloy from the slag phase, resulting in a low recovery rate. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for recovering valuable metals from waste tungsten slag with a high recovery rate of valuable metals.

[0005] The present invention provides a method for recovering valuable metals from waste tungsten slag, including the following steps:

[0006] A) Mix the first part of waste tungsten slag powder with a slag-forming agent and then perform cold isostatic pressing to obtain a master billet;

[0007] The slag-forming agent includes CaCO3 and SiO2;

[0008] Mix the second part of waste tungsten slag powder, calcium carbonate, and a metal additive evenly and then granulate to obtain a spherical billet;

[0009] B) Under an inert atmosphere, heat the master billet to 1300 - 1400 °C for melting. Add the spherical billet to the melted melt, continue to heat to 1400 - 1600 °C for melting, and after skimming the slag, obtain a stable melt;

[0010] Alternatively, under an inert atmosphere, the spherical blank is heated to 1300 - 1400 °C for melting, the master batch blank is added to the melted melt, and the temperature is further raised to 1400 - 1600 °C for melting. After skimming the slag, a stable melt is obtained;

[0011] C) Cooling the stable melt to obtain an alloy ingot enriched with valuable metals.

[0012] Preferably, in step A), the mass ratio of CaCO3 to SiO2 is 1:0.5 - 0.8;

[0013] Preferably, the slag-forming agent further includes CaF2, and the mass ratio of CaCO3, SiO2 and CaF2 is 1:0.5 - 0.8:0.05 - 0.15.

[0014] Preferably, in step A), in the waste tungsten slag powder, the mass content of W is 5% - 10%, the mass content of SiO2 is 30% - 40%, the mass content of Co is 1% - 5%, the mass content of Nb is 0.5% - 2%, the mass content of Ta is 1% - 5%, the mass content of S is 10% - 15%, and the mass content of organic matter is 20% - 40%; the sum of the mass contents of each component is 100%.

[0015] Preferably, in step A), the particle size of the waste tungsten slag powder is 1 - 10 μm.

[0016] Preferably, in step A), the mass ratio of the first part of the waste tungsten slag powder to the second part of the waste tungsten slag powder is 1:0.6 - 1.0;

[0017] Preferably, the mass ratio of the first part of the waste tungsten slag powder to the slag-forming agent is 1:0.2 - 0.4;

[0018] Preferably, the mass ratio of the second part of the waste tungsten slag powder, calcium carbonate to the metal auxiliary is 1:0.3 - 0.6:0.04 - 0.08;

[0019] Preferably, the metal auxiliary includes at least one of Fe, Ni and Co.

[0020] Preferably, in step A), the tap density of the master batch blank is 0.6 - 1.0 g / cm 3 3.

[0021] Preferably, in step B), the heating of the master batch blank to 1300 - 1400 °C for melting is carried out in a graphite crucible;

[0022] The master batch blank accounts for 25% - 80% of the volume of the graphite crucible.

[0023] Preferably, in step B), the heating rate of the masterbatch green body from room temperature to 1300 - 1400 °C is 5 - 15 °C / min;

[0024] The heating rate of further heating from 1400 - 1600 °C is 5 - 15 °C / min.

[0025] Preferably, in step C), cooling the stable melt includes:

[0026] First, cooling at a rate of 2 - 5 °C / min to 800 - 1200 °C, and then cooling at a rate of 5 - 10 °C / min to room temperature.

[0027] Preferably, in step C), in the alloy ingot enriched with valuable metals, the mass content of W is 20% - 50%, the mass content of Co is 10% - 40%, the mass content of Ta is 3% - 14%, and the mass content of Nb is 2% - 7%.

