Method for separating and purifying dust of intermediate alloy

Abstract

The present application relates to the technical field of comprehensive utilization of metallurgical solid waste resources, and particularly relates to a method for separating and purifying dust ash of intermediate alloy. The method provided by the present application comprises the following steps: after mixing dust ash and heavy liquid, the mixture is allowed to stand and stratify to obtain three layers, the middle layer is taken out, diluted, and the heavy liquid is removed to obtain coarse intermediate alloy; the coarse intermediate alloy is subjected to demagnetization treatment in a protective atmosphere, and then subjected to iron absorption treatment to obtain refined and purified intermediate alloy; and the refined and purified intermediate alloy is subjected to centrifugal treatment to obtain the intermediate alloy finished product after purification. The method can effectively separate iron and other impurities in the dust ash, so that the intermediate alloy after treatment can meet the technical standard for sale, and solve the industry pain point that the dust ash can only be directly smelted into blocks and then sold to steel enterprises at a low price, resulting in reduced profits of enterprises.

Description

A method for separating and purifying dust from intermediate alloys Technical Field

[0001] This invention relates to the field of comprehensive utilization technology of metallurgical solid waste resources, and in particular to a method for separating and purifying dust from intermediate alloys. Background Technology

[0002] Intermediate alloy dust is a product of the shot blasting process in the finishing of intermediate alloys. Its components include approximately 60% intermediate alloy powder, approximately 15% crushed shot blasting iron balls and iron powder, and approximately 25% alumina slag powder and refractory material powders such as graphite / magnesia bricks. Intermediate alloy dust is a major metallurgical solid waste generated during intermediate alloy production, and the loss of metal resources, especially rare metal resources, caused by intermediate alloy dust is incalculable.

[0003] Intermediate alloy dust contains a high iron content and a large proportion of impurities, making it unsuitable for sale as an alloy product. Currently, the main method for treating dust by major manufacturers is to directly smelt the untreated dust into metal briquettes, which are then sold directly to large steel companies as raw materials for steelmaking furnaces. However, this method has a low recovery rate for rare metal elements contained in the dust, and the low selling price results in significant losses for the companies.

[0004] Currently, there is almost no relevant information on the separation and purification of dust from intermediate alloy processing. There are also few cases of dust reuse in other metallurgical industries such as iron and steel and stainless steel. Furthermore, because the dust from the steel converter process and the dust from the intermediate alloy finishing process differ significantly in terms of material composition and system characteristics, there is little reference value.

[0005] Therefore, developing a separation and purification process for intermediate alloy dust, enabling the dust to be separated and purified to achieve same-level reuse and reduce enterprise losses, is an urgent problem to be solved in the intermediate alloy industry. Summary of the Invention

[0006] The purpose of this invention is to provide a method for separating and purifying intermediate alloy dust. This method can effectively separate iron and other impurities from the dust, so that the intermediate alloy obtained after processing meets the technical standards for sale. This solves the industry pain point that currently, dust can only be directly smelted into blocks and then sold to steel companies at low prices, resulting in reduced corporate profits.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for separating and purifying dust from intermediate alloys, comprising the following steps:

[0009] After mixing dust and heavy liquid, the mixture is allowed to stand and separate into upper, middle and lower layers. The middle layer is then diluted to remove the heavy liquid, resulting in a crude intermediate alloy.

[0010] In a protective atmosphere, the crude intermediate alloy is demagnetized and then subjected to iron absorption treatment to obtain a refined intermediate alloy.

[0011] The refined intermediate alloy is centrifuged to obtain the purified intermediate alloy product.

[0012] Preferably, the density of the heavy liquid is 3.8–7.5 g / cm³. 3 ;

[0013] The heavy liquid includes one or more of sodium polytungstate heavy liquid, Lorbachev heavy liquid, and Klerich heavy liquid.

[0014] Preferably, the mass ratio of the dust to the heavy liquid is 1:(5-15).

