Copper-molybdenum-gold-silver sulfide ore flotation reagent and gradient enrichment flotation method for copper-molybdenum-gold-silver sulfide ore

Abstract

The invention discloses a flotation reagent for copper-molybdenum-gold-silver sulfide ore and a cascade enrichment flotation method for the copper-molybdenum-gold-silver sulfide ore, and relates to the technical field of mineral flotation. A composite inhibitor is formed by compounding nitration modified humic acid and nano silicon dioxide according to the mass ratio, synchronous collection of copper, molybdenum and gold is enhanced under the action of a composite collecting agent, and the flotation efficiency of the copper-molybdenum-gold-silver sulfide ore is improved. According to the composite collecting agent, mercaptobenzothiazole and hydroximic acid are compounded, and the recovery rate of gold and silver is increased through the synergistic effect. The process comprises a mixed flotation stage and a stepped separation stage, and copper-molybdenum-gold-silver concentrate is finally obtained. The method solves the problems of difficult sulfur-noble metal separation and high medicament toxicity in the traditional process, and has the advantages of high efficiency, environmental protection and short process.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral flotation, and in particular, to a flotation reagent for copper-molybdenum-gold-silver sulfide ore and a stepped enrichment flotation method for copper-molybdenum-gold-silver sulfide ore. Background Art

[0002] In the beneficiation process of copper-molybdenum-gold-silver-sulfur polymetallic ore, pyrite (FeS2) is a major associated mineral, and its efficient inhibition and selective separation have always been technical difficulties. The traditional process generally uses cyanide as an inhibitor. Although it can effectively inhibit pyrite, there is a risk of highly toxic environmental pollution, and the complexation of cyanide with gold and silver will lead to a significant reduction in the recovery rate of precious metals. In addition, conventional inhibitors such as lime can replace cyanide to achieve sulfur inhibition, but due to its non-selective inhibition characteristics, molybdenum minerals are often simultaneously inhibited, resulting in a decrease in molybdenum recovery rate; while lignosulfonate inhibitors make it difficult for the recovery rate of gold and silver to exceed 70% due to their adsorption and shielding effects on gold and silver.

[0003] The prior art also has defects in the performance of collectors. Traditional thio-compound collectors have weak adsorption ability for gold and silver. In addition, under the multi-metal symbiotic system, the floatability of pyrite and valuable minerals is similar, forcing the separation of copper-molybdenum-gold-silver to rely on multi-stage cleaning processes, which not only increases reagent consumption and energy consumption, but also reduces the overall separation efficiency. Therefore, developing a new separation method with environmental friendliness, high selectivity and multi-metal synergistic recovery efficiency has become the key direction to solve the technical bottleneck in this field.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a flotation reagent for copper-molybdenum-gold-silver sulfide ore, wherein the composite inhibitor chelates with pyrite Fe through carboxyl (-COOH) to form a hydrophilic film; the -NO2 functional group generates a complex [Cu(NO2)4] with Cu on the surface of chalcopyrite (CuFeS2), playing a role in inhibiting copper-activated sulfur. The surface silanol (Si-OH) of nano-silica (n-SiO2) forms a hydrogen bond (bond length ≤ 2.1 Å) with the interlayer sulfur of molybdenite (MoS2), protecting the floatability of molybdenum. The composite collector selectively adsorbs chalcopyrite through the S-Cu bond; C=N-OH coordinates with the empty orbitals on the surfaces of gold and silver to improve the recovery rates of gold and silver. 3+ 2+ 3- [[Cu(NO2)4]] 3-

[0006] The second purpose of the present invention is to provide a stepped enrichment flotation method for copper-molybdenum-gold-silver sulfide ore, which uses the above-mentioned flotation reagent for flotation separation.

[0007] The present invention is implemented as follows: ​The present invention provides a flotation reagent for copper-molybdenum-gold-silver sulfide ore, and the reagent comprises a composite inhibitor and a composite collector; The composite inhibitor comprises nitrification-modified humic acid and nano-silica; The composite collector comprises mercaptobenzothiazole hydroxamic acid and mercaptobenzothiazole.

