Lead depressant in copper-lead mixed concentrate separation flotation and its preparation method and application

Abstract

The present application provides a lead depressant in the separation flotation of copper-lead mixed concentrate and its preparation method and application, including: using β-cyclodextrin as a raw material and a modifier for esterification to obtain modified β-cyclodextrin; the modifier is a cyclic anhydride formed by a dicarboxylic acid; 50 to 100 parts of modified β-cyclodextrin and 10 to 20 parts of anhydrous sodium silicate are mixed uniformly by weight to obtain a lead depressant. The lead depressant prepared in the present application uses anhydrous sodium silicate and modified β-cyclodextrin as the main components, avoiding the shortcomings of the traditional dichromate toxicity and environmental pollution; modified β-cyclodextrin and anhydrous sodium silicate can improve the selectivity for lead ore; the lead depressant of the present application is used under weakly alkaline conditions to avoid the problem of equipment corrosion under acidic conditions. In addition, the lead depressant provided in the present application also has the characteristics of low cost, easy storage, good inhibition effect, small usage, and no pollution to the concentrate after flotation.

Description

Technical Field

[0001] The present application relates to the technical field of mineral flotation, and in particular to a lead depressant in the separation flotation of copper-lead mixed concentrate, and a preparation method and application thereof. Background Art

[0002] In nature, there are many types of copper minerals that have been identified, but it is reported that only a dozen of them have industrial application value. According to the nature of geochemistry, copper and lead belong to the copper-type ion structure, and copper metal belongs to the sulfur-loving element family. Therefore, copper minerals and lead minerals in nature mostly appear in the form of copper sulfide ores and lead sulfide ores. Copper minerals can be divided into primary copper sulfide ores (such as chalcopyrite), secondary copper sulfide ores (such as chalcocite) and copper oxide ores (such as malachite) according to their chemical composition and genesis. Among copper sulfide ores, the main and more common ones are chalcopyrite and chalcocite. Galena (PbS), a primary ore, is the main component mineral of lead sulfide ores, and galena is widely distributed.

[0003] Ores containing copper and lead sulfide are called complex sulfide ores. The mineral composition of such ores is extremely complex, the symbiotic relationship between minerals is dense, the content of valuable components fluctuates widely, the structure is diverse, and the embedded particle size varies widely. They are difficult to beneficiate ores, and their mineralization conditions have a controlling influence on the selectivity of the ores. For the treatment of such ores, very complex beneficiation processes are often used.

[0004] For complex copper-lead ores where the minerals are unevenly embedded or densely intergrown, since the surface properties of copper and lead minerals are similar and their floatability is extremely similar, the copper and lead ores are generally mixed for flotation to obtain a copper-lead mixed concentrate, and then the copper concentrate and the lead concentrate are separated. The methods for separating the copper concentrate and the lead concentrate include the "lead suppression and copper floating" method and the "copper suppression and lead floating" method. The general principle is: when the lead content in the ore is much higher than that of copper, lead should be suppressed and copper should be floated; conversely, when the copper content is close to or more than that of lead, copper should be suppressed and lead should be floated.

[0005] The existing methods for suppressing lead and copper flotation include two categories: inorganic lead inhibitors and organic lead inhibitors. One type of inorganic lead inhibitor is dichromate, which has little effect on the flotation of copper minerals and is one of the most studied agents. However, the pH value of dichromate must be strictly controlled when it is used, and hexavalent chromium is highly toxic and will pollute the environment; another type of inorganic lead inhibitor is represented by sulfite or pyrophosphate, but sulfite and pyrophosphate need to be used under acidic slurry conditions, which has the defects of corroding equipment and affecting stable production.

[0006] Carboxymethyl cellulose is the most commonly used organic lead inhibitor. Organic lead inhibitors are easy to control, but have the disadvantage of poor selectivity. Summary of the invention

[0007] The present application provides a lead depressant in the flotation of a copper-lead mixed concentrate separation, and a preparation method and application thereof, in order to solve the problems of high toxicity, equipment corrosion when used under acidic conditions, and poor selectivity of the lead depressant in the existing copper-lead mixed concentrate separation flotation.

[0008] In a first aspect, the present application provides a method for preparing a lead depressant in the separation flotation of a copper-lead mixed concentrate, comprising: using β-cyclodextrin as a raw material and esterifying it with a modifier to obtain modified β-cyclodextrin; the modifier is a cyclic acid anhydride formed by a dicarboxylic acid; and uniformly mixing 50 to 100 parts of the modified β-cyclodextrin with 10 to 20 parts of anhydrous sodium silicate by weight to obtain the lead depressant.

[0009] In the preparation method of the lead inhibitor of the present application, β-cyclodextrin is used as a raw material, and a cyclic acid anhydride is reacted to obtain a modified β-cyclodextrin containing carboxyl and hydroxyl groups in the molecule, and the carboxyl groups on the modified β-cyclodextrin and the PbOH on the surface of the lead ore are used to obtain a modified β-cyclodextrin. + Electrostatic interaction is generated between the hydroxyl groups on the modified β-cyclodextrin and the HPbO on the surface of the lead ore. 2- Hydrogen bonding occurs, and the holes and hydroxyl groups of modified β-cyclodextrin interact with the Pb on the surface of lead ore. 2+ Chelation allows the modified β-cyclodextrin to be adsorbed on the surface of the lead ore. The surface of the modified β-cyclodextrin adsorbed on the surface of the lead ore contains hydroxyl and carboxyl groups, which form a layer of water film on the surface of the lead ore, resulting in the lead ore being inhibited from floating, while the modified β-cyclodextrin has no effect on the floating of the copper ore, thereby achieving the separation of copper and lead in the flotation of the copper-lead mixed concentrate.

