Composite inhibitor, composite flotation reagent and method for selective flotation separation of barite and gangue

Abstract

The invention belongs to the field of mineral flotation, and particularly relates to a composite inhibitor, a composite flotation reagent and a method for selective flotation separation of barite and gangue, and the composite inhibitor comprises a component A and a component B in a weight ratio of (5-9): (1-5); wherein the component A is a product obtained by carrying out esterification reaction on a compound shown in a formula 1 (# imgabs0 #) and starch; and the component B is water glass. In the invention, the starch modified by the formula 1 is the key for realizing synergy with the component B, strengthening the gangue inhibition effect and further facilitating the separation selectivity of gangue and barite. The research shows that the formula 1 of the component A and the component proportion of the starch are further optimized, so that the network structure of the component A is further optimized, and the selective inhibition effect of the component A and the component B in barite gangue minerals is expected to be further enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to the field of barite flotation. Background Art

[0002] Barite (BaSO 4 ) is a non-metallic mineral with important industrial value. Its main component, barium sulfate, gives it high density, chemical inertness and excellent physical and chemical properties, so it is widely used in many fields such as petroleum, chemical industry, building materials, medicine and coatings. In the petroleum industry, barite is used as a weighting agent for drilling mud, which can effectively control well pressure and prevent blowouts; in the chemical industry, barite is an important raw material for the preparation of barium salts; in the building materials industry, barite is used to manufacture radiation-proof concrete and high-end building materials due to its high density and radiation shielding properties.

[0003] However, with the increasing depletion of high-grade barite resources, the development of low-grade barite has gradually become the focus of industry development. Low-grade barite is usually accompanied by calcite (CaCO 3 )、Dolomite(CaMg(CO 3 ) 2 ) and other carbonate minerals. These associated minerals have high similarities with barite in physical and chemical properties. Especially in the flotation process, their surface wettability and floatability are similar, which makes it difficult to achieve efficient separation of barite and associated minerals by traditional flotation process. In addition, silicate minerals such as mica and feldspar in low-grade ores are finely embedded and have serious mudification, which are easily activated and floated by metal ions in the pulp, further increasing the difficulty of sorting.

[0004] In flotation technology, the prior art also reports some inhibitors such as water glass, starch, carboxymethyl cellulose, starch, etc. For example, the Chinese patent document with publication number CN110102412A discloses a method for preparing high-purity fluorite powder and efficient utilization of tailings barite, and specifically records starch as an inhibitor. In addition, the Chinese patent document with publication number CN101585016A discloses a low-grade fluorite barite flotation separation method, and specifically records the use of starch, sodium sulfate, hydrochloric acid and sodium hexametaphosphate as inhibitors of barite minerals.

[0005] Although existing inhibitors can inhibit the floating of associated minerals to a certain extent, their selectivity is poor, making it difficult to achieve efficient enrichment of barite in complex mineral systems. At the same time, the use of existing inhibitors often requires a high dosage of reagents, which not only increases production costs but may also have a negative impact on the environment. Therefore, the development of an efficient and highly selective inhibitor has become the key to solving the problem of low-grade barite ore sorting. Summary of the invention

[0006] In order to solve the problem of unsatisfactory flotation selectivity of barite and gangue during barite flotation, the first object of the present invention is to provide a composite inhibitor for selective flotation separation of barite and gangue, aiming to selectively inhibit the gangue associated with barite minerals and improve the flotation grade of barite.

[0007] The second object of the present invention is to provide a composite flotation reagent comprising the composite depressant, so as to improve the selective flotation separation effect of barite and gangue.

[0008] The third object of the present invention is to provide a method for selectively flotating and separating barite and gangue, aiming at improving the flotation recovery rate and selectivity of barite.

[0009] Barite is often intercalated with gangue (mainly calcium-containing minerals and silicate minerals), and the flotation separation of the two is difficult. In addition, as the grade of barite decreases, the difficulty of its selective flotation separation increases significantly. In view of this problem, the present invention has conducted in-depth research and provided the following improvement plan:

[0010] A composite inhibitor for selectively flotating and separating barite and gangue, comprising component A and component B in a weight ratio of 5-9:1-5; wherein the component A is a product of an esterification reaction (also called a modification reaction) of a compound of formula 1 and starch; and the component B is water glass;

[0011]

[0012] Formula 1.

