A calcium-magnesium mineral inhibitor and a method for direct flotation of copper oxide

Abstract

The present invention discloses a calcium and magnesium mineral inhibitor and a method for direct flotation of copper oxide, belonging to the technical field of ore flotation. The method comprises the steps of adjusting the pulp of raw ore containing both copper oxide minerals and calcium and magnesium gangue minerals to obtain pulp; adding flotation reagents including the calcium and magnesium mineral inhibitor of formula I and a collector for copper oxide minerals to the pulp for flotation, thereby obtaining copper oxide froth concentrate and calcium and magnesium gangue tailings. The inhibitor of the present invention has good water solubility, mildness and high selectivity. When it is used for the direct flotation of copper oxide, it can selectively inhibit the calcium and magnesium gangue mineral dolomite without inhibiting the copper oxide minerals due to the complexing property of its phosphate group, thereby enhancing the difference in floatability between copper oxide ore and dolomite, having a high copper recovery rate and selectivity, and simultaneously significantly reducing the wet smelting production cost of subsequent copper oxide concentrate.

Description

Technical Field

[0001] The present invention belongs to the technical field of ore flotation, and particularly relates to a calcium and magnesium mineral inhibitor and a method for direct flotation of copper oxide. Background Art

[0002] Copper metal is widely used in the national defense industry, electronics and electrical appliances, and the development of new technologies, resulting in an increasing demand for copper metal. Copper ore is a non-renewable strategic resource. With the exploitation and utilization of copper ore resources, sulfide copper ore and rich ore are decreasing day by day, and refractory copper oxide ore has been developed and utilized. However, the exploitation of medium and high-grade copper oxide ore resources is becoming increasingly exhausted, and low-grade copper oxide ore is gradually being utilized. Nowadays, for low-grade copper oxide ore, there are often a large number of gangue minerals containing calcium and magnesium carbonates, such as dolomite. Direct leaching of such minerals will consume a large amount of acid, greatly increasing the production cost. Using conventional "sulfidation-xanthate" flotation will cause a large amount of dolomite to be entrained in the copper concentrate, seriously affecting the grade of the copper concentrate, increasing the acid consumption in the subsequent hydrometallurgical process, and significantly increasing the production cost. Therefore, it is of great significance to find an efficient dolomite inhibitor for the direct flotation of low-grade high-calcium and magnesium copper oxide ore to strengthen the separation of useful minerals and gangue minerals.

[0003] The currently widely used dolomite inhibitors mainly include sodium silicate, sodium hexametaphosphate, sodium carboxymethyl cellulose (CMC), and sodium tripolyphosphate. However, the disadvantages of these inhibitors are poor selectivity, large dosage, and high cost. Some researchers have studied new organic inhibitors. For example, Chinese Patent Application CN112371346A reported "A Dolomite Inhibitor and Its Application Method", which uses iminodisuccinate as a dolomite inhibitor and has been successfully applied to the separation of apatite and magnesium-containing carbonate minerals in phosphate ore flotation, but has poor selectivity for copper oxide minerals such as malachite. Chinese Patent Application CN103691574A reported "A Preparation Method and Application of a Dolomite Inhibitor", which prepares a dolomite inhibitor by mixing sulfuric acid, hydrochloric acid, benzoic acid, and sulfates in a certain proportion, but has a high preparation cost and is prone to environmental pollution. Chinese Patent Application CN111215251A reported "A Dolomite Inhibitor and Its Use Method", which prepares a dolomite inhibitor by mixing xanthan gum and pullulan polysaccharide at mass fractions of 80 - 95% and 5 - 20% respectively, but has a high preparation cost. Chinese Patent Application CN117943209A published "A Composite Inhibitor and Its Application in the Flotation of Fine-Grained Copper Oxide Ores", which combines nitrilotriacetic acid, lactic acid, tannin extract, and polyferric sulfate to prepare an inhibitor for the separation of fine-grained copper oxide ores and gangue minerals, but the preparation process is cumbersome and the cost is high. Chinese Patent Application CN109261346A reported "A Mineral Processing Method for Copper-Cobalt Ores Containing Easy-Floating Calcium and Magnesium Minerals", which adds at least one of carboxymethyl cellulose, carboxyethyl cellulose, and guar gum to inhibit calcium and magnesium minerals, but the reagent cost is high and it is not conducive to large-scale promotion and application. Chinese Patent Application CN108654844A discloses an organophosphoric acid compound used as a flotation inhibitor for calcium-containing gangue minerals and applied to the flotation separation of scheelite and calcium-containing gangue minerals. This method is prepared by esterification reaction and hydrolysis reaction of phosphorus trichloride, R-COOH, and water, but its preparation process is complex, its water solubility is poor, and it contains two phosphate groups with strong complexing ability, resulting in poor selectivity for the same type of carbonate minerals and being unable to be applied to the flotation system of low-grade copper oxide ores. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, such as poor water solubility of calcium and magnesium mineral inhibitors and poor selectivity for the same type of carbonate minerals, the first object of the present invention is to provide a calcium and magnesium mineral inhibitor, which has good water solubility, mildness, and high selectivity, and has excellent universality with the copper oxide ore flotation system.