[0010] Anhydrous sodium silicate can react with lead ions on the surface of lead ore to generate hydrophilic lead silicate to form a water film, which increases the hydrophilicity of the lead ore and inhibits the floatability of the lead ore. The synergistic effect of anhydrous sodium silicate and modified β-cyclodextrin can enhance the inhibitory effect on the lead ore. The lead inhibitor prepared by mixing modified β-cyclodextrin and anhydrous sodium silicate, the method of the present application uses β-cyclodextrin as a raw material, has the advantages of low raw material price and easy acquisition, and the method of preparing the lead inhibitor of the present application is easy to operate, has few synthesis steps, and is easy to purify.

[0011] The lead inhibitor prepared in the present application has anhydrous sodium silicate and modified β-cyclodextrin as main components, avoiding the shortcomings of traditional dichromate, such as high toxicity and environmental pollution; and the carboxyl and hydroxyl groups on the modified β-cyclodextrin are combined with ions and lead salt ions on the surface of the lead ore, and the holes of the modified β-cyclodextrin can also include or complex lead salt ions and lead ions to inhibit the floatability of the lead ore without affecting the floating of the copper ore, and sodium silicate and lead ions can also form water-soluble lead silicate to form a water film on the surface of the lead ore to inhibit the floating of the lead ore, and the modified β-cyclodextrin and anhydrous sodium silicate can improve the selectivity for the lead ore; the lead inhibitor of the present application is used under weakly alkaline conditions, thereby avoiding the problem of equipment corrosion under acidic conditions.

[0012] Optionally, the structural formula of the modifier is:

[0013]

[0014] Among them, R is n=1~8.

[0015] Optionally, the above-mentioned esterification of β-cyclodextrin as a raw material with a modifier to obtain modified β-cyclodextrin comprises the following steps:

[0016] S101, adding β-cyclodextrin and a modifier into a reaction container, and mixing them evenly to obtain a substrate mixed system;

[0017] S102, heating the substrate mixture system to 85-92° C. in a water bath, adding concentrated sulfuric acid to the substrate mixture system, and stirring the reaction for 5-10 minutes;

[0018] S103, after the reaction is completed, water is quickly added to the reaction solution, cooled to room temperature and then filtered;

[0019] S104. Take the filter cake obtained by filtration in S103, recrystallize it with a polar protic solvent, filter it again, take the filter cake, and dry it at a constant temperature of -0.06 to -0.09 MPa and 40 to 50° C. for 1 to 2 hours to obtain modified β-cyclodextrin.

[0020] Optionally, the molar ratio of β-cyclodextrin to the modifier is 1:7 to 1:8.4;

[0021] The concentration of concentrated sulfuric acid is 95-98%, and the amount of concentrated sulfuric acid used is 0.5-1% of the mass of the substrate mixed system. In the present application, concentrated sulfuric acid is a catalyst, which plays the role of destroying the hydrogen bonds between the hydroxyl groups of β-cyclodextrin and dehydrating.

[0022] Optionally, the polar protic solvent is one or more of water, methanol, ethanol, propanol or isopropanol.

[0023] In a second aspect, the present application provides a lead depressant for separation and flotation of a copper-lead mixed concentrate, the lead depressant being prepared by the method of the first aspect; wherein the structural formula of the modified β-cyclodextrin is:

[0024]

[0025] Wherein, R1, R2, R3, R4, R5, R6, R7 are hydroxyl groups or

[0026] R is n=1~8.

[0027] The lead depressant in the separation and flotation of the copper-lead mixed concentrate provided by the present application has the characteristics of β-cyclodextrin having holes that can complex or include lead ions and the characteristics of the modified groups that are easy to complex the lead ions and lead salt ions on the surface of the lead ore. The modified β-cyclodextrin can be quickly complexed or combined with the lead ions on the surface of the lead ore by utilizing the hydrophilicity of the hydroxyl and carboxyl groups and the characteristics of the holes of β-cyclodextrin itself, so that the modified β-cyclodextrin can be attached to the surface of the lead ore and form a hydrophilic film to inhibit the floating of the lead ore during flotation; anhydrous sodium silicate forms hydrophilic lead silicate with the surface of the lead ore, which can further inhibit the flotation of the lead ore. Therefore, the lead depressant of the present application is composed of modified β-cyclodextrin as the main component and anhydrous sodium silicate, which has the characteristics of being easily soluble in water, easy to prepare, low cost, non-toxic, and also has the characteristics of short precipitation time.

[0028] Optionally, the lead inhibitor further includes 15 to 25 parts of aluminum sulfate. When aluminum sulfate is added to the lead inhibitor, aluminum ions in the aluminum sulfate can be hydrolyzed in a solution, especially under weak alkaline conditions, to form aluminum hydroxide, and the colloidal precipitate produced after the hydrolysis of aluminum sulfate can effectively adsorb and flocculate lead ore particles, thereby accelerating the precipitation of the lead ore.

