Beneficiation method for vanadium-containing shale by re-flotation and combined separation to remove calcium and enrich vanadium

Abstract

The present invention belongs to the technical field of vanadium-containing mineral beneficiation and discloses a vanadium-containing shale beneficiation method for removing calcium and enriching vanadium by gravity flotation and combined selection. The method comprises the following steps: S1. crushing the raw ore, adding water to ball milling, and then preparing a slurry. The slurry is then passed through a spiral launder for gravity selection to obtain a coarse-grained vanadium ore product and a fine-grained vanadium ore product; S2. the coarse-grained vanadium ore product is slurried with water and subjected to reverse flotation to obtain vanadium concentrate I and tailings I; S3. the fine-grained vanadium ore product is first desludged to obtain vanadium concentrate II and desludified minerals. The desludified minerals are then slurried with water and subjected to direct flotation to obtain vanadium concentrate III and tailings II; S4. the vanadium concentrates I, II, and III are combined to form a final concentrate, and the tailings I and II are combined to form a final tailings. The method has the characteristics of high V recovery, good Ca separation effect, simple process, and environmental friendliness.

Description

Technical Field

[0001] The present invention relates to the technical field of vanadium ore beneficiation, and in particular to a beneficiation method for vanadium-containing shale by re-floatation and combined separation to remove calcium and enrich vanadium. Background Art

[0002] It is generally believed that vanadium-containing raw materials with a CaO content greater than 5.00% are high-calcium vanadium-containing raw materials. The main minerals in this type of vanadium-containing shale include dolomite, calcite, quartz, illite, and kaolin. Vanadium is contained in the crystal lattice of mica minerals such as muscovite and illite. Direct acid leaching of vanadium from this type of vanadium-containing shale is difficult. Furthermore, the high content of acid-consuming substances such as dolomite and calcite in the ore results in high acid consumption during the leaching process. Extended sodium roasting processes not only generate toxic and harmful gases, but also easily form water-insoluble calcium vanadate from vanadium, resulting in low water leaching yields. Ore dressing not only removes calcium-containing minerals from vanadium-containing raw materials but also effectively enriches vanadium-containing minerals.

[0003] CN105032598A discloses a method for pre-enriching vanadium by flotation from high-calcium mica-type vanadium-containing stone coal. The method obtains vanadium concentrate through a mineral processing process of reverse flotation followed by direct flotation. The method has the advantages of a simple process flow, low vanadium grade in tailings, and minimal vanadium loss. However, the method requires acid to be added again to adjust the pH of the slurry to an acidic condition after reverse flotation with an anionic collector under alkaline conditions, and then forward flotation with a cationic collector. This leads to conflicts in reagent systems and high acid and alkali consumption.

[0004] CN104959212A discloses a classification and beneficiation method for mixed calcareous and siliceous stone coal-vanadium ore. The method involves ball milling the raw ore and then directly separating it into coarse and fine fractions using screening or hydraulic classification. The coarse fraction is then further ground and then subjected to positive flotation to collect vanadium, while the fine fraction is subjected to reverse flotation to collect vanadium. This technology primarily relies on the grinding process to classify the coarse and fine fractions, which can be difficult to control. Summary of the Invention

[0005] The present invention provides a vanadium-containing shale re-floatation and combined separation method for removing calcium and enriching vanadium. The obtained vanadium concentrate has low calcium content and high vanadium recovery rate, avoiding the problem of high acid consumption in the subsequent acid leaching process.

[0006] The technical solution of the present invention is to provide a beneficiation method for vanadium-containing shale by re-flotation and combined separation to remove calcium and enrich vanadium, comprising the following steps:

[0007] S1. Crushing the raw ore, adding water and ball milling to form slurry, and gravity separation of the slurry through a spiral chute to obtain coarse-grained vanadium ore products and fine-grained vanadium ore products;

[0008] S2. Add water to the coarse-grained vanadium ore product to prepare a slurry, and perform reverse flotation operation to obtain vanadium concentrate I and tailings I;

[0009] S3. The fine-grained vanadium ore product is first deslimed to obtain vanadium concentrate II and deslimed minerals. The deslimed minerals are then slurried with water and subjected to direct flotation to obtain vanadium concentrate III and tailings II.

[0010] S4, vanadium concentrate I, vanadium concentrate II and vanadium concentrate III are combined to form the final concentrate, and tailings I and tailings II are combined to form the final tailings.

[0011] Optionally, the V2O5 grade of the raw ore is 0.80 wt%~1.10 wt%, and the CaO grade is 6.00 wt%~12.00 wt%.