[0005] The second object of the present invention is to provide a method for using a calcium and magnesium mineral inhibitor in the direct flotation of copper oxide. By adding a small amount of the calcium and magnesium mineral inhibitor, dolomite, a calcium and magnesium gangue mineral, can be selectively inhibited without inhibiting copper oxide minerals due to the complexing property of phosphate groups, thereby enhancing the floatability difference between copper oxide ore and dolomite, and having a high copper recovery rate and selectivity.

[0006] To achieve the above technical object, the present invention provides a calcium and magnesium mineral inhibitor with the following structural formula:

[0007] ;

[0008] Formula I;

[0009] Wherein, M represents a metal ion.

[0010] The appropriate complexing ability and good water solubility of the inhibitor of the present invention for calcium and magnesium minerals are the keys to ensuring good inhibitory effects and high selectivity for calcium and magnesium minerals. Specifically, currently, glycerol phosphates include α-glycerol phosphate and β-glycerol phosphate. The inhibitor of the present invention belongs to α-glycerol phosphate because, compared with β-glycerol phosphate, the phosphate group of the present invention is at the end position and can form a more compact and stable five-membered or six-membered ring structure adsorption layer by coordinating with multiple hydroxyl groups during the flotation of calcium and magnesium, effectively inhibiting the adsorption of collectors; at the same time, the diphosphate group has strong complexing properties compared with the monophosphate group of the present invention and has a complexing effect on metal ions in the same type of carbonate minerals (such as malachite CuCO3•Cu(OH)2, dolomite CaMg(CO3)2), making it difficult to distinguish the target metals in different minerals, and thus showing poor selectivity. At the same time, the monophosphate group in the present invention is not directly connected to the hydrocarbon group and there is steric hindrance between it and the hydroxyl group, which also improves the hydrophilicity and selectivity of the inhibitor of the present invention to a certain extent.

[0011] Furthermore, the inhibitor of the present invention can be used in the direct flotation of copper oxide ore to remove the calcium and magnesium gangue mineral dolomite, wherein the copper oxide ore includes artificial mixed ore and the flotation of actual industrial copper oxide minerals.

[0012] As a preferred embodiment, M in the present invention can be sodium, and the glycerol phosphate in the present invention also includes its hydrate.

[0013] The present invention also provides a method for using a calcium and magnesium mineral inhibitor in the direct flotation of copper oxide. The method is to adjust the pulp of the raw ore containing both copper oxide minerals and calcium and magnesium gangue minerals to obtain a pulp; a flotation reagent containing the calcium and magnesium mineral inhibitor of the formula and a collector for copper oxide minerals is added to the pulp for flotation, and a copper oxide foam concentrate and a calcium and magnesium gangue tailing are obtained.