[0028] The present invention provides a method for recovering valuable metals from waste tungsten slag, comprising the following steps: A) Mixing a first part of waste tungsten slag powder with a slag-making agent and then performing cold isostatic pressing to obtain a masterbatch green body; the slag-making agent includes CaCO3 and SiO2; mixing a second part of waste tungsten slag powder, calcium carbonate and a metal additive, and then granulating to obtain a spherical green body; B) In an inert atmosphere, heating the masterbatch green body to 1300 - 1400 °C to melt, adding the spherical green body into the melted melt, and then continuing to heat to 1400 - 1600 °C to melt, and after slag removal, obtaining a stable melt; or in an inert atmosphere, heating the spherical green body to 1300 - 1400 °C to melt, adding the masterbatch green body into the melted melt, and then continuing to heat to 1400 - 1600 °C to melt, and after slag removal, obtaining a stable melt; C) Cooling the stable melt to obtain an alloy ingot enriched with valuable metals. The recovery method provided by the present invention can adjust the viscosity of the slag phase, which not only promotes the thermal reduction reaction but also improves the sedimentation rate of metal droplets. At the same time, the addition of the metal additive can significantly increase the density of high-entropy carbides (refractory phases) and also promote the sedimentation of the alloy liquid, thereby reducing the residual valuable metals in the slag phase and improving the recovery rate of valuable metals. Detailed embodiments

[0029] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0030] The present invention provides a method for recovering valuable metals from waste tungsten slag, comprising the following steps:

[0031] A) Mix the first part of the waste tungsten slag powder with a slag-forming agent, and then perform cold isostatic pressing to obtain a mother stock billet;

[0032] The slag-forming agent includes CaCO3 and SiO2;

[0033] Mix the second part of the waste tungsten slag powder, calcium carbonate, and a metal auxiliary agent, and then granulate to obtain a spherical billet;

[0034] B) Under an inert atmosphere, heat the mother stock billet to 1300-1400°C to melt it, add the spherical billet to the melted melt, continue to heat to 1400-1600°C to melt it, and after skimming the slag, obtain a stable melt;

[0035] Or under an inert atmosphere, heat the spherical billet to 1300-1400°C to melt it, add the mother stock billet to the melted melt, continue to heat to 1400-1600°C to melt it, and after skimming the slag, obtain a stable melt;

[0036] C) Cool the stable melt to obtain an alloy ingot enriched with valuable metals.

[0037] In step A):

[0038] In the present invention, the first part of the waste tungsten slag powder is mixed with a slag-forming agent, and then cold isostatic pressing is performed to obtain a mother stock billet;

[0039] The slag-forming agent includes CaCO3 and SiO2.

[0040] In certain embodiments of the present invention, the waste tungsten slag powder is dry waste tungsten slag powder.

[0041] In certain embodiments of the present invention, the mass ratio of CaCO3 to SiO2 is 1:0.5-0.8; specifically, it can be 1:0.6.

[0042] In certain embodiments of the present invention, the slag-forming agent further includes CaF2, and the mass ratio of CaCO3, SiO2, and CaF2 is 1:0.5-0.8:0.05-0.15; specifically, it can be 1:0.6:0.05, 1:0.7:0.1.

[0043] In certain embodiments of the present invention, in the waste tungsten slag powder, the mass content of W is 5% to 10%, the mass content of SiO2 is 30% to 40%, the mass content of Co is 1% to 5%, the mass content of Nb is 0.5% to 2%, the mass content of Ta is 1% to 5%, the mass content of S is 10% to 15%, and the mass content of organic matter is 20% to 40%; the sum of the mass contents of each component is 100%. In certain embodiments, in the waste tungsten slag powder, the mass content of W is 6%, the mass content of SiO2 is 36%, the mass content of Co is 4.5%, the mass content of Nb is 1.5%, the mass content of Ta is 3%, the mass content of S is 15%, and the mass content of organic matter is 34%. In certain embodiments, in the waste tungsten slag powder, the mass content of W is 8%, the mass content of SiO2 is 34%, the mass content of Co is 4%, the mass content of Nb is 2%, the mass content of Ta is 4%, the mass content of S is 15%, and the mass content of organic matter is 33%.

[0044] In certain embodiments of the present invention, the particle size of the waste tungsten slag powder is 1 to 10 μm.

[0045] In certain embodiments of the present invention, the mass ratio of the first part of the waste tungsten slag powder to the slag former is 1:0.2 to 0.4; specifically, it can be 1:0.28, 1:0.4.