[0029] In a third aspect, the present application provides an application of a lead depressant in the separation flotation of a copper-lead mixed concentrate, including: the lead depressant is added by preparing the lead depressant into a solution with a mass concentration of 1 to 10% and then adding the solution.

[0030] The present application applies a lead depressant to the separation flotation of a copper-lead mixed concentrate. The lead depressant has a good inhibitory effect on lead ore and can replace the traditional dichromate which is highly toxic and pollutes the environment.

[0031] In a fourth aspect, the present application provides a method for using a lead depressant in the flotation separation of a copper-lead mixed concentrate, wherein the lead depressant is added during the roughing, concentrating and scavenging processes of the flotation separation process of the copper-lead mixed concentrate; the flotation separation process includes one roughing, three concentrating processes and one scavenging process.

[0032] The lead depressant in the separation flotation of the copper-lead mixed concentrate of the present application has the advantages of no pollution to the environment, small dosage, high selectivity for lead ore and good depressant performance during use.

[0033] Optionally, the flotation separation process comprises:

[0034] a) Based on the dry weight of each ton of copper-lead mixed concentrate, calcium oxide is added into the ball mill, and the copper-lead mixed concentrate and water are added into the ball mill in a ratio of 1:1 for grinding, until the grinding fineness of the material discharged from the ball mill is not more than 0.074 mm, accounting for 75-80%, and the pH value of the pulp is 7.0-12.0;

[0035] b) Adding lead inhibitor, collector Z200 (ethylthiocarbamate, chemical name: O-isopropyl-N-ethylthiocarbamate), and MIBC foaming agent (methyl isobutyl carbinol, chemical name: 1,3-dimethylbutanol) to the slurry, and obtaining copper rough concentrate and copper rough tailings after a rough selection; the usage amount of lead inhibitor is 100-500g / t, the usage amount of collector Z200 is 10-50g / t, and the usage amount of MIBC foaming agent is 40-60g / t;

[0036] c) The copper concentrate is obtained by three concentrations, wherein 100-300 g / t of lead inhibitor, 30-40 g / t of collector Z200 and 40-60 g / t of MIBC foaming agent are added in the first concentration; 200-400 g / t of lead inhibitor and 40-50 g / t of collector Z200 are added in the second concentration; 300-500 g / t of lead inhibitor is added in the third concentration;

[0037] d) The copper rougher tailings are subjected to a scavenging process to obtain lead concentrate, wherein 300-450 g / t of lead depressant, 30-45 g / t of collector Z200, and 50-60 g / t of MIBC foaming agent are added during the scavenging process;

[0038] e) The intermediate ores produced in each step of concentration and scavenging are returned to the previous step in sequence.

[0039] The lead depressant in the separation flotation of copper-lead mixed concentrate provided in the present application and its preparation method and application, by using modified β-cyclodextrin with introduced carboxyl groups as the main component and combining with anhydrous sodium silicate to obtain the lead depressant, has the following beneficial effects:

[0040] 1) The preparation method of the lead inhibitor provided in the present application can prepare the target compound, modified β-cyclodextrin, through a one-step reaction. It has the characteristics of short synthesis steps, easy operation, low equipment requirements, and a simple and easy-to-operate product purification method. In addition, the raw material β-cyclodextrin is cheap and easy to obtain, so the preparation cost is low.

[0041] 2) The lead inhibitor provided by the present application is non-toxic, low-cost, and environmentally friendly. The main ingredients, modified β-cyclodextrin and anhydrous sodium silicate, can form a water film on the surface of the lead ore to inhibit the floatability of the lead ore without affecting the floatability of the copper ore, and has the characteristics of good separation effect. In addition, the raw materials are easily available, and the main ingredient, modified β-cyclodextrin, is simple to prepare and easy to purify. The finished lead inhibitor is non-flammable, non-explosive, non-hazardous, and easy to store.

[0042] 3) The lead depressant provided in the present application is used under weakly alkaline conditions, thus avoiding the corrosion of equipment under acidic conditions, and has a good inhibitory effect on lead ore, good selectivity, and will not pollute the concentrate after flotation. It can completely replace dichromate and become an excellent lead ore depressant in the separation and flotation of copper-lead mixed concentrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] Figure 1 This is a closed-circuit test process flow chart provided for Experimental Example 2 of this application. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0046] In a first aspect, the present application provides a method for preparing a lead depressant in the separation flotation of a copper-lead mixed concentrate, comprising:

[0047] The modified β-cyclodextrin is prepared by esterifying β-cyclodextrin as a raw material with a modifier; the modifier is a cyclic acid anhydride formed by a dicarboxylic acid;

[0048] By weight, 50 to 100 parts of modified β-cyclodextrin and 10 to 20 parts of anhydrous sodium silicate are uniformly mixed to obtain a lead inhibitor.

[0049] Optionally, the structural formula of the modifier is:

[0050]

[0051] Among them, R is n=1~8.

[0052] Preferably, n=1-3, that is, the modifier is malonic anhydride, succinic anhydride or glutaric anhydride, because these three anhydrides are easy to obtain and inexpensive, and have short carbon chains and are stably combined with the surface of the lead ore.

