Method for removing sulfur in fluorite mixed ore

Abstract

The invention discloses a method for removing sulfur in fluorite mixed ore, which comprises the following steps: pulping the fluorite mixed ore to obtain first ore pulp; the pH of the first ore pulp is adjusted to be acidic, and second ore pulp is obtained; the second ore pulp is mixed with an oxidizing agent and a catalyst for an oxidation reaction, and oxidized fluorite mixed ore is obtained after solid-liquid separation; and the oxidized fluorite mixed ore is subjected to flotation, and desulfurized fluorite is obtained. According to the method, an oxidation-flotation combined method is adopted, hydrophilic sulfur substances on the surface of the sulphide ore in the fluorite mixed ore are efficiently oxidized into hydrophobic sulfur through an oxidation system composed of an oxidizing agent and a catalyst, oriented regulation and control of the floatability of the surface of the sulphide ore are achieved, conditions are created for effective separation of the sulphide ore and fluorite in the flotation process, and the flotation efficiency is improved. Therefore, high-purity desulfurized fluorite is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to a method for removing sulfur from fluorite mixed ore. Background Art

[0002] Fluorite is an important strategic mineral resource and is widely used in metallurgy, construction, fluorine chemical industry and other fields. High-purity hydrofluoric acid produced from fluorite is the most important basic raw material in fluorine chemical industry. High-purity hydrofluoric acid is widely used in semiconductor, electronics, photovoltaic and other industries. The production process of high-purity hydrofluoric acid has high requirements for the purity of fluorite. Sulfur impurities will seriously affect the stability of production and product purity. Among them, sulfide ores such as chalcopyrite, sphalerite, pyrite, and pyrrhotite will be converted into elemental sulfur during the acid production process, blocking the condensation pipeline and causing production suspension. In severe cases, it will cause safety accidents and greatly affect the stability of production. It is very difficult to remove impurities from fluorite in depth, and it is difficult to completely remove sulfur-containing impurities by conventional methods. At present, hydrofluoric acid production enterprises often set up elemental sulfur condensation devices in the condensation pipeline to intercept and collect elemental sulfur, but the high content of sulfide ores in fluorite concentrate produces elemental sulfur at a faster rate. After a period of production, the production needs to be stopped and cleared, affecting production efficiency. Therefore, removing sulfur-containing impurities through pretreatment before acid production can reduce the generation of elemental sulfur from the source, which can fundamentally alleviate the problem of pipeline blockage and improve production stability.

[0003] At present, the common methods for desulfurization in fluorite are magnetic separation, roasting and flotation. Magnetic separation is only effective for magnetic sulfide ores, and roasting is costly and has poor effects on trace sulfide ores, and neither is an ideal removal method. Due to the differences in the surface properties of different minerals, flotation is usually used to separate sulfide ores from fluorite. However, the sulfur content in fluorite concentrate is low and there are many hydrophilic substances on its surface. The conventional flotation method has a low recovery rate and it is difficult to deeply separate fluorite from trace sulfur. Chinese patent CN105439183A discloses a fluorite concentrate processing process, which floats the ground fluorite ore powder, adds hydrogen fluoride solution and stirs to react to obtain ore powder, and reacts the obtained ore powder with alkaline solutions such as potassium hydroxide, sodium hydroxide and calcium hydroxide to obtain the refined ore powder. The ore powder obtained by this method has a low purity, cannot meet the quality standard of acid-grade fluorite concentrate, and cannot remove trace sulfur impurities. Chinese patent CN103570053A discloses a fluorite powder finishing process, which uses an acidic hydrogen fluoride solution to treat fluorite powder containing barite, adds an alkaline solution to adjust the pH to 10-14 after filtration, and the purity of the fluorite powder can reach more than 97% after filtration and drying. Although this method can meet the quality standards, it can only remove barite impurities in a targeted manner, and the separation effect of trace sulfur impurities is poor.

[0004] The existing fluorite powder purification technology has the following problems: ① It is only effective for gangue minerals such as calcite and barite, and it is difficult to deeply remove sulfur-containing gangue minerals such as sulfide ores; ② The amount of reagents used is large, the types are many, and the cost is high; ③ The process flow is complicated. Summary of the invention

[0005] In view of the above deficiencies in the prior art, the purpose of the present invention is to provide a method for removing sulfur from fluorite mixed ore, so as to solve the technical problems of large dosage of reagents, high cost, complicated process flow and poor desulfurization effect in the existing fluorite ore purification technology.

