Method for removing sulfur from a fluorite mixed ore

Abstract

The application discloses a method for removing sulfur from a fluorite mixed ore, and comprises the following steps: preparing a first ore slurry by slurry preparation of the fluorite mixed ore; adjusting the pH of the first ore slurry to be acidic to obtain a second ore slurry; mixing the second ore slurry with an oxidizing agent and a catalyst to perform an oxidation reaction, and obtaining an oxidized fluorite mixed ore after solid-liquid separation; and performing flotation on the oxidized fluorite mixed ore to obtain desulfurized fluorite. The method realizes directional regulation of the floatability of the surface of the sulfide ore by efficiently oxidizing the hydrophilic sulfur material on the surface of the sulfide ore in the fluorite mixed ore into hydrophobic sulfur by using an oxidation system composed of an oxidizing agent and a catalyst, creates conditions for effective separation of the sulfide ore and the fluorite in the flotation process, and thus high-purity desulfurized fluorite is obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of mineral processing, and particularly relates to a method for removing sulfur from fluorite mixed ore. BACKGROUND

[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, and is widely used in the semiconductor, electronic, photovoltaic and other industries. The production process of high-purity hydrofluoric acid has a high requirement on the purity of fluorite, and sulfur impurities will seriously affect the stability of production and the purity of products. Among them, chalcopyrite, sphalerite, pyrite and pyrrhotite will be converted into elemental sulfur in the acid production process, which will block the condensation pipeline and cause production stoppage, and even cause safety accidents, greatly affecting the stability of production. It is very difficult to remove sulfur impurities from fluorite, and conventional methods cannot completely remove sulfur impurities. At present, hydrofluoric acid production enterprises usually set up an elemental sulfur condensation device in the condensation pipeline to intercept and collect elemental sulfur, but the elemental sulfur generated by the high content of sulfide ore in fluorite powder is generated at a relatively fast speed, and the production needs to be stopped for pipe blockage after a period of time, which affects the production efficiency. Therefore, removing sulfur impurities through pretreatment before acid production can reduce the generation of elemental sulfur from the source, and fundamentally slow down the pipe blockage problem and improve the stability of production.

[0003] At present, the commonly used methods for removing sulfur from fluorite include magnetic separation method, roasting method and flotation method. The magnetic separation method is only effective for sulfide ores with magnetism, the roasting method has high cost and poor effect on trace sulfide ores, and neither of them is an ideal removal method. Due to the difference in surface properties of different minerals, the flotation method is usually used to separate sulfide ores from fluorite. However, the sulfur content in fluorite powder is low, and there are many hydrophilic substances on the surface, so the recovery rate of conventional flotation method is low, and it is difficult to deeply separate fluorite from trace sulfur. Chinese patent CN105439183A discloses a fluorite powder processing technology, which performs flotation on ground fluorite ore powder, adds hydrogen fluoride solution for stirring and reaction to obtain ore powder, and reacts the obtained ore powder with alkaline solutions such as potassium hydroxide, sodium hydroxide and calcium hydroxide to obtain finished ore powder. The purity of the ore powder obtained by this method is low, which cannot meet the quality standard of acid-grade fluorite powder, and trace sulfur impurities cannot be removed. Chinese patent CN103570053A discloses a fluorite powder finishing process, which uses an acidic hydrogen fluoride solution to treat fluorite powder containing barite, adjusts the pH to 10-14 by adding an alkaline solution after filtration, and dries the fluorite powder after filtration to obtain a fluorite powder with a purity of more than 97%. Although this method can meet the quality standard, it can only remove barite impurities and has poor separation effect on trace sulfur impurities.

[0004] In the existing fluorite powder purification technology, the following problems exist: ①only effective for barite, barite and other gangue minerals, difficult to remove sulfur-containing gangue minerals such as sulfide ore; ②large amount of reagent, multiple types, high cost; ③complex process flow. SUMMARY

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

[0006] To achieve the above purpose, the technical scheme is as follows:

[0007] The present application provides a method for removing sulfur from fluorite mixed ore, comprising the following steps:

[0008] S1. Slurry the fluorite mixed ore to obtain a first slurry;

[0009] S2. Adjust the pH of the first slurry to be acidic to obtain a second slurry;

[0010] S3. Mix the second slurry with an oxidizing agent and a catalyst to perform an oxidation reaction, and after solid-liquid separation, obtain an oxidized fluorite mixed ore;

[0011] S4. Float the oxidized fluorite mixed ore to obtain desulfurized fluorite concentrate.

[0012] Preferably, in step S1, the mass concentration of the first slurry is 35-65%.

