Process for recovering phosphorus from vanadium titano-magnetite tailings

Abstract

The invention relates to the technical field of mineral processing, and provides a process for recovering phosphorus from vanadium titano-magnetite tailings, which comprises the following steps: S1, magnetic separation: carrying out ore grinding treatment and low intensity magnetic separation tailing discarding treatment on the vanadium titano-magnetite tailings to obtain magnetic minerals and non-magnetic minerals for later use; s2, pulp mixing is conducted, specifically, water is added into non-magnetic minerals, stirring is conducted, and ore pulp is obtained for standby application; a sodium carbonate aqueous solution is added into the ore pulp, stirring is carried out, a gangue inhibitor and water are added, stirring is carried out, a collecting agent and water are added, stirring and foam scraping are carried out, roughed concentrate and scavenging feed ore are obtained for standby application, and the gangue inhibitor is a mixture of modified water glass and sodium hexametaphosphate with the mass ratio being 1: (0.3-0.6); and S4, concentration is conducted, specifically, primary concentration, secondary concentration and third concentration are conducted on the roughed concentrate, and final phosphate concentrate is obtained. The process for recycling phosphorus from the vanadium titano-magnetite tailings has the advantages that the flotation reagent dosage is low, and the obtained phosphorus concentrate has the high phosphorus grade.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing, and in particular to a process for recovering phosphorus from vanadium-titanium magnetite tailings. Background Art

[0002] Phosphate rock is a non-metallic mineral with strategic significance. It is mainly used to make phosphate fertilizer and other phosphate salts, and is used in agriculture, medicine, food, national defense and other industries. It is irreplaceable and non-renewable. At present, the depletion of phosphorus resources has become a global problem. Strengthening the utilization of medium and low-grade phosphate rocks and expanding the scope of available phosphate resources are urgent tasks to solve the shortage of phosphorus resources.

[0003] Vanadium-titanium magnetite is an important type of ferrous metal mineral resource in China, and vanadium-titanium magnetite tailings refer to the waste generated during the beneficiation process of vanadium-titanium magnetite. It has a low grade and is generally considered to be a low-grade phosphate ore. At present, there is no mature recovery process for vanadium-titanium magnetite tailings, and they are often discarded as waste ore, resulting in a serious waste of phosphorus resources. Therefore, the development of a process for recovering phosphorus from vanadium-titanium magnetite tailings is imperative, which is of great significance to improving the comprehensive utilization rate of resources and realizing the sustainable development of China's phosphate fertilizer industry and agriculture.

[0004] Phosphate flotation is a key step in extracting effective components from phosphate ore, and collectors are indispensable chemical agents for this process. Collectors can selectively adsorb on the surface of phosphate minerals to enhance their hydrophobicity, thereby achieving separation from gangue minerals. Among them, fatty acid collectors, such as oleic acid and linoleic acid, are the most commonly used agents in phosphate flotation. This type of collector has good selectivity and collection ability, and can effectively improve the recovery rate of phosphate minerals. However, this type of collector generally has problems with solubility and poor dispersion, resulting in increased use of flotation agents and reduced phosphorus recovery. This results in a waste of mineral resources.

[0005] Patent CN 110935560 A discloses a beneficiation method for recovering phosphorus from vanadium-titanium magnetite tailings with extremely low phosphorus content. The specific scheme of the method is: further grinding, sulfur separation, iron separation, After titanium selection, a strong magnetic separation process is used to remove some weakly magnetic minerals. The resulting non-magnetic product is desludging and flotation to obtain high-quality phosphate concentrate, which can be applied to vanadium-titanium magnetite tailings and can better recover phosphate minerals in the tailings. It has low cost and good economic benefits. The collector used in this application is still a fatty acid collector, but the application does not solve the problem of its poor solubility and dispersibility, which will result in the recovery of phosphorus failing to achieve the ideal effect.