[0008] In some preferred embodiments, the composite inhibitor is formed by mechanically chemically activating and compounding the nitrification-modified humic acid and the nano-silica; The nitro content of the nitrification-modified humic acid (N-HA) is ≥5.2 wt%, and the carboxyl content is ≥4.5 mmol / g; The nano-silica (n-SiO2) has a mesoporous structure, a specific surface area of ≥600 m² / g, and a surface silicon hydroxyl density of ≥3.8 OH / nm²; The mass ratio of the nitrification-modified humic acid to the nano-silica is 1:1 - 2.

[0009] In some preferred embodiments, the preparation method of the nitrification-modified humic acid comprises the following steps: mixing humic acid and water at a mass ratio of 1:7 - 10, after ultrasonic treatment for 30 - 60 min, in an ice-water bath at 0 - 5 °C, mixing the humic acid and concentrated nitric acid at a mass ratio of 1:6 - 8, controlling the system temperature <10 °C, and carrying out a nitrification reaction; then raising the temperature to 58 - 62 °C, adding urea, and reacting for 4 - 8 h until the nitrification degree is ≥15% to obtain a reaction solution; Adjusting the pH of the reaction solution to 7 - 8 with an alkali solution, then centrifuging at 8000 - 10000 rpm for 15 - 30 min, and carrying out dialysis for 45 - 50 h after centrifugation; finally, freeze-drying to obtain a yellow powder with a yield of ≥85%.

[0010] In some preferred embodiments, the mass ratio of the hydroxamic acid to the mercaptobenzothiazole is 1:2 - 3; The hydroxamic acid is a C7 - C9 alkyl hydroxamic acid, and the hydroxamic group content is ≥90%; The purity of the mercaptobenzothiazole is ≥98%, and the sulfur content is ≥25 wt%.

[0011] In some preferred embodiments, the contact angle of the composite inhibitor on pyrite is reduced by ≥40°, and the change in the contact angle on molybdenite is ≤5°, which is suitable for the flotation separation of sulfide ore containing precious metals.

[0012] In some preferred embodiments, the adsorption energy of the composite collector on Au is ≤ - 2.9 eV, and the adsorption energy on CuFeS2 is ≤ - 3.2 eV; in the range of pH = 8 - 10, the fluctuation of the gold and silver adsorption rate is ≤5%; it is suitable for the flotation separation of copper-molybdenum-gold-silver ore.

[0013] The present invention also provides a cascade enrichment flotation method using a flotation agent for copper, molybdenum, gold and silver sulfide ores, the steps of which include: Grinding the raw copper, molybdenum, gold, silver and sulfide ore and adding water to obtain ore pulp; The pH value of the slurry is adjusted to 8.5-10, and 80-120 g / t of the composite collector is added thereto to obtain a copper, molybdenum, gold and silver mixed flotation concentrate and tailings; The copper, molybdenum, gold and silver mixed flotation concentrate is subjected to three-stage roughing suppression-activation separation to obtain a roughing concentrate and a roughing tailing, and a composite collector of 20-30 g / t is added to the roughing tailing, and two concentrations are performed to obtain a concentrated concentrate and a concentrated tailing; The selected concentrate and the rougher concentrate are mixed to obtain copper, molybdenum, gold and silver concentrates, and the selected tailings and the rougher tailings are mixed to obtain sulfur-containing tailings.

[0014] In some preferred embodiments, the three-stage roughing inhibition-activation separation process is to add different masses of composite inhibitors in the roughing I, roughing II and roughing III stages, and the mass ratio of the composite inhibitors added in the three stages is: 4-6:2-4:1-3; before the roughing II, a molybdenum activator is added, the stirring time is ≥2min, and the mixing is uniform; during the two selection processes, the pH value of the system is controlled to be 8.0-8.5.

[0015] In some preferred embodiments, the copper-molybdenum-gold-silver mixed flotation concentrate has a Cu content ≥15%, a Mo content ≥0.5%, an Au content ≥1g / t and an Ag content ≥30g / t.

[0016] In some preferred embodiments, the Cu content in the copper-molybdenum-gold-silver concentrate is ≥25%, the Mo content is ≥1.2%, the Au content is ≥10g / t and the Ag content is ≥150g / t, and the sulfur content is ≤5%; the Cu recovery rate in the copper-molybdenum-gold-silver concentrate is ≥90%, the Mo recovery rate is ≥85%, the Au recovery rate is ≥80%, and the Ag recovery rate is ≥75%; and the sulfur suppression rate is ≥93%.