[0053] In the present application, the modifier is an acid anhydride formed by a dicarboxylic acid, which will hydrolyze and open the ring during the reaction with β-cyclodextrin. After one molecule of carboxylic acid forms an ester with the hydroxyl group on the β-cyclodextrin, the carboxyl group of the other molecule becomes free. In this way, carboxyl groups are introduced into β-cyclodextrin. The acid anhydride formed by a dicarboxylic acid is used as a modifier. Compared with the acid anhydride formed by a monocarboxylic acid or a dicarboxylic acid, not only can carboxyl groups be introduced into β-cyclodextrin, but also no carboxylic acid is free after the reaction to cause waste of resources, and the reaction selectivity is high. Therefore, the acid anhydride formed by a dicarboxylic acid is selected as a modifier, which has the advantage of high atomic utilization.

[0054] Optionally, the structure of the modifier is specifically as follows:

[0055] wait.

[0056] Optionally, in another possible implementation, the method for preparing the lead inhibitor comprises the following steps:

[0057] S101, adding β-cyclodextrin and a modifier into a reaction container, and mixing them evenly to obtain a substrate mixed system;

[0058] S102, heating the substrate mixture system to 85-92° C. in a water bath, adding concentrated sulfuric acid to the substrate mixture system, and stirring the reaction for 5-10 minutes;

[0059] S103, after the reaction is completed, quickly add 2 to 5 times the volume of water to the reaction solution, cool to room temperature and then filter;

[0060] S104. Take the filter cake obtained by filtration in S103, recrystallize it with a polar protic solvent, filter it again, take the filter cake, and dry it at a constant temperature of -0.06 to -0.09 MPa and 40 to 50° C. for 1 to 2 hours to obtain modified β-cyclodextrin.

[0061] S105. By weight, 50 to 100 parts of modified β-cyclodextrin, 15 to 25 parts of aluminum sulfate and 10 to 20 parts of anhydrous sodium silicate are uniformly mixed to obtain a lead inhibitor.

[0062] The method of the present application has short synthesis steps and is easy to operate. The reaction raw materials are cheap and readily available. No other organic solvents are used in the reaction process, which is easy to separate and purify. The concentrated sulfuric acid used in the reaction process can also be recovered and reused, so it has the characteristics of low cost. The post-treatment process of the reaction is easy to operate and almost no waste solvent is generated.

[0063] In the present application, aluminum sulfate is also added to the lead inhibitor. The aluminum ions in the aluminum sulfate can be hydrolyzed in the solution to form hydrophilic aluminum hydroxide. The aluminum hydroxide and the lead ions on the surface of the lead ore are combined with electrostatic force or hydrogen bonds to form a water film, thereby exerting an inhibitory effect; and the colloidal precipitate produced after the hydrolysis of aluminum sulfate can effectively adsorb and flocculate the lead ore particles, thereby accelerating the precipitation of the lead ore.

[0064] Optionally, the molar ratio of β-cyclodextrin to modifier is 1:7 to 1:8.4; the concentration of concentrated sulfuric acid is 95 to 98%, and the amount of concentrated sulfuric acid is 0.5 to 1% of the mass of the substrate mixed system. In the present application, concentrated sulfuric acid is a catalyst to destroy the hydrogen bonds between β-cyclodextrin hydroxyl groups and dehydrate them.

[0065] Optionally, the polar protic solvent is one or more of water, methanol, ethanol, propanol or isopropanol.

[0066] In a second aspect, the present application provides a lead depressant for separation flotation of a copper-lead mixed concentrate, comprising anhydrous sodium silicate and a modified β-cyclodextrin prepared by the method of the first aspect, wherein the modified β-cyclodextrin has the structural formula:

[0067]

[0068] Wherein, R1, R2, R3, R4, R5, R6, R7 are hydroxyl groups or R is n = 1 to 8;

[0069] By weight, the modified beta-cyclodextrin is 50 to 100 parts, and the anhydrous sodium silicate is 10 to 20 parts.

[0070] In the present application, the main body of β-cyclodextrin has the characteristics of "hydrophobic inside and hydrophilic outside", the carboxyl and hydroxyl groups in the modified β-cyclodextrin can be combined with the surface of the lead ore through electrostatic action or hydrogen bonding, and the hydroxyl groups outside the modified β-cyclodextrin can be combined with water molecules by hydrogen bonding to form a water film, and the hole structure of the β-cyclodextrin main body can be complexed with the ions on the surface of the lead ore, and the modified β-cyclodextrin molecules can be combined with the surface of the lead ore, thereby increasing the hydrophilicity of the lead ore; anhydrous sodium silicate can form a hydrophilic lead silicate with the lead ions on the surface of the lead ore to form a water film. Therefore, the lead inhibitor provided in the present application increases the hydrophilicity of the lead ore and inhibits the floatability of the lead ore by combining the inhibitor with the surface of the lead ore to form a water film, and the anhydrous sodium silicate and the modified β-cyclodextrin can synergistically enhance the inhibitory effect on the lead ore.

[0071] Optionally, the lead inhibitor further comprises 15 to 25 parts of aluminum sulfate.