[0006] Therefore, there is an urgent need on the market for a process for recovering phosphorus from vanadium-titanium magnetite tailings, which requires low flotation reagent dosage and produces a phosphate concentrate with a high phosphorus grade. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. On the basis of the existing process for phosphorus flotation, the steps and reaction conditions are optimized, and a gangue inhibitor and a collector are added by design, wherein the gangue inhibitor is a mixture of modified water glass and sodium hexametaphosphate, which has the characteristics of low flotation agent dosage and high phosphorus grade of the obtained phosphate concentrate.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows: In one aspect, the present invention provides a process for recovering phosphorus from vanadium-titanium magnetite tailings, comprising the following steps: S1. Magnetic separation: Grind the vanadium-titanium magnetite tailings, and perform weak magnetic separation and tailings separation to obtain magnetic minerals and non-magnetic minerals for standby use; S2, slurry preparation: adding water to the non-magnetic mineral in step S1, stirring, and obtaining slurry for standby use; S3, roughing: adding sodium carbonate aqueous solution to the ore pulp of step S2, stirring, adding gangue inhibitor and water, stirring, adding collector and water, stirring, scraping foam, obtaining roughing concentrate and scavenging feed for standby use, Wherein, the gangue inhibitor is a mixture of modified water glass and sodium hexametaphosphate, with a mass ratio of 1: (0.3-0.6); S4, beneficiation: The rougher concentrate of step S3 is subjected to the first, second and third beneficiation to obtain the final phosphate concentrate.

[0009] In some embodiments of the present invention, the magnetic field strength in the weak magnetic separation tailing treatment in step S1 is 0.3-0.6T.

[0010] In some embodiments of the present invention, the ratio of the non-magnetic mineral to water in step S2 is (30-40) g: 100ml.

[0011] In some embodiments of the present invention, the mass ratio of the non-magnetic mineral, the gangue inhibitor and the collector is 1t: (150-350)g: (200-400)g.

[0012] Preferably, the mass ratio of the non-magnetic mineral, the gangue inhibitor and the collector is 1t:200g:300g.

[0013] In some embodiments of the present invention, the method for preparing the modified water glass in step S3 comprises the following steps: Add water glass into 25-35wt% oxalic acid aqueous solution, stir and concentrate to obtain modified water glass.

[0014] In some embodiments of the present invention, the ratio of water glass to oxalic acid aqueous solution is 1 g: (8-9) ml.

[0015] Preferably, the ratio of water glass to oxalic acid aqueous solution is 1g:8.5ml.

[0016] The applicant selected oxalic acid aqueous solution to acidify and modify water glass, which can make the sodium silicate in the water glass move toward the direction of silicate colloid particles, thereby making the silicate colloid particles more active and hydrophilic, and thus having a stronger inhibitory effect on gangue, thereby improving the phosphorus grade in the phosphate concentrate. In addition, the applicant unexpectedly discovered that mixing modified water glass and sodium hexametaphosphate in a certain mass ratio to form a gangue inhibitor can effectively improve the phosphorus grade in the phosphate concentrate. It is speculated that the reason is that the addition of sodium hexametaphosphate can cause the surface charge of the mineral to change, so that the interaction force between the mineral particles changes accordingly, and the dispersion of the mineral particles is increased, thereby optimizing the mineral flotation conditions, and further promoting the improvement of the phosphorus grade in the phosphate concentrate.

[0017] In some embodiments of the present invention, the method for preparing the collector in step S3 comprises the following steps: (1) Add palmitic acid to a reaction vessel, add chlorosulfonic acid at 55-65°C while stirring, raise the temperature to 90-100°C, stir, stand, and cool to 55-65°C to obtain product 1 for later use; (2) adding acetone and deionized water to the product 1 of step (1), heating to 80-90° C., standing to cool until crystals precipitate, filtering, washing, and drying to obtain the product 2 for later use; (3) Take the product 2 of step (2), heat it to 55-65°C, add sodium hydroxide aqueous solution until it becomes neutral, stir, and obtain a palmitic acid derivative for use; (4) Mix tartaric acid and n-dodecyl alcohol, stir at 80-90° C., add the palmitic acid derivative of step (3), and stir to obtain a collector.

