Method for separating copper-sulfur minerals through pre-oxidation-xanthate-free flotation

Abstract

The invention discloses a method for separating copper-sulfur minerals through pre-oxidation-xanthate-free flotation, and belongs to the technical field of ore separation. The method comprises the steps that firstly, sodium percarbonate is added into copper-sulfur mineral primary ore pulp for pulp mixing, then dibutyl oxalate or diisopropyl malonate is added into the ore pulp to serve as a collecting agent, and copper concentrate and tailings are obtained after one-time roughing, two-time sweeping and two-time concentration grading operation. The high-selectivity ester collecting agent is adopted, the selective collecting capacity and foamability are both considered, copper-sulfur mineral flotation separation can be achieved under the lime-free, high-alkali and xanthate-free conditions, the problems of high-alkali pollution, poor xanthate selectivity and the like in a traditional copper-sulfur separation process are effectively solved, and the method has the multiple advantages of being low in cost, simple in process, environmentally friendly and the like.

Description

Technical Field

[0001] This invention relates to a method for separating copper-sulfur minerals by pre-oxidation-xanthate-free flotation, specifically relating to the field of mineral separation technology. Background Technology

[0002] Chalcopyrite is the main source of copper metal and is often found in association with pyrite. Flotation is the primary method for separating the two minerals. However, domestic copper resources are generally characterized by being poor, fine-grained, and complex. Furthermore, chalcopyrite and pyrite have similar natural floatability, posing a significant challenge to their efficient flotation separation and recovery.

[0003] Currently, lime is commonly used in industry as a pyrite inhibitor, while xanthate and its derivatives are used as collectors for copper-sulfur separation under high alkalinity conditions. This method suffers from drawbacks such as high inhibitor dosage, low collector selectivity, pipeline blockage caused by large amounts of lime, and a series of subsequent environmental problems. Patent application CN201210173054.9 discloses a pyrite inhibitor for low alkalinity conditions, composed of sodium thiosulfate, citric acid, and low molecular weight polyacrylamide, which effectively replaces lime for copper-sulfur mineral separation. However, this combined inhibitor does not demonstrate a cost advantage. Furthermore, polyacrylamide exhibits poor solubility and strong flocculation and sedimentation capabilities in industrial applications, which will seriously hinder the large-scale application of this inhibitor and the recovery of fine-grained minerals. Patent application CN201910184927.8 discloses an organophosphoric acid compound, its synthesis method, and its application as a collector for chalcopyrite. The collector is synthesized from organic acid, phosphorous acid, and phosphorus pentoxide under certain conditions, with the structure RC(PO3Na2)2OH. This collector effectively separates siliceous gangue (quartz and mica) type copper-sulfur minerals. However, this type of collector has the disadvantage of significantly higher cost compared to conventional xanthate collectors. At the same time, organophosphoric acid compounds are greatly affected by high calcium and magnesium ores or water quality, so the scope of application of this method is relatively limited. Summary of the Invention

[0004] To address the inhibition-collection problem in the flotation separation of copper-sulfur ores, this invention provides a method that uses sodium percarbonate for pre-oxidation and slurry conditioning, followed by the use of dibutyl oxalate or diisopropyl malonate as a collector for chalcopyrite, which combines high selectivity and foaming ability, to effectively achieve efficient separation of copper-sulfur minerals.

[0005] The technical solution of the present invention is as follows: sodium percarbonate (2Na2CO3·3H2O2) is used as an oxidation modifier to take into account both dispersion and oxidation effects. Dibutyl oxalate and diisopropyl malonate, which have both high selectivity and foaming ability, are used as chalcopyrite collectors, which can effectively achieve flotation separation of chalcopyrite and pyrite.

[0006] Preferably, the copper-sulfur flotation separation method specifically includes the following steps: (1) After grinding the copper-sulfur ore, a primary slurry with a fineness of -200 mesh and a content of 70~75% is obtained, which is introduced into the stirring tank I, and sodium percarbonate is added for pre-oxidation treatment. The stirring time is 10 min.

