A lignin-based combination inhibitor and its use for separating calcium-containing gangue minerals

Abstract

The application discloses a lignin-based combined depressant and application of the depressant in separating calcium-containing gangue minerals. The calcium-containing gangue mineral depressant comprises sulfomethylated depolymerized alkali lignin and carboxymethyl cellulose salt, has excellent selective inhibition effect on calcium-containing gangue minerals such as fluorite and calcite, has strong inhibition capacity, and is easy to be degraded under natural conditions, and cannot cause environmental pollution.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of floatation reagent, in particular to a kind of calcium gangue mineral inhibitor, and also relates to its application in scheelite flotation separation, belongs to the technical field of mineral processing. BACKGROUND

[0002] As an important strategic resource, tungsten mainly exists in the form of scheelite and wolframite in nature. With the gradual decrease of wolframite resources, the development and utilization of scheelite (CaWO4) has attracted much attention. However, scheelite is often associated with fluorite and calcite. Due to the calcium ions on the surface of the minerals, scheelite, fluorite and calcite exhibit similar chemical properties to collectors and are difficult to separate. Therefore, an effective inhibitor is necessary for the separation of the three minerals.

[0003] In the scheelite flotation industry, inorganic inhibitors (including silicates and phosphates) are often used to inhibit calcite and fluorite. However, they have low selectivity, require large amounts, and cause serious environmental pollution. When used in large amounts, scheelite can also be inhibited by inorganic inhibitors. Organic inhibitors have the advantages of wide sources, high efficiency, non-toxicity, and designable structure. They have become a popular research topic. Currently, lignosulfonate, an organic inhibitor, has been widely used and developed in the flotation separation of calcium and magnesium minerals. However, lignosulfonate has a large molecular weight and low functional group content, resulting in weak interaction between lignosulfonate and minerals. Therefore, lignosulfonate has poor inhibitory ability for calcium and magnesium minerals. Sodium carboxymethyl cellulose, an organic inhibitor, exhibits strong inhibitory ability for fluorite and calcite, but when the dosage is increased, it can form hydrophobic association on the surface of scheelite, thereby causing certain inhibition to scheelite. Therefore, it is urgent to explore a high-selectivity, high-inhibition, and environmentally friendly inhibitor.

[0004] Recently, researchers have paid more attention to composite inhibitors. Chinese patent CN113477409A discloses a scheelite flotation combined inhibitor and its use method, which still uses sodium hexametaphosphate as one of the components of the inhibitor, which is not conducive to environmental protection. Chinese patent CN107433230A discloses a scheelite flotation inhibitor, which consists of 40% liquid sodium silicate, 20% sulfuric acid, 15% copper sulfate, 10% carboxymethyl cellulose, and 15% lead nitrate. The presence of heavy metal ions such as lead in the flotation inhibitor causes serious environmental pollution. SUMMARY

[0005] In view of the defects of the calcium-containing gangue mineral depressant used in the scheelite flotation process in the prior art, a first object of the present application is to provide a calcium-containing gangue mineral depressant mainly comprising sulfomethylated depolymerized alkali lignin and carboxymethyl cellulose salt, which has excellent selective inhibition effect on calcium-containing gangue minerals such as fluorite and calcite, and the inhibition effect is strong, and the depressant is easy to degrade under natural conditions and does not cause environmental pollution.

[0006] A second object of the present application is to provide an application of the calcium-containing gangue mineral depressant in the flotation separation of scheelite and calcium-containing gangue, and in the scheelite flotation separation process, the calcium-containing gangue mineral depressant has a small addition amount, has a significant selective inhibition effect on calcium-containing gangue minerals such as fluorite and calcite, greatly improves the flotation recovery rate and grade of scheelite, and the calcium-containing gangue mineral depressant is environmentally friendly and does not cause environmental pollution.

[0007] In order to achieve the above technical objects, the present application provides a calcium-containing gangue mineral depressant comprising sulfomethylated depolymerized alkali lignin and carboxymethyl cellulose salt.