[0018] In some embodiments of the present invention, in step (1), the molar ratio of palmitic acid to chlorosulfonic acid is 1:(1.2-1.6).

[0019] Preferably, in step (1), the molar ratio of palmitic acid to chlorosulfonic acid is 1:1.4.

[0020] In some embodiments of the present invention, in step (4), the mass ratio of the palmitic acid derivative to tartaric acid is 1:(0.08-0.12).

[0021] Preferably, in step (4), the mass ratio of the palmitic acid derivative to tartaric acid is 1:0.1.

[0022] Fatty acid collectors are the most commonly used agents in phosphate ore flotation. Their mechanism of action is mainly through the chemical reaction between the carboxyl group and the metal ions on the surface of the phosphate mineral to generate hydrophobic metal fatty acid salts, thereby achieving the flotation of the phosphate mineral. Among them, oleic acid has been widely used in phosphate ore flotation due to its wide source and low price, but it has the disadvantage of poor water solubility, so its collection effect needs to be improved.

[0023] On the one hand, the applicant introduced sulfonic acid groups into the structure of the saturated fatty acid palmitic acid by structural modification and derivatization of functional groups, and used sodium hydroxide to perform a saponification reaction on it, thereby improving its hydrophilicity and water solubility. The sulfonic acid groups can react with metal ions on the surface of phosphate minerals to form stable complexes, thereby improving the collection performance of the collector. On the other hand, the applicant used tartaric acid and n-dodecanol as raw materials, and synthesized an esterification product by controlling the mass ratio of the two and the reaction conditions. The applicant unexpectedly found that the flotation performance of the collector was greatly improved by compounding the esterification product with a palmitic acid derivative in a certain ratio. It is speculated that the reason is that the synthesized esterification product has hydroxyl groups, carboxyl groups and ester groups at the same time, and these groups can effectively improve the collection performance and solubility.

[0024] In some embodiments of the present invention, according to the process for recovering phosphorus from vanadium-titanium magnetite tailings described in the above technical solution, the phosphorus grade in the phosphate concentrate is not less than 37%.

[0025] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The process steps and reaction conditions are optimized on the basis of the existing phosphorus flotation process, and a gangue inhibitor and a collector are added. The gangue inhibitor is a mixture of modified water glass and sodium hexametaphosphate, which has the characteristics of low flotation reagent dosage and high phosphorus grade of the obtained phosphate concentrate.

[0026] (2) The present invention uses oxalic acid aqueous solution to acidify and modify water glass and mixes the modified water glass and sodium hexametaphosphate in a certain mass ratio to form a gangue inhibitor, which synergistically improves the inhibitory effect on gangue and further improves the grade of phosphorus in phosphate concentrate.

[0027] (3) The present invention prepares a collector by structurally modifying the saturated fatty acid palmitic acid and deriving the functional groups thereof, and then compounding the esterification product synthesized from tartaric acid and n-dodecyl alcohol as raw materials. The collector has good solubility and collecting performance, and can effectively improve the grade of phosphorus in phosphate concentrate.

[0028] (4) The process of recovering phosphorus from vanadium-titanium magnetite tailings of the present invention has the advantage of high phosphorus grade in the phosphate concentrate being not less than 37%. DETAILED DESCRIPTION

[0029] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0030] In the following examples, except for the modified water glass and the collector, the other compound monomers and related reagents used can be purchased from the market.

[0031] Preparation Example 1 The synthetic method of modified water glass A comprises the following steps: 12 g of water glass was added into 100 ml of 30 wt % oxalic acid aqueous solution, stirred for 2 h, and concentrated to 5 wt % to obtain modified water glass A.

[0032] Preparation Example 2 Modified water glass B, the specific implementation method is the same as modified water glass A, the difference is: the volume of the oxalic acid aqueous solution is replaced with 90 ml.