[0072] In the present application, aluminum sulfate is also added to the lead inhibitor. The aluminum ions in the aluminum sulfate can be hydrolyzed in the solution to form hydrophilic aluminum hydroxide. The aluminum hydroxide and the lead ions on the surface of the lead ore are combined with electrostatic force or hydrogen bonds to form a water film, thereby exerting an inhibitory effect; and the colloidal precipitate produced after the hydrolysis of aluminum sulfate can effectively adsorb and flocculate the lead ore particles, thereby accelerating the precipitation of the lead ore.

[0073] Optionally, the flotation separation process comprises:

[0074] a) Based on the dry weight of each ton of copper-lead mixed concentrate, calcium oxide is added into the ball mill, and the copper-lead mixed concentrate and water are added into the ball mill in a ratio of 1:1 for grinding, until the grinding fineness of the material discharged from the ball mill is not more than 0.074 mm, accounting for 75-80%, and the pH value of the pulp is 7.0-12.0;

[0075] b) adding lead inhibitor, collector Z200 and MIBC foaming agent to the slurry, and obtaining copper rough concentrate and copper rough tailings after a rough selection; the usage amount of lead inhibitor is 100-500g / t, the usage amount of collector Z200 is 10-50g / t, and the usage amount of MIBC foaming agent is 40-60g / t;

[0076] c) The copper concentrate is obtained by three concentrations, wherein 100-300 g / t of lead inhibitor, 30-40 g / t of collector Z200 and 40-60 g / t of MIBC foaming agent are added in the first concentration; 200-400 g / t of lead inhibitor and 40-50 g / t of collector Z200 are added in the second concentration; 300-500 g / t of lead inhibitor is added in the third concentration;

[0077] d) The copper rougher tailings are subjected to a scavenging process to obtain lead concentrate, wherein 300-450 g / t of lead depressant, 30-45 g / t of collector Z200, and 50-60 g / t of MIBC foaming agent are added during the scavenging process;

[0078] e) The intermediate ores produced in each step of concentration and scavenging are returned to the previous step in sequence.

[0079] In the present application, before the roughing step, the copper-lead mixed concentrate needs to be de-doped. Optionally, the de-doping method is to use stirring washing de-doping or activated carbon de-doping.

[0080] The stirring, washing and drug removal steps are as follows: add water to the copper-lead mixed concentrate to be floated at a solid-liquid ratio of 1:1 to 1:2 to form a slurry, stir at a speed of 300 to 400 rpm for 0.5 to 1.5 hours, and then filter. After filtration, wash the filter cake three times with clean water 1.2 to 2 times the mass of the copper-lead mixed concentrate to complete the drug removal.

[0081] Activated carbon dedoping is to add 1000-1400g / t activated carbon to the copper-lead mixed concentrate to be floated, and then stir at a speed of 600-800rpm for 10-30min to complete the dedoping.

[0082] In a specific example, the drug removal treatment can also adopt at least one of: re-grinding drug removal, sodium sulfide drug removal, sodium sulfide and activated carbon combined drug removal, and heating drug removal.

[0083] The present invention is further described in detail below with reference to the embodiments.

[0084] Embodiment 1:

[0085] A method for preparing a lead depressant in the separation flotation of a copper-lead mixed concentrate comprises the following steps:

[0086] 1) adding β-cyclodextrin and succinic anhydride into a reaction container and mixing them evenly to obtain a substrate mixed system; wherein the molar ratio of β-cyclodextrin to succinic anhydride is 1:7.8;

[0087] 2) The substrate mixture system was heated to 85° C. in a water bath, and concentrated sulfuric acid was added to the substrate mixture system, and stirred for 10 min; the concentration of the concentrated sulfuric acid was 98%, and the amount of the concentrated sulfuric acid was 0.5% of the mass of the substrate mixture system.

[0088] 3) After the reaction is completed, quickly add 3 times the volume of water to the reaction solution, cool to room temperature and then filter;

[0089] 4) Taking the filter cake obtained by filtration in step 3), recrystallizing with water, filtering again, taking the filter cake, and drying it at a constant temperature of -0.06Mpa and 40°C for 2h to obtain modified β-cyclodextrin.

[0090] 5) Take 75 parts of modified β-cyclodextrin and 15 parts of anhydrous sodium silicate by weight and mix them evenly to obtain a lead inhibitor.

[0091] Embodiment 2:

[0092] A method for preparing a lead depressant in the separation flotation of a copper-lead mixed concentrate comprises the following steps:

[0093] 1) adding β-cyclodextrin and malonic anhydride into a reaction container and mixing them evenly to obtain a substrate mixed system, wherein the molar ratio of β-cyclodextrin to malonic anhydride is 1:8.4;

[0094] 2) The substrate mixture system was heated to 92° C. in a water bath, and concentrated sulfuric acid was added to the substrate mixture system, and stirred for 5 minutes; the concentration of the concentrated sulfuric acid was 96%, and the amount of the concentrated sulfuric acid was 0.8% of the mass of the substrate mixture system.

[0095] 3) After the reaction is completed, water twice the volume of the reaction solution is quickly added to the reaction solution, cooled to room temperature and then filtered;

[0096] 4) The filter cake obtained by filtration in step 3) is recrystallized with methanol, filtered again, and the filter cake is dried at a constant temperature of -0.09 MPa and 50° C. for 1 h to obtain modified β-cyclodextrin.

[0097] 5) Take 100 parts of modified β-cyclodextrin and 10 parts of anhydrous sodium silicate by weight and mix them evenly to obtain a lead inhibitor.