[0014] The calcium and magnesium mineral inhibitor of the present invention has a strong selective inhibitory effect on dolomite, a calcium and magnesium carbonate mineral in copper oxide ore. By adding the inhibitor, efficient separation of malachite, the useful mineral, and dolomite, the gangue mineral, in the direct flotation of copper oxide ore can be achieved. The main mechanism is as follows:

[0015] This inhibitor contains a large number of hydroxyl groups and appropriate phosphoric acid groups and other hydrophilic and solid-philic groups. Although both malachite and dolomite are carbonate minerals, due to the difference in the crystal structures of malachite and dolomite ores, and because of the good water solubility of the inhibitor, it can spatially match the exposed Ca and Mg active sites on the surface of dolomite, strongly adsorb on the surface of dolomite through the coordination reaction mechanism, and produce a hydrophilic film to make the surface of dolomite hydrophilic, thereby realizing the selective inhibition of gangue minerals in copper oxide ore and further preventing the adsorption of collectors, increasing the floatability difference between copper oxide minerals and gangue minerals. For malachite, due to the small radius and large charge density of copper ions on its surface, the coordination with the inhibitor is inhibited by the steric hindrance effect, and it can be more easily adsorbed on its surface through the synergistic action of collectors, thus realizing the efficient separation of copper oxide minerals and calcium and magnesium gangue minerals.

[0016] As a preferred scheme, the pH range of the pulp is 6 - 12. Within the pH range of the present invention, high recovery rate of copper in copper oxide minerals and high selective inhibitory effect on calcium and magnesium can be effectively achieved. Further preferably, the pH range of the pulp is 9 - 12.

[0017] As a preferred scheme, the dosage of the calcium and magnesium mineral inhibitor is 10 - 100 mg / L. With the increase of the inhibitor concentration, the flotation of malachite is hardly affected, while the recovery rate of dolomite decreases significantly. Further preferably, the dosage of the inhibitor is 60 - 100 mg / L.

[0018] As a preferred scheme, the flotation reagent also includes a sulfiding agent with a dosage of 100 - 500 mg / L and a foaming agent with a dosage of 35 - 50 mg / L. The sulfiding agent used in the present invention is further preferably sodium sulfide and / or sodium hydrosulfide. During the flotation process of copper oxide minerals, by adding a sulfiding agent in the present invention, the surface chemical properties of copper oxide minerals can be changed through surface sulfidation reaction, making them transformed into a hydrophobic surface of sulfide ore, thereby improving the adsorption ability of xanthate collectors. And increasing the foaming agent can further increase the floatability of minerals.

[0019] As a preferred scheme, the collector includes xanthate collectors and / or fatty acid collectors, with a dosage of 80 - 500 mg / L. Further, the xanthate collectors used in the present invention include butyl xanthate and / or amyl xanthate, and the fatty acid collectors used include sodium oleate.

[0020] As a preferred embodiment, the raw ore includes malachite and dolomite.

[0021] As a preferred embodiment, the copper grade in the raw ore is greater than or equal to 0.5%, the calcium grade is greater than or equal to 5%, and the magnesium grade is greater than or equal to 5%. The direct flotation method of the present invention also has good effects on the recovery of copper in low-grade copper oxide ores with high calcium and magnesium.

[0022] Compared with the prior art, the present invention has the following beneficial technical effects:

[0023] (1) The inhibitor provided by the present invention has good water solubility, mildness and high selectivity, and has excellent universality with the copper oxide ore flotation system.

[0024] (2) The inhibitor provided by the present invention has a small dosage, low cost, safe use, wide source, non-toxic, strong biodegradability, and can effectively achieve high recovery of copper in copper oxide minerals and high selective inhibition of calcium and magnesium within a relatively wide pH range.

[0025] (3) The inhibitor provided by the present invention has a strong selective inhibitory effect on calcium and magnesium carbonate minerals in copper oxide ores. By adding the inhibitor, efficient separation of the useful mineral malachite from the gangue mineral dolomite in the direct flotation of copper oxide ores can be achieved.