[0017] The present invention has the following beneficial effects: (1) The flotation reagent for copper, molybdenum, gold and silver sulfide ores provided by the present invention comprises a nitrated modified humic acid in the composite inhibitor which reacts with the Fe of pyrite via a carboxyl group. 3+ Chelate to form a hydrophilic film, while its -NO2 functional group binds to Cu on the surface of chalcopyrite 2+ The formation of a stable complex selectively inhibits pyrite and reduces the activation of copper on sulfur; nano-silicon dioxide forms hydrogen bonds with the interlayer sulfur of molybdenite through silanol groups to protect the floatability of molybdenum. The composite collector is composed of thiobenzothiazole, which efficiently captures chalcopyrite through a strong S-Cu bond, while the C=N-OH group of hydroxylamine coordinates with the empty orbital on the surface of gold and silver, increasing the recovery rate by 30%~40%, solving the problem of weak adsorption of gold and silver by traditional collectors.

[0018] (2) The step enrichment process proposed by the present invention not only realizes the efficient separation and enrichment of multi-metals by optimizing the reagent system and operation parameters in the bulk flotation and separation stages, but also reduces energy consumption through process simplification, and has both environmental friendliness and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a process flow diagram of the enrichment flotation method for copper-molybdenum-gold-silver sulfide ore in this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0022] The first aspect of the present invention provides a flotation reagent for copper-molybdenum-gold-silver sulfide ore, and the reagent includes a composite inhibitor and a composite collector; The composite inhibitor includes nitrification-modified humic acid and nano-silica, and the composite inhibitor is formed by mechanically chemically activating and compounding the nitrification-modified humic acid and the nano-silica; wherein the nitro content of the nitrification-modified humic acid (N-HA) ≥ 5.2 wt%, and the carboxyl content ≥ 4.5 mmol / g; the nano-silica (n-SiO2) has a mesoporous structure, the specific surface area ≥ 600 m² / g, and the surface silicon hydroxyl density ≥ 3.8 OH / nm².

[0023] The nitrification-modified humic acid chelates with the iron of pyrite through the carboxyl group (-COOH) 3+ to form a hydrophilic film, and the -NO2 functional group forms a 2+ [Cu(NO2)4] complex with the Cu on the surface of chalcopyrite (CuFeS2) 3- to inhibit the activation of sulfur by copper; the surface silicon hydroxyl groups (Si-OH) of the nano-silica (n-SiO2) form hydrogen bonds (bond length ≤ 2.1 Å) with the interlayer sulfur of molybdenite (MoS2) to protect the floatability of molybdenum.

[0024] In some specific embodiments of the present invention, the mass ratio of the nitrated modified humic acid to the nano-silica is 1:1 - 2, such as any value between 1:1 or 1:2 or the range value composed of the two point values, preferably 1:1.5. When the proportion of nano-silica (n-SiO2) > 66%, the recovery rate of gold and silver decreases by ≥ 25%. At this time, silanol groups will excessively adsorb Au 0 ; when the proportion of nitrated modified humic acid (N-HA) > 50%, the molybdenum grade decreases by ≥ 18%.

[0025] In some specific embodiments of the present invention, the preparation method of the nitrated modified humic acid comprises the following steps: Mix humic acid and water at a mass ratio of 1:7 - 10, after ultrasonic treatment for 30 - 60 min, remove ash, control the ash content ≤ 3%, in an ice-water bath at 0 - 5 °C, mix humic acid and concentrated nitric acid at a mass ratio of 1:6 - 8, control the system temperature < 10 °C, and carry out nitration reaction; then raise the temperature to 58 - 62 °C, add urea, urea inhibits over-oxidation, react for 4 - 8 h until the nitration degree ≥ 15% to obtain a reaction solution; wherein the nitration degree detection is by FTIR to detect the peak intensity changes of 1720 cm -1 (-COOH) and 1530 cm -1 (-NO2), and the nitration degree is calculated based on the N element content.

[0026] Adjust the pH of the reaction solution to 7 - 8 with an alkali solution, then centrifuge at 8000 - 10000 rpm for 15 - 30 min, after centrifugation, carry out dialysis for 45 - 50 h to remove free nitrate ions; finally, freeze-dry to obtain a yellow powder with a yield ≥ 85%.

