A method for separating copper-molybdenum sulfide ore by high-entropy depressant flotation

Abstract

The application is a method for separating copper sulfide molybdenum ore by adopting high-entropy depressant, aiming at the technical problem that the copper sulfide mineral in the copper-molybdenum mixed concentrate obtained by copper-molybdenum mixed flotation has been affected by the collecting agent and has good hydrophobicity, the inhibitory effect of the conventional sodium sulfide depressant is not good, the dosage is large, the number of cleaning is large, and the grade of molybdenum concentrate is difficult to meet the requirements, the high-entropy depressant formed by the combination of five kinds of depressants is used to inhibit the copper sulfide mineral, the surface inhibition entropy of the copper sulfide mineral is improved, the adsorption of the depressant on the mineral surface is promoted, and the inhibitory effect of the copper sulfide mineral is improved, under the condition of reducing the total dosage of the reagent and reducing the number of cleaning, the grade and recovery rate of the molybdenum concentrate are improved. The method has the characteristics of low reagent cost, simple process structure, easy management and operation, stable production index and the like.

Description

Technical Field

[0001] This invention relates to a method for separating copper-molybdenum sulfide ore by flotation using a high-entropy inhibitor, belonging to the field of mineral processing technology. Background Technology

[0002] Molybdenum is widely used in high-temperature alloys, electrical and electronic equipment, thermal spray coatings, medical devices, and aerospace and defense components. According to the International Molybdenum Association, over 80% of molybdenum products are used in the metallurgical industry, and approximately 14% are used in the chemical industry. Molybdenite is the primary molybdenum mineral, and nearly half of the world's molybdenum is stored in porphyry copper deposits. When the Mo grade of the ore is greater than 0.01%, recovering molybdenum from copper concentrate obtained through flotation of porphyry copper ores is economically viable.

[0003] There are two common flotation processes for recovering molybdenum from porphyry copper-molybdenum ores. The first process is mixed flotation-copper-molybdenum separation, where copper and molybdenum minerals are recovered together via mixed flotation, and then selective depressants are added to separate the copper and molybdenum minerals. The advantages of this process are its simplicity and high molybdenum recovery rate, but the consumption of depressants during copper-molybdenum separation is often relatively high. The second process is preferential flotation of molybdenum minerals followed by copper minerals. This involves recovering molybdenum minerals using non-polar oil flotation before the molybdenum ore is strongly collected, and then further refining the rougher molybdenum concentrate to obtain a suitable grade of molybdenite concentrate. The advantage of this process is lower reagent consumption, but it suffers from a lower molybdenum recovery rate. In practice, the first process is widely used to improve molybdenum recovery.

[0004] Sulfur-containing inhibitors, such as Na₂S, NaHS, sodium trithiocarbonate (Na₂CS₃), P-Nokes (P₂S₅+NaOH), As-Nokes (As₂O₃+Na₂S) (US 4425230), Knox reagent (US 3375924), sodium mercaptoacetate (US 3329266), dithiocarbonates or trithiocarbonates (US 4425230), Na₂SO₃, and Na₂S₂O₃, are used to inhibit copper sulfide minerals in copper-molybdenum separation processes. Cyanide-containing inhibitors, such as NaCN, Na₄Fe(CN)₆, Na₃Fe(CN)₆, KCN, Zn(CN)₂, and Ca(CN)₂, have good inhibitory effects on copper sulfide minerals in copper-molybdenum separation; however, these agents are toxic and rarely used industrially. The use of these inorganic depressants primarily aims to desorb the collectors adsorbed on the surface of chalcopyrite, thereby inhibiting the extraction of copper sulfide ores. However, the use of these inorganic depressants has some drawbacks. For example, when the pulp pH is acidic, toxic gases such as hydrogen sulfide may be released; these depressants also have a certain inhibitory effect on molybdenite, affecting the improvement of molybdenum recovery; and due to their weak ability to inhibit copper sulfide minerals, multiple cleaning processes are required to obtain molybdenum concentrate of acceptable grade. Therefore, extensive research has been conducted on developing alternative depressants, and organic depressants have become promising candidates due to their environmental friendliness and low cost.