[0046] In certain embodiments of the present invention, the pressure used for cold isostatic pressing is 170 to 200 MPa; specifically, it can be 190 MPa.

[0047] In certain embodiments of the present invention, the tapped density of the masterbatch powder is 0.6 to 1.0 g / cm 3 ; specifically, it can be 0.9 g / cm 3 .

[0048] In the present invention, after mixing the second part of the waste tungsten slag powder, calcium carbonate and metal additives evenly, granulation is carried out to obtain a spherical green body.

[0049] In certain embodiments of the present invention, the mass ratio of the first part of the waste tungsten slag powder to the second part of the waste tungsten slag powder is 1:0.6 to 1.0; specifically, it can be 1:0.8, 1:1.

[0050] The mass ratio of the second part of the waste tungsten slag powder, calcium carbonate and metal additives is 1:0.3 to 0.6:0.04 to 0.08; specifically, it can be 1:0.6:0.06, 1:0.6:0.04, 1:0.3:0.04.

[0051] In certain embodiments of the present invention, the metal promoter includes at least one of Fe, Ni, and Co. In certain embodiments, the metal promoter is Fe or Co or Ni; in certain embodiments, the metal promoter includes Fe and Ni, and the mass ratio is 1:0.7 to 1, specifically, 1:1; in certain embodiments, the metal promoter includes Fe, Ni, and Co, and the mass ratio is 1:0.7 to 1:0.8 to 1.2, specifically, 1:0.7:0.8, 1:1:1.2.

[0052] In certain embodiments of the present invention, the particle size of the spherical blank is 10 to 15 mm.

[0053] Step B) includes two cases:

[0054] Under an inert atmosphere, the master blank is heated to 1300 to 1400 °C to melt, the spherical blank is added to the melted melt, and then heated to 1400 to 1600 °C to melt. After skimming, a stable melt is obtained;

[0055] Or under an inert atmosphere, the spherical blank is heated to 1300 to 1400 °C to melt, the master blank is added to the melted melt, and then heated to 1400 to 1600 °C to melt. After skimming, a stable melt is obtained.

[0056] The first case:

[0057] Under an inert atmosphere, the master blank is heated to 1300 to 1400 °C to melt, the spherical blank is added to the melted melt, and then heated to 1400 to 1600 °C to melt. After skimming, a stable melt is obtained.

[0058] In certain embodiments of the present invention, the gas forming the inert atmosphere includes argon or nitrogen.

[0059] In certain embodiments of the present invention, the heating of the master blank to 1300 to 1400 °C for melting is carried out in a graphite crucible; the master blank accounts for 25% to 80% of the volume of the graphite crucible; specifically, it can be 80%.

[0060] In certain embodiments of the present invention, the heating rate of the master blank to 1300 to 1400 °C is 5 to 15 °C / min; specifically, it can be 10 °C / min.

[0061] In certain embodiments of the present invention, the melting temperature is 1350 °C.

[0062] In some embodiments of the present invention, the spherical blank is added to the molten melt at one time; in some embodiments, the spherical blank is added to the molten melt in multiple times; specifically, it can be added in two times, and the mass ratio of the spherical blanks added each time is 1:0.6 - 1; specifically, it is 1:1.

[0063] In some embodiments of the present invention, the heating rate for continuously heating to 1400 - 1600 °C is 5 - 15 °C / min; specifically, it can be 5 °C / min.

[0064] In some embodiments of the present invention, continue to heat to 1500 °C.

[0065] In some embodiments of the present invention, after continuously heating to 1400 - 1600 °C and melting, it further includes: keeping warm for 2 h.

[0066] The second case:

[0067] Under an inert atmosphere, heat the spherical blank to 1300 - 1400 °C for melting, add the master blank to the molten melt after melting, continue to heat to 1400 - 1600 °C for melting, and after skimming the slag, a stable melt is obtained.

[0068] In some embodiments of the present invention, the gas forming the inert atmosphere includes argon or nitrogen.