[0027] In some specific embodiments of the present invention, the composite collector comprises mercaptobenzothiazole hydroxamic acid and mercaptobenzothiazole, wherein the hydroxamic acid is C7 - C9 alkyl hydroxamic acid, and the content of the hydroxamic group ≥ 90%; the purity of mercaptobenzothiazole ≥ 98%, and the sulfur content ≥ 25 wt%.

[0028] The composite collector enhances the selective adsorption of copper, molybdenum, gold and silver minerals through synergistic effects. Mercaptobenzothiazole (MBT) forms a strong chemical adsorption (adsorption energy ≤ -3.2 eV) with Cu on the surface of chalcopyrite through its mercapto group (-SH). The high stability of the S-Cu bond ensures the efficient selective collection of chalcopyrite, while reducing the mis-collection of pyrite; the hydroxamic acid chelates and coordinates with the empty d orbitals on the surface of gold and silver through the C=N-OH functional group (Au adsorption energy ≤ -2.9 eV). Its unique electron donor property can effectively overcome the surface inertness of gold and silver, and significantly enhance the adsorption capacity for fine-grained gold and silver. 2+ The unique electron donor property can effectively overcome the surface inertness of gold and silver, and significantly enhance the adsorption capacity for fine-grained gold and silver.

[0029] In some specific embodiments of the present invention, the mass ratio of the hydroxamic acid to the mercaptobenzothiazole is 1:2 - 3, such as any point value or the range value composed of two point values among 1:2 or 1:3, and preferably 1:2.5. Within this range, mercaptobenzothiazole preferentially adsorbs copper minerals to form a hydrophobic layer, while hydroxamic acid is oriented on the surfaces of gold and silver, further inhibiting the flotation of pyrite through steric hindrance effect, increasing the recovery rate of gold and silver by 30% - 40%. In addition, this compound system still maintains high activity under weak alkaline (pH 8.5 - 9.0) conditions, avoiding the inhibition of molybdenum in a strong alkaline environment, while reducing the consumption of reagents, and having both high efficiency and economy.

[0030] In some specific embodiments of the present invention, the contact angle of the composite inhibitor with pyrite is reduced by ≥40°, and the change in its contact angle with molybdenite is ≤5°, which is applicable to the flotation separation of sulfide ores containing precious metals.

[0031] In some specific embodiments of the present invention, the adsorption energy of the composite collector to Au is ≤ - 2.9 eV, and the adsorption energy to CuFeS2 is ≤ - 3.2 eV; within the range of pH = 8 - 10, the fluctuation of the adsorption rate of gold and silver is ≤5%; it is applicable to the flotation separation of copper - molybdenum - gold - silver ores.

[0032] The second aspect of the present invention provides a step - by - step enrichment flotation method for copper - molybdenum - gold - silver sulfide ores, which uses the above - mentioned flotation reagents and includes the following steps: Grind the original copper - molybdenum - gold - silver - sulfur ore and add water to prepare a pulp. Adjust the pH value of the pulp to 8.5 - 10, and add 80 - 120 g / t of the composite collector thereto to obtain a copper - molybdenum - gold - silver bulk flotation concentrate and tailings. Carry out step - by - step three - stage roughing inhibition - activation separation on the copper - molybdenum - gold - silver bulk flotation concentrate to obtain a roughing concentrate and roughing tailings. Add 20 - 30 g / t of the composite collector to the roughing tailings and carry out two - stage cleaning to obtain a cleaning concentrate and cleaning tailings. Mix the cleaning concentrate and the roughing concentrate to obtain a copper - molybdenum - gold - silver concentrate, and mix the cleaning tailings and the roughing tailings to obtain sulfur - containing tailings.

[0033] In some specific embodiments of the present invention, in the three-stage roughing inhibition-activation separation process of the steps, different masses of a composite inhibitor are added in the first roughing stage, the second roughing stage, and the third roughing stage. The mass ratio of the composite inhibitor added in the three stages is: 4-6:2-4:1-3, such as any point value or a range value composed of any two point values among 4:2:1, 4:2:2, 4:3:1, 4:3:2, 4:4:1, 4:4:2, 4:4:3, 5:2:1, 5:2:2, 5:3:1, 5:3:2, 5:4:1, 5:4:2, 5:4:3, 6:2:1, 6:2:2, 6:3:1, 6:3:2, 6:4:1, 6:4:2, 6:4:3; Before performing the second roughing, a molybdenum activator is added, and the stirring time is ≥2 min to mix evenly; during the two-stage cleaning process, the pH value of the system is controlled to be 8.0-8.5.