[0013] Preferably, in step S2, the pH of the first slurry is adjusted to 1-3.

[0014] Preferably, in step S3, the oxidizing agent is at least one of persulfate and hydrogen persulfate, and the catalyst is a soluble silver salt.

[0015] Preferably, in step S3, the amount of oxidizing agent is 80-150 g / t of raw ore, and the amount of catalyst is 8-20 g / t of raw ore.

[0016] Preferably, in step S3, the reaction temperature of the oxidation reaction is 55-85℃, and the reaction time is 2-6h.

[0017] Preferably, in step S4, the flotation process comprises:

[0018] S4.1. Slurry the oxidized fluorite mixed ore to obtain a third slurry;

[0019] S4.2. Adjust the pH of the third slurry to be acidic to obtain a fourth slurry;

[0020] S4.3. mixing the flotation reagent with the fourth ore slurry, and obtaining desulfurized fluorite concentrate after flotation.

[0021] Preferably, in step S4.1, the mass concentration of the third ore slurry is 20-35 %.

[0022] Preferably, in step S4.2, the pH of the third ore slurry is adjusted to 6-9.

[0023] Preferably, in step S4.3, the flotation reagent includes a collector and a frother; the amount of the collector is 35-75 g / t of raw ore, and the amount of the frother is 15-45 g / t.

[0024] The beneficial effects of the present application are:

[0025] The present application aims at the problem of difficult removal of trace sulfur impurities in fluorite concentrate for high-purity hydrofluoric acid, uses an oxidation-flotation combined method, and uses an oxidation system composed of an oxidizing agent and a catalyst to efficiently oxidize the hydrophilic sulfur material on the surface of sulfide ore in fluorite mixed ore into hydrophobic sulfur, realizes directional regulation of floatability of the surface of the sulfide ore, creates favorable conditions for subsequent flotation separation of the sulfide ore and the fluorite, and only needs to use a simple process of one-stage flotation to realize a good index of a desulfurization rate of more than 97 %, thereby solving the problem of difficult deep removal of sulfur impurities in high-purity acid-grade fluorite concentrate.

[0026] The method provided by the present application has few types of reagents, low cost, and a simple and controllable process flow in the process of realizing deep removal of trace sulfur impurities, can effectively solve the problem of pipeline blockage in the production of high-purity hydrogen fluoride, and improves the economic benefit of enterprises. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings of the embodiments will be briefly introduced below.

[0028] Figure 1 The present application provides a method for removing sulfur from fluorite mixed ore. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0030] The present application provides a method for removing sulfur from fluorite mixed ore, as shown in Figure 1 The method includes the following steps:

[0031] (1) Oxidation: The fluorite mixed ore is slurried to obtain a first ore slurry with a mass concentration of 35-65%, i.e., the mass of the minerals in the first ore slurry accounts for 35-65% of the total mass of the ore slurry; the pH of the first ore slurry is adjusted to 1-3 to obtain a second ore slurry; the second ore slurry is mixed with an oxidizing agent and a catalyst, and is subjected to oxidation reaction at a temperature of 55-85 ℃ for 2-6 h, and the oxidized fluorite mixed ore is obtained after solid-liquid separation. The amount of the oxidizing agent is 80-150 g / t of the raw ore, and the amount of the catalyst is 8-20 g / t of the raw ore. The oxidizing agent is at least one of persulfate and peroxymonosulfate, for example, the persulfate can be one or more of ammonium persulfate, potassium persulfate, and sodium persulfate, and the peroxymonosulfate can be one or more of potassium peroxymonosulfate and sodium peroxymonosulfate. The catalyst is a soluble silver salt, including but not limited to silver nitrate and silver fluoride.

[0032] (2) Flotation: The oxidized fluorite mixed ore is slurried to obtain a third ore slurry with a mass concentration of 20-35%; the pH of the third ore slurry is adjusted to 6-9 to obtain a fourth ore slurry; a flotation reagent is mixed with the fourth ore slurry, and high-purity desulfurized fluorite is obtained after flotation. The flotation reagent includes a collector and a frother; the amount of the collector is 35-75 g / t of the raw ore, and the amount of the frother is 15-45 g / t. The collector includes one or more of butyl xanthate, ethyl xanthate, and ethylthiuram; and the frother includes one or more of methyl isobutyl carbinol (MIBC), No. 2 oil, and pine oil. During the flotation, the stirring speed can be 800-1500 r / min, the aeration amount is 0.1-0.3 m 3 / h, and the flotation time is 5-15 min.