[0006] To achieve the above object, the present invention is implemented through the following technical solutions: The present invention provides a method for removing sulfur from fluorite mixed ore, comprising the following steps: S1. Slurrying the fluorite mixed ore to obtain a first slurry; S2. adjusting the pH of the first slurry to acidic to obtain a second slurry; S3. mixing the second slurry with an oxidant and a catalyst, performing an oxidation reaction, and obtaining an oxidized fluorite mixed ore after solid-liquid separation; S4. The oxidized fluorite mixed ore is floated to obtain desulfurized fluorite concentrate.

[0007] Preferably, in step S1, the mass concentration of the first slurry is 35-65%.

[0008] Preferably, in step S2, the pH of the first slurry is adjusted to 1-3.

[0009] Preferably, in step S3, the oxidant is at least one of persulfate and hydrogen persulfate, and the catalyst is a soluble silver salt.

[0010] Preferably, in step S3, the amount of the oxidant is 80-150 g / t of the raw ore, and the amount of the catalyst is 8-20 g / t of the raw ore.

[0011] Preferably, in step S3, the reaction temperature of the oxidation reaction is 55-85° C., and the reaction time is 2-6 h.

[0012] Preferably, in step S4, the flotation process includes: S4.1. Slurrying the oxidized fluorite mixed ore to obtain a third slurry; S4.2. adjusting the pH of the third slurry to acidic to obtain a fourth slurry; S4.3. Mix the flotation reagent with the fourth slurry, and obtain desulfurized fluorite concentrate after flotation.

[0013] Preferably, in step S4.1, the mass concentration of the third slurry is 20-35%.

[0014] Preferably, in step S4.2, the pH of the third slurry is adjusted to 6-9.

[0015] Preferably, in step S4.3, the flotation reagents include a collector and a frother; the amount of the collector is 35-75 g / t of the original ore, and the amount of the frother is 15-45 g / t.

[0016] The beneficial effects of the present invention are: Aiming at the problem of difficulty in removing trace sulfur impurities in fluorite concentrate for high-purity hydrofluoric acid, the present invention uses an oxidation-flotation combined method, and uses an oxidation system composed of an oxidant and a catalyst to efficiently oxidize hydrophilic sulfur substances on the surface of sulfide ore in fluorite mixed ore into hydrophobic sulfur, thereby achieving directional regulation of the floatability of the sulfide ore surface, creating favorable conditions for subsequent flotation separation of sulfide ore and fluorite, and only needs to adopt a simple flotation process to achieve a good index of more than 97% desulfurization rate, thereby solving the problem that it is difficult to deeply remove sulfur impurities in high-purity acid-grade fluorite concentrate.

[0017] The method provided by the present invention uses fewer types of reagents, has low cost, and has a simple and controllable process flow in the process of achieving deep removal of trace sulfur-containing impurities. It can effectively solve the problem of pipeline blockage during the production of high-purity hydrogen fluoride and improve the economic benefits of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings of the embodiment are briefly introduced below.

[0019] Figure 1 The present invention is a flow chart of a method for removing sulfur from fluorite mixed ore. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The present application provides a method for removing sulfur from a fluorite mixed ore. Figure 1 As shown, the following steps are included: (1) Oxidation: Pulping the fluorite mixed ore to obtain a first slurry with a mass concentration of 35-65%, that is, the mineral mass in the first slurry accounts for 35-65% of the total mass of the slurry; adjusting the pH of the first slurry to 1-3 to obtain a second slurry; mixing the second slurry with an oxidant and a catalyst, and performing an oxidation reaction at a temperature of 55-85 °C for 2-6 hours, and obtaining an oxidized fluorite mixed ore after solid-liquid separation. The amount of the oxidant is 80-150 g / t of the original ore, and the amount of the catalyst is 8-20 g / t of the original ore. The oxidant is at least one of a persulfate and a hydrogen persulfate, for example, the persulfate can be one or more of ammonium persulfate, potassium persulfate, and sodium persulfate, and the hydrogen persulfate can be one or more of potassium hydrogen persulfate and sodium hydrogen persulfate. The catalyst is a soluble silver salt, including but not limited to silver nitrate, silver fluoride, etc.