[0005] Organic inhibitors of copper sulfide minerals have relatively low toxicity and are effective even at low doses. Thioglycolic acid was one of the earliest organic inhibitors used to inhibit copper sulfide minerals, and it has been successfully applied at a copper company in Utah, USA. Subsequently, more organic inhibitors have emerged, such as thiol chitosan (CN 105537002 A), DL-dithiothreitol (CN110404689 A), sodium carboxymethyl trithiocarbonate, disodium bis(carboxymethyl)trithiocarbonate, 2,3-dithiosuccinic acid, and chitosan. These organic compounds have been designed, synthesized, and applied to inhibit the flotation of chalcopyrite. The donor atoms in these compounds, such as S, N, and O, coordinate with Cu and Fe on chalcopyrite in neutral or ionic form, forming mononuclear or polynuclear complexes that adsorb onto the surface of copper sulfide minerals, reducing the hydrophobicity of the sulfide minerals and thus achieving inhibition. L-cysteine ​​(CN 107138286 A) and sodium alginate also have certain inhibitory effects on copper sulfide minerals. L-cysteine ​​is a naturally occurring protein-derived amino acid that is non-toxic and water-soluble. Its thiol, carboxyl, and primary amine groups ensure a strong binding affinity between L-cysteine ​​and metal ions. Adding L-cysteine ​​during copper-molybdenum separation can inhibit the growth of copper sulfide minerals to some extent. High molecular weight polymers, such as acrylamide-modified compounds (PAM-ATU) (CN 106583050 A) and their derivatives, are also potential chalcopyrite inhibitors. The chemisorption of PAM-ATU on the chalcopyrite surface can also reduce the hydrophobicity of copper sulfide minerals to some extent. However, these organic inhibitors are expensive and, compared to inorganic inhibitors, have poorer selectivity and exhibit varying degrees of inhibition on molybdenite, which limits their application in copper-molybdenum flotation separation.

[0006] Combined inhibitors have shown better ability to suppress copper sulfide minerals during the flotation separation of chalcopyrite and molybdenite. For example, the combination of sodium sulfide with sodium mercaptoacetate (CN 106944246 A), N-(2-hydroxyethyl)-2-mercaptoacetamide with sodium sulfide (CN 109482357 A), and a mixture of sodium polyhydroxyxanthate, sodium phosphate, and carboxymethyl trithiocarbonate (CN106733212 A) all demonstrate significant inhibitory effects on copper sulfide minerals. Combined inhibitors for chalcopyrite also employ inorganic and organic combinations, such as the combination of oxime starch with Na2S, L-cysteine ​​with NaHS, and P-Nokes, Na2CS3, and sodium mercaptoacetate. Using Na2S + oxime starch as a chalcopyrite inhibitor successfully achieved a copper inhibition effect similar to that of Na2S alone, with a significantly reduced amount of Na2S in the combined inhibitor. L-cysteine ​​combined with NaHS to suppress chalcopyrite at a ratio of 1:30 resulted in the suppression of approximately 97% of the copper content. The combination of NaOH + Ca(ClO)₂ + C₂H₃O₂SNa yielded a molybdenum concentrate with a Mo grade of 49.67% and a Cu content of 0.16%.

[0007] In summary, current copper-molybdenum separation methods suffer from the following problems: large reagent dosage and high cost; poor reagent stability and easy oxidation; high reagent toxicity and harsh operating environment. Therefore, we have developed a highly efficient high-entropy inhibitor for copper sulfide minerals to address the challenges of poor copper-molybdenum separation and low molybdenum recovery. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides a method for achieving efficient separation of copper-molybdenum mixed concentrates in a short process using a high-entropy inhibitor. This method features low reagent costs, a simple process structure, easy management and operation, and stable production indicators.

