Method for separating scandium, titanium and iron from titanium slag

Abstract

The invention provides a method for separating scandium, titanium and iron from titanium slag, and belongs to the field of metallurgy. The invention provides a method for separating scandium, titanium and iron from titanium slag, which comprises the following steps: mixing a calcium source and / or a silicon source with titanium slag, an inorganic scandium compound and carbon to obtain a mixture; the mixture is subjected to vacuum reduction smelting, cooling and separation, and slag rich in scandium, elemental iron and titanate rich in titanium are obtained; the calcium-silicon ratio of the mixture is (0.5-1.25): 1; the temperature of the vacuum reduction smelting is 1200 to 1400 DEG C. Based on the specific chemical property of scandium in the titanium slag and the ore phase transformation behavior in the high-temperature process, a specific compound is added to adjust the calcium-silicon ratio of the titanium slag and control the temperature of vacuum reduction smelting to change the distribution and enrichment state of scandium, titanium, iron and other metals in the titanium slag, then enriched products can be effectively obtained, and efficient recovery is achieved.

Description

Technical Field

[0001] The present invention relates to the field of metallurgy, and particularly to a method for separating scandium, titanium and iron from titanium slag. Background Art

[0002] With the rapid development of modern industry, the demand for metals such as scandium, titanium and iron is increasing day by day. Titanium slag is an intermediate product obtained after smelting ilmenite, which contains rich elements such as scandium, titanium and iron. However, there are many problems in the current methods for separating and extracting scandium, titanium and iron from titanium slag, such as low separation efficiency, high cost and great environmental impact. Some existing separation technologies are difficult to achieve efficient and precise separation of scandium, titanium and iron, resulting in serious waste of resources and restricting the development of related industries. Therefore, it is of great practical significance to develop a method for separating scandium, titanium and iron from titanium slag with high efficiency, environmental protection and low cost. Summary of the Invention

[0003] The present invention provides a method for separating scandium, titanium and iron from titanium slag, and the method of the present invention can efficiently, environmentally friendly and low-cost separate scandium, titanium and iron from titanium slag.

[0004] The present invention provides a method for separating scandium, titanium and iron from titanium slag, comprising the following steps:

[0005] Mixing a calcium source and / or a silicon source with titanium slag, an inorganic scandium compound and carbon to obtain a mixture;

[0006] Performing vacuum reduction smelting, cooling and separation on the mixture to obtain slag enriched with scandium element, elemental iron and titanate enriched with titanium element;

[0007] The calcium-silicon ratio of the mixture is 0.5 to 1.25:1;

[0008] The temperature of the vacuum reduction smelting is 1200 to 1400 °C.

[0009] Preferably, by mass fraction, the titanium slag comprises the following elements: O 30-36%, Fe 5-8%, Mg 2-3%, Al 5-8%, Si 10-12%, S 0.1-0.2%, Sc 0.005-0.1%, Ca 1.5-1.8%, Ti 25-30%, Mn 0.5-1% and the remaining elements 10-15%.

[0010] Preferably, the calcium source comprises CaO, the silicon source comprises SiO2; the inorganic scandium compound comprises Sc2O3.

[0011] Preferably, before mixing, the calcium source, the silicon source, the titanium slag and the inorganic scandium compound are respectively dried.

[0012] Preferably, the drying temperature is 105 - 130 °C and the time is 8 - 12 h.

[0013] Preferably, after mixing, it further includes: grinding the obtained mixture to obtain the mixture. Preferably, the mass fraction of Sc2O3 in the mixture is 0.2-0.4%.

[0014] Preferably, the mass fraction of carbon in the mixture is 5 - 8%;

[0015] The carbon includes coke.

[0016] Preferably, the current growth rate for heating up to the temperature of the vacuum reduction smelting is 5 - 10 A every 20 min, the holding time of the vacuum reduction smelting is 3 - 5 h, and the vacuum degree ≤ 10 Pa.

[0017] Preferably, the separation includes screening after crushing.