[0007] (2) Introduce the slurry from step (1) into the mixing tank II, add dibutyl oxalate or diisopropyl malonate as copper mineral collector, and stir for 5 minutes.

[0008] (3) The slurry from step (2) is introduced into the flotation machine and subjected to one roughing, two scavenging and two cleaning separation operations to obtain copper concentrate and tailings.

[0009] Preferably, the method and dosage of adding sodium percarbonate as the modifier in step (1) is as follows: add it by preparing a 20% aqueous solution, with a dosage of 800-1000 g / t.

[0010] Preferably, in step (2), the amount of collector dibutyl oxalate or diisopropyl malonate is 65-80 g / t, and in step (3), the amount of collector for scavenging I is 25-30 g / t, and the amount of collector for scavenging II is 10-15 g / t. After entering the flotation machine, the roughing operation only involves skimming.

[0011] The structural formulas of dibutyl oxalate and diisopropyl malonate are shown below:

[0012]

[0013] dibutyl oxalate

[0014]

[0015] Diisopropyl malonate

[0016] Preferably, the coarse scavenging operation in step (3) takes 6-8 minutes, the fine scavenging operation takes 5-6 minutes, and each intermediate mineral product is returned step by step to form a closed loop.

[0017] Preferably, the copper-sulfur ore has a copper grade of 0.5%-0.6%, with chalcopyrite being the main copper-bearing mineral, and a sulfur grade of 8%-10%, with pyrite being the main sulfur-bearing mineral.

[0018] The basic principle of this invention:

[0019] (1) Modifier. Sodium percarbonate (2Na2CO3·3H2O2) will gradually undergo the following reaction in water: decomposition reaction of sodium percarbonate, Sodium carbonate hydrolysis reaction, + Hydrogen peroxide hydrolysis reaction, The above reaction products indicate that sodium percarbonate aqueous solution has both alkaline and oxidizing properties. Introducing it into primary copper-sulfur ore will further trigger the following reaction:

[0020] Oxidation and hydroxylation reactions on the surface of pyrite Where n1-n4 and x, y are reaction process coefficients; chalcopyrite surface oxidation and hydroxylation reactions, Where n1-n6 and x, y are the reaction process coefficients;

[0021] The above reactions indicate that, after adjustment with sodium percarbonate, although chalcopyrite exhibits hydrophilic oxidation, it still retains active sites for copper sulfide flotation. Pyrite, after oxidation, shows stronger surface hydroxylation, resulting in poorer flotation activity. Simultaneously, the bicarbonate, carbonate, and hydroxide ions produced by sodium carbonate hydrolysis increase the negative charge on the mineral surface, enhance electrostatic repulsion between particles, and thus improve pulp dispersibility.

[0022] (2) Collector. The carbonyl group (C=O) in the ester groups of dibutyl oxalate and diisopropyl malonate has a lone pair of electrons, which can coordinate with copper or iron on the mineral surface. The dibutyl group in dibutyl oxalate and the diisopropyl group in diisopropyl malonate have a hydrophobic effect. In addition, the ester group (-OCO-) plays a foaming role in the process. After the action of sodium carbonate, due to the difference in oxidation on the surfaces of chalcopyrite and pyrite, the adsorption of dibutyl oxalate and diisopropyl malonate on the chalcopyrite surface is almost unaffected, while the adsorption on the pyrite surface is greatly reduced, thus achieving efficient flotation separation of chalcopyrite and pyrite.

[0023] The beneficial effects of this invention are:

[0024] (1) The sodium percarbonate used in this invention has the dual function of inhibiting oxidation and dispersing slurry. Compared with conventional oxidants such as hydrogen peroxide, calcium hypochlorite, ammonium persulfate and potassium ferrate, it has many advantages such as low price, stable properties and good product indicators.