[0013] The present invention innovatively adopts a combination of a starch product (component A) modified by formula 1 and component B, and further coordinates the joint control of the proportions of the components. In this way, based on the interaction of hydrogen bonds between the components, the network structure of the material can be optimized, so that the gangue in the barite mineral can be highly selectively suppressed without substantially suppressing the barite, thereby facilitating the selective separation of barite and gangue.

[0014] In the present invention, the starch is at least one of corn starch and potato starch.

[0015] In the present invention, the preparation method of component A is as follows: starch and formula 1 are subjected to esterification reaction, followed by drying and dehydration to obtain component A.

[0016] In the present invention, the solvent for the esterification reaction can be water, wherein the mass ratio of starch to water is 1:10-20.

[0017] In the present invention, the weight ratio of the compound of formula 1 to starch is 1:1-10; further, it can be 1:1.5-3; and more preferably, it is 1:1.8-2.2. In the present invention, at the ratio, the synergy of the prepared component A and other components can be effectively improved, especially at the preferred ratio, which helps to further optimize the network of component A, helps to further strengthen its synergy with component B, and helps to further strengthen the capture capacity and selectivity of barite.

[0018] In the present invention, the esterification reaction time can be 0.25-1 h, and the esterification reaction temperature can be 50-100° C.

[0019] In the present invention, after the esterification reaction is completed, a dehydration treatment can be performed in advance in a medium vacuum drying oven, wherein the temperature of the dehydration stage can be 30-70°C, further can be 50-70°C, and the dehydration time can be 12-24 hours. Subsequently, drying is performed, and the drying temperature can be 80-130°C, further can be 100-130°C, and the drying time can be 3-7 hours.

[0020] In the present invention, the modification of starch by formula 1 is the key to achieve synergy with component B, strengthen the gangue inhibition effect, and thus facilitate the selectivity of gangue and barite separation. Studies have shown that further optimization of the component ratio of formula 1 of component A and starch is helpful to further optimize the network structure of component A, and is expected to further strengthen the selective inhibition effect of it and component B in barite gangue minerals.

[0021] In the present invention, the weight ratio of component A to component B is 7-8:2-3, and more preferably 8:2. Studies have shown that under the preferred ratio, the synergy of components A and B can be further enhanced, which helps to further improve the selective inhibition effect of the intergrowth of the barite.

[0022] In the present invention, the gangue includes at least one of carbonate minerals and silicate minerals.

[0023] The present invention also provides a composite flotation agent for selectively flotating and separating barite and gangue, comprising a collector and an inhibitor, wherein the inhibitor is the composite inhibitor described in the present invention.

[0024] In the present invention, the collector may be any collector known in the industry that can be used for barite collection. For example, as an optional solution, it may be a compound having a structure of Formula 2;

[0025] Formula 2

[0026] The R is a saturated or partially unsaturated carbon chain, a benzene ring or a substituted benzene ring having 10 to 20 carbon atoms, and the substituted benzene ring is a phenyl group having at least one substituent selected from the group consisting of an alkyl group, an alkoxy group, a halogen group, a nitro group and a trifluoromethyl group.

[0027] Furthermore, the collector is at least one of oleic acid and its salt (also component C), linoleic acid and its salt (also component D); preferably, oleic acid and its salt, and linoleic acid and its salt. The present invention shows that the combination of the composite inhibitor and the composite collector can further cooperate and enhance the separation selectivity of barite and gangue.

[0028] The salts of oleic acid and linoleic acid may be their respective water-soluble salts, such as sodium salts.

[0029] Furthermore, in the collector, the weight ratio of oleic acid and its salts, and linoleic acid and its salts is 5-9:1-5; preferably 6-8:2-4; more preferably 7-8:2-3. Studies have shown that at this preferred ratio, it is helpful to further cooperate with the composite inhibitor and further improve the barite collection capacity and separation selectivity.

[0030] In the present invention, the composite flotation reagent further comprises at least one other flotation aid selected from the group consisting of a pH regulator and a frother.

[0031] In the present invention, the composite flotation reagent is an inhibitor for selectively flotating and separating barite and gangue.

[0032] Preferably, the gangue includes at least one of carbonate minerals and silicate minerals.

[0033] The present invention also provides a method for selectively flotating and separating barite and gangue, wherein the mineral to be selected containing barite and gangue is subjected to flotation treatment in a flotation agent containing the composite depressant to obtain barite concentrate and gangue tailings.