[0033] Preparation Example 3 The synthetic method of collector A comprises the following steps: 1) Add 0.1 mol of palmitic acid into a reaction vessel, add 0.14 mol of chlorosulfonic acid while stirring at 60°C, raise the temperature to 95°C, stir for 3 hours, let stand for 1 hour, and cool to 60°C to obtain product 1 for use; (2) Add 30 ml of acetone and 60 ml of deionized water to the product 1 of step (1), heat to 85°C, cool to precipitate crystals, filter, wash three times with a mixture of 30 ml of acetone and 60 ml of deionized water, and dry naturally to obtain product 2 for use; (3) Take 20 g of the product 2 of step (2), heat to 60° C., add 40 w % sodium hydroxide aqueous solution until neutral, stir for 2 h, and obtain a palmitic acid derivative for use; (4) Mix 2 g of tartaric acid and 10 g of n-dodecanol, stir at 85 °C for 1 h, add 20 g of the palmitic acid derivative prepared in step (3), and stir for 30 min to obtain collector A.

[0034] Preparation Example 4 Collector B has the same specific implementation as Collector A, except that: in step (1), the molar number of chlorosulfonic acid is replaced with 0.1 mol.

[0035] Preparation Example 5 Collector C has the same specific implementation method as Collector A, except that in step (4), the mass of tartaric acid is replaced with 1.4 g.

[0036] Example 1: A process for recovering phosphorus from vanadium-titanium magnetite tailings, comprising the following steps: S1. Magnetic separation: Grind the vanadium-titanium magnetite tailings (grind to less than 0.074 mm), and perform weak magnetic separation and tailing treatment (magnetic field strength is 0.4 T) to obtain magnetic minerals and non-magnetic minerals for standby use; S2, slurry preparation: add water to the non-magnetic mineral in step S1, stir for 1 minute, and obtain slurry for use. Among them, the ratio of non-magnetic minerals to water is 35g:100ml; S3, roughing: add 1300g 5wt% sodium carbonate aqueous solution to the ore pulp of step S2, stir for 2min, add 200g gangue inhibitor and 10kg water, stir for 2min, add 300g collector A and 15kg water, stir for 2min, scrape and foam for 5min, obtain roughing concentrate and scavenging feed for standby use, Wherein, the gangue inhibitor is a mixture of modified water glass A and sodium hexametaphosphate, with a mass ratio of 1:0.5; S4, concentration: The roughing concentrate of step S3 is subjected to the first, second and third concentrations (the three concentrations are blank concentrations, and the scraping and foaming times are 2 min, 2 min and 1.5 min respectively) to obtain the final phosphate concentrate.

[0037] Example 2: A process for recovering phosphorus from vanadium-titanium magnetite tailings, comprising the following steps: S1. Magnetic separation: Grind the vanadium-titanium magnetite tailings (grind to less than 0.074 mm), and perform weak magnetic separation and tailing treatment (magnetic field strength is 0.3 T) to obtain magnetic minerals and non-magnetic minerals for standby use; S2, slurry preparation: add water to the non-magnetic mineral in step S1, stir for 1 minute, and obtain slurry for use. Among them, the ratio of non-magnetic minerals to water is 30g:100ml; S3, roughing: add 1300g 5wt% sodium carbonate aqueous solution to the ore pulp of step S2, stir for 2min, add 150g gangue inhibitor and 7.5kg water, stir for 2min, add 200g collector A and 10kg water, stir for 2min, scrape and foam for 5min, obtain roughing concentrate and scavenging feed for standby use, Wherein, the gangue inhibitor is a mixture of modified water glass A and sodium hexametaphosphate, with a mass ratio of 1:0.3; S4, concentration: The roughing concentrate of step S3 is subjected to the first, second and third concentrations (the three concentrations are blank concentrations, and the scraping and foaming times are 2 min, 2 min and 1.5 min respectively) to obtain the final phosphate concentrate.