[0008] The calcium-containing gangue mineral depressant provided by the present application mainly consists of sulfomethylated depolymerized alkali lignin and carboxymethyl cellulose salt, and the carboxymethyl cellulose salt has strong inhibition ability on fluorite and calcite, but when used in the scheelite flotation process, the concentration of the carboxymethyl cellulose salt is slightly high, which can form a hydrophobic association on the surface of the scheelite and also has a certain inhibition ability on the scheelite, so the selectivity of the carboxymethyl cellulose salt alone is poor, which can affect the flotation of the scheelite and is difficult to realize the flotation separation of the scheelite and calcium-containing gangue minerals such as fluorite and calcite. The sulfomethylated depolymerized alkali lignin cannot well inhibit fluorite and calcite, but a large amount of researches show that after the sulfomethylated depolymerized alkali lignin and the carboxymethyl cellulose salt are used together, the inhibition effect on fluorite and calcite is strengthened, and after the amount is increased, the floatability of the scheelite is not affected, so the flotation separation efficiency of the scheelite can be greatly improved.

[0009] As a preferred scheme, the calcium-containing gangue mineral depressant consists of the following mass percentage components: sulfomethylated depolymerized alkali lignin 50-85%; carboxymethyl cellulose salt 15-50%. Within the feasible ratio range of the sulfomethylated depolymerized alkali lignin and the carboxymethyl cellulose salt, as the mass ratio of the sulfomethylated depolymerized alkali lignin increases, the flotation recovery rate of the scheelite generally shows an upward trend, but the recovery rate of gangue minerals such as fluorite and calcite will also decrease, so a further preferred scheme is that the calcium-containing gangue mineral depressant consists of the following mass percentage components: sulfomethylated depolymerized alkali lignin 80-85%; carboxymethyl cellulose salt 15-20%.

[0010] As a preferred scheme, the sulfomethylated depolymerized alkali lignin is prepared by the following method: alkali lignin is subjected to oxidation treatment to obtain depolymerized alkali lignin; the depolymerized alkali lignin is subjected to a hydroxymethylation reaction with formaldehyde under alkaline conditions to obtain hydroxymethylated depolymerized alkali lignin; and the hydroxymethylated depolymerized alkali lignin is subjected to a sulfonation reaction with a sulfite salt to obtain the sulfomethylated depolymerized alkali lignin. After the oxidation depolymerization treatment of alkali lignin, the subsequent methylation and sulfonation processes are more favorable, and the sulfonation degree of alkali lignin can be greatly improved. Research shows that the higher the sulfonation degree of alkali lignin, the more obvious the improvement in the inhibition ability of the alkali lignin to calcium-containing gangue minerals.

[0011] As a preferred scheme, the oxidation treatment is performed at a temperature of 85-95℃ for 1-3 hours.

[0012] As a preferred scheme, the hydroxymethylation reaction is performed at a pH value of 8-10 at a temperature of 70-80℃ for 0.5-1.5 hours.

[0013] As a preferred scheme, the sulfonation reaction is performed at a temperature of 85-95℃ for 4-6 hours.

[0014] As a preferred scheme, hydrogen peroxide with a concentration of 20-40% is used as the oxidizing agent in the oxidation treatment, and the amount of the hydrogen peroxide is 15%-20% of the mass of the alkali lignin. The amount of the oxidizing agent can control the degree of the oxidation depolymerization of the alkali lignin. The hydrogen peroxide is, for example, industrial hydrogen peroxide (35%).

[0015] As a preferred scheme, the amount of formaldehyde used in the hydroxymethylation reaction is 1.5-1.75 times the mass of the alkali lignin. The amount of the formaldehyde relative to the alkali lignin is excessive, which can ensure the introduction of more hydroxymethyl groups.

[0016] As a preferred scheme, the mass ratio of the sulfite salt to the alkali lignin is 0.8-1.2:1 in the sulfonation reaction. The sulfite salt is, for example, sodium sulfite.

[0017] As a preferred scheme, the carboxymethyl cellulose salt is sodium carboxymethyl cellulose.

[0018] The application further provides a use of the calcium-containing gangue mineral inhibitor in the flotation separation of scheelite and calcium-containing gangue.