[0009] This invention is achieved through the following technical solution: a method for separating copper-molybdenum sulfide ore by flotation using a high-entropy inhibitor, comprising the following steps:

[0010] (1) Mix carbon disulfide and sodium hydroxide in equal molar amounts, and stir and knead for 2 hours to obtain reagent A;

[0011] (2) Mix carbon disulfide and sodium hydrosulfide in equal molar amounts and knead for 2 hours to form reagent B;

[0012] (3) Sodium sulfide, sodium thioglycolate, cysteine, cationic polyacrylamide, reagent A synthesized in step (1) and reagent B synthesized in step (2) are mixed in a mass ratio of 8-4.5:1.5-0.5:1.2-0.8:2-0.5:0.5-0.1:0.5-0.1 to form a high-entropy inhibitor C for copper sulfide minerals;

[0013] (4) Add 2000 g / t of sodium sulfide and 2000 g / t of activated carbon to the copper-molybdenum mixed concentrate, and grind until more than 80% of the molybdenum minerals are liberated to obtain grinding slurry I;

[0014] (5) Add copper sulfide mineral high entropy inhibitor C 3000 g / t ~ 4000 g / t to slurry I, stir and react for 5 min ~ 8 min to obtain slurry II;

[0015] (6) Add 40 g / t to 120 g / t of molybdenite collector to slurry II and stir for 4 min to 5 min to obtain slurry III;

[0016] (7) Add 20 g / t to 60 g / t of foaming agent to slurry III and stir for 2 min to 3 min to obtain slurry IV;

[0017] (8) The pulp IV undergoes a closed-circuit flotation process involving one roughing, one scavenging, and three cleaning processes, with the middlings being returned sequentially, to obtain the final molybdenum concentrate and copper concentrate.

[0018] The copper-molybdenum mixed concentrate is obtained by copper-molybdenum mixed flotation, wherein the mass percentage of molybdenum is 0.5%–1.5% and the mass percentage of copper is 15%–25%. The molybdenite collector is kerosene or diesel oil.

[0019] The foaming agents are No. 2 flotation oil (also known as No. 2 oil) and pine oil.

[0020] After high-entropy inhibitor C is adsorbed on the surface of copper sulfide minerals, the surface inhibition entropy change caused by the adsorption of the inhibitor is as follows:

[0021]

[0022] In the formula: ΔS d To suppress entropy change on the surface of copper sulfide minerals; R is the gas constant; x i denoted as the mole fraction of the i-th inhibiting component on the surface of copper sulfide minerals, expressed as a decimal.

[0023] For uninhibited copper sulfide minerals, only one surface component is considered: the product of the reaction between copper sulfide and the collector, i=1. In this case, the surface inhibition entropy becomes zero, the mineral is not inhibited, and the copper sulfide mineral will float during molybdenite flotation, resulting in poor copper-molybdenum separation. When using a high-entropy inhibitor C for copper sulfide minerals, assuming that the surface copper sulfide component is partially covered by the inhibitor component (with five types of surface inhibition components), the surface inhibition entropy change can be calculated by measuring the adsorption amount of each inhibitor on the surface. Clearly, after inhibition by the high-entropy inhibitor C, the surface inhibition entropy of the copper sulfide minerals is significantly increased, which is beneficial for the flotation separation of copper and molybdenum and can significantly improve the inhibition effect of copper sulfide minerals.

[0024] (1) The high entropy suppression of the present invention significantly increases the suppression entropy change value of the process of separating copper-molybdenum mixed concentrate by flotation of copper sulfide ore. Under the condition of minimal enthalpy change, the high entropy change makes the collector desorption and inhibitor adsorption on the surface of copper sulfide ore have a high reaction tendency. Compared with single or two inhibitors, the floatability of copper sulfide is significantly reduced due to the significant increase in the suppression entropy change on the surface of sulfide ore.

[0025] (2) The use of high-entropy inhibitors in this invention can significantly reduce the hydrophobicity of the sulfide mineral surface in copper-molybdenum concentrate, increase the difference in hydrophobicity between copper sulfide ore and molybdenum sulfide, realize the short-process rapid flotation separation of copper-molybdenum mixed concentrate, and reduce costs.