[0022] (2) Flotation: Pulp the oxidized fluorite mixed ore to obtain a third pulp with a mass concentration of 20-35%; adjust the pH of the third pulp to 6-9 to obtain a fourth pulp; mix the flotation agent with the fourth pulp, and obtain high-purity desulfurized fluorite after flotation. The flotation agent includes a collector and a frother; the amount of the collector is 35-75 g / t of the original ore, and the amount of the frother is 15-45 g / t. The collector includes one or more of butyl xanthate, ethyl xanthate, and ethyl thiocyanate, and the frother includes one or more of methyl isobutyl carbinol (MIBC), No. 2 oil, and pine oil. During flotation, the stirring speed can be 800-1500 r / min, and the aeration volume is 0.1-0.3 m 3 / h, flotation time is 5~15 min.

[0023] The oxidation principle of the present invention is to utilize the catalytic effect of a catalyst (such as silver ions in a soluble silver salt) on an oxidant (such as hydrogen persulfate, etc.) to develop an oxidation system with extremely strong oxidizing properties, which can efficiently oxidize sulfur on the surface of sulfide ore into hydrophobic S8, S 0 The surface properties can be directional controlled by the oxidized sulfide ore particles, and the sulfur removal rate can reach more than 97%, which also shortens and simplifies the process.

[0024] In order to make the purpose, technical scheme and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below. In the following examples and comparative examples, the sulfur content in the fluorite mixed ore is 1%, so as to simulate the fluorite concentrate containing trace sulfur impurities, which is obtained by mixing fluorite with a purity of 99.1% and sulfide ore, wherein the sulfide ore is obtained by mixing pyrite, chalcopyrite and pyrrhotite in a mass ratio of 1:1:1.

[0025] Example 1 A method for removing sulfur from a fluorite mixed ore comprises the following steps: (1) Oxidation: Mix the fluorite mixed ore with ultrapure water to obtain a first slurry with a mass concentration of 35%. Add sulfuric acid to the first slurry to adjust the pH to 1 to obtain a second slurry. Add potassium persulfate in an amount of 80 g / t of the original ore to the second slurry, and add silver nitrate in an amount of 8 g / t of the original ore. Control the temperature to 55°C, stir at a stirring speed of 300 r / min for 2 h, and then filter to obtain the oxidized fluorite mixed ore.

[0026] (2) Flotation: The oxidized fluorite mixed ore was mixed with ultrapure water to obtain a third slurry with a mass concentration of 20%. Sodium hydroxide was added to the third slurry to adjust the pH to 6 to obtain a fourth slurry. Butyl xanthate was added to the fourth slurry at a rate of 35 g / t of the original ore, and then methyl isobutyl carbinol (MIBC) was added at a rate of 15 g / t of the original ore for flotation. The flotation temperature was 25°C, the stirring speed was 800 r / min, and the aeration volume was 0.1 m 3 / h, the time is 5 min. After one flotation, concentrate and tailings are obtained. The concentrate is the sulfide ore containing sulfur impurities, and the tailings is the purified fluorite concentrate.

[0027] Example 2 A method for removing sulfur from a fluorite mixed ore comprises the following steps: (1) Oxidation: Mix the fluorite mixed ore with ultrapure water to obtain a first slurry with a mass concentration of 45%. Add sulfuric acid to the first slurry to adjust the pH to 2 to obtain a second slurry. Add potassium persulfate in an amount of 120 g / t of the original ore and silver nitrate in an amount of 15 g / t of the original ore to the second slurry. Control the temperature to 75°C, stir at a stirring speed of 500 r / min for 4 h, and then filter to obtain the oxidized fluorite mixed ore.

[0028] (2) Flotation: The oxidized fluorite mixed ore was mixed with ultrapure water to obtain a third slurry with a mass concentration of 25%. Sodium hydroxide was added to the third slurry to adjust the pH to 7 to obtain a fourth slurry. Butyl xanthate was added to the fourth slurry at a rate of 45 g / t of the original ore, and then methyl isobutyl carbinol (MIBC) was added at a rate of 20 g / t of the original ore for flotation. The flotation temperature was 35°C, the stirring speed was 1000 r / min, and the aeration volume was 0.2 m 3 / h, the time is 10 min. After one flotation, concentrate and tailings are obtained. The concentrate is the sulfide ore containing sulfur impurities, and the tailings is the purified fluorite concentrate.