[0033] The principle of the oxidation in the present application is that: by using the catalytic effect of the catalyst (such as silver ions in the soluble silver salt) on the oxidizing agent (such as peroxymonosulfate, etc.), a highly oxidizing oxidation system is developed, which can efficiently oxidize the sulfur on the surface of the sulfide ore into hydrophobic S8, S 0 , etc., realizing the directional regulation of the surface properties while effectively reducing the amount of reagents. Through subsequent flotation, the oxidized sulfide ore particles can be efficiently removed, and the sulfur removal rate reaches more than 97% while the process flow is shortened and simplified.

[0034] To make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below. In the following examples and comparative examples, the sulfur content in the fluorite mixed ore is 1%, which simulates fluorite powder containing trace amounts of sulfur impurities, which is obtained by mixing fluorite with a purity of 99.1% and sulfide ore. The sulfide ore is obtained by mixing pyrite, chalcopyrite, and pyrrhotite in a mass ratio of 1:1:1.

[0035] Example 1

[0036] A method for removing sulfur from a mixed fluorite ore, comprising the following steps:

[0037] (1) Oxidation: Fluorite mixed ore was mixed with ultrapure water to prepare a first slurry with a mass concentration of 35%. Sulfuric acid was added to the first slurry to adjust the pH to 1, resulting in a second slurry. Potassium persulfate was added to the second slurry at a rate of 80 g / t of raw ore, and silver nitrate was added at a rate of 8 g / t of raw ore. The temperature was controlled at 55℃, and the mixture was stirred at a stirring speed of 300 r / min for 2 h. After stirring, the mixture was filtered to obtain the oxidized fluorite mixed ore.

[0038] (2) Flotation: The oxidized fluorite mixed ore was mixed with ultrapure water to prepare a third pulp with a mass concentration of 20%. Sodium hydroxide was added to the third pulp to adjust the pH to 6, resulting in a fourth pulp. Butyl xanthate was added to the fourth pulp at a rate of 35 g / t of raw ore, and then methyl isobutyl methanol (MIBC) was added at a rate of 15 g / t of raw ore for flotation. The flotation temperature was 25℃, the stirring speed was 800 r / min, and the aeration rate was 0.1 m³ / min. 3 / h, time is 5 min. After one flotation, concentrate and tailings are obtained. The concentrate is sulfide ore containing sulfur impurities, and the tailings is purified fluorite concentrate.

[0039] Example 2

[0040] A method for removing sulfur from a mixed fluorite ore, comprising the following steps:

[0041] (1) Oxidation: Fluorite mixed ore was mixed with ultrapure water to prepare a first slurry with a mass concentration of 45%. Sulfuric acid was added to the first slurry to adjust the pH to 2, resulting in a second slurry. Potassium persulfate was added to the second slurry at a rate of 120 g / t of raw ore, and silver nitrate was added at a rate of 15 g / t of raw ore. The temperature was controlled at 75℃, and the mixture was stirred at a stirring speed of 500 r / min for 4 h. After stirring, the mixture was filtered to obtain the oxidized fluorite mixed ore.

[0042] (2) Flotation: The oxidized fluorite mixture was mixed with ultrapure water to prepare a third pulp with a mass concentration of 25%. Sodium hydroxide was added to the third pulp to adjust the pH to 7, resulting in a fourth pulp. Butyl xanthate was added to the fourth pulp at a rate of 45 g / t of raw ore, followed by methyl isobutyl methanol (MIBC) at a rate of 20 g / t of raw ore for flotation. The flotation temperature was 35℃, the stirring speed was 1000 r / min, and the aeration rate was 0.2 m³ / min. 3 / h, time is 10 min. After one flotation, concentrate and tailings are obtained. The concentrate is sulfide ore containing sulfur impurities, and the tailings is purified fluorite concentrate.

[0043] Example 3

[0044] A method for removing sulfur from a mixed fluorite ore, comprising the following steps:

[0045] (1) Oxidation: Fluorite mixed ore was mixed with ultrapure water to prepare a first slurry with a mass concentration of 55%. Sulfuric acid was added to the first slurry to adjust the pH to 2, resulting in a second slurry. Potassium persulfate was added to the second slurry at a rate of 90 g / t of raw ore, and silver nitrate was added at a rate of 10 g / t of raw ore. The temperature was controlled at 80℃, and the mixture was stirred at a stirring speed of 600 r / min for 3 h. After stirring, the mixture was filtered to obtain the oxidized fluorite mixed ore.