[0019] As a preferred scheme, the calcium-containing gangue mineral includes fluorite and / or calcite.

[0020] As a preferred scheme, the flotation separation uses sodium oleate as a scheelite collector, and the amount of the sodium oleate in the ore pulp system is 50-100 mg / L, and the amount of the calcium-containing gangue mineral inhibitor in the ore pulp system is 10 mg / L-50 mg / L.

[0021] The application provides a method for using the calcium-containing gangue mineral inhibitor for scheelite flotation separation, and the method comprises the following steps:

[0022] (1) grinding the scheelite ore (scheelite, fluorite and calcite) to-75 mu, and mixing the scheelite ore with water to prepare an ore pulp (the concentration is about 62.5%); (2) adjusting the pH of the ore pulp to 10-12 (hydrochloric acid and sodium hydroxide); (3) adding the calcium-containing gangue inhibitor to the ore pulp, stirring, adding a collector, and obtaining a scheelite concentrate through flotation scraping (5 min).

[0023] The preparation process of the sulfomethylated depolymerized alkali lignin is as follows: 2 g of alkali lignin, 100 mL of distilled water and 0.3 g of hydrogen peroxide (35%) are added to a three-necked flask, first, stirring in a water bath at 90 DEG C for 2 h. Then, the temperature is reduced to 75 DEG C, 3.0 g of HCHO is added to the solution, and the pH is adjusted to 9 with NaOH, and stirring for 1 h. Finally, 2 g of Na2SO3 is added, and stirring is carried out at 90 DEG C for 5 h. After the solution is cooled to room temperature, 1000 Da dialysis bag is used for dialysis to remove inorganic salts, and finally drying in a 60 DEG C oven.

[0024] Compared with the prior art, the technical scheme of the application has the beneficial technical effects:

[0025] The sulfomethylated depolymerized alkali lignin and the carboxymethyl cellulose salt used in the application have high selective inhibitory effect on calcite and fluorite, and do not affect the floatability of scheelite, so that the flotation separation efficiency of scheelite can be greatly improved.

[0026] The sulfomethylated depolymerized alkali lignin and the carboxymethyl cellulose salt used in the application have low use cost, are easy to degrade, are friendly to the environment, and have simple preparation method, so that the application is conducive to large-scale popularization and use. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 The influence of carboxymethyl cellulose sodium, sulfonated alkali lignin, sulfonated depolymerized alkali lignin and sulfomethylated depolymerized alkali lignin on the flotation recovery rate of three single minerals of scheelite, fluorite and calcite.

[0028] Figure 2 The influence of the proportion of the sulfomethylated depolymerized alkali lignin and the carboxymethyl cellulose sodium complex inhibitor on the floatability of three minerals of scheelite, fluorite and calcite.

[0029] Figure 3The concentration of the sulfomethylated depolymerized alkali lignin and sodium carboxymethyl cellulose composite inhibitor on the floatability of scheelite, fluorite and calcite three minerals.

[0030] Figure 4 The zeta potential changes of single mineral before and after the action of sulfomethylated depolymerized alkali lignin and sodium carboxymethyl cellulose composite inhibitor.

[0031] Figure 5 The single mineral flotation flow chart.

[0032] Figure 6 The mixed ore flotation flow chart. DETAILED DESCRIPTION

[0033] The technical solutions of the present application will be further described below in combination with the specific embodiments of the present application. It should be noted that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments; these embodiments are only for better understanding of the present application, rather than limiting the scope of the present application.

[0034] The preparation methods of sulfonated alkali lignin, sulfonated depolymerized alkali lignin and sulfomethylated depolymerized alkali lignin in the following examples are as follows:

[0035] The preparation method of sulfonated alkali lignin is as follows: 4g of lignin and 40mL of H2O, the solution is adjusted to pH 9, stirred at 75℃ for one hour, 4g of sodium sulfite is added, the temperature is raised to 90℃, and the reaction is continued for 3h, and then the solution is cooled to room temperature, 1000Da dialysis bag is used to remove unreacted substances and other impurities, and the filtrate is dried to obtain brown powder of sulfonated lignin (SL).