[0015] Preferably, the mixing is carried out under stirring conditions;

[0016] The stirring time is 20-40 minutes; the settling and stratification time is 2-4 hours.

[0017] Preferably, the method for removing heavy liquid is drying;

[0018] The drying temperature is 80-100℃, and the time is 2-5 hours.

[0019] Preferably, the protective atmosphere is an argon atmosphere;

[0020] The demagnetization treatment is performed at a temperature of 170–770°C for a time of 0.5–4 hours.

[0021] Preferably, the magnetizing process is performed using an electromagnet.

[0022] Preferably, the centrifugation process is carried out at a speed of 1200–2000 r / min for 1–3 h.

[0023] This invention provides a method for separating and purifying intermediate alloy dust, comprising the following steps: mixing dust and heavy liquid, allowing the mixture to stand and separate into upper, middle, and lower layers; diluting the middle layer to remove the heavy liquid, yielding a crude intermediate alloy; demagnetizing the crude intermediate alloy in a protective atmosphere, followed by iron absorption treatment to obtain a refined intermediate alloy; and centrifuging the refined intermediate alloy to obtain the purified intermediate alloy product. Compared with the prior art, this invention has the following advantages: the intermediate alloy dust treated by the method of this invention achieves a Fe impurity removal rate of over 98.9% and a graphite and alumina impurity removal rate of over 99.7%, enabling the intermediate alloy product purified from the dust to meet supply standards and achieving same-level reuse of intermediate alloy processing waste, thus creating significant benefits for enterprises. Attached Figure Description

[0024] Figure 1 is a schematic diagram of the process for separating and purifying dust from intermediate alloys according to the present invention. Detailed Implementation

[0025] As shown in Figure 1, the present invention provides a method for separating and purifying dust from intermediate alloys, comprising the following steps:

[0026] After mixing dust and heavy liquid, the mixture is allowed to stand and separate into upper, middle and lower layers. The middle layer is then diluted to remove the heavy liquid, resulting in a crude intermediate alloy.

[0027] In a protective atmosphere, the crude intermediate alloy is demagnetized (i.e., high-temperature demagnetization in Figure 1) and then subjected to magnetization (i.e., magnetic attraction in Figure 1) to obtain a refined intermediate alloy.

[0028] The refined intermediate alloy is centrifuged to obtain the purified intermediate alloy product.

[0029] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0030] This invention involves mixing dust and heavy liquid, allowing the mixture to stand and separate into upper, middle, and lower layers, then diluting the middle layer to remove the heavy liquid, resulting in a crude intermediate alloy.

[0031] In this invention, the density of the heavy liquid is preferably 3.8–7.5 g / cm³. 3 More preferably, it is 4.5–7.0 g / cm³. 3 The optimal value is 5.0–6.0 g / cm³. 3The heavy liquid preferably includes one or more of sodium polytungstate heavy liquid, Lorbachev heavy liquid, and Klerich heavy liquid. When the heavy liquid is two or more of the above-mentioned specific selections, the present invention does not impose any special limitation on the ratio of the above-mentioned specific substances, and they can be mixed in any ratio. When the density of the heavy liquid does not meet the above requirements, it is preferable to adjust it with water.

[0032] In this invention, the mass ratio of dust to heavy liquid is preferably 1:(5-15), more preferably 1:(7-13), and most preferably 1:(8-10). In this invention, the mixing is preferably carried out under stirring conditions, and the stirring time is preferably 20-40 min, more preferably 25-35 min, and most preferably 28-32 min. This invention does not impose any special limitation on the stirring speed; a speed well-known to those skilled in the art can be used to ensure that the dust is fully dispersed in the heavy liquid.

[0033] In this invention, the settling time is preferably 2 to 4 hours, more preferably 2.5 to 3.5 hours, and most preferably 2.8 to 3.2 hours.

