A kind of oligothiourethane collector and its preparation and application in flotation

Abstract

The present invention belongs to the field of flotation and specifically relates to an oligomeric thiourethane collector, which is a polymer modified with thiourethane groups on an oligomeric polyvinyl alcohol polymer chain; wherein the molecular weight of the oligomeric polyvinyl alcohol is 13,000 to 25,000. The present invention also provides a preparation method and application of the oligomeric thiourethane collector. Furthermore, the present invention discloses a composite collector comprising the oligomeric thiourethane collector and a small molecule thiourethane, and its application in flotation. The oligomeric collector and composite collector described herein can effectively improve the recovery rate of mineral separation, particularly the recovery rate of fine-grained minerals.

Description

Technical Field

[0001] The invention belongs to the field of flotation reagents and relates to the synthesis and application of an oligothiocarbamate collector. Background Art

[0002] Thiocarbamate collectors are chelating agents characterized by good selectivity, low dosage, and ease of use. They are widely used in the flotation of copper sulfide ores. However, with the widespread mining of copper mineral resources, readily separable copper sulfide ores have drastically decreased. The recovery of fine, lean, and mixed copper ore resources, which have become composed of fine, complex minerals, has become a challenge. To achieve sufficient monomer dissociation of the target mineral, fine grinding of the target ore is essential. However, as the particle size of the useful ore decreases, the probability of collision and adhesion of fine mineral particles with bubbles decreases, making it difficult for them to adhere to the bubble surface. This leads to a sharp decrease in flotation recovery and a significant waste of resources. Conventional thiocarbamate collectors are no longer suitable for the flotation recovery of such fine-grained ores.

[0003] To solve the above problems, the methods currently proposed include selective flocculation flotation, oil agglomeration flotation, and flotation column flotation (Tatu Miettinen. The limits of fine particle flotation, Minerals Engineering, 2010, (23), 420-437). Selective flocculation flotation is to add a water-soluble polymer flocculant such as polyacrylamide to the slurry to increase the particle size of the ore particles through the bridging effect of the flocculant, thereby improving the floatability of the mineral. However, on the one hand, this method lacks a highly selective flocculant, and on the other hand, the molecular weight is relatively large, making it difficult to solve the problem of sludge entrainment, resulting in low selectivity; oil agglomeration flotation is to add neutral oil to perform hydrophobic agglomeration flotation while adding a collector. This method requires the use of a large amount of neutral oil, and the hydrophobic agglomeration force is limited, making it difficult to significantly improve the flotation recovery rate; flotation column flotation is to generate a large number of tiny bubbles to improve the flotation recovery rate, but this method requires a comprehensive change to the existing process equipment, and the equipment investment is large, making it unsuitable for application in existing processes.

[0004] Therefore, it is of great significance to develop a flotation collector suitable for fine-grained copper ore based on existing process equipment. Summary of the Invention

[0005] In order to solve the problem of unsatisfactory flotation performance of fine-particle minerals, the first purpose of the present invention is to provide an oligomeric thiourethane collector, aiming to provide a new oligomeric collector with excellent collecting ability.

[0006] The second object of the present invention is to provide a method for preparing the oligothiourethane collector.

[0007] The third object of the present invention is to provide a composite collector comprising the oligothiourethane collector.

[0008] The fourth object of the present invention is to provide a flotation method for minerals, especially fine-grained minerals, using the oligomeric collector and the composite collector, so as to improve the separation recovery rate of minerals, especially fine-grained minerals.

[0009] Thiourethane collectors and flocculation flotation methods both have unsatisfactory recovery rates for the separation of fine-particle minerals. To address this issue, a low-molecular-weight thiourethane collector is provided, which is a polymer modified with thiourethane groups on the low-molecular-weight polyvinyl alcohol polymer chain.

[0010] Among them, the molecular weight of oligomeric polyvinyl alcohol is 13,000 to 25,000.

[0011] The present invention has found that grafting modification of thiourethane groups and the OH groups of oligomeric polyvinyl alcohol polymer chains, combined with the joint control of the polymer (molecular weight), can unexpectedly achieve synergy, effectively solving the problems of difficult separation and easy entrainment of fine-grained minerals, and effectively improving the grade and yield of flotation concentrates.

[0012] Preferably, the oligothiourethane collector has the structural formula 1:

[0013]

[0014] Said n is 300 to 500;

[0015] The R is C1~C 10 The alkyl group is an alkyl group or an alkyl group with a substituent; the substituent is at least one of an alkenyl group, an alkynyl group, and a phenyl group.