[0036] The preparation method of sulfonated depolymerized alkali lignin is as follows: 4g of lignin + 40mL of H2O, 0.6g of hydrogen peroxide (35%) is added, and the reaction is carried out at 90℃ for 2h, and then the solution is cooled and adjusted to pH 9, 4g of sodium sulfite is added, and the reaction is carried out at 90℃ for 3h, and then the solution is cooled to room temperature, 1000Da dialysis bag is used to remove unreacted substances and other impurities, and the filtrate is dried to obtain brown powder of sulfonated depolymerized lignin (SDL).

[0037] The preparation method of sulfomethylated depolymerized alkali lignin is as follows: 2g of alkali lignin, 100mL of distilled water and 0.3g of hydrogen peroxide (35%) are added to a three-necked flask, first, stirring in a 90℃ water bath for 2h. Then, the temperature is reduced to 75℃, 3.0g of HCHO is added to the solution and the pH is adjusted to 9 with NaOH, and stirring for 1h. Finally, 2g of Na2SO3 is added, and stirring is carried out at 90℃ for 5h. After the solution is cooled to room temperature, dialysis is carried out with a 1000Da dialysis bag to remove inorganic salts, and finally dried in a 60℃ oven to obtain brown powder of sulfonated depolymerized lignin (SMDL).

[0038] Example 1

[0039] In the experiment, 2 g of single mineral (scheelite, fluorite or calcite) was weighed, and three kinds of minerals were respectively experimented, 2 g each time, which was added with appropriate amount of water into a flotation tank with a volume of 30 mL for stirring for 3 min, sodium hydroxide and hydrochloric acid were added as pH adjuster to adjust the pH of the slurry to 11, and stirred for 3 min; a certain amount of depressor was added, and stirred for 3 min; sodium oleate solution was added, with a concentration of 70 mg / L, and stirred for 3 min. Finally, flotation scraping operation was carried out, and the scraping time was 5 min. The product was dried, weighed, and the recovery rate was calculated.

[0040] The effect of the dosage of sodium oleate, the collector, on the flotation recovery rate of single mineral was known from Figure 1 a, with the increase of the dosage of carboxymethyl cellulose (CMC), the recovery rates of the three minerals all decreased with the increase of the dosage of carboxymethyl cellulose (CMC), and the decrease of the recovery rate of scheelite was much smaller than that of fluorite and calcite. When the concentration of carboxymethyl cellulose (CMC) was 50 mg / L, the recovery rates of scheelite, fluorite and calcite were 61.76%, 0.00% and 8.19% respectively. Therefore, carboxymethyl cellulose (CMC) can preliminarily achieve the effective separation of scheelite from fluorite and calcite, but the selectivity for scheelite is weak, so a depressor with strong selectivity for scheelite needs to be introduced for compounding to obtain a green and efficient flotation depressor with both selectivity and inhibition capacity.