[0018] Based on the fact that scandium in titanium slag tends to exist in silicate or titanate minerals in an oxidized state (Sc 3+ ), and forms composite oxide phases with metals such as titanium and calcium. Titanium in titanium slag exists in the form of titanates (such as CaTiO3, FeTiO3) at high temperatures. At high temperatures, these mineral phases form slag by atomic rearrangement or reacting with other oxides (such as Sc2O3), changing the melting characteristics of the slag system. By adding specific compounds (calcium source and / or silicon source) to adjust the calcium-silicon ratio of titanium slag and control the temperature of vacuum reduction smelting, the distribution and enrichment state of metal elements such as scandium, titanium, and iron in titanium slag are changed (Sc 3+ tends to replace Ti in titanates (such as CaTiO3, FeTiO3) or silicates in the form of isomorphous substitution 4+ / Ca 2+ , forming slag; when titanium exists as stable titanates such as CaTiO3 and FeTiO3, it is necessary to change its activity by adjusting the calcium-silicon ratio (CaO / SiO2), and iron ions are reduced to elemental form), and then enriched products can be effectively obtained to achieve efficient recovery. And the method of the present invention has a simple process flow. While realizing the comprehensive recycling of tail slag, it reduces the extraction cost and environmental pollution, has important theoretical and practical significance, and has obvious separation effect. The results of the examples show that this method can recover metals such as titanium and iron from titanium slag while improving the extraction efficiency of scandium, increasing the scandium content from 0.288% before smelting to 2.3% after smelting, and scandium is enriched by about 9 times. Description of the Drawings

[0019] Figure 1 SEM-BSE image and element distribution maps of the glass slag in Example 1;

[0020] Figure 2SEM-BSE images and elemental distribution maps of the titanate enriched with titanium element in Example 4;

[0021] Figure 3 The physical diagram of the mixture after smelting in Comparative Example 2. Detailed implementation manners

[0022] The present invention provides a method for separating scandium, titanium and iron from titanium slag, comprising the following steps:

[0023] Mix a calcium source and / or a silicon source with titanium slag, inorganic scandium compound and carbon to obtain a mixture;

[0024] Perform vacuum reduction smelting, cooling and separation on the mixture to obtain a slag enriched with scandium element, elemental iron and a titanate enriched with titanium element;

[0025] The calcium-silicon ratio of the mixture is 0.5-1.25:1;

[0026] The temperature of the vacuum reduction smelting is 1200-1400 °C.

[0027] The present invention mixes a calcium source and / or a silicon source with titanium slag, an inorganic scandium compound, and carbon to obtain a mixture.

[0028] Before mixing, the present invention preferably dries the calcium source, silicon source, titanium slag and inorganic scandium compound respectively.

[0029] In the present invention, by mass fraction, the titanium slag preferably comprises the following elements: O 30-36%, Fe 5-8%, Mg 2-3%, Al 5-8%, Si 10-12%, S 0.1-0.2%, Sc 0.005-0.1%, Ca 1.5-1.8%, Ti 25-30%, Mn 0.5-1% and the remaining elements 10-15%, more preferably O 35.8101%, Fe 6.24%, Mg 2.3847%, Al 5.0986%, Si 10.2358%, S 0.1147%, Sc 0.0059%, Ca 1.7192%, Ti 26.6471%, Mn 0.729% and the remaining elements 11.0149%.

[0030] In the present invention, the calcium source preferably comprises CaO, the silicon source preferably comprises SiO2; the inorganic scandium compound preferably comprises Sc2O3; the carbon preferably comprises coke.

[0031] In the present invention, the drying temperature is preferably 105-130 °C, and the time is preferably 8-12 h.

[0032] In the present invention, the titanium slag is obtained after electric furnace smelting.

[0033] In the present invention, the particle size of the titanium slag is preferably above 100 mesh.

[0034] In the present invention, the mass fraction of Sc2O3 in the mixture is preferably 0.2 - 0.4%.

[0035] In the present invention, the mass fraction of carbon in the mixture is preferably 5 - 8%, and the carbon preferably includes coke.

[0036] In the present invention, the calcium-silicon ratio of the mixture is preferably 0.5 - 1.25:1. In specific embodiments of the present invention, the calcium-silicon ratio of the mixture can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, or 1.25:1;

[0037] In the present invention, after mixing, it is preferably further included to grind the obtained mixture to obtain the mixture.

[0038] After obtaining the mixture, in the present invention, the mixture is subjected to vacuum reduction smelting, cooling, and separation to obtain a slag enriched with scandium element, elemental iron, and a titanate enriched with titanium element.