[0026] (3) The use of the high entropy inhibitor in this invention reduces the amount of traditional sodium sulfide or sodium hydrosulfide, reduces the alkalinity and S content in the mineral processing return water, and the molybdenum grade of the molybdenum concentrate is greater than 40% and the molybdenum recovery rate is greater than 85%. Detailed Implementation

[0027] Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased. Example 1

[0028] Raw material: Copper-molybdenum mixed concentrate obtained by copper-molybdenum mixed flotation, with a molybdenum mass percentage of 0.5% and a copper mass percentage of 25%.

[0029] (1) Mix carbon disulfide and sodium hydroxide in equal molar amounts, and stir and knead for 2 hours to obtain reagent A;

[0030] (2) Mix carbon disulfide and sodium hydrosulfide in equal molar amounts and knead for 2 hours to form reagent B;

[0031] (3) Sodium sulfide, sodium thioglycolate, cysteine, cationic polyacrylamide, reagent A synthesized in step (1) and reagent B synthesized in step (2) are mixed in a mass ratio of 8:0.8:1.2:2:0.1:0.5 to form a high entropy inhibitor C for copper sulfide minerals;

[0032] (4) Add 2000 g / t of sodium sulfide and 2000 g / t of activated carbon to the copper-molybdenum mixed concentrate, and grind until more than 80% of the molybdenum minerals are liberated to obtain grinding slurry I;

[0033] (5) Add copper sulfide mineral high entropy inhibitor C4000 g / t to slurry I, stir and react for 5 min to 8 min to obtain slurry II;

[0034] (6) Add 40g / t of molybdenite collector kerosene to slurry II and stir for 4min~5min to obtain slurry III;

[0035] (7) Add 20 g / t of frother pine oil to slurry III and stir for 2 min to 3 min to obtain slurry IV;

[0036] (8) The pulp IV undergoes a closed-circuit flotation process involving one roughing, one scavenging, and three cleaning processes, with the middlings being returned sequentially, to obtain the final molybdenum concentrate and copper concentrate.

[0037] The molybdenum concentrate contains 40% molybdenum and 1.5% copper, with a molybdenum recovery rate of 80%. Example 2

[0038] Raw material: Copper-molybdenum mixed concentrate obtained by copper-molybdenum mixed flotation, with a molybdenum mass percentage of 1.0% and a copper mass percentage of 20%.

[0039] (1) Mix carbon disulfide and sodium hydroxide in equal molar amounts, and stir and knead for 2 hours to obtain reagent A;

[0040] (2) Mix carbon disulfide and sodium hydrosulfide in equal molar amounts and knead for 2 hours to form reagent B;

[0041] (3) Sodium sulfide, sodium thioglycolate, cysteine, cationic polyacrylamide, reagent A synthesized in step (1) and reagent B synthesized in step (2) are mixed in a mass ratio of 6:0.5:0.8:1.5:0.3:0.1 to form a high entropy inhibitor C for copper sulfide minerals;

[0042] (4) Add 2000 g / t of sodium sulfide and 2000 g / t of activated carbon to the copper-molybdenum mixed concentrate, and grind until more than 80% of the molybdenum minerals are liberated to obtain grinding slurry I;

[0043] (5) Add copper sulfide mineral high entropy inhibitor C3500 g / t to slurry I, stir and react for 5 min to 8 min to obtain slurry II;

[0044] (6) Add 80g / t of molybdenite collector kerosene to slurry II and stir for 4min~5min to obtain slurry III;

[0045] (7) Add 40g / t of foaming agent No. 2 oil to slurry III and stir for 2min~3min to obtain slurry IV;

[0046] (8) The pulp IV undergoes a closed-circuit flotation process involving one roughing, one scavenging, and three cleaning processes, with the middlings being returned sequentially, to obtain the final molybdenum concentrate and copper concentrate.

[0047] The molybdenum concentrate contains 45% molybdenum and 1.0% copper, with a molybdenum recovery rate of 85%. Example 3

[0048] Raw material: Copper-molybdenum mixed concentrate obtained by copper-molybdenum mixed flotation, with a molybdenum mass percentage of 1.5% and a copper mass percentage of 15%.