[0069] In some embodiments of the present invention, the melting of the spherical blank to 1300 - 1400 °C is carried out in a graphite crucible; the spherical blank accounts for 25% - 80% of the volume of the graphite crucible; specifically, it can be 80%.

[0070] In some embodiments of the present invention, the heating rate for heating the spherical blank to 1300 - 1400 °C is 5 - 15 °C / min; specifically, it can be 10 °C / min.

[0071] In some embodiments of the present invention, the melting temperature is 1350 °C.

[0072] In some embodiments of the present invention, the master blank is added to the molten melt at one time; in some embodiments, the master blank is added to the molten melt in multiple times.

[0073] In some embodiments of the present invention, the heating rate for continuously heating to 1400 - 1600 °C is 5 - 15 °C / min; specifically, it can be 5 °C / min.

[0074] In some embodiments of the present invention, continue to heat to 1500 °C.

[0075] In certain embodiments of the present invention, after continuously heating to 1400 - 1600 °C for melting, it further includes: heat preservation for 2 h.

[0076] In step C):

[0077] Cool the stable melt to obtain an alloy ingot enriched with valuable metals.

[0078] In certain embodiments of the present invention, cooling the stable melt includes:

[0079] First, cool it at a rate of 2 - 5 °C / min to 800 - 1200 °C, and then cool it at a rate of 5 - 10 °C / min to room temperature.

[0080] Specifically, first cool it to 1200 °C; the cooling rate for the first stage is 5 °C / min; the cooling rate for the second stage is 8 °C / min.

[0081] In certain embodiments of the present invention, in the alloy ingot enriched with valuable metals, the mass content of W is 20% - 50%, the mass content of Co is 10% - 40%, the mass content of Ta is 5% - 20%, and the mass content of Nb is 2% - 10%.

[0082] In certain embodiments of the present invention, the mass recovery rate of the alloy in the waste tungsten slag is not less than 84%.

[0083] To further illustrate the present invention, the following describes in detail a method for recovering valuable metals from waste tungsten slag provided by the present invention in combination with embodiments, but it should not be construed as a limitation to the protection scope of the present invention.

[0084] Example 1

[0085] In the waste tungsten slag powder, the mass content of W is 6%, the mass content of SiO2 is 36%, the mass content of Co is 4.5%, the mass content of Nb is 1.5%, the mass content of Ta is 3%, the mass content of S is 15%, and the mass content of organic matter is 34%. The particle size of the waste tungsten slag powder is 1 - 10 μm.

[0086] A method for recovering valuable metals from waste tungsten slag includes the following steps:

[0087] 1) Take 5 kg of the first part of dry waste tungsten slag powder and mix it with a slag-forming agent in a mass ratio of 1:0.28, and then perform cold isostatic pressing at a pressure of 190 MPa to obtain a master batch body; the slag-forming agent includes CaCO3, SiO2, and CaF2, and the mass ratio of CaCO3, SiO2, and CaF2 is 1:0.6:0.05; the tap density of the master batch body is 0.9 g / cm 3 ;

[0088] 2) Take the second part of the dried waste tungsten slag powder according to the mass ratio of the first part of the dried waste tungsten slag powder to the second part of the dried waste tungsten slag powder of 1:0.8. After mixing the second part of the dried waste tungsten slag powder, calcium carbonate and the metal auxiliary agent Fe evenly according to the mass ratio of 1:0.6:0.06, granulate to obtain a spherical blank with a particle size of 10-15 mm;

[0089] 3) Place the master batch blank in a graphite crucible. The master batch blank accounts for 80% of the volume of the graphite crucible. Under a nitrogen atmosphere, heat the master batch blank to 1350 °C at a rate of 10 °C / min for melting. Add the spherical blank into the melted melt at one time, heat it to 1500 °C at a rate of 5 °C / min for melting, keep it warm for 2 h, and remove the slag to obtain a stable melt;

[0090] 4) Cool the stable melt to 1200 °C at a rate of 5 °C / min first, and then cool it to room temperature at a rate of 8 °C / min to obtain an alloy ingot enriched with valuable metals.