[0029] Example 3 A method for removing sulfur from a fluorite mixed ore comprises the following steps: (1) Oxidation: Mix the fluorite mixed ore with ultrapure water to obtain a first slurry with a mass concentration of 55%. Add sulfuric acid to the first slurry to adjust the pH to 2 to obtain a second slurry. Add potassium persulfate in an amount of 90 g / t of the original ore and silver nitrate in an amount of 10 g / t of the original ore to the second slurry. Control the temperature to 80°C, stir at a stirring speed of 600 r / min for 3 h, and then filter to obtain the oxidized fluorite mixed ore.

[0030] (2) Flotation: The oxidized fluorite mixed ore was mixed with ultrapure water to obtain a third slurry with a mass concentration of 30%. Sodium hydroxide was added to the third slurry to adjust the pH to 6 to obtain a fourth slurry. Butyl xanthate was added to the fourth slurry at a rate of 55 g / t of the original ore, and then methyl isobutyl carbinol (MIBC) was added at a rate of 30 g / t of the original ore for flotation. The flotation temperature was 30°C, the stirring speed was 1500 r / min, and the aeration volume was 0.3 m 3 / h, the time is 15 min. After one flotation, concentrate and tailings are obtained. The concentrate is the sulfide ore containing sulfur impurities, and the tailings is the purified fluorite concentrate.

[0031] Example 4 A method for removing sulfur from a fluorite mixed ore comprises the following steps: (1) Oxidation: Mix the fluorite mixed ore with ultrapure water to obtain a first slurry with a mass concentration of 65%. Add sulfuric acid to the first slurry to adjust the pH to 3 to obtain a second slurry. Add potassium persulfate in an amount of 150 g / t of the original ore and silver nitrate in an amount of 20 g / t of the original ore to the second slurry. Control the temperature to 60°C, stir at a stirring speed of 700 r / min for 5 h, and then filter to obtain the oxidized fluorite mixed ore.

[0032] (2) Flotation: The oxidized fluorite mixed ore was mixed with ultrapure water to obtain a third slurry with a mass concentration of 35%. Sodium hydroxide was added to the third slurry to adjust the pH to 8 to obtain a fourth slurry. Butyl xanthate was added to the fourth slurry at a rate of 75 g / t of the original ore, and then methyl isobutyl carbinol (MIBC) was added at a rate of 45 g / t of the original ore for flotation. The flotation temperature was 40°C, the stirring speed was 1200 r / min, and the aeration volume was 0.25 m 3 / h, the time is 12 min. After one flotation, concentrate and tailings are obtained. The concentrate is the sulfide ore containing sulfur impurities, and the tailings is the purified fluorite concentrate.

[0033] Example 5 A method for removing sulfur from a fluorite mixed ore comprises the following steps: (1) Oxidation: Mix the fluorite mixed ore with ultrapure water to obtain a first slurry with a mass concentration of 50%. Add sulfuric acid to the first slurry to adjust the pH to 1 to obtain a second slurry. Add potassium persulfate in an amount of 100 g / t of the original ore to the second slurry, and add silver nitrate in an amount of 15 g / t of the original ore. Control the temperature to 85°C, stir at a stirring speed of 400 r / min for 6 hours, and then filter to obtain the oxidized fluorite mixed ore.

[0034] (2) Flotation: The oxidized fluorite mixed ore was mixed with ultrapure water to obtain a third slurry with a mass concentration of 25%. Sodium hydroxide was added to the third slurry to adjust the pH to 9 to obtain a fourth slurry. Butyl xanthate was added to the fourth slurry at a rate of 60 g / t of the original ore, and then methyl isobutyl carbinol (MIBC) was added at a rate of 25 g / t of the original ore for flotation. The flotation temperature was 32°C, the stirring speed was 1300 r / min, and the aeration volume was 0.2 m 3 / h, the time is 8 min. After one flotation, concentrate and tailings are obtained. The concentrate is the sulfide ore containing sulfur impurities, and the tailings is the purified fluorite concentrate.

[0035] Example 6 The method of this embodiment is basically the same as that of embodiment 1, except that the oxidation temperature is 25°C.

[0036] Example 7 The method of this embodiment is basically the same as that of embodiment 1, except that the oxidation time is 1 h.