[0049] (1) Mix carbon disulfide and sodium hydroxide in equal molar amounts, and stir and knead for 2 hours to obtain reagent A;

[0050] (2) Mix carbon disulfide and sodium hydrosulfide in equal molar amounts and knead for 2 hours to form reagent B;

[0051] (3) Sodium sulfide, sodium thioglycolate, cysteine, cationic polyacrylamide, reagent A synthesized in step (1) and reagent B synthesized in step (2) are mixed in a mass ratio of 4.5:1.5:1:0.5:0.5:0.3 to form a high entropy inhibitor C for copper sulfide minerals;

[0052] (4) Add 2000 g / t of sodium sulfide and 2000 g / t of activated carbon to the copper-molybdenum mixed concentrate, and grind until more than 80% of the molybdenum minerals are liberated to obtain grinding slurry I;

[0053] (5) Add copper sulfide mineral high entropy inhibitor C3000 g / t to slurry I, stir and react for 5 min to 8 min to obtain slurry II;

[0054] (6) Add 120g / t of molybdenite collector diesel oil to slurry II and stir for 4min~5min to obtain slurry III;

[0055] (7) Add 60 g / t of frother pine oil to slurry III and stir for 2 min to 3 min to obtain slurry IV;

[0056] (8) The pulp IV undergoes a closed-circuit flotation process involving one roughing, one scavenging, and three cleaning processes, with the middlings being returned sequentially, to obtain the final molybdenum concentrate and copper concentrate.

[0057] The molybdenum concentrate contains 48% molybdenum and 0.8% copper, with a molybdenum recovery rate of 85%.

[0058] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for separating copper-molybdenum sulfide ore by flotation using a high-entropy depressant, characterized in that... Follow these steps: (1) Mix carbon disulfide and sodium hydroxide in equal molar amounts, and stir and knead for 2 hours to obtain reagent A; (2) Mix carbon disulfide and sodium hydrosulfide in equal molar amounts, and stir and knead for 2 hours to obtain reagent B; (3) Sodium sulfide, sodium thioglycolate, cysteine, cationic polyacrylamide, reagent A synthesized in step (1) and reagent B synthesized in step (2) are mixed in a mass ratio of 8-4.5:1.5-0.5:1.2-0.8:2-0.5:0.5-0.1:0.5-0.1 to form a high-entropy inhibitor C for copper sulfide minerals; (4) Add 2000 g / t of sodium sulfide and 2000 g / t of activated carbon to the copper-molybdenum mixed concentrate, and grind until more than 80% of the molybdenum minerals are liberated to obtain grinding slurry I; (5) Add copper sulfide mineral high entropy inhibitor C 3000 g / t ~ 4000 g / t to slurry I, stir and react for 5 min ~ 8 min to obtain slurry II; (6) Add 40 g / t to 120 g / t of molybdenite collector to slurry II and stir for 4 min to 5 min to obtain slurry III; (7) Add 20 g / t to 60 g / t of foaming agent to slurry III and stir for 2 min to 3 min to obtain slurry IV; (8) The pulp IV undergoes a closed-circuit flotation process involving one roughing, one scavenging, and three cleaning processes, with the middlings being returned sequentially, to obtain the final molybdenum concentrate and copper concentrate.

2. The method for separating copper-molybdenum sulfide ore by flotation using a high-entropy inhibitor according to claim 1, characterized in that, The copper-molybdenum mixed concentrate is a copper-molybdenum mixed concentrate obtained by copper-molybdenum mixed flotation, with a molybdenum mass percentage of 0.5% to 1.5% and a copper mass percentage of 15% to 25%.

3. The method for separating copper-molybdenum sulfide ore by flotation using a high-entropy inhibitor according to claim 1, characterized in that, The molybdenite collector is kerosene or diesel oil.

4. The method for separating copper-molybdenum sulfide ore by flotation using a high-entropy inhibitor according to claim 1, characterized in that, The foaming agent is pine oil.