[0091] Analyze the obtained alloy ingot enriched with valuable metals. After testing by ICP-AES, the W content in the alloy ingot is 30%, the Co content is 20%, the Ta content is 14%, the Nb content is 6.5%, and the alloy mass recovery rate in the waste tungsten slag reaches 90%.

[0092] Example 2

[0093] The difference between this example and Example 1 is that:

[0094] In the waste tungsten slag powder, the mass content of W is 8%, the mass content of SiO2 is 34%, the mass content of Co is 4%, the mass content of Nb is 2%, the mass content of Ta is 4%, the mass content of S is 15%, and the mass content of organic matter is 33%. The particle size of the waste tungsten slag powder is 1-10 μm.

[0095] Analyze the obtained alloy ingot enriched with valuable metals. After testing by ICP-AES, the W content in the alloy ingot is 32%, the Co content is 18%, the Ta content is 16%, the Nb content is 7.5%, and the alloy mass recovery rate in the waste tungsten slag reaches 88%.

[0096] Example 3

[0097] The difference between this example and Example 1 is that:

[0098] The mass ratio of the first part of the dried waste tungsten slag powder to the slag-making agent is 1:0.4.

[0099] The obtained alloy ingots enriched with valuable metals were analyzed. By ICP-AES testing, the W content in the alloy ingots was 26%, the Co content was 16%, the Ta content was 10%, the Nb content was 5.5%, and the alloy mass recovery rate from the waste tungsten slag reached 86%.

[0100] Example 4

[0101] The difference between this example and Example 1 lies in that:

[0102] In the slag-making agent, the mass ratio of CaCO3, SiO2, and CaF2 was 1:0.7:0.1.

[0103] The obtained alloy ingots enriched with valuable metals were analyzed. By ICP-AES testing, the W content in the alloy ingots was 28%, the Co content was 18%, the Ta content was 10%, the Nb content was 5%, and the alloy mass recovery rate from the waste tungsten slag reached 84%.

[0104] Example 5

[0105] The difference between this example and Example 1 lies in that:

[0106] The dosage of the first part of the dried waste tungsten slag powder was the same, but the mass ratio of the first part of the dried waste tungsten slag powder to the second part of the dried waste tungsten slag powder was 1:1.

[0107] The obtained alloy ingots enriched with valuable metals were analyzed. By ICP-AES testing, the W content in the alloy ingots was 28%, the Co content was 19%, the Ta content was 15%, the Nb content was 5%, and the alloy mass recovery rate from the waste tungsten slag reached 88%.

[0108] Example 6

[0109] The difference between this example and Example 1 lies in that:

[0110] In step 2), the mass ratio of the second part of the dried waste tungsten slag powder, calcium carbonate, and the metal auxiliary was 1:0.6:0.04.

[0111] The obtained alloy ingots enriched with valuable metals were analyzed. By ICP-AES testing, the W content in the alloy ingots was 30%, the Co content was 20%, the Ta content was 12%, the Nb content was 6%, and the alloy mass recovery rate from the waste tungsten slag reached 86%.

[0112] Example 7

[0113] The difference between this example and Example 1 lies in that:

[0114] In step 2), the mass ratio of the second part of the dried waste tungsten slag powder, calcium carbonate, and the metal auxiliary was 1:0.3:0.04.

[0115] The obtained alloy ingot enriched with valuable metals was analyzed. By ICP - AES testing, the content of W in the alloy ingot was 28%, the content of Co was 18%, the content of Ta was 12%, the content of Nb was 7.5%, and the alloy mass recovery rate from the waste tungsten slag reached 86%.

[0116] Example 8

[0117] The difference between this example and Example 1 is as follows:

[0118] In step 2), the metal additives are Fe and Ni, and the mass ratio is 1:1.

[0119] The obtained alloy ingot enriched with valuable metals was analyzed. By ICP - AES testing, the content of W in the alloy ingot was 30%, the content of Co was 20%, the content of Ta was 10%, the content of Nb was 5.5%, and the alloy mass recovery rate from the waste tungsten slag reached 88%.

[0120] Example 9

[0121] The difference between this example and Example 1 is as follows:

[0122] In step 2), the metal additives are Fe, Ni and Co, and the mass ratio is 1:1:1.2.