[0012] Optionally, when the particle size is controlled to be less than 0.074 mm, accounting for 73% to 84%, water is added to prepare a slurry, and the concentration of the slurry is 15 wt % to 25 wt %.

[0013] Optionally, when a spiral chute is used for gravity separation, the outer diameter of the spiral chute is 400-900 mm; the pitch-to-diameter ratio is 0.36-0.45; the pitch is 144 mm; the lateral inclination angle is 6-8.5°; and the number of spiral groove turns is 3-5.

[0014] Optionally, the reverse flotation operation in S2 includes one roughing selection, one cleaning selection and one scavenging selection.

[0015] Optionally, the reverse flotation reagent includes a pH adjuster, a depressant and a collector.

[0016] Optionally, the pH adjuster is sodium carbonate, the inhibitor is water glass, and the collector is a fatty acid anion collector; the added amounts are 1000-3000 g / ton, 600-1000 g / ton, and 600-1500 g / ton, respectively, based on the dry basis mass of coarse-grained minerals.

[0017] Optionally, the forward flotation includes one roughing step and two scavenging steps.

[0018] Optionally, the positive flotation reagents include a pH adjuster, a depressant, a dispersant and a collector.

[0019] Optionally, the pH adjuster is sulfuric acid, the inhibitor is sodium fluorosilicate, the dispersant is acidic water glass, and the collector is an amine cationic collector, and the added amounts are 300-500 g / ton, 1000-2000 g / ton, 800-1000 g / ton and 700-900 g / ton respectively based on the dry basis mass of the fine-grained mineral.

[0020] The present invention has the following beneficial effects:

[0021] For high-calcium vanadium-containing shale, since vanadium is mainly found in muscovite and clay minerals, it is mostly present in the fine particle size after grinding. If reverse flotation is performed using anionic fatty acids as collectors, there will be problems such as high foam viscosity and obvious entrainment, resulting in low fine particle size separation efficiency. The present invention introduces a chute gravity separation process before flotation, which can not only classify the ore by particle size, but also enrich the minerals by the density of different ores, effectively separating fine and coarse vanadium-containing raw materials. For the coarse particle size minerals classified by gravity separation, reverse flotation is directly performed according to the principle of suppressing more and floating less. For the fine particle size minerals classified by gravity separation, direct flotation is directly performed.

[0022] The method provided by the present invention avoids the situation in which alkali is added first and then acid is added in the traditional direct and reverse flotation process, and also avoids the situation in which cationic and anionic collector ions are present in the wastewater and are difficult to return to the flotation process for reuse. The wastewater generated by the direct and reverse flotation processes of the present invention can be directly reused in the corresponding processes, without causing the problems of decreased concentrate indicators and reduced recovery rate, thus realizing the recycling of wastewater, reducing water resource consumption, and being environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Attachment Figure 1 The present invention provides a process flow chart of the mineral processing method. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0025] The experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials, reagents, etc. used in the following examples are all commercially available products unless otherwise specified. To clearly illustrate the present invention, in the following examples, the fatty acid anion collector is sodium oleate and the amine collector is dodecylamine during the flotation process. However, the technical solution of the present invention does not limit the type of collector, and other fatty acid anion collectors and amine collectors commonly used in the mineral processing industry can also be applied to the present invention.

[0026] The raw ore in the following examples and comparative examples has a vanadium pentoxide content of 1.05 wt% and a calcium oxide content of 10.06 wt%.

[0027] Example 1

[0028] Beneficiation method for vanadium-containing shale by re-flotation and combined separation to remove calcium and enrich vanadium:

[0029] Step 1: crushing the raw ore to a particle size of -10 mm to obtain the crushed raw ore, mixing the crushed raw ore with water at a mass ratio of 1:1, and entering into a ball mill for ball milling until the particle size is less than 0.074 mm, accounting for 76%, adding water to adjust the slurry concentration to 24%, thereby obtaining a mixed slurry, and conveying the mixed slurry to a spiral chute (spiral chute outer diameter 400 mm, pitch-to-diameter ratio 0.36, screw pitch 144 mm, transverse inclination angle 8.5°, spiral groove number 5 turns) via a slurry pump for separation to obtain coarse-grained vanadium ore products and fine-grained vanadium ore products;

[0030] Step 2: The coarse-grained vanadium ore product obtained in Step 1 is slurried with water to obtain a slurry with a concentration of 25%. The slurry is then subjected to a reverse flotation process to obtain vanadium concentrate I and tailings I. The reverse flotation process involves reverse flotation decalcification. The reverse flotation process comprises a primary roughing process, a primary cleaning process, and a primary scavenging process. The flotation reagents added in the roughing process are, in the following order: pH adjuster sodium carbonate, depressant water glass, and collector fatty acid anion collector. The total amount added, relative to the dry weight of the coarse-grained ore separated by the chute, is: 2500 g / ton of pH adjuster, 800 g / ton of depressant, and 1400 g / ton of collector. The amount of collector added in the cleaning process is 500 g / ton, and the amount of depressant added in the scavenging process is 400 g / ton.