[0025] (2) The collectors dibutyl oxalate and diisopropyl malonate used in this invention have the dual functions of collecting and foaming. Compared with conventional collectors such as xanthate, black powder and thiocyanate, they have the characteristics of being environmentally friendly, highly selective and low in cost.

[0026] (3) The method for separating copper-sulfur minerals by pre-oxidation-xanthate flotation provided by the present invention has multiple advantages, including simple process, high copper-sulfur separation efficiency, low cost, and environmental benefits. It can bring good economic benefits to enterprises that develop copper-sulfur resources. Attached Figure Description

[0027] Figure 1 The process flow diagrams are for embodiments 1 and 2 of the present invention;

[0028] Figure 2 The above are process flow diagrams for comparative embodiments 1 and 2 of the present invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0030] Example 1:

[0031] Mineral raw materials: Primitive copper-sulfur ore from the Dapingzhang copper mine area in Simao, Pu'er, Yunnan Province. The copper content is approximately 0.5%, and the sulfur content is approximately 8%. Other minerals include quartz, mica, and a small amount of calcite. The main copper-bearing mineral is chalcopyrite, and the main sulfur-bearing mineral is pyrite.

[0032] The specific steps are as follows:

[0033] (1) The raw ore is crushed, ground and classified to obtain a slurry with 70% of -200 mesh. The slurry is introduced into the mixing tank I, 800g / t sodium percarbonate is added and a 20% aqueous solution is prepared for addition, and the stirring time is about 10min.

[0034] (2) The slurry after being treated with sodium percarbonate is introduced into the mixing tank II and 65g / t of collector is added. The mixing time is about 5min.

[0035] (3) The slurry after the reagent has been applied is introduced into the flotation machine for one roughing, two scavenging and two cleaning flotation operations to obtain copper concentrate and copper tailings. The collector addition amount for scavenging operation I is 25g / t, the collector addition amount for scavenging operation II is 10g / t, no reagent is added for cleaning operation, and only frothing is required for roughing. The roughing and scavenging operation time is 6min, and the cleaning operation time is 5min. The mineral products are returned to the previous stage according to the operation sequence, thus forming a closed-loop process.

[0036] In this embodiment, the collectors in steps (2) and (3) are the same. Dibutyl oxalate was used first, and then diisopropyl malonate was used for comparison. The methods of use for both were exactly the same. In this embodiment, the middlings are returned to the previous stage in sequence to form a closed loop.

[0037] Example 1 Workflow is as follows Figure 1 As shown in Table 1, the product specifications are as follows.

[0038] Example 2:

[0039] Example 2 treated copper-sulfur ore samples from the same mining area as Example 1, with a copper grade of approximately 0.55% and a sulfur content of approximately 9%, and other gangue minerals were basically the same. Except for an increase in the dosage of modifier and collector, the remaining operational procedures were the same as in Example 1, and the variables for each reagent are shown below:

[0040] (1) The raw ore is crushed, ground and classified to obtain a slurry with 72% -200 mesh. The slurry is introduced into the mixing tank I, and 900 g / t of sodium percarbonate is added and a 20% aqueous solution is prepared for addition. The mixing time is about 10 min. (2) The slurry after the action of the modifier sodium percarbonate is introduced into the mixing tank II. In this embodiment, the amount added to the mixing tank II is 70 g / t, and the mixing time is about 5 min.

[0041] (3) The slurry after the reagent has been applied is introduced into the flotation machine for one roughing, two scavenging and two cleaning flotation operations to obtain copper concentrate and copper tailings. The amount of collector added in scavenging operation I is 25g / t, the amount of collector added in scavenging operation II is 15g / t, and no reagent is added in cleaning operation.

[0042] In this embodiment, the collectors in steps (2) and (3) are the same. Dibutyl oxalate was used first, and then diisopropyl malonate was used for comparison. The methods of use for both were exactly the same. In this embodiment, the middlings are returned to the previous stage in sequence to form a closed loop.