[0034] In some specific embodiments of the present invention, the Cu content in the copper-molybdenum-gold-silver bulk flotation concentrate is ≥15%, the Mo content is ≥0.5%, the Au content is ≥1 g / t, and the Ag content is ≥30 g / t.

[0035] In some specific embodiments of the present invention, the Cu content in the copper-molybdenum-gold-silver concentrate is ≥25%, the Mo content is ≥1.2%, the Au content is ≥10 g / t, and the Ag content is ≥150 g / t, and the sulfur content is ≤5%; in the copper-molybdenum-gold-silver concentrate, the Cu recovery rate is ≥90%, the Mo recovery rate is ≥85%, the Au recovery rate is ≥80%, and the Ag recovery rate is ≥75%; the sulfur inhibition rate is ≥93%.

[0036] The features and properties of the present invention are further described in detail below in conjunction with examples.

[0037] Example 1 This example provides a stepwise enrichment flotation method for copper-molybdenum-gold-silver sulfide ore. The process is as Figure 1 shown. The mineral raw material in this example is a copper-molybdenum-gold-silver-sulfur polymetallic ore in a certain place in Inner Mongolia. The main metal mineral composition is: chalcopyrite, molybdenite, native gold, native silver, pyrite, and the gangue minerals are mainly quartz and feldspar. The original ore grade: Cu 1.8 g / t, Mo 0.6 g / t, Au 1.5 g / t, Ag 40 g / t, S 20 g / t. It mainly includes the following steps: (1) Reagent preparation: Preparation of composite inhibitor: Humic acid and deionized water were mixed at a mass ratio of 1:10 and sonicated for 30 minutes at 40 kHz and 600 W to fully disperse and remove ash (control ash content ≤ 3%). Subsequently, under the condition of an ice-water bath at 0 - 5 °C, 100 g of pretreated humic acid was slowly added to 500 mL of concentrated nitric acid, and the temperature was strictly controlled below 10 °C to inhibit side reactions. After the nitration reaction was heated to 60 ± 2 °C, 10 g of urea was added as an antioxidant and the reaction was carried out for 4 hours. During this period, the characteristic peak intensities of 1720 cm -1 (-COOH) and 1530 cm -1 (-NO2) were detected by FTIR to ensure that the nitration degree ≥ 15% (calculated based on the N element content).

[0038] After the reaction, the pH was adjusted to 7 - 8 with NaOH, and insoluble impurities were removed by centrifugation at 8000 rpm for 15 min. Then, it was dialyzed and purified for 48 hours until the conductivity < 50 μS / cm. Finally, it was freeze-dried to obtain a yellow powder-like N-HA product with a yield ≥ 85%, a nitro content of 5.8 wt%, and a carboxyl content of 4.7 mmol / g.

[0039] Meanwhile, highly active nano-silica (n-SiO2) with a specific surface area of 620 m² / g and a silicon hydroxyl density of 4.0 OH / nm² was selected as the composite component.

[0040] N-HA and n-SiO2 were mixed at an optimized mass ratio of 1:1.5, with a ball-to-material ratio of 5:1, a rotation speed of 300 rpm, and a time of 30 min using mechanical ball milling to prepare the composite inhibitor.

[0041] Preparation of composite collector: Mercaptobenzothiazole with a purity of 98.5% and C8 alkylhydroxamic acid with a content of 92% were compounded at a mass ratio of 2.5:1 to obtain the composite collector.

[0042] (2) Bulk flotation of copper, molybdenum, gold, silver, and sulfur: The raw ore was ground to 80% passing - 0.074 mm, and the pulp pH was adjusted to 9.0 with Na2CO3. 80 g / t of the composite collector was added to obtain the bulk flotation concentrate and tailings of copper, molybdenum, gold, and silver.

