Beneficiation method for removing calcium and enriching vanadium from vanadium-containing shale through gravity-flotation combined separation

Abstract

The invention belongs to the technical field of beneficiation of vanadium-containing minerals, and discloses a beneficiation method for removing calcium and enriching vanadium from vanadium-containing shale through gravity-flotation combined separation, which comprises the following steps: S1, crushing raw ore, adding water and ball-milling to prepare ore pulp, and carrying out gravity separation on the ore pulp through a spiral launder to obtain a coarse-grained vanadium ore product and a fine-grained vanadium ore product; s2, water is added into the coarse-fraction vanadium ore product for size mixing, reverse flotation operation is carried out, and vanadium concentrate I and tailings I are obtained; s3, the fine-fraction vanadium ore product is firstly subjected to desliming treatment, vanadium concentrate II and deslimed minerals are obtained, water is added into the deslimed minerals for size mixing, then direct flotation operation is conducted, and vanadium concentrate III and tailings II are obtained; and S4, the vanadium concentrate I, the vanadium concentrate II and the vanadium concentrate III are combined to obtain final concentrate, and the tailings I and the tailings II are combined to obtain final tailings. The method has the characteristics of high V recovery rate, good Ca separation effect, simple process and environmental friendliness.

Description

Technical Field

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

[0002] It is generally believed that the CaO content in vanadium-containing raw materials>5.00% is a high-calcium vanadium-containing raw material. The main minerals of this type of vanadium-containing shale are dolomite, calcite, quartz, illite, and kaolin. Vanadium is contained in the crystal lattice of mica minerals such as muscovite and illite. It is difficult to directly extract vanadium from this type of vanadium-containing shale by acid leaching. At the same time, the content of acid-consuming substances such as dolomite and calcite in the ore is relatively high, resulting in a relatively large acid consumption in the leaching process. The continued use of the sodium roasting process will not only produce toxic and harmful gases, but also vanadium is easy to generate water-insoluble calcium vanadate, resulting in a low water leaching rate. Ore dressing can not only remove calcium-containing minerals from vanadium-containing raw materials, but also effectively enrich 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 beneficiation process of reverse flotation followed by positive flotation. The method has the advantages of simple process flow, low vanadium grade in tailings, and less vanadium loss. However, the method requires acid to be added again to adjust the pH of the ore pulp to acidic conditions after reverse flotation with an anionic collector under alkaline conditions, and positive flotation with a cationic collector. This method has the problems of reagent system conflicts and large acid and alkali consumption.

[0004] CN104959212A discloses a grading beneficiation method for mixed calcareous and siliceous stone coal vanadium ore, which is to ball-mill the raw ore and then directly use screening classification or hydraulic classification to separate the coarse and fine particles, and then further grind the coarse particles and collect vanadium by positive flotation, and collect vanadium by reverse flotation of the fine particles. This technology mainly classifies the coarse and fine particles according to the grinding process, which has the problem of being difficult to control. Summary of the invention

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

[0006] The technical solution of the present invention is to provide a vanadium-containing shale refloatation and combined selection method for removing calcium and enriching vanadium, comprising the following steps: S1. Crushing the raw ore, adding water and ball milling to make 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, adding water to the coarse-grained vanadium ore product to prepare the slurry, and performing 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 slurried with water and then subjected to positive 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.

[0007] Optionally, the V2O5 grade of the raw ore is 0.80wt%~1.10wt%, and the CaO grade is 6.00wt%~12.00wt%.

[0008] 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 %.

[0009] 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 turns.

[0010] Optionally, the reverse flotation operation in S2 includes one roughing selection, one fine selection and one scavenging selection.

[0011] Optionally, the reverse flotation reagent includes a pH adjuster, a depressant and a collector.

[0012] 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.

[0013] Optionally, the positive flotation includes one roughing selection and two scavenging selections.

[0014] Optionally, the positive flotation reagents include a pH adjuster, a depressant, a dispersant and a collector.

[0015] 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.

[0016] The present invention has the following beneficial effects: For high-calcium vanadium-containing shale, since vanadium is mainly found in muscovite and clay minerals, it mostly exists in the fine particle size after grinding. If the reverse flotation method uses 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, and efficiently separate the fine and coarse vanadium-containing raw materials. For the coarse-grained minerals classified by gravity separation, reverse flotation is directly performed according to the principle of suppressing more and floating less, and for the fine-grained minerals classified by gravity separation, positive flotation is directly performed.