[0034] In this invention, the upper layer obtained after static stratification is slag and refractory slag, the middle layer is intermediate alloy powder and iron microparticles, and the lower layer is iron balls and large-sized fragments (iron shot blasting balls).

[0035] In this invention, the diluent used for dilution is preferably deionized water, and the dilution temperature is preferably 20-85°C, more preferably 40-75°C, and most preferably 50-65°C.

[0036] In this invention, the preferred method for removing heavy liquid is drying. The drying temperature is preferably 80–100°C, more preferably 85–95°C, and most preferably 88–92°C; the drying time is preferably 2–5 hours, more preferably 3.5–4.5 hours, and most preferably 3.8–4.2 hours. In this invention, using the above-mentioned drying temperature can prevent oxidation of the metal materials in the dust.

[0037] In this invention, the density of graphite and alumina in the dust is less than 3.5 g / cm³. 3 The density of the intermediate alloy is 3.8–4.3 g / cm³. 3 The density of the iron ball and iron powder is 7.8 g / cm³. 3 Therefore, when the dust is placed at a concentration of 3.8–7.5 g / cm³, 3After thorough stirring in the heavy liquid, the dust will stratify, specifically presenting an upper layer of alumina slag and micro-slag of refractory materials such as graphite, a middle layer of intermediate alloy powder and some Fe powder, and a lower layer of fragmented shot blasting balls. Removing the upper and lower layers at this point removes the slag, refractory materials, and large iron balls. Simultaneously, the coarse intermediate alloy obtained after the above treatment contains some iron particles and iron powder. This is mainly because during the shot blasting process, the intermediate alloy powder undergoes prolonged collisions and friction with the iron balls, causing the powder to acquire weak magnetism. When the intermediate alloy powder and iron particles are of similar size, the magnetic attraction between them makes separation even more difficult.

[0038] In this invention, the advantages of using gravity separation (a method of separation using heavy liquid) to remove slag, refractory materials and large iron balls are: gravity separation is simple to operate, low in cost, and the heavy liquid is generally an organic water-soluble solvent, which can be separated by washing and drying with water, and no pollutants are introduced after gravity separation treatment.

[0039] After obtaining the crude master alloy, the present invention performs demagnetization treatment on the crude master alloy in a protective atmosphere and then performs iron absorption treatment to obtain a refined master alloy.

[0040] In this invention, the protective atmosphere is preferably an argon atmosphere, and the argon atmosphere is preferably an argon atmosphere with a purity of 99.9%. In this invention, the protective atmosphere cannot be a nitrogen atmosphere, because nitrogen is an impurity gas element in titanium alloys and high-temperature alloy intermediate alloys, which will reduce the quality of the intermediate alloy products.

[0041] In this invention, the temperature of the demagnetization treatment is preferably 170-770℃, more preferably 180-203℃, and most preferably 190-200℃; the time is preferably 0.5-4h, more preferably 0.5-2h, and most preferably 0.5-1.5h.

[0042] In this invention, since each magnetic material has its corresponding magnetic transition temperature (also known as the Curie point), the material can transform into a paramagnetic material when this temperature is reached. The magnetic materials in dust collector ash include two types: weakly magnetic intermediate alloy powder and strongly magnetic shot-blasted iron pellets. Iron has a Curie temperature of 770°C. However, after extensive testing, it was found that the magnetic transition temperature of the intermediate alloy powder in the dust collector ash (the tested alloy powders included vanadium-aluminum alloys with vanadium grades of 40-80 and molybdenum-aluminum alloys with molybdenum grades of 60-85) is 170-203°C. The purpose of this step in this invention is to remove iron using magnetism; therefore, it is necessary to retain the magnetism of the iron. Thus, the holding temperature must be higher than the Curie temperature of the weakly magnetic intermediate alloy but lower than the Curie temperature of the iron.