[0016] Preferably, R is a C3-C5 branched alkyl group. In the present invention, the preferred branched substituent, combined with the oligomeric graft structure of the present invention, helps to further improve the separation recovery rate of fine-grained minerals and improve the concentrate grade and recovery rate.

[0017] The present invention also provides a method for preparing the oligomeric thiourethane collector, which comprises subjecting oligomeric polyvinyl alcohol to xanthate reaction, esterification and aminolysis reaction to obtain the oligomeric thiourethane collector.

[0018] The preferred preparation method of the oligothiourethane collector of the present invention comprises the following steps:

[0019] Step (1): subjecting the oligomeric polyvinyl alcohol of formula 2, carbon disulfide and alkali to xanthate reaction to prepare an oligomeric xanthate;

[0020]

[0021] Step (2):

[0022] Esterifying oligomeric xanthate with halogenated acetate to obtain oligomeric ester (oligomeric xanthate);

[0023] Step (3):

[0024] Ammonolysis of the oligoester and the fatty amine of formula 3 to obtain the oligomeric thiourethane collector;

[0025] R-NH2 Formula 3.

[0026] In the present invention, the base is an alkali metal hydroxide;

[0027] Preferably, the halogenated acetate is at least one of sodium chloroacetate and potassium chloroacetate;

[0028] Preferably, the mass ratio of the oligomeric polyvinyl alcohol, carbon disulfide, and alkali is 1:2-4:1-1.2;

[0029] Preferably, the mass ratio of halogenated acetate to polyvinyl alcohol is 2.3-2.5:1;

[0030] Preferably, the molar ratio of fatty amine:haloacetate is 1.02-1.1:1.

[0031] Preferably, in step (1), the reaction temperature is 15-30°C, preferably 25-28°C, and the reaction time is 2-4 hours;

[0032] Preferably, in step (2), the esterification reaction temperature is 30-80°C, preferably 50-70°C, and the time is 2-3 hours;

[0033] Preferably, in step (3), the temperature of the ammonolysis reaction is 60-80° C., and the time is 2-3 hours.

[0034] A preferred method for preparing an oligomeric collector of the present invention specifically comprises the following steps:

[0035] Step (1): Add low molecular weight polyvinyl alcohol and carbon disulfide to a reaction flask, mix well, add alkali solution dropwise, and stir and react at 25-28°C for 2-4 hours. The mass ratio of polyvinyl alcohol, carbon disulfide, and sodium hydroxide is 1:2-4:1-1.2. The polyvinyl alcohol in step (1) is low molecular weight polyvinyl alcohol, such as model 0588 with a degree of polymerization of 500, and model 0386 with a degree of polymerization of 300. No ore entrainment occurs.

[0036] Step (2): Add sodium chloroacetate to the solution obtained in step (1), raise the temperature to 50-70°C, and react for 2-3 hours. Using polyvinyl alcohol as the reference substance, the mass ratio of sodium chloroacetate to polyvinyl alcohol is 2.3-2.5:1.

[0037] Step (3): Cool the reaction solution obtained in step (2) to room temperature, add the fatty amine dropwise, and after the addition is complete, raise the temperature to 60-80°C and react for 2-3 hours. Using sodium chloroacetate as the reference substance, the fatty amine: sodium chloroacetate (molar ratio) = 1.02-1.1:1;

[0038] Step (4): Separate the liquid to obtain the upper oily substance, which is the finished product.

[0039] The present invention also provides a composite collector comprising the small molecule thiourethane of formula 4 and the oligomeric thiourethane collector;

[0040]

[0041] The R1 and R2 are independently C2~C 10 The alkyl group is an alkyl group or an alkyl group with a substituent; the substituent is at least one of an alkenyl group, an alkynyl group, and a phenyl group.

[0042] The present invention has found that combining the small molecule thiourethane and the oligomeric thiourethane collector facilitates better dispersion of the collector in the ore pulp, improves selective aggregation of minerals, increases the probability of collision and adhesion between ore particles and bubbles, and thus improves flotation recovery. In addition, the problem of ore slime entrainment can be resolved. The collector retains the advantages of the thiourethane nonionic collector, has little interaction with ore slime and invalid metal ions, and has the advantages of good selectivity and low dosage.

