Application and method of an oxidant combined with an organic phosphonic acid inhibitor in flotation separation of copper-zinc sulfide ore

Abstract

This invention belongs to the field of mineral processing and flotation separation technology, and discloses the application and method of an oxidant-organophosphonic acid combined inhibitor in the flotation separation of copper-zinc sulfide ores. The combined inhibitor, composed of an oxidant and an organophosphonic acid reagent, is added in a stepwise manner during the flotation separation of chalcopyrite and sphalerite. Hydrogen peroxide is added first for pulp pretreatment, followed by the addition of hydroxyethylidene diphosphonic acid (HEDP), the organophosphonic acid reagent. The oxidant selectively oxidizes and regulates the surface of sphalerite, providing active sites for the adsorption of the organophosphonic acid reagent. The organophosphonic acid reagent coordinates with the metal sites on the sphalerite surface, forming a hydrophilic film and complexing activated copper ions in the pulp, achieving highly efficient and selective inhibition of sphalerite while maintaining good floatability of chalcopyrite. This invention achieves efficient separation of copper-zinc sulfide ores under medium-low alkalinity conditions, and has advantages such as good selectivity, low reagent dosage, safety and environmental friendliness, and promising industrial application prospects.

Description

Technical Field

[0001] This invention relates to the field of mineral processing and flotation separation technology, specifically to the application and method of an oxidant synergistic with an organophosphonic acid inhibitor in the flotation separation of copper-zinc sulfide ores, used for the flotation separation of chalcopyrite and sphalerite. Background Technology

[0002] The efficient separation of copper-zinc sulfide ores is an international challenge in mineral processing, the core of which lies in achieving the selective separation of chalcopyrite and sphalerite. This is because the two are densely intergrowthed, with fine grain sizes, and sphalerite is easily separated by Cu dissolved in the slurry. 2+ Activation results in similar floatability for both chalcopyrite and copper, making separation extremely difficult. Currently, the preferred flotation process of "zinc-suppressed copper flotation" is widely used in industrial production, and the key lies in the selection of sphalerite depressants. The most widely used traditional depressant system is the combination of zinc sulfate and lime, which requires strongly alkaline conditions (pH>11). However, a highly alkaline environment causes excessive oxidation of the chalcopyrite surface, leading to a decrease in copper recovery. Furthermore, subsequent acid treatment is costly and environmentally burdensome. While cyanide is a highly effective depressant, it has been phased out due to its extreme toxicity. Large-molecule organic depressants (such as dextrin, carboxymethyl cellulose, and cationic guar gum) are environmentally friendly, but they suffer from insufficient selectivity, large reagent dosages, and poor adaptability.

[0003] In recent years, small-molecule organophosphonic acid compounds have attracted widespread attention due to their strong coordination ability with metal ions. Among them, hydroxyethylidene diphosphonic acid (HEDP) can bind to Cu in the slurry through its phosphonic acid groups. 2+ Zn 2+ Metal ions form stable complexes, thereby consuming free activated ions in the solution and reducing the copper activation degree of sphalerite. However, the adsorption rate of single organophosphonic acid reagents on the surface of sphalerite is limited, making efficient industrial application difficult. Oxidants (such as hydrogen peroxide and potassium permanganate) have concentration-dependent and mineral-selective regulating effects in sulfide ore flotation, but single oxidants are prone to over-oxidation or insufficient selectivity. To address the shortcomings of the existing technology, this invention proposes a combined oxidant and organophosphonic acid inhibitor system using H2O2 and HEDP as inhibitors, along with its application method, to improve the flotation separation efficiency and separation index of copper-zinc sulfide ores. Summary of the Invention

[0004] This invention aims to solve the technical problems of poor selectivity, large reagent dosage, and the need for high alkalinity operation in the flotation separation of chalcopyrite and sphalerite in the prior art. To this end, this invention provides an application and method of an oxidant-organophosphonic acid combined inhibitor in the flotation separation of copper-zinc sulfide ores, wherein the oxidant is hydrogen peroxide (H2O2) and the organophosphonic acid reagent is hydroxyethylidene diphosphonic acid (HEDP).