[0123] The obtained alloy ingot enriched with valuable metals was analyzed. By ICP - AES testing, the content of W in the alloy ingot was 23%, the content of Co was 40%, the content of Ta was 8%, the content of Nb was 4%, and the alloy mass recovery rate from the waste tungsten slag reached 86%.

[0124] Example 10

[0125] The difference between this example and Example 1 is as follows:

[0126] In step 3), the spherical billets are added to the melted melt in two times, and the mass ratio of the spherical billets added each time is 1:1.

[0127] The obtained alloy ingot enriched with valuable metals was analyzed. By ICP - AES testing, the content of W in the alloy ingot was 31%, the content of Co was 21%, the content of Ta was 11%, the content of Nb was 5%, and the alloy mass recovery rate from the waste tungsten slag reached 89%.

[0128] Example 11

[0129] The difference between this example and Example 1 is as follows:

[0130] The slag - forming agent in Example 1 was replaced with CaO and SiO2, and the mass ratio of CaO to SiO2 was 1:0.6.

[0131] The obtained alloy ingot enriched with valuable metals was analyzed. By ICP - AES testing, the W content in the alloy ingot was 34%, the Co content was 26%, the Ta content was 11%, the Nb content was 5%, and the alloy mass recovery rate from the waste tungsten slag reached 88%.

[0132] Example 12

[0133] The difference between this example and Example 1 lies in step 3). The step 3) of this example is as follows:

[0134] Place the spherical billet in a graphite crucible. The spherical billet occupies 80% of the volume of the graphite crucible. Under a nitrogen atmosphere, heat the spherical billet at a rate of 10 °C / min to 1350 °C for melting. Add the master billet into the melted melt at one time, then heat it to 1500 °C at a rate of 5 °C / min for melting, keep it warm for 2 h, and remove the slag to obtain a stable melt.

[0135] The obtained alloy ingot enriched with valuable metals in this example was analyzed. By ICP - AES testing, the W content in the alloy ingot was 29%, the Co content was 21%, the Ta content was 14%, the Nb content was 6%, and the alloy mass recovery rate from the waste tungsten slag reached 89%.

[0136] Comparative Example 1

[0137] The waste tungsten slag powder is the same as that in Example 1.

[0138] A method for recovering valuable metals from waste tungsten slag includes the following steps:

[0139] 1) Take 9 kg of dry waste tungsten slag powder and 1.4 kg of slag - forming agent, mix them evenly, and perform cold isostatic pressing at a pressure of 190 MPa to obtain a billet. The slag - forming agent includes CaCO3, SiO2, and CaF2, and the mass ratio of CaCO3, SiO2, and CaF2 is 1:0.6:0.05. The tapped density of the billet is 0.9 g / cm 3 ;

[0140] 3) Place the billet in a graphite crucible. Under a nitrogen atmosphere, heat the billet at a rate of 10 °C / min to 1350 °C for melting, and then heat it to 1500 °C at a rate of 5 °C / min for melting, keep it warm for 2 h, and remove the slag to obtain a stable melt;

[0141] 4) Cool the stable melt to 1200 °C at a rate of 5 °C / min first, and then cool it to room temperature at a rate of 10 °C / min to obtain an alloy ingot enriched with valuable metals.

[0142] By ICP - AES analysis of the obtained alloy ingot enriched with valuable metals, the alloy mass recovery rate from the waste tungsten slag only reached 40%.

[0143] Comparative Example 2

[0144] The difference between this comparative example and Example 1 lies in that:

[0145] The metal promoter in step 2) of Example 1 was omitted.

[0146] After the melting was completed, a very thin alloy layer was formed at the bottom of the crucible. A large amount of metal droplets were contained in the slag phase. After testing by ICP-AES, the mass recovery rate of valuable metals W, Co, Ta, and Nb alloys in the waste tungsten slag was only 15%.

[0147] Comparative Example 3

[0148] The difference between this comparative example and Example 1 lies in that:

[0149] The calcium carbonate in step 2) of Example 1 was omitted.