[0034] In the present invention, the flotation reagent is the composite flotation reagent comprising the composite depressant and the collector as described in the present invention.

[0035] In the present invention, the flotation process and operation can be controlled based on existing means and principles. For example, the ore to be selected can be subjected to roughing treatment to obtain roughing concentrate and roughing tailings. In addition, the roughing concentrate can be further selected and the roughing tailings can be scavenged as needed.

[0036] In the present invention, the dosage of the drug can be adjusted as needed.

[0037] Preferably, in the roughing process, the dosage of the composite inhibitor is 500-2000 g / t, preferably 500-1500 g / t, more preferably 1000-1500 g / t; further preferably 1000-1200 g / t.

[0038] In the roughing process, the amount of the collector is 300-600 g / t, preferably 300-500 g / t, more preferably 400-500 g / t; further preferably 400-450 g / t.

[0039] In the present invention, the temperature during the flotation process is 0-40°C, and further can be 0-30°C.

[0040] Preferably, the pH value during the flotation process is 7.5 to 11.0, and may further be 8.5 to 9.5.

[0041] In the present invention, the composite depressant of the present invention is selected for selection during the selection process. The number of selection stages can be adjusted as needed. For example, when multi-stage selection is used, the dosage of the selection agent is reduced step by step. The reduction range can be 30-60%. The final barite concentrate is obtained in the last stage of selection, and the middlings in the selection process are returned to the previous flotation process.

[0042] In the present invention, the scavenging process uses the collector of the present invention for scavenging. The scavenged concentrate is returned to the roughing process, and the scavenged tailings are the final tailings. The scavenging collector is 10-50% of the amount of the roughing collector.

[0043] Preferably, in the selected mineral, the grade of the barite can be 20-70%, and further can be 50-70%.

[0044] In addition, the mineral to be selected may also be a fine-grained refractory mineral, and its particle size may be 5-20 μm.

[0045] Preferably, the gangue minerals in the low-grade barite ore are fine-grained carbonate minerals and silicate minerals.

[0046] In addition, the embedded particle size of the gangue mineral can be 2-10 μm, and the flotation method of the present invention also has a good inhibitory effect on the fine-grained gangue mineral.

[0047] Beneficial Effects

[0048] 1. The present invention provides a composite inhibitor comprising component A and component B, which can be combined and synergized based on the type of component A, component B and the ratio between the components to optimize the inhibition selectivity of gangue in barite, thereby facilitating the improvement of the selective separation of barite and gangue.

[0049] The inhibitor of the present invention has good inhibitory effect and selectivity and uses less dosage.

[0050] 2. The present invention innovatively combines the composite inhibitor and the collector, especially the composite collector comprising oleic acid and its salts and linoleic acid and its salts, which can further enhance the capture capacity and selectivity of barite in the flotation process and strengthen the inhibition capacity and selectivity of gangue minerals.

[0051] 3. The reagent provided by the present invention has good flotation effect under neutral and alkaline pulp conditions, has a wide tolerance to pulp pH, and is insensitive to changes in flotation pulp temperature. At lower temperatures, the flotation indicators are better, the pollution is lower, and the reagent selectivity is stronger. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The XRD diagram of the mineral to be selected in Example 1;

[0053] Figure 2 This is a closed-circuit flotation flow chart of the low-grade barite "one roughing, three fines and one sweeping" process of the present invention. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with specific embodiments and drawings.

[0055] The composite inhibitor of the present invention comprises component A and component B, wherein the component A can be obtained by modification reaction of formula 1 and starch; and component B is water glass.

[0056] In the composite inhibitor, the weight content of component A is ≥ 60%, further can be 60-90%, further can be 70-80%.

[0057] In the present invention, the water glass is Na 2 O·nSiO 2 , its modulus is 2~2.4.

[0058] In the present invention, by controlling the ratio of each agent in the composite inhibitor, the flotation result of low-grade barite can be significantly improved, and the separation effect between barite and carbonate minerals and silicate minerals can be improved.

[0059] The present invention also provides a collector, which includes at least one of oleic acid and its salt (component C) and linoleic acid and its salt (component D). The components C and D are sodium salts, potassium salts, etc. of oleic acid and linoleic acid.

[0060] The collector comprises component C and component D, wherein the weight content of component C is 60-80%, preferably 70-80%.