[0005] The technical solution of the present invention is as follows: an application of an oxidant synergistic with an organophosphonic acid inhibitor in the flotation separation of copper-zinc sulfide ores. In the flotation separation process of chalcopyrite and sphalerite, an oxidant is first added to the slurry for slurry conditioning and pretreatment, and then a small molecule phosphonic acid reagent is added as a selective inhibitor of sphalerite, so that a hydrophilic complex is formed on the surface of sphalerite and selectively inhibited, while chalcopyrite maintains good floatability, thereby achieving efficient separation of chalcopyrite and sphalerite.

[0006] The oxidant is hydrogen peroxide, and the organophosphonic acid reagent is hydroxyethylidene diphosphonic acid.

[0007] The mass ratio of the oxidant to the organophosphonic acid reagent is 1:0.6 to 1:1.

[0008] A method for flotation separation of chalcopyrite and sphalerite using a combination of inhibitors includes the following steps: Pure chalcopyrite and molybdenite are placed in a flotation cell, deionized water is added and stirred to form a homogeneous slurry with a concentration of 6%-7%. First, dilute sulfuric acid or sodium hydroxide solution is added to adjust the pH of the slurry. Then, oxidant H2O2 and organophosphonic acid reagent HEDP are added sequentially and allowed to react for 3-5 minutes each to fully complete the mineral surface reaction. After that, collector and frother are added, and after stirring, aeration is carried out for flotation. The frothy product obtained is copper concentrate, and the product in the cell is zinc concentrate.

[0009] During flotation, the pH of the pulp is adjusted to be in the range of 6.0 to 8.0.

[0010] The dosage of the combined inhibitor during flotation is 100 mg / L.

[0011] The collector is butyl xanthate, and the dosage of the collector is 1.5–8.0 mg / L; the foaming agent is No. 2 oil, and the dosage of the foaming agent is 1.5–7.5 mg / L.

[0012] This invention proposes a pretreatment method in the flotation separation of chalcopyrite and sphalerite: first, H2O2 is added to the pulp for conditioning, and then HEDP is added as a selective inhibitor for sphalerite. The selective oxidation regulation of the sphalerite surface by H2O2 provides more favorable adsorption sites for HEDP; simultaneously, HEDP forms a dense hydrophilic film on the sphalerite surface through strong coordination with the phosphonic acid groups, and efficiently complexes Cu in the pulp. 2+ This weakens the copper activation of sphalerite. The two work synergistically to achieve highly efficient selective inhibition of sphalerite, while chalcopyrite maintains good floatability.

[0013] The beneficial effects of this invention are: Compared with existing technologies, this invention employs a combined inhibitor system of oxidants and organophosphonic acids. Through a pre-treatment oxidation followed by coordination inhibition, the flotation selectivity of chalcopyrite and sphalerite is significantly improved. This achieves good floatability of chalcopyrite while effectively inhibiting sphalerite, resulting in higher copper recovery and lower zinc inclusions. The combination of hydrogen peroxide and HEDP exhibits particularly outstanding separation effects, demonstrating superior copper-zinc separation performance and more stable process adaptability compared to other oxidants or organophosphonic acid reagents.

[0014] This invention can be implemented under low alkalinity conditions, effectively avoiding the adverse effects of traditional high-alkalinity processes on the chalcopyrite surface, reducing the consumption of alkaline reagents such as lime, and simplifying subsequent slurry treatment processes, thus exhibiting good economic efficiency. Furthermore, this invention does not use highly toxic inhibitors such as cyanide; the reagent system is green and environmentally friendly, safe to operate, and meets the development requirements of clean production and green mine construction, demonstrating promising prospects for industrial application. Attached Figure Description

[0015] Figure 1 This is a flow chart of the oxidant-organophosphonic acid combined inhibitor process for the flotation separation of copper-zinc sulfide ores proposed in this invention. Detailed Implementation