[0043] Preferably, the weight ratio of the small molecule thiourethane to the oligomeric thiourethane collector is 1-1.1:2-3.

[0044] The present invention also provides a mineral flotation method, which floats the mineral in a flotation reagent containing a collector, wherein the collector contains the oligothiourethane collector or the composite collector.

[0045] The mineral flotation method of the present invention is for fine-grained minerals. The technical solution of the present invention has better performance and value in the flotation of fine-grained minerals than the existing technology.

[0046] Preferably, the particle size of the fine-grained mineral is greater than or equal to 90% of -0.074 mm, or greater than or equal to 80% of -0.037 mm.

[0047] Preferably, the mineral is a copper-containing mineral; preferably a copper-containing sulfide ore.

[0048] In the present invention, the amount of the collector can be adjusted as needed. Taking into account the flotation efficiency, effect and cost, the amount of the collector is 60 to 200 g / t. For example, when the mineral is a sulfide ore, the amount of the collector can be further preferably 60 to 90 g / t; when the mineral is an oxide ore, the amount of the collector can be further preferably 150 to 200 g / t.

[0049] Preferably, the flotation reagent further comprises a foaming agent;

[0050] Preferably, the foaming agent is at least one of No. 2 oil and methyl isobutyl carbinol;

[0051] Preferably, the amount of the foaming agent is 10-45 g / t.

[0052] Preferably, during the flotation process, components such as pH adjusters and activators may be added as needed.

[0053] Beneficial effects:

[0054] 1. The present invention provides a new oligomeric collector, which chemically modifies the polyvinyl alcohol polymer chain with thiourethane, and further cooperates with the joint control of the polymer to achieve synergy and improve the flotation separation effect of minerals, especially the separation effect of fine-grained minerals.

[0055] The oligomeric collector of the present invention solves the problem of sludge entrainment; the collector retains the advantages of the thiocarbamate nonionic collector, has a small interaction force with sludge and invalid metal ions, has the advantages of good selectivity and small dosage.

[0056] 2. Combining the oligomeric collector and the small molecule collector can further achieve synergy, further improve the dispersibility of the oligomeric collector, and synergistically improve the recovery rate of mineral separation, especially the recovery rate of fine mineral separation.

[0057] 3. The present invention can improve the flotation effect of fine-grained minerals. For example, taking fine-grained copper as an example, the flotation recovery rate can be increased to 5-10%. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The infrared spectrum of the oligothiourethane prepared in Example 4 shows that the -1 NH symmetric stretching vibration peak, 1544 cm -1 C(=S)NH composite vibration peak, 1215cm -1 is the COC asymmetric stretching vibration, 1093 cm -1 For CNC asymmetric vibration, 676cm -1It is C=S vibration, and the infrared spectrum conforms to the characteristic peaks of thiocarbamate. DETAILED DESCRIPTION

[0059] Example 1

[0060] 30 g of low molecular weight polyvinyl alcohol (model 0588, n=500) and 90 g of carbon disulfide were added to a reaction flask and mixed thoroughly. 75 g of 40% sodium hydroxide lye was added dropwise and stirred at 25-28°C for 2.6 hours. 72 g of sodium chloroacetate was added to the reaction solution, and the temperature was raised to 65-70°C and the reaction was carried out for 2.5 hours. The temperature was cooled to room temperature, and 38.8 g of isopropylamine was added dropwise. After the addition was complete, the temperature was raised to 68-72°C and the reaction was carried out for 3 hours. The liquids were separated, and the upper oily substance was oligomeric thiourethane.

[0061] Example 2

[0062] 30 g of low molecular weight polyvinyl alcohol (model 0386, n=300) and 96 g of carbon disulfide were added to a reaction flask and mixed thoroughly. 79 g of 40% sodium hydroxide lye was added dropwise and stirred at 25-28°C for 2.6 hours. 76 g of sodium chloroacetate was added to the reaction solution, and the temperature was raised to 65-70°C and the reaction was carried out for 2.5 hours. The temperature was cooled to room temperature, and 39.4 g of isopropylamine was added dropwise. After the addition was complete, the temperature was raised to 68-72°C and the reaction was carried out for 3 hours. The liquids were separated, and the upper oily substance was oligomeric thiourethane.