[0039] In the present invention, the temperature of the vacuum reduction smelting is 1200 - 1400 °C. In specific embodiments of the present invention, the temperature of the vacuum reduction smelting can be 1200 °C, 1250 °C, 1300 °C, 1350 °C, or 1400 °C. The heat preservation time is preferably 3 h, and the vacuum degree is preferably ≤ 10 Pa; the current growth rate for heating up to the temperature of the vacuum reduction smelting is preferably 5 - 10 A every 20 min. In specific embodiments of the present invention, the current growth rate for heating up to the temperature of the vacuum reduction smelting is preferably 6 A every 20 min, 7 A every 20 min, 8 A every 20 min, or 9 A every 20 min.

[0040] In the present invention, the separation preferably includes screening after crushing.

[0041] The method for separating scandium, titanium, and iron from titanium slag provided by the present invention will be described in detail below in conjunction with examples. It is obvious, but they cannot be understood as limiting the protection scope of the present invention.

[0042] Example 1

[0043] 1. After passing the titanium slag (the chemical element composition is shown in Table 1) through a 100-mesh sieve, it is placed in a blast drying oven for drying; wherein, the oven temperature is 110 °C, and the drying time is 12 h;

[0044] Table 1 Main chemical element composition of titanium slag

[0045] Element O Fe Mg Al Si S Sc Ca Ti Mass fraction 35.8101 6.24 2.3847 5.0986 10.2358 0.1147 0.0059 1.7192 26.6471 Element Mn The remaining elements — — — — — — — Mass fraction 0.729 11.0149 — — — — — — —

[0046] 2. Put Sc2O3 and SiO2 into a forced-air drying oven with a chamber temperature of 110 °C and dry for 12 h. Then adjust the calcium-silicon ratio of the dried SiO2 to 0.65. Add Sc2O3 accounting for 0.288% of the total mass of titanium slag, SiO2, coke, and Sc2O3 and 5% coke, and grind the titanium slag with them in an agate mortar for more than 30 min until evenly mixed. Put it into a high-purity graphite crucible, and transfer the crucible to a vacuum induction melting furnace with a vacuum degree of 10 Pa. Adjust the heating current rate to 10 A / 20 min to heat up to 1400 °C and keep it at a constant temperature for 3 h. After the heat preservation ends, cool it with the furnace. After crushing and screening, the preparation is completed.

[0047] Figure 1 SEM-BSE images and elemental distribution maps of the glass slag (slag enriched with scandium element) in Example 1.

[0048] Through analysis, it can be seen that the glass slag contains Ca 50.5 wt%, Si 16.1 wt%, O 30.8 wt%, Sc 2.3 wt%, and Ti 0.1 wt%. By calculation, the content of scandium has increased from 0.288% before melting to 2.3% after melting, and scandium has been enriched by about 9 times.

[0049] Example 2

[0050] 1. Pass the titanium slag (chemical element composition is shown in Table 1) through a 100-mesh sieve and put it into a forced-air drying oven for drying; among them, the chamber temperature is 110 °C and the drying time is 12 h;

[0051] 2. Put Sc2O3 and SiO2 into a forced-air drying oven with a chamber temperature of 110 °C and dry for 12 h. Then adjust the calcium-silicon ratio of the dried SiO2 to 0.85. Add Sc2O3 accounting for 0.288% of the total mass of Sc2O3, SiO2, coke, and Sc2O3 and 5% coke, and grind the titanium slag with them in an agate mortar for more than 30 min until evenly mixed. Put it into a high-purity graphite crucible, and transfer the crucible to a vacuum induction melting furnace with a vacuum degree of 10 Pa. Adjust the heating current rate to 10 A / 20 min to heat up to 1400 °C and keep it at a constant temperature for 3 h. After the heat preservation ends, cool it with the furnace. After crushing and screening, the preparation is completed.

[0052] Analyze the titanate enriched with titanium element. The titanate enriched with titanium element contains Ca 19.1 wt%, Si 4.4 wt%, O 26.9 wt%, Sc 0.5 wt%, and Ti 11.1 wt%. The enrichment of scandium is not obvious, and the enrichment amount of titanium increases.