[0016] To achieve the above-mentioned objectives, the present invention provides the following technical solution: An application of an oxidant-organophosphonic acid combination inhibitor in the flotation separation of copper-zinc sulfide ores: In the flotation separation process of chalcopyrite and sphalerite, an oxidant is first added to the pulp for pulp conditioning and pretreatment, and then a small molecule phosphonic acid reagent is added as a selective inhibitor for sphalerite. This causes the sphalerite surface to form a hydrophilic complex and is selectively inhibited, while chalcopyrite maintains good floatability, thereby achieving efficient separation of chalcopyrite and sphalerite.

[0017] Furthermore, the oxidant is selected from hydrogen peroxide, and the organophosphonic acid reagent is hydroxyethylidene diphosphonic acid (HEDP).

[0018] The present disclosure is described below based on embodiments. However, it is worth noting that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. In the detailed description of the present disclosure below, some specific details are described in detail. However, for the parts not described in detail, those skilled in the art will fully understand the present disclosure.

[0019] Example 1 In this embodiment, chalcopyrite and sphalerite were obtained from a copper-zinc deposit. They were manually selected, crushed, dry-ground using a three-head grinder, and sieved for classification, selecting samples with a particle size of -0.074mm to +0.038mm, all with a purity of over 95%. Approximately 1g each of chalcopyrite and molybdenite samples were weighed and placed in a suspended small flotation cell. 30mL of deionized water was added and stirred to form a homogeneous slurry. First, dilute sulfuric acid or sodium hydroxide solution was added to adjust the slurry pH to 8.0. Then, 55mg / L of oxidant H2O2 was added and stirred for 3 minutes. Next, 45mg / L of HEDP (H2O2:HEDP mass ratio = 1:0.82) was added and stirred for 3 minutes. Subsequently, 8.0mg / L of butyl xanthate was added and stirred for 2 minutes. Finally, 7.5mg / L of No. 2 oil was added, and after stirring for 1 minute, aeration was initiated. Flotation was performed under stirring conditions, and the frothy product and the bottom product were collected.

[0020] In this embodiment, the Cu grade in the concentrate was 27.52% with a recovery rate of 80.68%, and the Zn grade was 14.80% with a recovery rate of 22.23%.

[0021] Example 2 This embodiment is basically the same as Embodiment 1, except that the amount of H2O2 used in this embodiment is 62.5 mg / L, the amount of HEDP used is 37.5 mg / L, and the mass ratio is 1:0.6.

[0022] After flotation, the Cu grade in the concentrate was tested to be 28.16% with a recovery rate of 78.67%, and the Zn grade was 13.20% with a recovery rate of 18.60%.

[0023] Example 3 This embodiment is basically the same as Embodiment 1, except that the amount of H2O2 used in this embodiment is 50 mg / L, the amount of HEDP used is 50 mg / L, and the mass ratio is 1:1.

[0024] After flotation, the Cu grade in the concentrate was tested to be 20.09% with a recovery rate of 78.51%, and the Zn grade was 14.03% with a recovery rate of 20.77%.

[0025] Comparative Example 1 This comparative example is basically the same as Example 1, except that HEDP is added first, and then H2O2 is added.

[0026] After flotation, the concentrate showed a Cu grade of 25.09% and a recovery rate of 68.56%, and a Zn grade of 18.29% and a recovery rate of 24.71%. The poor separation effect in this comparative example was due to the initial addition of HEDP, which partially adsorbed onto the surface of the chalcopyrite or reacted with Cu in the solution. 2+Pre-complexation was achieved, but a dense film could not be formed on the zincblende surface. Subsequent addition of H₂O₂ may oxidize the already adsorbed HEDP or excessively oxidize the mineral surface, leading to a significant decrease in Cu recovery and a deterioration in Zn suppression. (Comparative Example 2) This comparative example is basically the same as Example 1, except that in this comparative example, the oxidant and organophosphonic acid are mixed with water in a certain proportion before being added to the slurry all at once.