[0043] In this invention, the iron-attracting process is preferably performed using an electromagnet. Furthermore, the iron-attracting process is preferably carried out by using an inert gas to lift the powder before attracting the iron, which improves the iron-attracting efficiency and reduces the loss of alloy powder due to the adhesion between the attracted fine iron powder and the alloy powder.

[0044] In this invention, the number of times the demagnetization treatment and the iron attraction treatment are both preferably ≤2 times.

[0045] In this invention, the demagnetization and iron-attracting processes can only remove small amounts of iron inclusions and some iron powder. The remaining iron powder, due to its small particle size difference with the alloy powder, is more likely to stick together. While attracting the iron powder, the iron powder will also carry the intermediate alloy powder. To avoid the loss of alloy powder caused by this situation, the number of demagnetization and iron-attracting processes is controlled to be ≤2 times.

[0046] After obtaining the refined intermediate alloy, the present invention centrifuges the refined intermediate alloy to obtain the purified intermediate alloy product.

[0047] In this invention, since the refined intermediate alloy powder obtained after demagnetization and iron absorption still contains some iron powder with small particle size, it needs to be centrifuged in the following process.

[0048] In this invention, the centrifugation speed is preferably 1200-2000 r / min, more preferably 1300-1800 r / min, and most preferably 1400-1600 r / min; the time is preferably 1-3 h, more preferably 1.5-2.5 h, and most preferably 1.8-2.2 h.

[0049] In this invention, the ion treatment utilizes the different deposition rates of substances with different specific gravities under centrifugal force to separate substances of different densities. When particle size differences are small, centrifugation is the optimal method for separating substances of different densities. The vanadium-aluminum master alloy and molybdenum-aluminum master alloy involved in this invention have densities of 4–5.8 g / cm³. 3 Iron has a density of 7.86 g / cm³. 3 Therefore, during the centrifugal separation process, the iron falls concentrated near the central axis, while the lighter intermediate alloy powder is distributed outside the centrifuge chamber.

[0050] The following detailed description of the method for separating and purifying intermediate alloy dust provided by the present invention, in conjunction with embodiments, should not be construed as limiting the scope of protection of the present invention.

[0051] Example 1

[0052] 10.0 kg of V40Al intermediate alloy dust was weighed and placed into a container with a density of 4.0 g / cm³. 3 The dust was stirred thoroughly for 20 minutes in a heavy liquid mixture of Krelich heavy liquid and water to ensure uniform dispersion of the dust. After standing for 3.0 hours, the suspension was allowed to separate into clear layers. At this point, the upper layer was a mixture of slag and refractory slag, the middle layer was a mixture of V40Al master alloy and some Fe powder, and the lower layer mainly consisted of fragmented Fe shot blasting pellets. The middle layer, a mixture of V40Al master alloy, some Fe powder, and heavy liquid, was separated. This mixture was continuously diluted and washed with 50°C deionized water, and then dried at 80°C for 3 hours to obtain crudely purified V40Al master alloy powder.

[0053] The crudely purified V40Al master alloy powder was placed in a protective atmosphere of 99.9% argon and heated to 175°C for demagnetization treatment for 1 hour. After cooling to room temperature, the demagnetized mixed powder was subjected to two Fe absorption operations using an electromagnet. After Fe removal by the electromagnet, the refined V40Al master alloy powder was obtained.

[0054] The refined V40Al master alloy powder was placed in a centrifuge, the speed was set to 1700 r / min, and the centrifugation time was 1.5 h. The powder inside and outside the centrifuge chamber was collected to obtain the finished V40Al master alloy. The compositional characterization data of V40Al master alloy before and after dust removal treatment are shown in Table 1:

[0055] Table 1. Composition characteristics of dust ash before and after treatment (wt%)

[0056] Composition VAlFe Others and Unmelted Matter Before Treatment 26.11 38.51 14.32 21.06 After Treatment 40.33 50.81 0.15 50.023 surface

[0057] As shown in Table 1, after treatment by the method of the present invention, the Fe removal rate in the dust of V40Al intermediate alloy reached 98.92%, and the removal rate of slag and refractory material micro-slag reached 99.89%.