[0031] Step 3: The fine-grained vanadium ore product obtained in Step 1 is deslimed in a cyclone to obtain vanadium concentrate II and deslimed minerals. The deslimed minerals are slurried with water to a slurry concentration of 20%, and then subjected to direct flotation to obtain vanadium concentrate III and tailings II. The direct flotation process comprises a single roughing process and two scavenging processes. The flotation reagents added in the roughing process are sulfuric acid for pH adjustment, sodium fluorosilicate as a depressant, acidic water glass as a dispersant, and an amine cationic collector. The total amount added, relative to the dry weight of the coarse-grained minerals sorted in the chute, is 300 g / ton of pH adjuster, 1250 g / ton of depressant, 900 g / ton of dispersant, and 900 g / ton of collector. The depressant used in the scavenging process is 400 g / ton.

[0032] Step 4: combining the vanadium concentrate I obtained in step 2 with the vanadium concentrate II and vanadium concentrate III obtained in step 3 to form a final concentrate, and combining the tailings I obtained in step 2 with the tailings II obtained in step 3 to form a final tailings.

[0033] In this embodiment, the final concentrate yield obtained is 58.22%, the V2O5 grade is 1.65%, the CaO grade is 4.06%, and the V2O5 recovery rate is 91.52%.

[0034] Example 2

[0035] Beneficiation method for vanadium-containing shale by re-flotation and combined separation to remove calcium and enrich vanadium:

[0036] Step 1: crushing the raw ore to a particle size of -10 mm to obtain crushed raw ore, mixing the crushed raw ore with water at a mass ratio of 1:1, and entering into a ball mill for ball milling until 80% of the particles have a particle size of less than 0.074 mm, adding water to adjust the slurry to a slurry concentration of 20% to obtain a mixed slurry, and conveying the mixed slurry to a spiral launder (with the same parameters as in Example 1) through a slurry pump for sorting to obtain a coarse-grained vanadium ore product and a fine-grained vanadium ore product;

[0037] Step 2: The coarse-grained vanadium ore product obtained in step 1 is slurried with water to obtain a slurry with a slurry concentration of 30%, and a reverse flotation process is introduced to obtain vanadium concentrate I and tailings I. The reverse flotation process is reverse flotation decalcification, and the reverse flotation is a mineral processing process of one roughing selection, one cleaning selection, and one scavenging selection. The flotation agents added in the roughing selection and the order of addition are as follows: pH adjuster sodium carbonate, inhibitor water glass, collector fatty acid anion collector, and the total amount added relative to the dry weight of the coarse-grained minerals sorted in the chute is as follows: pH adjuster 2600 g / ton, inhibitor 850 g / ton, collector 1300 g / ton, the amount of collector added in the cleaning selection is 620 g / ton, and the amount of inhibitor added in the scavenging selection is 350 g / ton.

[0038] Step 3: The fine-grained vanadium ore product obtained in step 1 is deslimed by a cyclone to obtain vanadium concentrate II and deslimed minerals. The deslimed minerals are slurried with water to a pulp concentration of 24%, and then introduced into a direct flotation process to obtain vanadium concentrate III and tailings II. The direct flotation is a mineral processing process with one roughing selection and two scavenging selections. The flotation agents added in the roughing selection and the order of addition are as follows: pH adjustment sulfuric acid, inhibitor sodium fluorosilicate, dispersant acidic water glass, collector amine cationic collector, and the total amount added relative to the dry weight of the coarse-grained minerals sorted in the chute is as follows: pH adjuster 320 g / ton, inhibitor 1200 g / ton, dispersant 950 g / ton, collector 850 g / ton, and the amount of inhibitor used in the first scavenging selection is 450 g / ton.

[0039] Step 4: combining the vanadium concentrate I obtained in step 2 with the vanadium concentrate II and vanadium concentrate III obtained in step 3 to form a final concentrate, and combining the tailings I obtained in step 2 with the tailings II obtained in step 3 to form a final tailings.

[0040] In this embodiment, the final concentrate yield obtained is 56%, the V2O5 grade is 1.54%, the CaO grade is 4.52%, and the V2O5 recovery rate is 85.58%.