[0043] Example 2 Workflow is as follows Figure 1 As shown in Table 1, the product specifications are as follows.

[0044] Example 3:

[0045] Example 3 treated copper-sulfur ore samples from the same mining area as Example 1, with a copper grade of approximately 0.6% and a sulfur content of approximately 10%, and other gangue minerals were basically the same. Except for an increase in the dosage of modifier and collector, the remaining operating procedures were the same as in Example 1, and the variables for each reagent are shown below:

[0046] (1) The raw ore is crushed, ground and classified to obtain a slurry with 75% of -200 mesh. The slurry is introduced into the mixing tank I, 1000g / t sodium percarbonate is added and a 20% aqueous solution is prepared for addition, and the stirring time is about 10min.

[0047] (2) The slurry after being treated with sodium percarbonate is introduced into the mixing tank II. In this embodiment, the amount added to the mixing tank II is 80g / t, and the mixing time is about 5min.

[0048] (3) The slurry after the reagent has been applied is introduced into the flotation machine for one roughing, two scavenging and two cleaning flotation operations to obtain copper concentrate and copper tailings. The amount of collector added in scavenging operation I is 30g / t, the amount of collector added in scavenging operation II is 10g / t, and no reagent is added in cleaning operation.

[0049] In this embodiment, the collectors in steps (2) and (3) are the same. Dibutyl oxalate was used first, and then diisopropyl malonate was used for comparison. The methods of use for both were exactly the same. In this embodiment, the middlings are returned to the previous stage in sequence to form a closed loop.

[0050] Example 3 Workflow is as follows Figure 1 As shown in Table 1, the product specifications are as follows.

[0051] Table 1 Product Indicators for Examples 1, 2, and 3

[0052]

[0053] The closed-circuit test results of Examples 1, 2, and 3 show that when dibutyl oxalate was used as the collector, a closed-circuit concentrate with a copper grade greater than 19.21% and a copper recovery rate greater than 92.47% was obtained. When diisopropyl malonate was used as the collector, a closed-circuit concentrate with a copper grade greater than 19.06% and a copper recovery rate greater than 91.86% was obtained. These results indicate that the present invention provides a method for separating copper-sulfur minerals by pre-oxidation-xanthate-free flotation. By adjusting the reagent dosage for copper-sulfur ores with different contents, efficient recovery of copper minerals can be effectively achieved, resulting in superior product indicators and excellent separation effect.

[0054] Example 3:

[0055] Comparative Example 1

[0056] The ore sample treatment in this embodiment is the same as in Example 1, using the high-alkali lime-xanthate method. The specific operation steps are as follows:

[0057] (1) The raw ore is crushed, ground and classified to obtain a slurry with 70% of the particles being -200 mesh. The slurry is introduced into mixing tank I, and 2000 g / t of lime milk is added to adjust the pH to ≥11.

[0058] (2) The slurry after being treated with lime milk is introduced into the mixing tank II, and collectors and foaming agents are added simultaneously for 5 minutes.

[0059] (3) The collector in step (2) is a 20% aqueous solution of ethyl xanthate and isopentyl xanthate in a 1:1 ratio. In this embodiment, the amount added to the stirring tank II is 65g / t.

[0060] (4) In step (2), the foaming agent is No. 2 oil, which is added directly according to the required weight. The amount added to mixing tank II is 20g / t.

[0061] (5) The slurry that has completed the reaction of the reagents is introduced into the flotation machine for flotation operation of one roughing, two scavenging and two cleaning to obtain copper concentrate and copper tailings.

[0062] (6) In step (3), the coarse scavenging operation takes 6 minutes and the fine scavenging operation takes 5 minutes. The mineral products are returned in the order of the operation, thus forming a closed-loop process.

[0063] (7) In step (3), the amount of collector added in scavenging operation I is 25g / t, the amount of collector added in scavenging operation II is 10g / t, and no agent is added in the fine selection operation.