[0098] Embodiment 3:

[0099] A method for preparing a lead depressant in the separation flotation of a copper-lead mixed concentrate comprises the following steps:

[0100] 1) adding β-cyclodextrin and glutaric anhydride into a reaction container and mixing them evenly to obtain a substrate mixed system, wherein the molar ratio of β-cyclodextrin to glutaric anhydride is 1:7;

[0101] 2) The substrate mixture system was heated to 87° C. in a water bath, and concentrated sulfuric acid was added to the substrate mixture system, and stirred for 10 min; the concentration of the concentrated sulfuric acid was 95%, and the amount of the concentrated sulfuric acid was 1% of the mass of the substrate mixture system.

[0102] 3) After the reaction is completed, quickly add 4 times the volume of water to the reaction solution, cool to room temperature and then filter;

[0103] 4) Taking the filter cake obtained by filtration in step 3), recrystallizing with ethanol, filtering again, taking the filter cake, and drying it at a constant temperature of -0.06Mpa, 40-50°C for 1-2h to obtain modified β-cyclodextrin.

[0104] 5) Take 75 parts of modified β-cyclodextrin and 15 parts of anhydrous sodium silicate by weight and mix them evenly to obtain a lead inhibitor.

[0105] Embodiment 4:

[0106] A method for preparing a lead depressant in the separation flotation of a copper-lead mixed concentrate, which is different from Example 1 in that:

[0107] During the mixing process of step 5), 22 parts of aluminum sulfate were also added.

[0108] Embodiment 5:

[0109] A method for using a lead depressant in the separation flotation of a copper-lead mixed concentrate comprises the following steps:

[0110] 1) Based on the dry weight of each ton of copper-lead mixed concentrate, calcium oxide is added into the ball mill, and the copper-lead mixed concentrate and water are added into the ball mill in a ratio of 1:1 for grinding, until the grinding fineness of the material discharged from the ball mill is no more than 0.074 mm, accounting for 75-80%, and the pH value of the pulp is 9.0;

[0111] 2) Adding the lead inhibitor, collector Z200 and MIBC foaming agent prepared in Example 1 to the ore pulp, and obtaining a rough copper concentrate and a rough copper tailings after a rough separation; the amount of the lead inhibitor is 500 g / t, the amount of the collector Z200 is 50 g / t, and the amount of the MIBC foaming agent is 40 g / t;

[0112] 3) The copper concentrate is obtained by three concentrations, wherein 300 g / t of lead inhibitor, 40 g / t of collector Z200 and 40-60 g / t of MIBC foaming agent are added in the first concentration; 400 g / t of lead inhibitor and 50 g / t of collector Z200 are added in the second concentration; 300 g / t of lead inhibitor is added in the third concentration;

[0113] 4) The copper rougher tailings are subjected to a scavenging process to obtain lead concentrate, wherein 450 g / t of lead depressant, 45 g / t of collector Z200, and 60 g / t of MIBC foaming agent are added during the scavenging process;

[0114] 5) The intermediate ores produced in each step of concentration and sweeping are returned to the previous step in sequence.

[0115] Embodiment 6:

[0116] A method for using a lead depressant in the separation flotation of a copper-lead mixed concentrate, which is different from Example 5 only in that the lead depressant used in the first roughing, third cleaning and second scavenging steps is the one prepared by Example 4.

[0117] Embodiment 7:

[0118] A method for using a lead depressant in the separation flotation of a copper-lead mixed concentrate comprises the following steps:

[0119] 1) adding β-cyclodextrin and a modifier into a reaction container and mixing them evenly to obtain a substrate mixed system; wherein the molar ratio of β-cyclodextrin to succinic anhydride is 1:7.8;

[0120] 2) The substrate mixture system was heated to 85° C. in a water bath, and concentrated sulfuric acid was added to the substrate mixture system, and stirred for 10 min; the concentration of the concentrated sulfuric acid was 98%, and the amount of the concentrated sulfuric acid was 0.5% of the mass of the substrate mixture system.

[0121] 3) After the reaction is completed, water 5 times the volume of the reaction solution is quickly added to the reaction solution, cooled to room temperature and then filtered;

[0122] 4) Taking the filter cake obtained by filtration in step 3), recrystallizing with water, filtering again, taking the filter cake, and drying it at a constant temperature of -0.06Mpa and 40°C for 2h to obtain modified β-cyclodextrin.

[0123] 5) Take 75 parts of modified β-cyclodextrin and 15 parts of anhydrous sodium silicate by weight and mix them evenly to obtain a lead inhibitor.

[0124] 6) Add water to the copper-lead mixed concentrate to be floated at a solid-liquid ratio of 1:2 to make a slurry, stir at a speed of 400 rpm for 0.5 h, and then filter. After filtration, wash the filter cake three times with clean water twice the mass of the copper-lead mixed concentrate to complete the drug removal.