[0038] Example 3: A process for recovering phosphorus from vanadium-titanium magnetite tailings, comprising the following steps: S1. Magnetic separation: Grind the vanadium-titanium magnetite tailings (grind to less than 0.074 mm), and perform weak magnetic separation and tailing treatment (magnetic field strength is 0.6 T) to obtain magnetic minerals and non-magnetic minerals for standby use; S2, slurry preparation: add water to the non-magnetic mineral in step S1, stir for 1 minute, and obtain slurry for use. Among them, the ratio of non-magnetic minerals to water is 40g:100ml; S3, roughing: add 1300g 5wt% sodium carbonate aqueous solution to the ore pulp of step S2, stir for 2min, add 350g gangue inhibitor and 17.5kg water, stir for 2min, add 400g collector A and 20kg water, stir for 2min, scrape and foam for 5min, obtain roughing concentrate and scavenging feed for standby use, Wherein, the gangue inhibitor is a mixture of modified water glass A and sodium hexametaphosphate, with a mass ratio of 1:0.6; S4, concentration: The roughing concentrate of step S3 is subjected to the first, second and third concentrations (the three concentrations are blank concentrations, and the scraping and foaming times are 2 min, 2 min and 1.5 min respectively) to obtain the final phosphate concentrate.

[0039] Example 4: This example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that in step S3, the mass ratio of modified water glass A to sodium hexametaphosphate in the gangue inhibitor is 1:0.15.

[0040] Example 5: This example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that in step S3, the mass ratio of modified water glass A to sodium hexametaphosphate in the gangue inhibitor is 1:0.8.

[0041] Example 6: This example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that modified water glass B replaces modified water glass A in equal amounts.

[0042] Example 7: This example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that collector A is replaced by collector B in equal amounts.

[0043] Example 8: This example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that collector A is replaced by collector C in equal amounts.

[0044] Example 9: This example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that the collector A is replaced by an equal amount of oleic acid.

[0045] Comparative Example 1 This comparative example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that modified water glass A is replaced by water glass in equal amounts.

[0046] Comparative Example 2 This comparative example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that the gangue inhibitor is replaced by modified water glass A in equal amounts.

[0047] Comparative Example 3 This comparative example provides a process for recovering phosphorus from vanadium-titanium magnetite tailings. The specific implementation method is the same as that of Example 1, except that the gangue inhibitor is replaced by an equal amount of sodium hexametaphosphate.

[0048] Performance test: The phosphorus grade in the phosphate concentrate of the process of recovering phosphorus from vanadium-titanium magnetite tailings of the above-mentioned Examples 1-9 and Comparative Examples 1-3 was tested. The test results are shown in Table 1.

[0049] The phosphorus grade in phosphate concentrate is the P in phosphate concentrate. 2 O 5 The content was determined by ion chromatography.

[0050] Table 1 Group <![CDATA[P in phosphate concentrate 2 O 5 Grade (%)]]> Example 1 37.85 Example 2 37.50 Example 3 37.62 Example 4 35.12 Example 5 35.40 Example 6 35.06 Example 7 34.17 Example 8 34.20 Example 9 32.07 Comparative Example 1 32.67 Comparative Example 2 32.45 Comparative Example 3 31.79 It can be seen from the data in Table 1 that the process of recovering phosphorus from vanadium-titanium magnetite tailings in Examples 1-3 of the present invention has the overall characteristic of high phosphorus grade in phosphate concentrate. Among them, Examples 4-5 changed the ratio between modified water glass A and sodium hexametaphosphate in the gangue inhibitor, so that the synergistic effect of the gangue inhibitor decreased, resulting in a decrease in the phosphorus grade in the phosphate concentrate; Example 6 changed the modification ratio of oxalic acid to the modified water glass during the synthesis of the modified water glass, so that the activity of the gangue inhibitor decreased, thereby resulting in a decrease in the phosphorus grade in the phosphate concentrate; Examples 7-8 changed the addition amount of key components in the collector synthesis process, so that the collector did not have good solubility and dispersibility, and then showed the phenomenon of decreased phosphorus grade in the phosphate concentrate; Example 9 used a conventional collector oleic acid to replace collector A in equal amounts, and Comparative Examples 1-3 respectively replaced modified water glass A with water glass and modified water glass A and sodium hexametaphosphate replaced the gangue inhibitor in equal amounts. Tests found that the phosphorus grade in the phosphate concentrate showed poor results.