[0064] (8) In step (3), the amount of foaming agent added in scavenging operation I is 10g / t, and the amount of collector added in scavenging operation II is 5g / t.

[0065] Comparative Example 1 Workflow is as follows Figure 2 As shown in Table 2, the product specifications are as follows.

[0066] Comparative Example 2

[0067] The ore sample treatment in this embodiment is the same as in Example 2, using the high-alkali lime-xanthate method. Except for an increase in the amount of lime and collector, the rest of the operation process is the same as in Comparative Example 1. The variables of each reagent are as follows:

[0068] (1) The raw ore is crushed, ground and classified to obtain a slurry with 72% of -200 mesh. The slurry is introduced into the mixing tank I, and 2500g / t of lime milk is added to adjust the pH to ≥11.

[0069] (2) The slurry after being treated with lime milk is introduced into the mixing tank II, and collectors and foaming agents are added simultaneously. The mixing time is about 5 minutes.

[0070] (3) The preparation and use of the collector in step (2) are the same as in comparative example 1. The amount added to the mixing tank II in this example is 80g / t.

[0071] (4) The amount of collector added for scavenging operation I is 30g / t, the amount of collector added for scavenging operation II is 10g / t, and no agent is added for fine cleaning operation.

[0072] (5) The amount and method of adding foaming agent are the same as those in Comparative Example 1.

[0073] Comparative Example 2 Workflow is as follows Figure 2 As shown in Table 2, the product specifications are as follows.

[0074] Table 2. Flotation Indicators of Comparative Examples

[0075]

[0076] Compared to Example 1, the quality of the copper concentrate product in Comparative Example 1 was significantly worse, with a decrease in copper grade of approximately 1 percentage point and a decrease in recovery rate of approximately 2.13 percentage points. Compared to Example 2, the copper concentrate grade in Comparative Example 2 was similar, but the copper recovery rate was significantly lower, decreasing by an average of 3.39 percentage points.

[0077] In summary, the pre-oxidation-xanthate-free flotation method for separating copper-sulfur minerals provided by this invention has multiple advantages, including low reagent consumption, low operating cost, environmental friendliness, and high copper-sulfur separation efficiency, and has significant innovative value for the development of copper-sulfur resources.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for separating copper-sulfur minerals by pre-oxidation-xanthate-free flotation, characterized in that, The specific steps are as follows: (1) The primary copper-sulfur mineral slurry was introduced into the stirred tank I and sodium percarbonate was added for pre-oxidation treatment; (2) Introduce the slurry after the preparation in step (1) into the mixing tank II, and add dibutyl oxalate or diisopropyl malonate as copper mineral collector and stir. (3) The slurry after stirring in step (2) is introduced into the flotation machine and subjected to a roughing, scavenging and cleaning process to obtain copper concentrate and tailings.

2. The method for pre-oxidation-xanthate-free flotation separation of copper-sulfur minerals according to claim 1, characterized in that: Step (1) The fineness of the raw slurry is -200 mesh, accounting for 70%-75%.

3. The method for pre-oxidation-xanthate-free flotation separation of copper-sulfur minerals according to claim 1, characterized in that: In step (1), sodium percarbonate is added in a 20% aqueous solution at a dosage of 800-1000 g / t, and the slurry preparation time is 10 min.

4. The method for pre-oxidation-xanthate-free flotation separation of copper-sulfur minerals according to claim 1, characterized in that: In step (2), the amount of collector dibutyl oxalate or diisopropyl malonate is 65-80 g / t. In step (3), the amount of scavenging collector I is 25-30 g / t, and the amount of scavenging collector II is 10-15 g / t.

5. The method for pre-oxidation-xanthate-free flotation separation of copper-sulfur minerals according to claim 1, characterized in that: In step (3), the coarse sweeping operation takes 6-8 minutes, and the fine sweeping operation takes 5-6 minutes.

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