[0026] (4) The inhibitor provided by the present invention has good separation effects in both artificial mixed ores and actual industrial copper oxide ores, and has good industrial promotion and application value.

[0027] (5) The flotation separation method of the present invention has a simple process. By adding a small amount of α-glycerophosphate inhibitor, calcium and magnesium gangue minerals dolomite can be selectively inhibited, and it will not inhibit copper oxide minerals due to the complexing property of its phosphate group, thereby enhancing the floatability difference between copper oxide ores and dolomite, having high copper recovery and selectivity, and significantly reducing the wet smelting production cost of subsequent copper oxide concentrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is the direct flotation reagent regime and flow chart of the artificial mixed ore and copper oxide actual ore of the present invention.

[0029] Figure 2 It is the experimental result of Example 1 of the present invention.

[0030] Figure 3 It is the infrared spectrogram of dolomite before and after the action of the α-glycerophosphate inhibitor of the present invention.

[0031] Figure 4 It is the experimental result of Example 2 of the present invention.

[0032] Figure 5 Experimental results of Comparative Example 1 of the present invention. Specific embodiments

[0033] The following specific examples are intended to further illustrate the content of the present invention, rather than limiting the protection scope of the claims of the present invention. For the reagents not indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0034] In the present invention, the pulp concentration refers to the mass concentration, and the dosage of the reagents is relative to the dosage of the raw ore.

[0035] Example 1

[0036] Malachite and dolomite pure minerals with a particle size of -0.074~+0.037 mm were uniformly mixed at a mass ratio of 1:9. 2 g of the artificial mixed ore was taken and 35 mL of deionized water was added to the flotation cell, and the pulp was adjusted by stirring at a rotation speed of 1560 r / min. The addition sequence and process of the flotation reagents are as Figure 1 shown. The pulp pH was adjusted to 8, and inhibitors α-glycerol phosphate disodium at 10, 20, 40, 60, 80, and 100 mg / L were added in sequence; the collector was sodium oleate at 80 mg / L; then flotation was carried out for 5 minutes to obtain foam products and tailings, and then they were filtered, dried, and weighed respectively to calculate the recovery rate. The results are as Figure 2 shown. The infrared spectra of dolomite before and after the action of the inhibitor are as Figure 3 shown. Among them, the structural formula of α-glycerol phosphate disodium is as follows:

[0037] ;

[0038] Formula I;

[0039] where M is sodium.

[0040] It can be seen from Example 1 that with the increase of the inhibitor concentration, the flotation of malachite is hardly affected, while the recovery rate of dolomite decreases significantly. When the inhibitor concentration is 60 mg / L, the recovery rate of malachite is 90.13%, while the recovery rate of dolomite is only 14.27%. From Figure 3 it can be seen that after the action of the inhibitor α-glycerol phosphate disodium, new characteristic peaks 3427.51 cm -1 and 1433.11 cm -1 appear on the surface of dolomite, corresponding to -OH and -P=O groups respectively, indicating that the inhibitor can be adsorbed on the surface of dolomite and has a selective inhibitory effect on dolomite.

[0041] Example 2

[0042] Malachite and dolomite pure minerals with a particle size of -0.074~+0.037 mm were uniformly mixed at a mass ratio of 1:4. 2 g of the artificially mixed ore was taken and 35 mL of deionized water was added to the flotation cell, and the pulp was adjusted by stirring at a rotation speed of 1560 r / min. The addition sequence and process of the flotation reagents are as Figure 1 shown. The pulp pH was adjusted to 6, 7, 8, 9, 10, 11, and 12 respectively, and an inhibitor (sodium α-glycerophosphate) of 60 mg / L was added successively; the collector was sodium oleate at 80 mg / L; then flotation was carried out for 5 minutes to obtain the foam product and tailings, and then they were filtered, dried, weighed respectively, and the recovery rate was calculated. The results are as Figure 4 shown.

[0043] As can be seen from the examples, with the increase of the pulp pH, the flotation recovery rate of malachite is basically about 90%, while the recovery rate of dolomite is only about 13%, indicating that this inhibitor has a selective inhibitory effect on dolomite in a wide pH range.