[0017] The method provided by the present invention avoids the situation that alkali is first added and then acid is added in the traditional forward and reverse flotation process, and at the same time avoids the situation that the anionic and cationic collector ions are present in the wastewater and are difficult to return to the flotation process for reuse. The wastewater generated by the forward and reverse flotation processes of the present invention can be directly reused in the corresponding process, and will not cause the problem of decreased concentrate indicators and reduced recovery rate, thereby realizing the recycling of wastewater, reducing the consumption of water resources, and being environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attached Figure 1 The invention provides a process flow chart of a mineral processing method. DETAILED DESCRIPTION

[0019] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0020] 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. In order to clearly illustrate the present invention, in the flotation process in the following examples, the fatty acid anion collector is sodium oleate and the amine collector is dodecylamine, but the technical scheme 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.

[0021] 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%.

[0022] Example 1 The vanadium-containing shale refloatation and combined separation method for removing calcium and enriching vanadium: Step 1: crush the raw ore to a particle size of -10 mm to obtain the crushed raw ore, mix the crushed raw ore with water according to the ore: water mass ratio of 1:1, and put it into a ball mill to grind until the particle size is less than 0.074 mm, accounting for 76%, and add water to adjust the slurry to a slurry concentration of 24% to obtain a mixed slurry, and transport the mixed slurry to a spiral chute (spiral chute outer diameter 400 mm, pitch-to-diameter ratio 0.36, pitch 144 mm, lateral inclination 8.5︒, spiral groove number 5) through a slurry pump to select coarse-grained vanadium ore products and fine-grained vanadium ore products; Step 2: add water to the coarse-grained vanadium ore product obtained in step 1 to obtain a pulp with a pulp concentration of 25%, and then introduce a reverse flotation process 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, one concentrating, and one scavenging. The flotation reagents added in the roughing and the order of addition are respectively: 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 by the chute is: pH adjuster 2500 g / ton, inhibitor 800 g / ton, collector 1400 g / ton. The amount of collector added in the concentrating is 500 g / ton, and the amount of inhibitor added in the scavenging is 400 g / ton.

[0023] Step 3: Desludging the fine-grained vanadium ore product obtained in step 1 through a cyclone to obtain vanadium concentrate II and desludging minerals. The desludging minerals obtained are slurried with water to a pulp concentration of 20%, and the direct flotation process is introduced to obtain vanadium concentrate III and tailings II. The direct flotation is a mineral processing process of one roughing and two scavenging. The flotation agents added in the roughing and the order of addition are: 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: pH adjuster 300 g / ton, inhibitor 1250 g / ton, dispersant 900 g / ton, collector 900 g / ton. The amount of scavenging inhibitor is 400 g / ton.

[0024] Step 4: Combining the vanadium concentrate I obtained in step 2 with the vanadium concentrate II and vanadium concentrate III obtained in step 3 into a final concentrate, and combining the tailings I obtained in step 2 with the tailings II obtained in step 3 into a final tailings.

[0025] In this embodiment, the final concentrate yield obtained is 58.22%, V2O5 grade is 1.65%, CaO grade is 4.06%, and V2O5 recovery rate is 91.52%.

[0026] Example 2 The vanadium-containing shale refloatation and combined separation method for removing calcium and enriching vanadium: 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 according to the ore: water mass ratio of 1:1, and entering the ball mill for ball milling until the particle size is less than 0.074 mm, accounting for 80%, adding water to adjust the slurry to a slurry concentration of 20%, and obtaining a mixed slurry, and conveying the mixed slurry to a spiral flow trough (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; Step 2: add water to the coarse-grained vanadium ore product obtained in step 1 to obtain a slurry with a slurry concentration of 30%, and then introduce a reverse flotation process 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, one concentrating, and one scavenging. The flotation agents added in the roughing and the order of addition are: 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 by the chute is: pH adjuster 2600 g / ton, inhibitor 850 g / ton, collector 1300 g / ton, the amount of collector added for concentrating is 620 g / ton, and the amount of inhibitor added for scavenging is 350 g / ton.

[0027] Step 3: Desliming the fine-grained vanadium ore product obtained in step 1 through a cyclone to obtain vanadium concentrate II and deslimed minerals. The deslimed minerals are slurried with water to a pulp concentration of 24%, and a direct flotation process is introduced to obtain vanadium concentrate III and tailings II. The direct flotation is a mineral processing process with one roughing and two scavenging. The flotation agents added in the roughing and the order of addition are: 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: 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 is 450 g / ton.