[0027] After flotation, the Cu grade in the concentrate was tested to be 24.48% with a recovery rate of 69.33%, and the Zn grade was 17.31% with a recovery rate of 25.04%. The results indicate that adding the oxidant H2O2 and the organophosphonic acid reagent HEDP to the pulp in a single batch before pre-mixing deteriorates the flotation separation effect. This is because H2O2 and HEDP may undergo premature oxidation or complexation reactions during mixing, generating products with weak selective inhibition of sphalerite, thus reducing the effective inhibitory component. (Comparative Example 3) Comparative Example 3 is basically the same as Example 1, except that KMnO4 is used instead of H2O2 in this example, with a dosage of 55 mg / L, and HEDP is still 45 mg / L.

[0028] After flotation, the Cu grade in the concentrate was 18.50% with a recovery rate of 36.85%, and the Zn grade was 10.42% with a recovery rate of 9.94%.

[0029] Comparative Example 4 Comparative Example 4 is basically the same as Example 1, except that ATMP is used instead of HEDP in this example, with a dosage of 45 mg / L, and H2O2 is still 55 mg / L.

[0030] After flotation, the Cu grade in the concentrate was 23.44% with a recovery rate of 64.48%, and the Zn grade was 12.02% with a recovery rate of 16.24%.

[0031] Comparative Example 5 Comparative Example 5 is basically the same as Example 1, except that EDTMP is used instead of HEDP in this comparative example, the dosage is 45 mg / L, and H2O2 is still 55 mg / L.

[0032] After flotation, the Cu grade in the concentrate was 21.80% with a recovery rate of 50.97%, and the Zn grade was 11.80% with a recovery rate of 13.79%.

[0033] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0034] The embodiments described above are merely illustrative of implementation methods of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent disclosure. It should be noted that those skilled in the art can make various modifications, equivalent substitutions, and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent disclosure should be determined by the appended claims.

Claims

1. The application of an oxidant-organophosphonic acid combined inhibitor in the flotation separation of copper-zinc sulfide ores, characterized in that, In the flotation separation process of chalcopyrite and sphalerite, an oxidant is first added to the pulp for pretreatment, and then a small molecule phosphonic acid reagent is added as a selective inhibitor of sphalerite. This causes the formation of hydrophilic complexes on the surface of sphalerite, which is selectively inhibited, while chalcopyrite maintains good floatability, thereby achieving efficient separation of chalcopyrite and sphalerite.

2. The application according to claim 1, characterized in that, The oxidant is hydrogen peroxide.

3. The application according to claim 1, characterized in that, The organophosphonic acid reagent is hydroxyethylidene diphosphonic acid.

4. The application according to claim 1, characterized in that, The mass ratio of the oxidant to the organophosphonic acid reagent is 1:0.6 to 1:

1.

5. A method for flotation separation of chalcopyrite and sphalerite using the combined inhibitors according to any one of claims 1-4, characterized in that, Includes the following steps: Pure chalcopyrite and molybdenite are placed in a flotation cell, deionized water is added and stirred to form a homogeneous slurry with a concentration of 6%-7%. First, dilute sulfuric acid or sodium hydroxide solution is added to adjust the pH of the slurry. Then, oxidant H2O2 and organophosphonic acid reagent HEDP are added sequentially and allowed to react for 3-5 minutes each to fully complete the mineral surface reaction. After that, collector and frother are added, and after stirring, aeration is carried out for flotation. The frothy product obtained is copper concentrate, and the product in the flotation cell is zinc concentrate.

6. The method according to claim 5, characterized in that, During flotation, the pH of the pulp is adjusted to be in the range of 6.0 to 8.

0.

7. The method according to claim 5, characterized in that, The dosage of the combined inhibitor during flotation is 100 mg / L.

8. The method according to claim 5, characterized in that, The collector is butyl xanthate, and the dosage of the collector is 1.5–8.0 mg / L; the foaming agent is No. 2 oil, and the dosage of the foaming agent is 1.5–7.5 mg / L.

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