[0150] It was found that a small amount of metal droplets were contained in the slag phase. The obtained alloy ingot enriched with valuable metals was analyzed. After testing by ICP-AES, the mass recovery rate of valuable metals W, Co, Ta, and Nb alloys in the waste tungsten slag reached 65%.

[0151] Comparative Example 4

[0152] The difference between this comparative example and Example 1 lies in that:

[0153] The calcium carbonate and metal promoter in step 2) of Example 1 were omitted.

[0154] After the melting was completed, there was no obvious alloy layer at the bottom of the crucible. All the alloy droplets were mixed in the slag phase and could not be effectively separated.

[0155] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for recovering valuable metals from waste tungsten slag, comprising the following steps: A) Mix the first part of the waste tungsten slag powder with a slag-forming agent, and then perform cold isostatic pressing to form a master blank; The slag-forming agent includes CaCO3 and SiO2; Mix the second part of the waste tungsten slag powder, calcium carbonate and a metal auxiliary agent, and then granulate to obtain a spherical blank; B) Under an inert atmosphere, heat the master blank to 1300-1400 °C to melt it, add the spherical blank to the melted melt, continue to heat up to 1400-1600 °C to melt it, and after skimming the slag, obtain a stable melt; Or under an inert atmosphere, heat the spherical blank to 1300-1400 °C to melt it, add the master blank to the melted melt, continue to heat up to 1400-1600 °C to melt it, and after skimming the slag, obtain a stable melt; C) Cool the stable melt to obtain an alloy ingot enriched with valuable metals.

2. The recovery method according to claim 1, characterized in that, In step A), the mass ratio of CaCO3 to SiO2 is 1:0.5-0.8; Preferably, the slag-forming agent further includes CaF2, and the mass ratio of CaCO3, SiO2 and CaF2 is 1:0.5-0.8:0.05-0.

15.

3. The recovery method according to claim 1, characterized in that In step A), in the waste tungsten slag powder, the mass content of W is 5%-10%, the mass content of SiO2 is 30%-40%, the mass content of Co is 1%-5%, the mass content of Nb is 0.5%-2%, the mass content of Ta is 1%-5%, the mass content of S is 10%-15%, and the mass content of organic matter is 20%-40%; the sum of the mass contents of the various components is 100%.

4. The recovery method according to claim 1, wherein In step A), the particle size of the waste tungsten slag powder is 1-10 μm.

5. The recycling method according to claim 1, characterized in that In step A), the mass ratio of the first part of the waste tungsten slag powder to the second part of the waste tungsten slag powder is 1:0.6-1.0; Preferably, the mass ratio of the first part of the waste tungsten slag powder to the slag-forming agent is 1:0.2-0.4; Preferably, the mass ratio of the second part of the waste tungsten slag powder, calcium carbonate and the metal auxiliary agent is 1:0.3-0.6:0.04-0.08; Preferably, the metal auxiliary agent includes at least one of Fe, Ni and Co.

6. The recycling method according to claim 1, characterized in that, In step A), the tapped density of the masterbatch body is 0.6 to 1.0 g / cm 3 .

7. The recovery method according to claim 1, characterized in that, In step B), heating the master blank to 1300-1400 °C for melting is carried out in a graphite crucible; The master blank accounts for 25%-80% of the volume of the graphite crucible.

8. The recycling method according to claim 1, characterized in that In step B), the heating rate of the master blank from room temperature to 1300-1400 °C is 5-15 °C / min; The heating rate of continuing to heat up to 1400-1600 °C is 5-15 °C / min.

9. The recovery method according to claim 1, wherein In step C), cooling the stable melt includes: First, cool it from the melting temperature to 800-1200 °C at a rate of 2-5 °C / min, and then cool it to room temperature at a rate of 5-10 °C / min.

10. The recovery method according to claim 1, wherein, In step C), in the alloy ingot enriched with valuable metals, the mass content of W is 20%-50%, the mass content of Co is 10%-40%, the mass content of Ta is 3%-14%, and the mass content of Nb is 2%-7%.