[0041] Example 2

[0042] The effect of sulfonated alkali lignin and sulfomethylated alkali lignin on the flotation recovery rate of single mineral (refer to example 1) was known from Figure 1 b, with the increase of the dosage of sulfonated alkali lignin, the recovery rates of the three minerals all decreased with the increase of the dosage of sulfonated alkali lignin SL. When the concentration of SL reached 30 mg / L, the recovery rates of scheelite, fluorite and calcite were 77.83%, 64.01% and 41.68% respectively, which indicated that the selectivity of sulfonated alkali lignin SL for scheelite was higher than that of carboxymethyl cellulose CMC, but the inhibition capacity was weak, so sulfonated alkali lignin cannot be used as an effective depressor for separating the three kinds of minerals. It was known from Figure 1 c that when the alkali lignin was first oxidized and depolymerized, and then sulfonated to obtain sulfonated depolymerized alkali lignin SDL, which was used as a depressor for the flotation of the three kinds of minerals, it was found that the recovery rates of the three minerals all decreased with the increase of the concentration of sulfonated depolymerized alkali lignin SDL. The decrease was greater than that of sulfonated alkali lignin SL. When the concentration of sulfonated depolymerized alkali lignin SDL reached 30 mg / L, the recovery rates of scheelite, fluorite and calcite were 59.88%, 39.81% and 32.4% respectively. It was known from Figure 1As shown in section d, after depolymerization of lignin, sulfonation modification was performed. It was found that the recovery rates of the three minerals decreased with increasing sulfonated polyalkali lignin (SMDL) concentration. Furthermore, the recovery rate of scheelite showed a relatively gradual increase with increasing SMDL concentration, while fluorite and calcite showed a significant decrease with increasing SMDL concentration. However, this decreasing trend was less pronounced than the decrease in recovery rate of calcium gangue when carboxymethyl cellulose (CMC) was used as an inhibitor. The sulfonation degrees of SL, SDL, and SMDL were measured to be 0.7, 1.0, and 1.7 mmol / g, respectively. Therefore, it can be concluded that the sulfonation degree has a significant impact on the flotation separation of the three minerals; the higher the sulfonation degree, the better the flotation separation effect. When the concentration of sulfonated methyl ether polylignin (SMDL) reached 30 mg / L, the recoveries of scheelite, fluorite, and calcite were 83.24%, 37.34%, and 35.62%, respectively. Therefore, SMDL can effectively separate the three minerals. Its selectivity for scheelite is much greater than that for carboxymethyl cellulose, but its inhibition ability on calcium gangue is less than that of sodium carboxymethyl cellulose (CMC). Therefore, the separation effect of sodium carboxymethyl cellulose (CMC) and sulfonated methyl ether polylignin (SMDL) when used in combination can be explored.

[0043] Example 3

[0044] In the experiment, 2g of a single mineral (scheelite, fluorite, or calcite) was weighed and added to a 30mL flotation tank along with an appropriate amount of water. The mixture was stirred for 3 minutes. Sodium hydroxide and hydrochloric acid were added to adjust the pH of the pulp to 11, and the mixture was stirred for another 3 minutes. A specific ratio of SMDL / CMC (50mg / L) was added, with a SMDL:CMC ratio of 1:1, 2:1, 3:1, 4:1, or 5:1, and the mixture was stirred for 3 minutes. A sodium oleate solution (70mg / L) was then added, and the mixture was stirred for another 3 minutes. Finally, flotation skimming was performed for 5 minutes. The product was dried, weighed, and the recovery rate was calculated.

[0045] To ensure strong inhibition and high selectivity, SMDL was combined with CMC and used in the flotation of scheelite, fluorite, and calcite. The flotation results are as follows: Figure 2 As shown. By changing the mass ratio of SMDL to CMC to 1:1, 2:1, 3:1, 4:1, and 5:1, the total inhibitor dosage was made to 50 mg / L; Figure 2In this case, with the increase of the mass ratio of SMDL, the scheelite recovery rate generally showed an upward trend. When the mass ratio of SML to CMC was 5:1, the mass fraction of SMDL / CMC was 81.23%. However, the recovery rates of fluorite and calcite decreased to 27.34% and 18.14%, respectively. Compared with single SMDL and CMC, SMDL / CMC had stronger inhibitory ability and higher selectivity for scheelite in fluorite and calcite.

[0046] Example 3

[0047] In the test, 2g of single mineral (scheelite, fluorite or calcite) was weighed and added into a flotation cell with a volume of 30mL with an appropriate amount of water for stirring for 3min. Sodium hydroxide and hydrochloric acid were added as pH adjusters to adjust the pH of the slurry to 11, and stirred for 3min. A certain proportion of SMDL / CMC was added, with a concentration of 10-50mg / L, and the proportion of SMDL: CMC was equal to 5:1, and stirred for 3min. Sodium oleate solution was added, with a concentration of 70mg / L, and stirred for 3min. Finally, the flotation scraping operation was carried out, and the scraping time was 5min. The product was dried, weighed, and the recovery rate was calculated.

[0048] The recovery rates of minerals under different SMDL / CMC dosages are shown in Table 1. Figure 3 With the increase of the dosage of SMDL / CMC, the recovery rate of scheelite changed little, and when the dosage of SMDL / CMC reached 50mg / L, the recovery rate of scheelite still remained at 81.23%. However, when the concentration of SMDL / CMC increased from 0mg / L to 50mg / L, the recovery rates of fluorite and calcite decreased significantly from 91.89% and 70.23% to only 3.63% and 14.7%, respectively. In this case, the separation of scheelite from fluorite and calcite can be achieved.