[0028] Step 4: Combining the vanadium concentrate I obtained in step 2 with the vanadium concentrate II and vanadium concentrate III obtained in step 3 into a final concentrate, and combining the tailings I obtained in step 2 with the tailings II obtained in step 3 into a final tailings.

[0029] 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%.

[0030] Example 3 The vanadium-containing shale refloatation and combined separation method for removing calcium and enriching vanadium: 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 according to the ore: water mass ratio of 1:1, and entering the 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%, and obtaining a mixed slurry, and conveying the mixed slurry to a spiral flow trough (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; Step 2: add water to the coarse-grained vanadium ore product obtained in step 1 to obtain a slurry with a slurry concentration of 24%, and then introduce a reverse flotation process. The reverse flotation process is reverse flotation decalcification. The reverse flotation is a mineral processing process of one roughing, one concentrating and one scavenging. The flotation agents added in the roughing and the order of addition are: 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: pH adjuster 3000 g / ton, inhibitor 750 g / ton, collector 1500 g / ton, the amount of collector added for concentrating is 580 g / ton, and the amount of inhibitor added for scavenging is 320 g / ton.

[0031] Step 3: Desliming the fine-grained vanadium ore product obtained in step 1 through a cyclone to obtain vanadium concentrate II and deslimed minerals. The deslimed minerals are slurried with water to a pulp concentration of 22%, and a direct flotation process is introduced to obtain vanadium concentrate III and tailings II. The direct flotation is a mineral processing process of one roughing and two scavenging. The flotation agents added in the roughing and the order of addition are: 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, and the amount of inhibitor used in the first scavenging is 360 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 into a final concentrate, and combining the tailings I obtained in step 2 with the tailings II obtained in step 3 into a final tailings.

[0033] In this embodiment, the final concentrate yield obtained is 56.56%, V2O5 grade is 1.68%, CaO grade is 3.92%, and V2O5 recovery rate is 90.49%.

[0034] Comparative Example 1 The other conditions are consistent with those in Example 1, except that: without the spiral chute sorting in step 1, reverse flotation-direct flotation is directly used to enrich vanadium. In this comparative example, the final concentrate yield obtained is 46.23%, the V2O5 grade is 1.62, the CaO grade is 3.65%, and the V2O5 recovery rate is 72.64%.

[0035] Comparative Example 2 The other conditions are the same as those in Example 1, except that: in step 3, no desludging treatment is performed, and in step 3, the fine-grained vanadium ore product is directly slurried with water for positive flotation. In this comparative example, the final concentrate yield is 45.56%, the V2O5 grade is 1.58%, the CaO grade is 5.21%, and the V2O5 recovery rate is 68.56%. By comparing Example 1 with Comparative Examples 1-2, it can be seen that the problem of low recovery rate of vanadium pentoxide 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 grade, reducing the calcium oxide content in the final concentrate, thereby improving the leaching rate.

[0036] Embodiment 4, 4-1, 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 in length from inside to outside, the spiral chute has a diameter ratio of 0.36, and the chute diameter is 600 mm. Others are the same as Example 1.

[0037] 4-2, 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 in length from inside to outside, the spiral chute has a diameter ratio of 0.36, and the chute diameter is 600 mm. Others are the same as Example 1.

[0038] 4-3, 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 in length from inside to outside, the spiral chute has a diameter ratio of 0.36, and the chute diameter is 900 mm. Others are the same as Example 1.

[0039] 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 in length from inside to outside, the spiral chute has a diameter ratio of 0.36, and the chute diameter is 900 mm. Others are the same as Example 1 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 of the chute length, the spiral chute has a diameter ratio of 0.46, and the chute diameter is 600mm. Others are the same as Example 1 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 The final concentrate obtained in this embodiment is tested and shown in the following Table 1.

[0040] Table 1

[0041] It can be seen from the above embodiments that increasing the diameter of the spiral chute will lead to an increase in the calcium oxide content of the concentrate. Although increasing the coarse particle size and the fine particle size will increase the final aluminum yield of the concentrate, 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 resulting in a low vanadium pentoxide recovery rate.

[0042] The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached 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 make 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, adding water to the coarse-grained vanadium ore product to prepare the slurry, and performing 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 slurried with water and then subjected to positive 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, characterized in that: The V2O5 grade of the original 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, characterized in that: When the particle size is controlled to be less than 0.074 mm and accounts for 73% to 84% during ball milling, water is added to form a slurry with a concentration of 15 wt % to 25 wt %.

4. The method according to claim 1, characterized in that: When the spiral chute is used 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 fine 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, 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: Positive flotation includes one roughing selection and two sweeping 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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