[0058] Example 2

[0059] 10.0 kg of AlMo60 intermediate alloy dust was weighed and placed into a 70.0 kg container with a density of 4.5 g / cm³. 3In a sodium polytungstate heavy liquid, the dust was stirred thoroughly for 30 minutes to ensure uniform dispersion. Afterward, it was allowed to stand for 3.0 hours to allow the suspension to clearly separate into layers. At this point, the upper layer was a mixture of slag and refractory slag, the middle layer was a mixture of AlMo60 master alloy and some Fe powder, and the lower layer mainly consisted of crushed Fe shot blasting pellets. The middle layer, a mixture of AlMo60 master alloy, some Fe powder, and heavy liquid, was separated. This mixture was continuously diluted and washed with deionized water at 65°C, and then dried at 80°C for 3.5 hours to obtain crudely purified AlMo60 master alloy powder.

[0060] The crudely purified AlMo60 intermediate alloy powder was placed in a protective atmosphere of 99.9% argon and heated to 194°C for demagnetization treatment for 1 hour. After cooling to room temperature, the demagnetized mixed powder was subjected to a Fe removal operation using an electromagnet. After Fe removal by the electromagnet, the refined AlMo60 intermediate alloy powder was obtained.

[0061] The refined AlMo60 intermediate alloy powder obtained in step 2 is placed in a centrifuge, the speed is set to 1750 r / min, the centrifugation time is 2.0 h, and the powder inside and outside the centrifuge chamber is collected to obtain the AlMo60 intermediate alloy product.

[0062] Table 2 shows the compositional characterization data of AlMo60 master alloy before and after dust removal treatment:

[0063] Table 2. Composition characteristics of dust ash before and after treatment (wt%)

[0064] Composition: Mo, Al, Fe, other, and unmelted matter. Before treatment: 38.69, 24.72, 17.22, 19.37. After treatment: 60.91, 38.90, 0.14, 60.044. surface

[0065] As shown in Table 2, after treatment by the method of the present invention, the Fe removal rate in the AlMo60 master alloy dust reached 99.16%, and the removal rate of slag and refractory material micro-slag reached 99.78%.

[0066] Example 3

[0067] The difference from Example 1 is that the selected dust is V55Al intermediate alloy dust, and the density of the heavy liquid used is 4.0 g / cm³. 3 The high-temperature demagnetization temperature is 182℃.

[0068] The compositional characterization data of the dust used in Example 3 before and after treatment are shown in Table 3:

[0069] Table 3. Composition characteristics of dust ash before and after treatment (wt%)

[0070] Composition VAlFe Others and Unmelted Matter Before Treatment 36.66 26.33 15.33 221.67 After Treatment 58.11 41.74 0.11 30.035 surface

[0071] As shown in Table 3, after treatment by the method of the present invention, the Fe removal rate in the dust of V55Al intermediate alloy reached 99.26%, and the removal rate of slag and refractory material micro-slag reached 99.84%.

[0072] Example 4

[0073] The difference from Example 1 is that the selected dust is V85Al intermediate alloy dust, and the density of the heavy liquid used is 5.0 g / cm³. 3 The high-temperature demagnetization temperature is 197℃.

[0074] The compositional characterization data of the dust used in Example 4 before and after treatment are shown in Table 4:

[0075] Table 4. Composition characteristics of dust ash before and after treatment (wt%)

[0076]

[0077]

[0078] As shown in Table 4, after treatment by the method of the present invention, the Fe removal rate in the dust of V85Al master alloy reached 98.97%, and the removal rate of slag and refractory material micro-slag reached 99.9%.

[0079] Example 5

[0080] The difference from Example 2 is that the selected dust is AlMo65 master alloy dust, and the density of the heavy liquid used is 4.8 g / cm³. 3 The high-temperature demagnetization temperature is 195℃.