[0061] The gangue minerals in the low-grade barite ore must include carbonate minerals and silicate minerals, and the carbonate minerals include at least one of calcite and dolomite.

[0062] The silicate mineral is mainly mica.

[0063] In the flotation method of the present invention, the mineral to be selected and the flotation reagent containing the composite depressant and the collector can be subjected to roughing to obtain roughing concentrate and tailings.

[0064] In the present invention, the rougher concentrate can be subjected to 1 to 4 stages of concentrating as required, wherein the last stage of concentrating obtains the barite concentrate. The middlings in the concentrating stage are returned to the previous stage of flotation. In addition, the reagent in the concentrating process is the composite depressant.

[0065] In the present invention, the roughing tailings can also be subjected to scavenging treatment, wherein the scavenged tailings are final tailings, and the selected concentrate is returned to the roughing process. In the present invention, the scavenging process uses the collector of the present invention.

[0066] In the roughing process of the present invention, the dosage of the composite inhibitor is 500-2000 g / t, preferably 500-1500 g / t, and further 1000-1500 g / t.

[0067] In the roughing process of the present invention, the amount of the collector is 300-600 g / t, preferably 300-500 g / t, and further can be 400-500 g / t.

[0068] The pH value in the flotation stage may be 7.5 to 11.0, preferably 8.5 to 9.5.

[0069] The flotation solution provided by the present invention requires a pulp temperature of 0-40°C, preferably 10-30°C.

[0070] Example 1

[0071] Example 1: Low-grade barite ore from the southwest region was used for flotation experiments. Figure 1 This is the semi-quantitative analysis result of XRD of barite ore. The main useful minerals in the ore are barite, among which BaSO 4 The content is 63%, and the main gangue minerals are quartz, feldspar, mica, chlorite, calcite, dolomite, etc., among which the calcite content is about 6.56% and the mica content is about 3.75%. Table 1 shows the particle size analysis of low-grade barite ore.

[0072]

[0073] As shown in Table 1, the embedded particle size of barite and gangue minerals in the flotation samples is relatively fine, of which 99% of the barite embedded particle size is ≤75μm, more than 70% of the barite embedded particle size is ≤25μm, and nearly 50% of the barite embedded particle size is ≤10μm. Similarly, the embedded particle size of most gangue minerals such as calcite, dolomite, mica, feldspar and quartz is ≤25μm, of which more than 50% of the mica embedded particle size is ≤10μm. The gravity separation method has almost no enrichment effect, and it belongs to low-grade fine-grained barite ore that is difficult to process.

[0074] The preparation method of component A is as follows: Formula 1, starch (corn starch in this case), and deionized water are mixed and heated and stirred in a mass ratio of 1:2:20. The stirring time during the heating and stirring process is 1 hour, and the stirring temperature is 50°C. After the stirring is completed, the mixed solution is placed in a vacuum drying oven for dehydration. The vacuum drying oven temperature during the dehydration process is 50°C, and the dehydration time is 24 hours. The dehydrated mixture is placed in a drying oven at a temperature of 120°C for 5 hours. The dried sample is washed with an ethanol solution to remove Formula 1. The washed sample is dried at room temperature to obtain component A.

[0075] After obtaining ingredient A, press Figure 2 The flotation process is carried out by flotation, and the steps are as follows:

[0076] 1. Crush and grind the low-grade barite ore to a suitable particle size (-0.074 mm accounts for 85%), adjust the pulp to a pulp concentration of 35%, control the flotation pH to 8.5, and the flotation pulp temperature to 30°C.

[0077] 2. Add composite depressants to the slurry after pulping, and change the ratio of composite depressants to explore the influence of depressant type and weight content on the final flotation index (the depressant composition, ratio and results are shown in Table 2). The depressant is stirred for 10 minutes, and the dosage of the roughing composite depressant is 1000g / t.

[0078] 3. Add the combined collectors of oleic acid and linoleic acid, wherein the weight content of oleic acid is 70% and the weight content of linoleic acid is 30%, stir for 5 minutes, and the dosage of the combined collector in the roughing stage is 400g / t.

[0079] 4. Flotation separation collects concentrate and tailings, and the concentrate is concentrating. During the concentrating process, only the composite depressant in step 2 is added, and the dosage is half of that in the previous stage. During the scavenging, only the collector in step 3 is added, and the dosage is 1 / 4 of that in the previous stage.