[0063] Example 3

[0064] 30 g of low molecular weight polyvinyl alcohol (model 0588) and 90 g of carbon disulfide were added to a reaction flask and mixed thoroughly. 75 g of 40% sodium hydroxide lye was added dropwise and stirred at 25-28°C for 2.6 hours. 72 g of sodium chloroacetate was added to the reaction solution, and the temperature was raised to 65-70°C and the reaction was carried out for 2.5 hours. The temperature was cooled to room temperature, and 48 g of isobutylamine was added dropwise. After the addition was complete, the temperature was raised to 68-72°C and the reaction was carried out for 3 hours. The liquids were separated, and the upper oily substance was the oligomeric thiourethane.

[0065] Example 4

[0066] 30 g of low molecular weight polyvinyl alcohol (model 0386) and 96 g of carbon disulfide were added to a reaction flask and mixed thoroughly. 79 g of 40% sodium hydroxide lye was added dropwise and stirred at 25-28°C for 2.6 hours. 76 g of sodium chloroacetate was added to the reaction solution, and the temperature was raised to 65-70°C and the reaction was carried out for 2.5 hours. The temperature was cooled to room temperature, and 48 g of isobutylamine was added dropwise. After the addition was complete, the temperature was raised to 68-72°C and the reaction was carried out for 3 hours. The liquids were separated, and the upper oily substance was the oligomeric thiourethane.

[0067] Application Example 1

[0068] A copper ore sample contains chalcopyrite as the main copper mineral, followed by chalcocite, chalcocite, tetrahedrite, etc. Other metallic minerals include small amounts of pyrite and hematite. The ore contains 0.88% copper, and the copper minerals are embedded in extremely fine particles. To meet the dissociation requirements, the grinding fineness must reach -0.074mm, accounting for more than 90%. Experimental process: primary roughing; grinding fineness: -0.074mm, accounting for 92%; flotation reagent dosage: lime dosage 1200g / (t raw ore), collector dosage 80g / (t raw ore), frother dosage 10g / (t raw ore); collectors in different experimental groups are:

[0069] Test 1: Collector is Z200;

[0070] Experiment 2: The collector is a mixed collector A; the mixed collector A is prepared by oligomeric isopropylthiocarbamate (Example 1) and Z200 in a weight ratio of 2:1.

[0071] Test 3: using the collector oligoisopropylthiocarbamate (Example 1) alone;

[0072] Test 4: The collector is Z200, and a certain amount of PVA0386 is added to the slurry.

[0073] The test results are shown in Table 1.

[0074] Test results show that using the mixed collector A, containing the present invention as the main component, yielded a copper concentrate with a grade of 11.56% and a recovery of 83.02%. This represents a 6.64% improvement in recovery compared to using the conventional collector Z200 alone. The flotation recovery using oligomeric isopropylthiocarbamate as the collector alone increased by 2.45% compared to Z200, while the copper concentrate recovery using a combination of Z200 and polyvinyl alcohol was only 58.34%. These tests demonstrate the effectiveness of oligomeric isopropylthiocarbamate. However, due to its relatively high viscosity and poor dispersibility in the ore pulp, the improvement in flotation recovery is limited. Combining oligomeric isopropylthiocarbamate with Z200 reduces the collector's viscosity, improves its dispersibility in the ore pulp, and effectively increases flotation recovery.

[0075] Table 1 Flotation test and results of thiocarbamate collector

[0076]

[0077] Application Example 2

[0078] The ore sand sample stored in the tailings pond of a mine contains 0.35% copper and has a copper oxidation rate of 10.38%. It is a mixed copper ore with fine-grained dissemination and a low oxidation rate. The main metal minerals are chalcocite, chalcopyrite, bornite, pyrite, malachite, hematite, etc. The main gangue minerals are quartz, dolomite, feldspar, calcite, etc. The test process consisted of one roughing run, two scavenging runs, and two cleaning runs. The grinding fineness was -0.037 mm, accounting for 82%. The flotation agent dosages were 200 g / t of ore, 180 g / t of collector, and 45 g / t of frother. The collectors used in Tests 1 and 2 were Z200 and mixed collector B, respectively. Mixed collector B consisted of oligomeric isobutylthionamide (Example 4) and Z200 in a weight ratio of 3:1. Test 3 used oligomeric isobutylthionamide (Example 4) alone. Test 4 used Z200 as the collector, with a certain amount of PVA0588 added to the ore pulp. The test results are detailed in Table 2. Test results show that using the mixed collector B, containing the present invention as the main component, yielded a copper concentrate with a grade of 20.58% and a recovery rate of 74.68%. This represents an 8.88% improvement in recovery compared to using the conventional collector Z200 alone. Using oligomeric isobutylthiocarbamate as the collector alone resulted in a slightly lower grade and a somewhat improved collection capacity compared to Z200. However, the copper concentrate recovery rate of the combined Z200 and polyvinyl alcohol reagent was only 51.10%. These tests further demonstrate the effectiveness of oligomeric isobutylthiocarbamate composite reagents.