[0081] The compositional characterization data of the dust used in Example 5 before and after treatment are shown in Table 5:

[0082] Table 5. Composition characteristics of dust ash before and after treatment (wt%)

[0083] Composition: Mo, Al, Fe, other, and unmelted matter. Before treatment: 41.62, 22.49, 17.73, 18.16. After treatment: 64.80, 35.01, 0.16, 50.025. surface

[0084] As shown in Table 5, after treatment by the method of the present invention, the Fe removal rate in the AlMo65 master alloy dust reached 99.07%, and the removal rate of slag and refractory material micro-slag reached 99.86%.

[0085] Comparative Example 1

[0086] The difference from Example 1 is that the density of the heavy liquid is 3.0 g / cm³. 3 .

[0087] Comparative Example 2

[0088] The difference from Example 1 is that the demagnetization temperature in step 2 is 120°C;

[0089] The composition of the dust treated by the methods of Comparative Example 1 and Comparative Example 2 was characterized, and the results are shown in Table 6.

[0090] Table 6. Composition characteristics of dust ash before and after treatment (wt%)

[0091] Composition V Al Fe Others and Unmelted Matter Before Treatment 26.11 38.51 14.32 21.06 Comparative Example 1 After Treatment 34.31 50.62 22.76 12.31 Comparative Example 2 After Treatment 38.62 56.98 4.36 40.036 surface

[0092] As shown in Table 6, the density of the heavy liquid in Comparative Example 1 was adjusted to 3.0 g / cm³. 3 Subsequently, due to the inability to effectively separate slag and refractory micro-slag, the content of other and unmelted matter (mainly Al2O3 slag and refractory slag) in the treated finished product reached as high as 12.31%, and the slag and refractory slag removal rate was only 41.51%. Moreover, due to the interference of slag and refractory slag in subsequent processing, the removal rate of impurity Fe also decreased, reaching only 80.75%. In Comparative Example 2, because the high-temperature demagnetization temperature was too low and did not reach the Curie temperature point, the removal effect of Fe powder and particles in steps 2 and 3 was affected, resulting in a final Fe removal rate of only 69.57%.

[0093] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for separating and purifying dust from intermediate alloys, characterized in that, Includes the following steps: After mixing dust and heavy liquid, the mixture is allowed to stand and separate into upper, middle, and lower layers. The middle layer is then diluted to remove the heavy liquid, yielding a crude intermediate alloy. The density of the heavy liquid is 3.8~7.5 g / cm³. 3 In a protective atmosphere, the crude master alloy is demagnetized and then subjected to iron absorption to obtain a refined master alloy. The refined master alloy is then centrifuged to obtain the purified master alloy product. The protective atmosphere is argon. The demagnetization temperature is 170~770℃ and the time is 0.5~4h. The dust is V40Al master alloy dust, AlMo60 master alloy dust, V55Al master alloy dust, V85Al master alloy dust, or AlMo65 master alloy dust. The master alloy dust includes slag, refractory slag, master alloy, iron particles, and iron shot blasting balls.

2. The method as described in claim 1, characterized in that, The heavy liquid includes one or more of sodium polytungstate heavy liquid, Lorbachev heavy liquid, and Klerich heavy liquid.

3. The method as described in claim 1 or 2, characterized in that, The mass ratio of the dust to the heavy liquid is 1:(5~15).

4. The method as described in claim 3, characterized in that, The mixing is carried out under stirring conditions; the stirring time is 20-40 minutes; the settling and stratification time is 2-4 hours.

5. The method as described in claim 1 or 4, characterized in that, The method for removing heavy liquid is drying; the drying temperature is 80~100℃ and the time is 2~5h.

6. The method as described in claim 1, characterized in that, The magnetizing process is performed using an electromagnet.

7. The method as described in claim 1, characterized in that, The centrifugation process is carried out at a speed of 1200~2000 r / min for 1~3 h.

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