[0043] (3) Separation of copper, molybdenum, gold, silver, and sulfur: The bulk flotation concentrate of copper, molybdenum, gold, and silver was subjected to a stepped three-stage roughing inhibition-activation separation process. 150 g / t, 90 g / t, and 60 g / t of the composite inhibitor were added in the first, second, and third stages of roughing respectively. Then, 40 g / t of molybdenum activator (NH4)2MoO4 was added before the second stage of roughing, and the stirring time was 3 min. After the stepped three-stage roughing inhibition-activation separation process, the roughing concentrate and roughing tailings were obtained; Add 20 g / t of composite collector to the roughly selected tailings and conduct two rounds of fine selection. Control the pH value during the fine selection process to be 8.3 to prepare fine concentrate and fine tailings. Mix the fine concentrate and the roughly selected concentrate to obtain copper-molybdenum-gold-silver concentrate, and mix the fine tailings and the roughly selected tailings to obtain sulfur-containing tailings.

[0044] Example 2 This example provides a cascade enrichment flotation method for copper-molybdenum-gold-silver sulfide ore. The process is as Figure 1 shown. The mineral raw material in this example is a copper-molybdenum-gold-silver-sulfur polymetallic ore in a certain place in Inner Mongolia. The main metal mineral composition is: chalcopyrite, molybdenite, native gold, native silver, pyrite, and the gangue minerals are mainly quartz and feldspar. The original ore grade: Cu 1.6 g / t, Mo 0.5 g / t, Au 1.3 g / t, Ag 37 g / t, S 25 g / t. It mainly includes the following steps: (1) Reagent preparation: Preparation of composite inhibitor: Mix humic acid and deionized water in a mass ratio of 1:10, and perform ultrasonic treatment at 40 kHz and 600 W for 30 minutes to fully disperse and remove ash (control the ash content ≤ 3%). Subsequently, under the condition of an ice-water bath at 0 - 5 °C, slowly add 100 g of pretreated humic acid to 500 mL of concentrated nitric acid, and strictly control the temperature below 10 °C to inhibit side reactions. After the nitrification reaction temperature rises to 60 ± 2 °C, add 10 g of urea as an antioxidant and react for 4 hours. During this period, monitor the characteristic peak intensities of 1720 cm -1 (carboxyl group) and 1530 cm -1 (nitro group) in real time by FTIR to ensure that the nitrification degree ≥ 15% (calculated based on the N element content).

[0045] After the reaction ends, adjust the pH to 7 - 8 with NaOH, set the centrifugation speed at 8000 rpm for 15 min to remove insoluble impurities, and then purify by dialysis for 48 hours until the conductivity < 50 μS / cm. Finally, freeze-dry to obtain a yellow powder-like N-HA product with a yield ≥ 85%, a nitro content of 5.8 wt%, and a carboxyl content of 4.7 mmol / g.

[0046] At the same time, select highly active nano-silica (n-SiO2) with a specific surface area of 620 m² / g and a silicon hydroxyl density of 4.0 OH / nm² as the composite component.

[0047] Mix N-HA and n-SiO2 in an optimized mass ratio of 1:2, with a ball-to-material ratio of 5:1, a rotation speed of 300 rpm, and a time of 30 min using mechanical ball milling to prepare the composite inhibitor.

[0048] Preparation of composite collector: Mercaptobenzothiazole with a purity of 98.5% and C8 alkyl hydroxamic acid with a content of 92% were compounded at a mass ratio of 2.5:1 to obtain the composite collector.

[0049] (2) Bulk flotation of copper, molybdenum, gold, silver and sulfur: The original ore was ground to 80% passing -0.074mm, and the pulp pH value was adjusted to 9.0 with Na2CO3. 80 g / t of the composite collector was added to obtain the bulk flotation concentrate and tailings of copper, molybdenum, gold, silver and sulfur.

[0050] (3) Separation operation of copper, molybdenum, gold, silver and sulfur: The bulk flotation concentrate of copper, molybdenum, gold, silver and sulfur was subjected to a stepped three - stage roughing inhibition - activation separation process. 150 g / t, 90 g / t and 60 g / t of the composite inhibitor were added in the first roughing, the second roughing and the third roughing respectively. Then, 40 g / t of molybdenum activator (NH4)2MoO4 was added before the second roughing, and the stirring time was 3 min. After the stepped three - stage roughing inhibition - activation separation process, the roughing concentrate and the roughing tailings were obtained; 20 g / t of the composite collector was added to the said roughing tailings, and two - stage cleaning was carried out, controlling the pH value at 8.3 during the cleaning process to prepare the cleaning concentrate and the cleaning tailings; The cleaning concentrate and the roughing concentrate were mixed to obtain the concentrate of copper, molybdenum, gold and silver, and the cleaning tailings and the roughing tailings were mixed to obtain the sulfur - containing tailings.