[0125] 7) Based on the dry weight of each ton of copper-lead mixed concentrate, calcium oxide is added into the ball mill, and the copper-lead mixed concentrate and water are added into the ball mill in a ratio of 1:1 for grinding, until the grinding fineness of the material discharged from the ball mill is no more than 0.074 mm, accounting for 75-80%, and the pH value of the slurry is 9.0;

[0126] 8) Adding the lead inhibitor, collector Z200 and MIBC foaming agent prepared in Example 1 to the ore pulp, and obtaining a rough copper concentrate and a rough copper tailings after a rough separation; the amount of the lead inhibitor is 500 g / t, the amount of the collector Z200 is 50 g / t, and the amount of the MIBC foaming agent is 40 g / t;

[0127] 9) The copper rough concentrate is subjected to three concentrations to obtain copper concentrate, wherein 300 g / t of lead inhibitor, 40 g / t of collector Z200, and 40-60 g / t of MIBC foaming agent are added in the first concentration; 400 g / t of lead inhibitor and 50 g / t of collector Z200 are added in the second concentration; and 300 g / t of lead inhibitor is added in the third concentration;

[0128] 10) The copper rougher tailings are subjected to a scavenging process to obtain lead concentrate, wherein 450 g / t of lead depressant, 45 g / t of collector Z200, and 60 g / t of MIBC foaming agent are added during the scavenging process;

[0129] 11) The intermediate ores produced in each step of concentration and sweeping are returned to the previous step in sequence.

[0130] Comparative Example 1:

[0131] A method for using a lead depressant in the separation flotation of a copper-lead mixed concentrate, which is different from Example 5 only in that the lead depressant used in the first roughing, third cleaning and first scavenging steps is aluminum sulfate.

[0132] Comparative Example 2:

[0133] A method for using a lead depressant in the separation flotation of a copper-lead mixed concentrate, which is different from Example 5 only in that the lead depressant used in the first roughing, third cleaning and first scavenging steps is modified β-cyclodextrin.

[0134] Comparative Example 3:

[0135] A method for using a lead depressant in the separation flotation of a copper-lead mixed concentrate, which is different from Example 5 only in that the lead depressant used in the first roughing, third cleaning and first scavenging steps is anhydrous sodium silicate.

[0136] Test Example 1:

[0137] Actual mineral flotation test (copper-lead ore)

[0138] Test method: The raw material is a copper-lead mixed concentrate, in which the copper grade is 4.79% and the lead grade is 36.35%. Copper mainly exists in the form of chalcopyrite, and lead mainly exists in the form of galena; the gangue minerals are mainly silicate minerals. The experiment was carried out in an XFG type hanging tank flotation machine, the speed of the flotation machine was 1650rpm, 2.0g of copper-lead mixed concentrate was taken, ultrasonically vibrated for 5min, and then put into a 40mL flotation tank, 30mL of distilled water was added, and the pH of the pulp was adjusted to 9-10 after stirring for 1min, and then the lead depressant prepared in Example 1 and Example 4 of this application was added in an amount of 500g / t (mixed concentrate), and then the collector Z200 was added in an amount of 35g / t (mixed concentrate) after stirring for 5min, and finally 40g / t (mixed concentrate) of MIBC foaming agent was added, and after stirring for 1min, the foam was scraped, and the foam product and the minerals in the tank were filtered, dried, and weighed. Under the same other conditions, the same amount of potassium dichromate was added as a control group. Each test case has 3 parallel cases, and the average value is taken. The lead grade and lead recovery rate in the copper concentrate obtained by roughing were determined, and the results are shown in Table 1.

[0139] Table 1

[0140] Example 1 Example 4 Control group Lead grade% 10.75 8.40 11.02 Lead recovery rate % 4.96 3.87 5.03

[0141] From the results of Example 1 and the control group, it can be seen that the inhibitor of the present application has a slightly better lead inhibition effect than the potassium dichromate control group, and the results of Example 4 show that after adding aluminum sulfate on the basis of the inhibitor of the present application, the lead inhibition effect is significantly improved. The above data show that the lead inhibitor of the present application can effectively inhibit the lead ore in the copper-lead mixed concentrate and reduce the content of lead ore in the copper concentrate, and also show that the lead inhibitor of the present application has good selectivity.

[0142] Test Example 2:

[0143] Closed circuit test

[0144] Test method: The raw materials are the same as those in Test Example 1. The closed-circuit test process is shown in Figure 1 The lead depressants in the test group were selected from the lead depressants prepared in Examples 1 to 4 of the present invention, and the control group was selected from the same amount of potassium dichromate. The grades of copper and lead in the concentrate obtained by flotation and the recovery rates of copper and lead were determined, and the selectivity index I was used to evaluate the separation effect of copper and lead:

[0145]

[0146] Where ε 1Cu , ε 1Pb is the recovery rate of copper and lead in copper concentrate; ε 2Cu , ε 2Pb is the recovery rate of copper and lead in lead concentrate. The results are shown in Table 2.

[0147] Table 2

[0148]

[0149]

[0150] It can be seen from the selectivity coefficient shown in Table 2 that the selectivity of the lead depressant prepared by the method of the present application is higher than that of the traditional potassium dichromate depressant, and the selectivity coefficient of Example 4 is higher than that of Examples 1 to 3, Comparative Examples 1 to 3 and the control group. The results of Comparative Examples 1 and 3 show that the separation effects of aluminum sulfate alone and anhydrous sodium sulfate alone are extremely poor, and the results of Comparative Example 1 show that the separation effect of modified β-cyclodextrin alone is unsatisfactory, but worse than the results of Examples 1, 4 and the potassium dichromate control group. Through the above results analysis, the lead depressant of the present application, the anhydrous sodium silicate and modified β-cyclodextrin contained in the formula can improve the separation effect of copper-lead concentrate, and the selectivity is better than potassium dichromate; the results of Example 4 show that adding aluminum sulfate on the basis of the lead depressant of the present application can improve the separation effect.