[0051] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for recovering phosphorus from vanadium-titanium magnetite tailings, characterized in that: The following steps are involved: S1. Magnetic separation: Grind the vanadium-titanium magnetite tailings, and perform weak magnetic separation and tailings separation to obtain magnetic minerals and non-magnetic minerals for standby use; S2, slurry preparation: adding water to the non-magnetic mineral in step S1, stirring, and obtaining slurry for standby use; S3, roughing: adding sodium carbonate aqueous solution to the ore pulp of step S2, stirring, adding gangue inhibitor and water, stirring, adding collector and water, stirring, scraping foam, obtaining roughing concentrate and scavenging feed for standby use, Wherein, the gangue inhibitor is a mixture of modified water glass and sodium hexametaphosphate, with a mass ratio of 1: (0.3-0.6); S4, beneficiation: the rougher concentrate of step S3 is subjected to first, second and third beneficiation to obtain the final phosphate concentrate; The preparation method of the modified water glass in step S3 comprises the following steps: Add water glass to 25-35wt% oxalic acid aqueous solution, stir, and concentrate to obtain modified water glass; The preparation method of the collector described in step S3 comprises the following steps: (1) Add palmitic acid to a reaction vessel, add chlorosulfonic acid at 55-65°C while stirring, raise the temperature to 90-100°C, stir, stand, and cool to 55-65°C to obtain product 1 for later use; (2) adding acetone and deionized water to the product 1 of step (1), heating to 80-90° C., standing to cool until crystals precipitate, filtering, washing, and drying to obtain the product 2 for later use; (3) Take the product 2 of step (2), heat it to 55-65°C, add sodium hydroxide aqueous solution until it becomes neutral, stir, and obtain a palmitic acid derivative for use; (4) Mix tartaric acid and n-dodecyl alcohol, stir at 80-90° C., add the palmitic acid derivative of step (3), and stir to obtain a collector.

2. The process for recovering phosphorus from vanadium-titanium magnetite tailings according to claim 1, characterized in that: The magnetic field strength in the weak magnetic separation tailing treatment in step S1 is 0.3-0.6T.

3. The process for recovering phosphorus from vanadium-titanium magnetite tailings according to claim 1, characterized in that: In step S2 The ratio of the non-magnetic mineral to water is (30-40) g:100 ml.

4. The process for recovering phosphorus from vanadium-titanium magnetite tailings according to claim 1, characterized in that: The non-magnetic The mass ratio of mineral, gangue inhibitor and collector is 1t: (150-350)g: (200-400)g.

5. The process for recovering phosphorus from vanadium-titanium magnetite tailings according to claim 1, characterized in that: The water glass The ratio of glass to oxalic acid aqueous solution is 1g:(8-9)ml.

6. The process for recovering phosphorus from vanadium-titanium magnetite tailings according to claim 1, characterized in that: In step (1) of the collector preparation method, the molar ratio of palmitic acid to chlorosulfonic acid is 1:(1.2-1.6).

7. The process for recovering phosphorus from vanadium-titanium magnetite tailings according to claim 1, characterized in that: In step (4) of the collector preparation method, the mass ratio of the palmitic acid derivative to tartaric acid is 1:(0.08-0.12).

8. The process for recovering phosphorus from vanadium-titanium magnetite tailings according to any one of claims 1 to 7, characterized in that: The phosphorus grade in the phosphate concentrate shall not be less than 37%.