[0041] Example 3

[0042] Beneficiation method for vanadium-containing shale by re-flotation and combined separation to remove calcium and enrich vanadium:

[0043] Step 1: crushing the raw ore to a particle size of -10 mm to obtain crushed raw ore, mixing the crushed raw ore with water at a mass ratio of ore to water of 1:1, and entering into a ball mill for ball milling until the particle size is less than 0.074 mm, accounting for 78%, adding water to adjust the slurry to a slurry concentration of 18% to obtain a mixed slurry, and conveying the mixed slurry to a spiral launder (with the same parameters as in Example 1) through a slurry pump for sorting to obtain a coarse-grained vanadium ore product and a fine-grained vanadium ore product;

[0044] Step 2: The coarse-grained vanadium ore product obtained in step 1 is slurried with water to obtain a slurry with a slurry concentration of 24%, and a reverse flotation process is introduced. The reverse flotation process is reverse flotation decalcification. The reverse flotation is a mineral processing process of one roughing, one cleaning, and one scavenging. The flotation agents added in the roughing are as follows: pH adjuster sodium carbonate, inhibitor water glass, collector fatty acid anion collector, and the total amount added relative to the dry weight of the coarse-grained ore separated by the chute is as follows: pH adjuster 3000 g / ton, inhibitor 750 g / ton, collector 1500 g / ton, the amount of collector added in the cleaning is 580 g / ton, and the amount of inhibitor added in the scavenging is 320 g / ton.

[0045] Step 3: The fine-grained vanadium ore product obtained in step 1 is deslimed by a cyclone to obtain vanadium concentrate II and deslimed minerals. The deslimed minerals are slurried with water to a pulp concentration of 22%, and are introduced into a direct flotation process to obtain vanadium concentrate III and tailings II. The direct flotation is a mineral processing process with one roughing selection and two scavenging selections. The flotation agents added in the roughing selection and the order of addition are as follows: pH adjustment sulfuric acid, inhibitor sodium fluorosilicate, dispersant acidic water glass, collector amine cationic collector, and the total amount added relative to the dry weight of the coarse-grained minerals sorted in the chute is 340 g / ton of pH adjuster, 1800 g / ton of inhibitor, 850 g / ton of dispersant, and 800 g / ton of collector. The amount of inhibitor used in the first scavenging selection is 360 g / ton.

[0046] Step 4: combining the vanadium concentrate I obtained in step 2 with the vanadium concentrate II and vanadium concentrate III obtained in step 3 to form a final concentrate, and combining the tailings I obtained in step 2 with the tailings II obtained in step 3 to form a final tailings.

[0047] In this embodiment, the final concentrate yield obtained is 56.56%, the V2O5 grade is 1.68%, the CaO grade is 3.92%, and the V2O5 recovery rate is 90.49%.

[0048] Comparative Example 1

[0049] Other conditions were consistent with those in Example 1, except that vanadium was directly enriched by reverse flotation-direct flotation without spiral chute separation in step 1. The final concentrate yield obtained in this comparative example was 46.23%, V2O5 grade was 1.62, CaO grade was 3.65%, and V2O5 recovery rate was 72.64%.

[0050] Comparative Example 2

[0051] All other conditions were the same as in Example 1, except that desludging was not performed in step 3. Instead, the fine-grained vanadium ore product was directly slurried with water for direct flotation. In this comparative example, the resulting concentrate yield was 45.56%, with a V2O5 grade of 1.58%, a CaO grade of 5.21%, and a V2O5 recovery of 68.56%.

[0052] By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that the problem of low vanadium pentoxide recovery rate in the final concentrate can be avoided after the raw ore is sorted by the chute. Adding a desliming step to the fine-grained vanadium product is beneficial to the separation of muscovite and dolomite in the fine-grained fraction, reducing the calcium oxide content in the final concentrate, thereby improving the leaching rate.

[0053] Example 4

[0054] 4-1 is based on Example 1, except that the interception points of the coarse-grained low-calcium product and the fine-grained high-calcium product in the spiral chute have a chute length ratio of 3:7 from the inside to the outside, the spiral chute has a height-to-diameter ratio of 0.36, and the chute diameter is 600 mm. Other configurations are the same as in Example 1.

[0055] 4-2 is based on Example 1, except that the interception points of the coarse-grained low-calcium product and the fine-grained high-calcium product in the spiral chute have a 4:6 chute length ratio from the inside to the outside, the spiral chute has a 0.36 aspect ratio, and the chute diameter is 600 mm. Other differences are the same as in Example 1.