[0151] It should be noted that, in the present invention, concentrations, ratios, etc. not specifically described are all weight concentrations, weight ratios, etc., which are commonly used writing habits by those skilled in the art, and therefore will not be described in detail in the present invention.

[0152] It should be noted that in the present invention, the detailed steps of some operations are not described in detail, but belong to the prior art known to those skilled in the art, so they will not be repeated here.

[0153] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing a lead depressant in the separation flotation of a copper-lead mixed concentrate, characterized in that: include: Using β-cyclodextrin as a raw material and a modifier to undergo esterification to obtain modified β-cyclodextrin; the modifier is a cyclic acid anhydride formed by a dicarboxylic acid; By weight, 50 to 100 parts of the modified β-cyclodextrin and 10 to 20 parts of anhydrous sodium silicate are uniformly mixed to obtain a lead inhibitor; The modified β-cyclodextrin is prepared by esterifying β-cyclodextrin as a raw material with a modifier, comprising: S101, adding β-cyclodextrin and a modifier into a reaction container, and mixing them evenly to obtain a substrate mixed system; S102, heating the substrate mixture system to 85-92° C. in a water bath, adding concentrated sulfuric acid to the substrate mixture system, and stirring the reaction for 5-10 minutes; S103, after the reaction is completed, quickly add 2 to 5 times the volume of water to the obtained reaction solution, cool to room temperature and then filter; S104, taking the filter cake obtained by filtration in S103, recrystallizing with a polar protic solvent, filtering again, taking the filter cake, and drying it at a constant temperature of -0.06 to -0.09 MPa and 40 to 50° C. for 1 to 2 hours to obtain modified β-cyclodextrin; The molar ratio of the β-cyclodextrin to the modifier is 1:7-1:8.4; the concentration of the concentrated sulfuric acid is 95-98%, and the amount of the concentrated sulfuric acid is 0.5-1% of the mass of the substrate mixing system.

2. The method for preparing a lead depressant in separation flotation of a copper-lead mixed concentrate according to claim 1, characterized in that: The structural formula of the modifier is: Among them, R is , n=1~8.

3. The method for preparing a lead depressant in separation flotation of a copper-lead mixed concentrate according to claim 1, characterized in that: The polar protic solvent is one or more of water, methanol, ethanol, propanol or isopropanol.

4. A lead depressant for separation flotation of copper-lead mixed concentrate, characterized in that: The lead inhibitor comprises a lead inhibitor prepared by the method according to any one of claims 1 to 3, and the structural formula of the modified β-cyclodextrin is: Wherein, R1, R2, R3, R4, R5, R6, R7 are hydroxyl groups or ; R is , n=1~8.

5. The lead depressant in the separation flotation of copper-lead mixed concentrate according to claim 4, characterized in that: The lead inhibitor also includes 15 to 25 parts of aluminum sulfate.

6. Use of the lead depressant in the separation flotation of copper-lead mixed concentrate according to claim 4 or 5, characterized in that: The lead inhibitor is added in the following manner: the lead inhibitor is prepared into a solution with a mass concentration of 1-10% and then added.

7. A method for using the lead depressant in the separation flotation of copper-lead mixed concentrate according to claim 4 or 5, characterized in that: The lead depressant is added during the roughing, cleaning and scavenging of the flotation separation process of the copper-lead mixed concentrate; The flotation separation process includes one roughing selection, three cleaning selections and one scavenging selection.

8. The method for using the lead depressant in the separation flotation of the copper-lead mixed concentrate according to claim 7, characterized in that: The steps of the flotation separation process are: a) Based on the dry weight of each ton of copper-lead mixed concentrate, calcium oxide is added into the ball mill, and the copper-lead mixed concentrate and water are added into the ball mill in a ratio of 1:1 for grinding, until the grinding fineness of the material discharged from the ball mill is no more than 0.074mm, accounting for 75-80%, and the pH value of the pulp is 7.0-12.0; b) adding lead inhibitor, collector Z200 and MIBC foaming agent to the slurry, and obtaining a copper concentrate and a copper tailings after a roughing process; the amount of the lead inhibitor is 100-500 g / t, the amount of the collector Z200 is 10-50 g / t, and the amount of the MIBC foaming agent is 40-60 g / t; c) The copper rough concentrate is subjected to three concentrations to obtain a copper concentrate, wherein 100-300 g / t of lead inhibitor, 30-40 g / t of collector Z200, and 40-60 g / t of MIBC foaming agent are added in the first concentration; 200-400 g / t of lead inhibitor and 40-50 g / t of collector Z200 are added in the second concentration; and 300-500 g / t of lead inhibitor is added in the third concentration; d) The copper rough tailings are subjected to a scavenging process to obtain lead concentrate, wherein 300-450 g / t of lead depressant, 30-45 g / t of collector Z200, and 50-60 g / t of MIBC foaming agent are added during the scavenging process; e) The intermediate ores produced in each step of the above-mentioned concentration and scavenging are returned to the previous step in sequence.

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