[0049] Example 4

[0050] In the test, 2g of mixed ore sample was weighed, with the proportion of scheelite: fluorite: calcite being 1:1:1, and added into a flotation cell with a volume of 30mL with an appropriate amount of water for stirring for 3min. Sodium hydroxide and hydrochloric acid were added as pH adjusters to adjust the pH of the slurry to 11, and stirred for 3min. A certain amount of SMDL / CMC was added, with a concentration of 40-50mg / L, and the proportion was 5:1, and stirred for 3min. Sodium oleate solution was added, with a concentration of 70mg / L, and stirred for 3min. Finally, the flotation scraping operation was carried out, and the scraping time was 5min, to obtain tungsten concentrate and tailings. They were dried, weighed, and the grade of WO3 in the concentrate was tested, and the recovery rate was calculated. The differences in the grade and recovery rate of tungsten concentrate under different concentrations of depressant were compared.

[0051] From Table 1, when only NaOL was added, the grade of scheelite was basically the same as the original ore, indicating that pure reliance on the collector could not achieve separation. After using SMDL / CMC, it was observed that when 40 mg / L of SMDL / CMC was added, the concentrate grade reached 32.11%, which was 10.52% higher than the original ore grade, and the recovery rate was 83.79%. When the concentration of SMDL / CMC was increased to 50 mg / L, the concentrate grade increased to 33.75%, which was 12.16% higher than the original ore, and the recovery rate was 79.33%. The results showed that SMDL / CMC could be used for the separation of scheelite from the three mixed minerals. Therefore, SMDL / CMC can be used as an inhibitor for the separation of scheelite from fluorite and calcite.

[0052] Table 1 is the flotation data of mixed ore with different inhibitor concentrations

[0053] SML / CMC concentration (mg / L) 0 40 50 WO3 grade in raw ore (%) 21.59 21.59 21.59 WO3 grade (%) after use of inhibitors 21.27 32.11 33.75 Scheelite recovery (%) 90.65 83.79 79.33

[0054] Example 5

[0055] The zeta potential of single minerals was determined by a zeta potential analyzer with a model of Zetasizer Nano ZS90. Pure mineral zeta potential measurement: 50 mg of mineral sample was dispersed in 50 m L of 0.001 mol / L KNO3 electrolyte solution, constantly stirred to form a uniform suspension. NaOH and HCl were added to adjust the pH, and 2 ml of supernatant was taken for standby. Pure mineral zeta potential measurement after reagent treatment: 50 mg of mineral sample was dispersed in 50 m L of 0.001 mol / L KNO3 electrolyte solution, constantly stirred to form a uniform suspension. NaOH and HCl were added to adjust the pH, and after mixing with the reagent for 10 minutes, the suspension was left to stand for 5 minutes. Finally, 2 m L of supernatant was taken for zeta potential determination. Each sample was measured 3 times. The average value was taken as the final value.