[0044] Comparative Example 1

[0045] Malachite and dolomite pure minerals with a particle size of -0.074~+0.037 mm were uniformly mixed at a mass ratio of 1:9. 2 g of the artificially mixed ore was taken and 35 mL of deionized water was added to the flotation cell, and the pulp was adjusted by stirring at a rotation speed of 1560 r / min. The addition sequence and process of the flotation reagents are as Figure 1 shown. The pulp pH was adjusted to 8, and the inhibitor (chemical formula: C2H8O7P2) disclosed in Patent CN108654844A was added. Inhibitors of 20, 40, 60, 80, and 100 mg / L were added successively; the collector was sodium oleate at 80 mg / L; then flotation was carried out for 5 minutes to obtain the foam product and tailings, and then they were filtered, dried, weighed respectively, and the recovery rate was calculated. The results are as Figure 5 shown. It can be seen that the recovery rates of both malachite and dolomite have decreased, indicating that this inhibitor has poor selectivity and it is difficult to effectively separate malachite from dolomite. Among them, the structural formula of the inhibitor is as follows:

[0046]

[0047] Formula II.

[0048] Example 3

[0049] 500 g of a certain copper oxide actual ore from Tibet was taken, crushed and ground. The grinding concentration was 60% to make the proportion of -200 mesh reach 70%, and then it was transferred to a 1.5 L single-cell flotation machine. The pulp concentration was 30 wt%, and the pulp was adjusted by stirring at a rotation speed of 1920 r / min. The addition sequence and process of the flotation reagents are as Figure 1As shown, the pulp pH was adjusted to 8.5, and a sulfurizing agent (Na2S, 500 mg / L) was added successively; an inhibitor (sodium α-glycerophosphate) at 0 and 60 mg / L, a collector of amyl xanthate at 500 mg / L; a frother of No. 2 oil at 35 mg / L, and then flotation was carried out for 5 minutes to obtain a froth product and tailings, which were then filtered, dried, weighed, and assayed respectively, and the recovery rate was calculated. The results are shown in Table 1.

[0050] As can be seen from Table 1, in the case of no addition of inhibitor, the Cu grade in the concentrate was 2.55%, the Ca grade was 7.86%, and the Mg grade was 7.07%; the copper recovery rate was 74.19%, the calcium recovery rate was 33.23%, and the magnesium recovery rate was 33.99%, indicating that the useful copper minerals and gangue mineral dolomite could not be effectively separated by positive flotation. When 60 mg / L of inhibitor was added and then flotation was carried out, the Cu grade in the concentrate was 3.24%, the Ca grade was 1.58%, and the Mg grade was 2.03%; the copper recovery rate was 80.71%, the calcium recovery rate was 5.72%, and the magnesium recovery rate was 8.36%, indicating that the inhibitor of the present invention still has excellent selective inhibitory effect when separating useful minerals and gangue mineral dolomite by positive flotation of actual oxidized copper ore.

[0051]

[0052] Comparative Example 2

[0053] 500 g of a certain actual oxidized copper ore from Tibet was taken, crushed and ground, the grinding concentration was 60%, and the proportion of -200 mesh accounted for 70%, and then it was transferred to a 1.5 L single-cell flotation machine, and the pulp concentration was 30 wt%, and the pulp was adjusted by stirring at a speed of 1920 r / min. The addition sequence and process of the flotation reagents were as Figure 1 shown. The pulp pH was adjusted to 8.5, and a sulfurizing agent (Na2S, 500 mg / L) was added successively; the inhibitor dosage in Comparative Example 1 was 60 mg / L, the collector was amyl xanthate at 500 mg / L; the frother was No. 2 oil at 35 mg / L, and then flotation was carried out for 5 minutes to obtain a froth product and tailings, which were then filtered, dried, weighed, and assayed respectively, and the recovery rate was calculated. The results are shown in Table 2. As can be seen from Table 2, compared with the inhibitor of the present invention, the copper recovery rate of the concentrate using the inhibitor with the chemical formula C2H8O7P2 was significantly reduced, and the selectivity was also significantly reduced, indicating that the inhibitor with the chemical formula C2H8O7P2 has poor selectivity and is not suitable for the flotation system of oxidized copper ore.