[0051] Comparative Example 1 This comparative example provides a flotation separation method for copper - molybdenum - gold - silver sulfide ore. The other conditions of this comparative example are the same as those of Example 1, except that: the ratio of N - HA to n - SiO2 in the composite inhibitor is 2:1.5; The ratio of mercaptobenzothiazole to C8 alkyl hydroxamic acid in the composite collector is 2.5:1.5.

[0052] The comparison results of the recovery rates of copper, molybdenum, gold and silver obtained in Examples 1 - 2 and Comparative Example 1 are shown in Table 1.

[0053] Table 1. Comparison results of the recovery rates of copper, molybdenum, gold and silver

[0054] According to the experimental results, by comparing the copper and molybdenum grades and recovery data of Example 1, Example 2 and the comparative example, the superiority of the step enrichment flotation method is verified. In terms of copper enrichment effect, Example 1 performs the best, with a final concentrate copper grade of 26.7g / t and a recovery rate of 89%, which is significantly higher than 24.32g / t and 87.69% of the comparative example. The recovery rate of molybdenum also shows the same trend. The final concentrate molybdenum grade of Example 1 is 1.5g / t and the recovery rate is 84%, which are both better than 1.25g / t and 80.36% of the comparative example. This shows that by optimizing the ratio of the composite depressor (N-HA and n-SiO2) and the composite collector (sulfur-benzothiazole and CS alkylhydroxylamine), the separation efficiency of the target mineral can be effectively improved.

[0055] Further analysis revealed that the difference between Example 1 (N-HA:n-SiO2=1:1.5) and Example 2 (N-HA:n-SiO2=1:2) is mainly reflected in the reagent ratio. The copper recovery rate of Example 1 is higher, while the molybdenum mixed flotation recovery rate of Example 2 is slightly better (87.55% vs 87%), which may be related to the weakening of the inhibition of molybdenum after increasing the N-HA ratio in the latter. At the same time, the increase in the proportion of CS alkylhydroxylamine in its collector may also enhance the molybdenum capture capacity. This phenomenon shows that the ratio of the reagent needs to be adjusted according to the characteristics of the target mineral: if copper is the main mineral, the ratio of Example 1 can be used; if molybdenum recovery needs to be taken into account, the optimization direction of Example 2 can be referred to.

[0056] The comparative example did not use the optimized reagent ratio, so its grade and recovery rate were significantly lower than those of the two examples, which highlights the importance of adding inhibitors and activators in stages in the step enrichment flotation method. Through the step inhibition (150g / t→90g / t→60g / t) and selective activation in the roughing stage, this method achieves efficient separation of minerals. In future industrial applications, it is recommended to adjust the reagent ratio in real time in combination with the fluctuation of ore composition, and use monitoring methods such as FTIR to ensure reaction stability, so as to maximize economic benefits.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A flotation reagent for copper-molybdenum-gold-silver sulfide ore, characterized in that, The medicament includes a composite inhibitor and a composite collector; The composite inhibitor includes nitrification-modified humic acid and nano-silica; The composite collector includes mercaptobenzothiazole hydroxamic acid and mercaptobenzothiazole.

2. The flotation reagent for copper-molybdenum-gold-silver sulfide ore according to claim 1, wherein The composite inhibitor is formed by mechanically chemically activating and compounding the nitrification-modified humic acid and the nano-silica; The nitro content of the nitrification-modified humic acid (N-HA) is ≥5.2 wt%, and the carboxyl content is ≥4.5 mmol / g; The nano-silica (n-SiO2) has a mesoporous structure, a specific surface area of ≥600 m² / g, and a surface silicon hydroxyl density of ≥3.8 OH / nm²; The mass ratio of the nitrification-modified humic acid to the nano-silica is 1:1 - 2.