[0080] 5. Collect barite concentrate and tailings, analyze and test to obtain the final indicators.

[0081]

[0082] Note: Compared with ingredient A1, the only difference between ingredient A is that the corn starch is not chemically modified by formula 1;

[0083] The only difference between component A2 and component A is that an equal amount of acetic acid is used to replace the formula 1.

[0084] The only difference between component A3 and component A is that an equal amount of phosphoric acid is used to replace the formula 1.

[0085] Among them, it can be seen from groups a, b, c, and d that combining component A and component B, especially in a ratio of 7~8:2~3, can optimize the network structure based on the hydrogen bonding effect of the components, and can synergistically enhance the separation selectivity of barite and gangue.

[0086] It can be seen from group b and comparison groups 1 to 6 that the grafting modification of starch using formula 1 of the present invention is helpful to form a special hydrogen bond network compared with other modification schemes and other conventional inhibitors, which helps to achieve synergy and enhance the sorting selectivity of barite and gangue.

[0087] Example 2

[0088] Compared with group b of Example 1, the only difference is that the preparation conditions of component A are changed. The experimental groups are:

[0089] Formula 1, starch (corn starch in this case) and deionized water were mixed, heated and stirred in a mass ratio of 1:2.5:25. The stirring time during the heating and stirring process was 0.25 h and the stirring temperature was 100°C. After the stirring was completed, the mixed solution was placed in a vacuum drying oven for dehydration. The vacuum drying oven temperature during the dehydration process was 60°C and the dehydration time was 20 h. The dehydrated mixture was placed in a drying oven at a temperature of 130°C for 4 h. The dried sample was washed with an ethanol solution to remove Formula 1. After washing, the sample was dried at room temperature to obtain component A. Other operations and parameters were the same as those in Group b of Example 1. After the flotation process, the flotation results were shown in Table 3.

[0090]

[0091] Example 2: BaSO can be obtained 4 The flotation results of the barite concentrate product with a grade of 91.67% and a recovery rate of 90.55% were similar to those of Group b in Example 1.

[0092] Example 3

[0093] Compared with group b of Example 1, the only difference is that the preparation conditions of component A are changed. The experimental groups are:

[0094] Formula 1, starch (potato starch in this case) and deionized water were mixed, heated and stirred in a mass ratio of 1:1.5:30. The stirring time during the heating and stirring process was 0.5h and the stirring temperature was 90°C. After the stirring was completed, the mixed solution was placed in a vacuum drying oven for dehydration. The vacuum drying oven temperature during the dehydration process was 70°C and the dehydration time was 18h. The dehydrated mixture was placed in a drying oven at a temperature of 110°C for 6h. The dried sample was washed with an ethanol solution to remove Formula 1. After washing, the sample was dried at room temperature to obtain component A. The other operations and parameters were the same as those in Group b of Example 1. After the flotation process, the flotation results are shown in Table 4.

[0095]

[0096] Example 3: BaSO can be obtained 4 The flotation results of the barite concentrate product with a grade of 92.28% and a recovery rate of 92.60% were similar to those of Group b in Example 1.

[0097] Example 4

[0098] The low-grade barite ore of Example 1 is selected, and the flotation operation steps of Example 4 are as follows:

[0099] 1. Crush and grind the low-grade barite ore to a suitable particle size (-0.074 mm accounts for 85%), adjust the pulp to a pulp concentration of 35%, control the flotation pH to 9.0, and the flotation pulp temperature to 30°C.

[0100] 2. A composite inhibitor is added to the slurry after slurry adjustment. The composite inhibitor consists of component A (same as in Example 1) and water glass. The weight content of component A is 80%, and the weight content of water glass is 20%. The inhibitor is stirred for 10 minutes. The amount of the roughing composite inhibitor is 800 g / t.

[0101] 3. Add oleic acid and linoleic acid as combined collectors, change the weight content of oleic acid and linoleic acid in the combined collector, explore the effect of the ratio of oleic acid and linoleic acid on the flotation results, stir for 5 minutes, and the dosage of the roughing combined collector is 300g / t.

[0102] 4. Flotation separation collects concentrate and tailings. The concentrate is selected. During the selection process, only composite depressants are added, and the amount used is half of that in the previous stage. During the scavenging selection, only collectors are added, and the amount used is 1 / 4 of that in the previous stage.