[0053] Example 3

[0054] 1. After passing the titanium slag (chemical element composition shown in Table 1) through a 100-mesh sieve, it is placed in a forced-air drying oven for drying; among them, the oven temperature is 110 °C and the drying time is 12 h;

[0055] 2. Sc2O3 and SiO2 are respectively placed in a forced-air drying oven with an oven temperature of 110 °C for drying for 12 h. Then, the calcium-silicon ratio of the dried SiO2 is adjusted to 1.05, and 0.288% of Sc2O3 and 5% of coke based on the total mass of titanium slag, SiO2, coke and Sc2O3 are added. The titanium slag and it are wet-ground in an agate mortar for more than 30 min until evenly mixed, and then placed in a high-purity graphite crucible. The crucible is moved to a vacuum induction melting furnace with a vacuum degree of 10 Pa; the temperature is adjusted to 1400 °C at a heating current rate of 10 A / 20 min and kept at a constant temperature for 3 h. After the heat preservation is completed, it is cooled with the furnace. After crushing and screening, the preparation is completed.

[0056] The titanate enriched with titanium element is analyzed. The titanate enriched with titanium element contains 9.8 wt% of Ca, 6.1 wt% of Si, 34.7 wt% of O, 0.5 wt% of Sc, and 21.2 wt% of Ti.

[0057] Example 4

[0058] 1. After passing the titanium slag (chemical element composition shown in Table 1) through a 100-mesh sieve, it is placed in a forced-air drying oven for drying; among them, the oven temperature is 110 °C and the drying time is 12 h;

[0059] 2. Sc2O3 and SiO2 are respectively placed in a forced-air drying oven with an oven temperature of 110 °C for drying for 12 h. Then, the calcium-silicon ratio of the dried SiO2 is adjusted to 1.15, and 0.288% of Sc2O3 and 5% of coke based on the total mass of titanium slag, SiO2, coke and Sc2O3 are added. The titanium slag and it are ground in an agate mortar for more than 30 min until evenly mixed, and then placed in a high-purity graphite crucible. The crucible is moved to a vacuum induction melting furnace with a vacuum degree of 10 Pa; the temperature is adjusted to 1400 °C at a heating current rate of 10 A every 20 min and kept at a constant temperature for 3 h. After the heat preservation is completed, it is cooled with the furnace. After crushing and screening, the preparation is completed.

[0060] Figure 2 Fig. SEM-BSE and element distribution maps of the titanate enriched with titanium element in Example 4. Through analysis, it can be seen that the titanate enriched with titanium element contains 26.4 wt% of Ca, 1.9 wt% of Si, 38.1 wt% of O, 0.4 wt% of Sc, and 30.8 wt% of Ti.

[0061] With the increase of the calcium-silicon ratio (basicity), the Sc enrichment effect gradually decreases, the titanium enrichment effect gradually increases, and titanium is enriched in the form of perovskite.

[0062] Comparative Example 1

[0063] 1. After screening the titanium slag (chemical element composition is shown in Table 1) through a 100-mesh sieve, place it in a forced-air drying oven for drying. Dry; among them, the box temperature is 110°C and the drying time is 12 h;

[0064] 2. Place Sc2O3 and SiO2 separately in a forced-air drying oven with an oven temperature of 110 °C for 12 h of drying. Then, adjust the calcium-silicon ratio of the dried SiO2 to 0.85, add 0.288% of Sc2O3 and 5% of coke based on the total mass of titanium slag, SiO2, coke, and Sc2O3, and grind the titanium slag and the above components in an agate mortar for more than 30 min until evenly mixed. Place the mixture in a high-purity graphite crucible, and transfer the crucible to a vacuum induction melting furnace with a vacuum degree of 10 Pa. Adjust the heating current rate to 10 A every 20 min to heat up to 1500 °C and keep it at a constant temperature for 3 h. After the heat preservation is completed, cool it with the furnace to complete the preparation. After taking out the crucible, it is found that the sample is adhered to the crucible and cannot be separated.

[0065] Comparative Example 2

[0066] 1. After screening the titanium slag (chemical element composition is shown in Table 1) through a 100-mesh sieve, place it in a forced-air drying oven for drying; among them, the oven temperature is 110 °C and the drying time is 12 h.