3. A copper-molybdenum-gold-silver sulfide ore flotation reagent according to claim 1, characterized in that, The preparation method of the nitrification-modified humic acid includes the following steps: Mix humic acid and water at a mass ratio of 1:7 - 10, after ultrasonic treatment for 30 - 60 min, in an ice-water bath at 0 - 5 °C, mix the humic acid and concentrated nitric acid at a mass ratio of 1:6 - 8, control the system temperature <10 °C, and carry out a nitrification reaction; then raise the temperature to 58 - 62 °C, add urea, and react for 4 - 8 h until the nitrification degree is ≥15% to obtain a reaction solution; Adjust the pH of the reaction solution to 7 - 8 with an alkali solution, then centrifuge at 8000 - 10000 rpm for 15 - 30 min, and carry out dialysis for 45 - 50 h after centrifugation; finally, freeze-dry to obtain a yellow powder with a yield of ≥85%.

4. A copper-molybdenum-gold-silver sulfide ore flotation reagent according to claim 1, characterized in that, The mass ratio of the hydroxamic acid to the mercaptobenzothiazole is 1:2 - 3; The hydroxamic acid is a C7 - C9 alkyl hydroxamic acid, and the hydroxamic group content is ≥90%; The purity of the mercaptobenzothiazole is ≥98%, and the sulfur content is ≥25 wt%.

5. A copper-molybdenum-gold-silver sulfide ore flotation reagent according to claim 1, characterized in that, The contact angle of the composite inhibitor on pyrite is reduced by ≥40°, and the change in the contact angle on molybdenite is ≤5°, which is suitable for the flotation separation of sulfide ores containing precious metals.

6. A copper-molybdenum-gold-silver sulfide ore flotation reagent according to claim 1, characterized in that, The adsorption energy of the composite collector on Au is ≤ - 2.9 eV, and the adsorption energy on CuFeS2 is ≤ - 3.2 eV; in the pH range of 8 - 10, the fluctuation of the gold and silver adsorption rate is ≤5%; it is suitable for the flotation separation of copper-molybdenum-gold-silver ores.

7. A stepwise enrichment flotation method for copper-molybdenum-gold-silver sulfide ore, characterized in that: Using the copper-molybdenum-gold-silver sulfide ore flotation medicament described in any one of claims 1 - 6, the steps include: Grind the original copper-molybdenum-gold-silver-sulfur ore and add water to prepare a pulp; Adjust the pH value of the pulp to 8.5 - 10, and add 80 - 120 g / t of the composite collector to obtain a copper-molybdenum-gold-silver bulk flotation concentrate and tailings; Carry out staged three-stage roughing inhibition - activation separation on the copper-molybdenum-gold-silver bulk flotation concentrate to obtain a roughing concentrate and roughing tailings, add 20 - 30 g / t of the composite collector to the roughing tailings, and carry out two-stage cleaning to obtain a cleaning concentrate and cleaning tailings; Mix the cleaning concentrate and the roughing concentrate to obtain a copper-molybdenum-gold-silver concentrate, and mix the cleaning tailings and the roughing tailings to obtain sulfur-containing tailings.

8. A stepwise enrichment flotation method for copper-molybdenum-gold-silver sulfide ore according to claim 7, characterized in that: The process of three-stage roughing inhibition-activation separation of the steps is to add different masses of composite inhibitors in the three stages of roughing I, roughing II, and roughing III. The mass ratio of the composite inhibitors added in the three stages is: 4-6:2-4:1-3; before carrying out the roughing II, a molybdenum activator is added, and the stirring time is ≥2 min and it is mixed evenly; during the two-stage cleaning process, the pH value of the system is controlled to be 8.0-8.

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9. A stepwise enrichment flotation method for copper-molybdenum-gold-silver sulfide ore according to claim 7, characterized in that: The Cu content in the copper-molybdenum-gold-silver bulk flotation concentrate is ≥15%, the Mo content is ≥0.5%, the Au content is ≥1 g / t, and the Ag content is ≥30 g / t.

10. A stepwise enrichment flotation method for copper-molybdenum-gold-silver sulfide ore according to claim 7, characterized in that: The Cu content in the copper-molybdenum-gold-silver concentrate is ≥25%, the Mo content is ≥1.2%, the Au content is ≥10 g / t, and the Ag content is ≥150 g / t, and the sulfur content is ≤5%; the Cu recovery rate in the copper-molybdenum-gold-silver concentrate is ≥90%, the Mo recovery rate is ≥85%, the Au recovery rate is ≥80%, and the Ag recovery rate is ≥75%; the sulfur inhibition rate is ≥93%.

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