[0054]

[0055] Example 4

[0056] Take 500 g of an actual copper oxide ore from the Democratic Republic of the Congo, crush and grind it. The grinding concentration is 60%, and the proportion of -200 mesh is 70%. Then transfer it to a 1.5 L single-cell flotation machine, and the pulp concentration is 30 wt%. Stir and condition the pulp at a rotational speed of 1920 r / min. The addition sequence and process of the flotation reagents are as Figure 1 shown. Adjust the pH of the pulp to 8.5, and successively add a sulfiding agent (Na2S, 500 mg / L); the dosage of the inhibitor α-glycerophosphoric acid disodium is 0, 60 mg / L, the collector is amyl xanthate 500 mg / L; the frother is No. 2 oil 35 mg / L. Then carry out flotation for 5 minutes to obtain a foam product and tailings, and then filter, dry, weigh, and assay them respectively to calculate the recovery rate. The results are shown in Table 3.

[0057] As can be seen from Table 3, without adding an inhibitor, the Cu grade in the concentrate is 3.65%, the Ca grade is 10.03%, and the Mg grade is 8.37%; the copper recovery rate is 82.63%, the calcium recovery rate is 39.47%, and the magnesium recovery rate is 38.57%. This indicates that the useful copper minerals and the gangue mineral dolomite cannot be effectively separated by positive flotation. When adding 60 mg / L of the inhibitor and then carrying out flotation, the Cu grade in the concentrate is 4.76%, the Ca grade is 2.56%, and the Mg grade is 2.04%; the copper recovery rate is 83.50% without a decrease, while the calcium recovery rate is 7.85% and the magnesium recovery rate is 7.33%. This shows that the inhibitor of the present invention still has a good selective inhibition effect when separating useful minerals and the gangue mineral dolomite in the positive flotation of the actual copper oxide ore.

[0058]

Claims

1. A calcium and magnesium mineral inhibitor, characterized in that: It has the following structural formula: ； Formula I; Wherein, M represents a metal ion.

2. The method for using a calcium and magnesium mineral inhibitor for positive flotation of copper oxide according to claim 1, characterized in that: The raw ore containing both copper oxide minerals and calcium magnesium gangue minerals is slurried to obtain slurry; the slurry is added with the formula The flotation is carried out using flotation reagents including calcium and magnesium mineral inhibitors and copper oxide mineral collectors to obtain copper oxide foam concentrate and calcium and magnesium gangue tailings.

3. The method for using a calcium and magnesium mineral inhibitor for positive flotation of copper oxide according to claim 2, characterized in that: The pH range of the slurry is 6-12.

4. The method for using a calcium and magnesium mineral inhibitor for positive flotation of copper oxide according to claim 2 or 3, characterized in that: The dosage of the calcium and magnesium mineral inhibitor is 10-100 mg / L.

5. The method for using a calcium and magnesium mineral inhibitor for positive flotation of copper oxide according to claim 2, characterized in that: The flotation reagent also includes a sulfiding agent in an amount of 100-500 mg / L and a frother in an amount of 35-50 mg / L.

6. The method for using a calcium and magnesium mineral inhibitor for positive flotation of copper oxide according to claim 5, characterized in that: The collector includes a xanthate collector and / or a fatty acid collector, and the dosage is 80-500 mg / L.

7. The method for using a calcium and magnesium mineral inhibitor for positive flotation of copper oxide according to claim 6, characterized in that: The raw ore includes malachite and dolomite.

8. The method for using a calcium and magnesium mineral inhibitor for positive flotation of copper oxide according to claim 7, characterized in that: The copper grade of the raw ore is greater than or equal to 0.5%, the calcium grade is greater than or equal to 5%, and the magnesium grade is greater than or equal to 5%.

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