[0079] Table 2 Flotation test and results of thiocarbamate collector

[0080]

Claims

1. A oligomeric thiourethane collector for flotation of fine-grained copper sulfide ores, characterized in that: It has the structural formula 1: Formula 1 Said n is 300-500; The R is C1~C 10 An alkyl group, or an alkyl group with a substituent; the substituent is at least one of an alkenyl group, an alkynyl group, and a phenyl group; The molecular weight of oligomeric polyvinyl alcohol is 13,000 to 25,000; The particle size of the fine copper-containing sulfide ore is greater than or equal to 90% of -0.074 mm, or greater than or equal to 80% of -0.037 mm.

2. The oligothiourethane collector according to claim 1, wherein The R is a C3~C5 branched alkyl group.

3. A method for preparing the oligothiourethane collector according to claim 1 or 2, characterized in that the steps include: Step (1): subjecting the oligomeric polyvinyl alcohol of formula 2, carbon disulfide and alkali to xanthate reaction to prepare an oligomeric xanthate; Formula 2 Step (2): Esterification of oligomeric xanthate with halogenated acetate to obtain oligomeric esters; Step (3): Ammonolysis of the oligoester and the fatty amine of formula 3 to obtain the oligomeric thiourethane collector; Formula 3.

4. The preparation method of the oligothiourethane collector according to claim 3, wherein The base is an alkali metal hydroxide.

5. The preparation method of the oligothiourethane collector according to claim 3, wherein The halogenated acetate is at least one of sodium chloroacetate and potassium chloroacetate.

6. The preparation method of the oligothiourethane collector according to claim 3, wherein The mass ratio of the oligomeric polyvinyl alcohol, carbon disulfide and alkali is 1:2-4:1-1.

2.

7. The preparation method of the oligothiourethane collector according to claim 3, wherein The mass ratio of halogenated acetate: polyvinyl alcohol is =2.3-2.5:

1.

8. The preparation method of the oligothiourethane collector according to claim 3, wherein The molar ratio of fatty amine:haloacetate is =1.02-1.1:

1.

9. The method for preparing the oligothiourethane collector according to claim 3, wherein In step (1), the reaction temperature is 15-30°C and the reaction time is 2-4 hours.

10. The method for preparing the oligothiourethane collector according to claim 3, wherein: In step (2), the esterification reaction temperature is 50-70°C and the time is 2-3 hours.

11. The method for preparing the oligothiourethane collector according to claim 3, wherein: In step (3), the temperature of the ammonolysis reaction is 60-80°C and the time is 2-3 hours.

12. A composite collector, characterized in that: Comprising the small molecule thiourethane of formula 4, and further comprising the oligomeric thiourethane collector of any one of claims 1 to 2; Formula 4 The R1 and R2 are independently C2~C 10 The alkyl group is an alkyl group or an alkyl group with a substituent; the substituent is at least one of an alkenyl group, an alkynyl group, and a phenyl group.

13. The composite collector according to claim 12, wherein The weight ratio of the small molecule thiourethane to the oligomeric thiourethane collector is 1-1.1:2-3.

14. A flotation method for fine-grained copper sulfide ore, wherein the ore is floated in a flotation reagent containing a collector, characterized in that: The collector comprises the oligothiourethane collector according to any one of claims 1 to 2, or the composite collector according to claim 12 or 13; The particle size of the fine-grained copper-containing sulfide ore is greater than or equal to 90% of -0.074 mm, or greater than or equal to 80% of -0.037 mm.

15. The flotation method according to claim 14, wherein: The amount of the collector is 60-200 g / t.

16. The flotation method according to claim 14, wherein: The flotation reagent also includes a foaming agent.

17. The flotation method according to claim 16, wherein: The foaming agent is at least one of No. 2 oil and methyl isobutyl carbinol.

18. The flotation method according to claim 16, wherein: The dosage of the foaming agent is 10-45 g / t.

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