[0056] Figure 4 The determination of mineral zeta potential before and after SMDL / CMC treatment was studied. Figure 4 In a, the zeta potential of scheelite was negative when the pH was less than 6, indicating that the isoelectric point of scheelite was below 6. In addition, the zeta potential gradually decreased in the pH range of 2-11, and gradually increased in the pH range of 11-12. The reason for this phenomenon is that the calcium ion in the aqueous solution of scheelite is more easily dissolved than WO3 2- , resulting in a large amount of WO3 2- remaining on the surface, making the surface negatively charged. Interestingly, when the solution is greater than 11, the increase of another CaOH + formed in the solution makes the zeta potential slightly increase. As Figure 4As shown in b, fluorite has an isoelectric point of 7.7, and its Zeta potential decreases at pH 6–12. In contrast to scheelite, Fa in aqueous solution... - Compared to Ca 2+ Fluorite is more soluble in water, therefore a large amount of Ca exists on its surface. 2+ This causes the fluorite surface to carry a positive charge. Similarly, calcite has an isoelectric point of 8.9, and its zeta potential decreases as pH increases from 6 to 12. This is because calcite, in its HCO3- form, becomes positively charged. - and CO3 2- Calcite is abundant in aqueous solutions, resulting in a large number of calcium ions on its surface, which gives it a positive charge. Figure 4 In step a, the addition of SMDL / CMC resulted in a negative shift in the zeta potential of scheelite, indicating a change in its electrochemical properties. However, compared to fluorite and calcite, the shift in scheelite's zeta potential was smaller. This is because scheelite has a more negative zeta potential than fluorite and calcite, leading to a stronger electrostatic repulsion between the scheelite surface and the anionic SMDL / CMC, resulting in less adsorption of SMDL / CMC. Figure 4 As shown in b, after SMDL / CMC treatment, the Zeta potentials of both fluorite and calcite showed a significant negative shift. This is because the presence of a large number of calcium ions on the surface causes the oppositely charged SMDL / CMC to adsorb onto the surfaces of fluorite and calcite, increasing their hydrophilicity. These results are consistent with the flotation test results.

[0057] The above embodiments are only for better explaining the principles and practical applications of the present invention, so that those skilled in the art can better understand and utilize the present invention, and are not intended to limit the patent scope of the present invention. All equivalent modifications made using the content of the present invention are within the patent protection scope of the present invention.

Claims

1. A calcium-containing gangue mineral inhibitor characterised in that: Sulfomethylated depolymerized alkali lignin 50~85%; carboxymethyl cellulose salt 15~50%.

2. A calcium-containing gangue mineral inhibitor according to claim 1 characterised in that: The sulfomethylated depolymerized alkali lignin is prepared by the following method: oxidizing alkali lignin to obtain depolymerized alkali lignin; performing a hydroxymethylation reaction on the depolymerized alkali lignin under alkaline conditions to obtain hydroxymethylated depolymerized alkali lignin; and performing a sulfonation reaction on the hydroxymethylated depolymerized alkali lignin with a sulfite salt to obtain the sulfomethylated depolymerized alkali lignin.

3. The calcium-containing gangue mineral inhibitor according to claim 2, characterized in that: The oxidation treatment is performed at a temperature of 85~95℃ for 1~3 hours. The hydroxymethylation reaction is performed at a pH value of 8~10 and a temperature of 70~80℃ for 0.5~1.5 hours. The sulfonation reaction is performed at a temperature of 85~95℃ for 4~6 hours.

4. The calcium-containing gangue mineral inhibitor according to claim 2 or 3, characterized in that: In the oxidation treatment, hydrogen peroxide with a concentration of 20~40% is used as the oxidant, and the amount of hydrogen peroxide used is 15%~20% of the mass of alkali lignin. In the hydroxymethylation reaction, the amount of formaldehyde used is 1.5~1.75 times the mass of alkali lignin. In the sulfonation reaction, the mass ratio of sulfite salt to alkali lignin is 0.8~1.2:

1.

5. A calcium-containing gangue mineral inhibitor according to claim 1, characterised in that: The carboxymethyl cellulose salt is sodium carboxymethyl cellulose.

6. A calcium-containing gangue mineral inhibitor according to claim 1, characterised in that: Sulfomethylated depolymerized alkali lignin 80~85%; carboxymethyl cellulose salt 15~20%.

7. Use of a calcium-containing silicate mineral inhibitor according to any one of claims 1 to 6, characterized in that: The calcium-containing gangue mineral inhibitor is applied to the flotation separation of scheelite and calcium-containing gangue.

8. Use of a calcium-containing gangue mineral inhibitor according to claim 7, characterised in that: The calcium-containing gangue mineral includes fluorite and / or calcite.

9. Use of a calcium-containing gangue mineral inhibitor according to claim 7, characterised in that: The flotation separation uses sodium oleate as a scheelite collector, and the amount of sodium oleate used in the ore slurry system is 50~100 mg / L, and the amount of calcium-containing gangue mineral inhibitor used in the ore slurry system is 10 mg / L~50 mg / L.

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