[0056] 4-3 is based on Example 1, except that the interception points of the coarse-grained low-calcium product and the fine-grained high-calcium product in the spiral chute have a chute length ratio of 3:7 from the inside to the outside, the spiral chute has a height-to-diameter ratio of 0.36, and the chute diameter is 900 mm. Other differences are the same as in Example 1.

[0057] 4-4, based on Example 1, the only difference is that the interception points of the coarse-grained low-calcium product and the fine-grained high-calcium product in the spiral chute are 4:6 from the inside to the outside, the spiral chute has a diameter ratio of 0.36, and the chute diameter is 900mm. Others are the same as Example 1

[0058] 4-5, based on Example 1, the only difference is that the interception points of the coarse-grained low-calcium product and the fine-grained high-calcium product in the spiral chute are 3:7 from the inside to the outside, the spiral chute has a diameter ratio of 0.46, and the chute diameter is 600mm. Others are the same as Example 1

[0059] 4-6, based on Example 1, the only difference is that the interception points of the coarse-grained low-calcium product and the fine-grained high-calcium product in the spiral chute are 5:5 from the inside to the outside, the spiral chute has a diameter ratio of 0.46, and the chute diameter is 600mm. Others are the same as Example 1

[0060] The final concentrate obtained in this embodiment is tested and shown in Table 1 below.

[0061] Table 1

[0062]

[0063] It can be seen from the above examples that increasing the spiral chute diameter will lead to an increase in the calcium oxide content of the concentrate. Although increasing the coarse particle size and fine particle size will increase the final aluminum concentrate yield, it will also lead to an increase in the calcium oxide content of the concentrate. Increasing the distance-to-diameter ratio will reduce the classification efficiency, ultimately leading to a low vanadium pentoxide recovery rate.

[0064] The above embodiments describe preferred embodiments of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the appended claims.

Claims

1. A vanadium-containing shale refloatation and combined separation method for removing calcium and enriching vanadium, characterized in that: The following steps are involved: S1. Crushing the raw ore, adding water and ball milling to form slurry, and gravity separation of the slurry through a spiral chute to obtain coarse-grained vanadium ore products and fine-grained vanadium ore products; S2. Add water to the coarse-grained vanadium ore product to prepare a slurry, and perform reverse flotation operation to obtain vanadium concentrate I and tailings I; S3. The fine-grained vanadium ore product is first deslimed to obtain vanadium concentrate II and deslimed minerals. The deslimed minerals are then slurried with water and subjected to direct flotation to obtain vanadium concentrate III and tailings II. S4, vanadium concentrate I, vanadium concentrate II and vanadium concentrate III are combined to form the final concentrate, and tailings I and tailings II are combined to form the final tailings.

2. The method according to claim 1, wherein: The V2O5 grade of the raw ore is 0.80wt%~1.10 wt%, and the CaO grade is 6.00 wt%~12.00 wt%.

3. The method according to claim 1, wherein: When the particle size is controlled to be less than 0.074 mm, accounting for 73% to 84%, water is added to prepare a slurry with a concentration of 15 wt % to 25 wt %.

4. The method according to claim 1, wherein: When using spiral chute for gravity separation, the outer diameter of the spiral chute is 400-900mm; the pitch-to-diameter ratio is 0.36~0.45; the pitch is 144mm; the lateral inclination angle is 6~8.5°; and the number of spiral groove turns is 3~5.

5. The method according to any one of claims 1 to 4, characterized in that: The reverse flotation operation in S2 includes one roughing selection, one cleaning selection and one scavenging selection.

6. The method according to any one of claims 1 to 4, characterized in that: Reverse flotation reagents include pH adjusters, depressants and collectors.

7. The method according to claim 6, characterized in that: The pH adjuster is sodium carbonate, the inhibitor is water glass, and the collector is a fatty acid anion collector; the added amounts are 1000-3000 g / ton, 600-1000 g / ton, and 600-1500 g / ton, respectively, calculated based on the dry basis mass of coarse-grained minerals.

8. The method according to any one of claims 1 to 4, characterized in that: Direct flotation includes one roughing selection and two scavenging selections.

9. The method according to any one of claims 1 to 4, characterized in that: Positive flotation reagents include pH adjusters, depressants, dispersants and collectors.

10. The method according to claim 9, characterized in that: The pH adjuster is sulfuric acid, the inhibitor is sodium fluorosilicate, the dispersant is acidic water glass, and the collector is an amine cationic collector. The added amounts are 300-500 g / ton, 1000-2000 g / ton, 800-1000 g / ton and 700-900 g / ton respectively based on the dry basis mass of fine-grained minerals.

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