[0067] 2. Grind the dried titanium slag in an agate mortar for more than 30 min, place it in a high-purity graphite crucible, and transfer the crucible to a vacuum induction melting furnace with a vacuum degree of 10 Pa. Adjust the heating current rate to 10 A every 20 min to heat up to 950 °C and keep it at a constant temperature for 3 h. After the heat preservation is completed, cool it with the furnace. After taking it out, it is found that the titanium slag has not melted, as Figure 3 shown. Figure 3 Figure of the physical object of the mixture after melting in Comparative Example 2.

[0068] It can be seen from Examples 1 to 4 that when using vacuum reduction melting experiments to melt electric furnace titanium slag, when the vacuum degree ≤ 5 Pa and the mass percentage of calcium oxide to silicon dioxide is 0.65 at 1400 °C, the enrichment of scandium can be increased by about 4.2 times; when the mass percentage of calcium oxide to silicon dioxide is 1.15 at 1400 °C, the enrichment of titanium can reach 30.8 wt%. When the temperature exceeds 1400 °C, the phenomenon of spraying materials and adhesion to the crucible will occur, and when the temperature is lower than 1200 °C, the sample will not melt.

[0069] Comparative Example 3

[0070] 1. After screening the titanium slag (chemical element composition is shown in Table 1) through a 100-mesh sieve, place it in a forced-air drying oven for drying; among them, the oven temperature is 110 °C and the drying time is 12 h.

[0071] 2. Put Sc2O3 and SiO2 into a blast drying oven with a box temperature of 110 °C and dry for 12 h. Then adjust the calcium-silicon ratio of the dried SiO2 to 1.3, add Sc2O3 accounting for 0.288% of the total mass of titanium slag, SiO2, coke and Sc2O3 and 5% of coke, and grind the titanium slag with it in an agate mortar for more than 30 min until evenly mixed. Put it into a high-purity graphite crucible, and move the crucible to a vacuum induction melting furnace with a vacuum degree of 10 Pa; adjust the heating current rate to 10 A every 20 min and heat up to 1400 °C and keep it at a constant temperature for 3 h. After the heat preservation is over, cool it with the furnace. After crushing and screening, the preparation is completed. After calculation, the sample volatilization rate is greater than 50%, and the experimental effect is not good.

[0072] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can still be made. These improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for separating scandium, titanium, and iron from titanium slag, characterized in that, It includes the following steps: Mix a calcium source and / or a silicon source with titanium slag, inorganic scandium compound, and carbon to obtain a mixture; Perform vacuum reduction smelting, cooling, and separation on the mixture to obtain a slag enriched in scandium element, elemental iron, and titanate enriched in titanium element; The calcium-silicon ratio of the mixture is 0.5 - 1.25:1; The temperature of the vacuum reduction smelting is 1200 - 1400 °C.

2. The method according to claim 1, characterized in that, By mass fraction, the titanium slag includes the following elements: O 30 - 36%, Fe 5 - 8%, Mg 2 - 3%, Al 5 - 8%, Si 10 - 12%, S 0.1 - 0.2%, Sc 0.005 - 0.1%, Ca 1.5 - 1.8%, Ti 25 - 30%, Mn 0.5 - 1%, and the remaining elements 10 - 15%.

3. The method according to claim 1 or 2, characterized in that, The calcium source includes CaO, the silicon source includes SiO2; the inorganic scandium compound includes Sc2O3.

4. The method according to claim 1, wherein Before mixing, dry the calcium source, silicon source, titanium slag, and inorganic scandium compound respectively.

5. The method according to claim 4, characterized in that, The temperature of the drying is 105 - 130 °C, and the time is 8 - 12 h.

6. The method according to claim 1, wherein After mixing, it further includes: grinding the mixed material to obtain the mixture.

7. The method according to claim 3, wherein The mass fraction of Sc2O3 in the mixture is 0.2 - 0.4%.

8. The method according to claim 1, wherein The mass fraction of carbon in the mixture is 5 - 8%; The carbon includes coke.

9. The method according to claim 1, wherein The current growth rate for heating up to the temperature of the vacuum reduction smelting is 5 - 10 A every 20 min, the heat preservation time of the vacuum reduction smelting is 3 - 5 h, and the vacuum degree ≤ 10 Pa.

10. The method according to claim 1, characterized in that, The separation includes crushing and then screening.

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