[0103] 5. Collect barite concentrate and tailings, analyze and test to obtain the final indicators. The structure is shown in Table 5.

[0104]

[0105] It can be seen from Table 5 that selecting oleic acid and linoleic acid as a combined collector, especially controlling the composite ratio of oleic acid to linoleic acid to be 6-8:2-4, can be combined with the agent of the present invention to further achieve synergy, which helps to further enhance the separation selectivity of barite and gangue.

[0106] Example 5

[0107] The low-grade barite ore of Example 1 was selected, and the flotation operation steps and reagent ratio of Example 5 were consistent with those of Group b of Example 1. The flotation process parameters were changed, and the experimental groups were respectively:

[0108] a: The flotation depressant in the roughing stage is 500 g / t; the dosage of the combined collector is 400 g / t, and the flotation pH is 7.5; other parameters such as the dosage ratio of the cleaning and scavenging agents and the previous flotation agents are the same as those in Group b of Example 1;

[0109] b: The flotation depressant in the roughing stage is 1500 g / t; the dosage of the combined collector is 500 g / t, and the flotation pH is 11; other parameters such as the dosage ratio of the cleaning and scavenging agents and the previous flotation agents are the same as those in Group b of Example 1;

[0110] c: The temperature of the flotation process is 10°C;

[0111] d: The temperature of the flotation process is 0°C;

[0112] The flotation results of each group are shown in Table 6. The flotation results are shown below.

[0113]

[0114] It can be seen from Table 6 that the method of the present invention can achieve excellent capture effect at a lower dosage of the agent. In addition, the method described in the present invention has a wide temperature range application requirement and can obtain good capture ability and selectivity even at low temperatures.

[0115] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A composite inhibitor for selectively flotating and separating barite and gangue, characterized in that: The invention comprises component A and component B in a weight ratio of 5-9:1-5; wherein the component A is a product of esterification reaction between a compound of formula 1 and starch; and the component B is water glass; ； Formula 1.

2. The composite inhibitor according to claim 1, characterized in that The starch is at least one of corn starch and potato starch; Wherein, the weight ratio of the compound of formula 1 to starch is 1:1-10.

3. The composite inhibitor according to claim 1 or 2, characterized in that: The weight ratio of component A to component B is 7-8:2-3; The gangue includes at least one of carbonate minerals and silicate minerals.

4. A composite flotation agent for selectively flotating and separating barite and gangue, comprising a collector and a depressant, characterized in that: The inhibitor comprises the composite inhibitor according to any one of claims 1 to 3.

5. The composite flotation reagent according to claim 4, characterized in that: The collector is a compound having a structure of formula 2; Formula 2; The R is a saturated or partially unsaturated carbon chain, a benzene ring or a substituted benzene ring having 10 to 20 carbon atoms, and the substituted benzene ring is a phenyl group having at least one substituent selected from the group consisting of an alkyl group, an alkoxy group, a halogen group, a nitro group and a trifluoromethyl group.

6. The composite flotation reagent according to claim 5, characterized in that: The collector includes oleic acid and its salts, and also includes linoleic acid and its salts; Wherein, the weight ratio of oleic acid and its salts, and linoleic acid and its salts is 5-9:1-5.

7. A method for selectively flotating and separating barite and gangue, characterized in that: The mineral to be selected containing barite and gangue is subjected to flotation treatment in a flotation agent containing the composite depressant according to any one of claims 1 to 3 to obtain a barite concentrate and a gangue tailing.

8. The method for selectively flotating and separating barite and gangue according to claim 7, characterized in that: The flotation reagent is the composite flotation reagent according to any one of claims 4 to 6.

9. The method for selectively flotating and separating barite and gangue according to claim 8, characterized in that: The flotation process includes a roughing process, wherein the dosage of the composite depressant in the roughing process is 500~2000g / t; the dosage of the collector is 300~600g / t; The temperature during flotation is 0~40℃; The pH during flotation is 7.5~11.

0.

10. The method for selectively flotating and separating barite and gangue according to claim 9, characterized in that: The flotation process also includes a process of using the composite depressant described in any one of claims 1 to 3 to beneficiate the rougher concentrate; and a process of using the collector in the composite flotation agent described in any one of claims 4 to 6 to scavenge the rougher tailings.

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