[0037] Comparative Example 1 The method of this comparative example is substantially the same as that of Example 1, except that the oxidizing agent potassium persulfate is not added.

[0038] Comparative Example 2 The method of this comparative example is basically the same as that of Example 1, except that the catalyst silver nitrate is not added.

[0039] The sulfur removal rates in Examples 1 to 7 and Comparative Examples 1 to 2 are shown in Table 1.

[0040] Table 1

[0041] As can be seen from Table 1, the method for removing sulfur from fluorite mixed ore provided by the present invention can effectively remove trace sulfide ores in high-purity acid-grade fluorite concentrate, and the removal rate can reach 97.18%. By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that without the use of oxidants and catalysts, the removal effect of elemental sulfur is poor, while the addition of oxidants and catalysts can significantly increase the removal rate of elemental sulfur to 97.18%, achieving the purpose of deep impurity removal. This is because the efficient oxidant potassium persulfate used in the embodiment of the present invention can achieve efficient surface oxidation and regulate hydrophilicity and hydrophobicity under the catalysis of silver ions, oxidizing the sulfur on the surface of sulfur-containing impurities into hydrophobic S8 and S 0 The comparison results of Example 1 and Examples 6 and 7 show that the temperature and time of the oxidation reaction will affect the degree of reaction between the oxidant and the surface of the sulfide ore. The optimal reaction temperature is 55-85 °C and the reaction time is 2-6 h.

[0042] In summary, the present invention adopts an oxidation-flotation combined process, and achieves deep impurity removal of sulfur-containing impurity minerals through oxidation regulation of the hydrophobicity of the surface of sulfide ore, and has a good sulfur removal effect, which can achieve deep removal of trace sulfide ores in fluorite concentrate. The method proposed in the present invention reduces the content of sulfur impurities in fluorite at the source, and can effectively alleviate the problem of elemental sulfur blockage in fluorite acid production.

[0043] The above-mentioned embodiments only express the implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for removing sulfur from fluorite mixed ore, characterized in that: The following steps are involved: S1. Slurrying the fluorite mixed ore to obtain a first slurry; S2. adjusting the pH of the first slurry to acidic to obtain a second slurry; S3. mixing the second slurry with an oxidant and a catalyst, performing an oxidation reaction, and obtaining an oxidized fluorite mixed ore after solid-liquid separation; S4. flotation the oxidized fluorite mixed ore to obtain desulfurized fluorite.

2. The method for removing sulfur from fluorite mixed ore according to claim 1, characterized in that: In step S1, the mass concentration of the first slurry is 35-65%.

3. The method for removing sulfur from fluorite mixed ore according to claim 1, characterized in that: In step S2, the pH of the first slurry is adjusted to 1-3.

4. The method for removing sulfur from fluorite mixed ore according to claim 1, characterized in that: In step S3, the oxidant is at least one of persulfate and hydrogen persulfate, and the catalyst is a soluble silver salt.

5. The method for removing sulfur from fluorite mixed ore according to claim 1, characterized in that: In step S3, the amount of the oxidant is 80-150 g / t of the raw ore, and the amount of the catalyst is 8-20 g / t of the raw ore.

6. The method for removing sulfur from fluorite mixed ore according to claim 1, characterized in that: In step S3, the reaction temperature of the oxidation reaction is 55-85°C, and the reaction time is 2-6 h.

7. The method for removing sulfur from fluorite mixed ore according to claim 1, characterized in that: In step S4, the flotation process includes: S4.

1. Pulping the oxidized fluorite mixed ore to obtain a third slurry; S4.

2. adjusting the pH of the third slurry to acidic to obtain a fourth slurry; S4.

3. Mix the flotation agent with the fourth slurry, and obtain desulfurized fluorite after flotation.

8. The method for removing sulfur from fluorite mixed ore according to claim 7, characterized in that: In step S4.1, the mass concentration of the third slurry is 20-35%.

9. The method for removing sulfur from fluorite mixed ore according to claim 7, characterized in that: In step S4.2, the pH of the third slurry is adjusted to 6-9.

10. The method for removing sulfur from fluorite mixed ore according to claim 7, characterized in that: In step S4.3, the flotation reagents include a collector and a frother; the amount of the collector is 35-75 g / t of the original ore, and the amount of the frother is 15-45 g / t.

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