[0046] (2) Flotation: The oxidized fluorite mixture was mixed with ultrapure water to prepare a third pulp with a mass concentration of 30%. Sodium hydroxide was added to the third pulp to adjust the pH to 6, resulting in a fourth pulp. Butyl xanthate was added to the fourth pulp at a rate of 55 g / t of raw ore, followed by methyl isobutyl methanol (MIBC) at a rate of 30 g / t of raw ore for flotation. The flotation temperature was 30℃, the stirring speed was 1500 r / min, and the aeration rate was 0.3 m³ / min. 3 / h, time is 15 min. After one flotation, concentrate and tailings are obtained. The concentrate is sulfide ore containing sulfur impurities, and the tailings is purified fluorite concentrate.

[0047] Example 4

[0048] A method for removing sulfur from a mixed fluorite ore, comprising the following steps:

[0049] (1) Oxidation: Fluorite mixed ore was mixed with ultrapure water to prepare a first slurry with a mass concentration of 65%. Sulfuric acid was added to the first slurry to adjust the pH to 3, resulting in a second slurry. Potassium persulfate was added to the second slurry at a rate of 150 g / t of raw ore, and silver nitrate was added at a rate of 20 g / t of raw ore. The temperature was controlled at 60℃, and the mixture was stirred at a stirring speed of 700 r / min for 5 h. After stirring, the mixture was filtered to obtain the oxidized fluorite mixed ore.

[0050] (2) Flotation: The oxidized fluorite mixed ore was mixed with ultrapure water to prepare a third slurry with a mass concentration of 35%. Sodium hydroxide was added to the third slurry to adjust the pH to 8, resulting in a fourth slurry. Butyl xanthate was added to the fourth slurry at a rate of 75 g / t of raw ore, and then methyl isobutyl methanol (MIBC) was added at a rate of 45 g / t of raw ore for flotation. The flotation temperature was 40℃, the stirring speed was 1200 r / min, and the aeration rate was 0.25 m³ / min. 3 / h, time is 12 min. After one flotation, concentrate and tailings are obtained. The concentrate is sulfide ore containing sulfur impurities, and the tailings is purified fluorite concentrate.

[0051] Example 5

[0052] A method for removing sulfur from a mixed fluorite ore, comprising the following steps:

[0053] (1) Oxidation: Fluorite mixed ore was mixed with ultrapure water to prepare a first slurry with a mass concentration of 50%. Sulfuric acid was added to the first slurry to adjust the pH to 1, resulting in a second slurry. Potassium persulfate was added to the second slurry at a rate of 100 g / t of raw ore, and silver nitrate was added at a rate of 15 g / t of raw ore. The temperature was controlled at 85℃, and the mixture was stirred at a stirring speed of 400 r / min for 6 h. After stirring, the mixture was filtered to obtain the oxidized fluorite mixed ore.

[0054] (2) Flotation: The oxidized fluorite mixture was mixed with ultrapure water to prepare a third pulp with a mass concentration of 25%. Sodium hydroxide was added to the third pulp to adjust the pH to 9, resulting in a fourth pulp. Butyl xanthate was added to the fourth pulp at a rate of 60 g / t of raw ore, followed by methyl isobutyl methanol (MIBC) at a rate of 25 g / t of raw ore for flotation. The flotation temperature was 32℃, the stirring speed was 1300 r / min, and the aeration rate was 0.2 m³ / min. 3 / h, time is 8 min. After one flotation, concentrate and tailings are obtained. The concentrate is sulfide ore containing sulfur impurities, and the tailings is purified fluorite concentrate.

[0055] Example 6

[0056] The method in this embodiment is basically the same as that in Embodiment 1, except that the oxidation temperature is 25°C.

[0057] Example 7

[0058] The method in this embodiment is basically the same as that in Embodiment 1, except that the oxidation time is 1 hour.

[0059] Comparative Example 1

[0060] The method of this comparative example is basically the same as that of Example 1, except that the oxidant potassium persulfate is not added.

[0061] Comparative Example 2

[0062] The method of this comparative example is basically the same as that of Example 1, except that the catalyst silver nitrate is not added.

[0063] The sulfur removal rates in Examples 1-7 and Comparative Examples 1-2 are shown in Table 1.

[0064] Table 1

[0065]

[0066] As shown in Table 1, the sulfur removal method for mixed fluorite ore provided by this invention can effectively remove trace amounts of sulfide minerals from high-purity acid-grade fluorite concentrate, achieving a removal rate of 97.18%. A comparison of Example 1 and Comparative Examples 1 and 2 shows that the sulfur removal effect is poor without the use of oxidants and catalysts, while the addition of oxidants and catalysts significantly increases the sulfur removal rate to 97.18%, achieving deep impurity removal. This is because the highly efficient oxidant potassium persulfate used in the embodiments of this invention can achieve efficient surface oxidation and regulate hydrophilicity and hydrophobicity under silver ion catalysis, oxidizing sulfur on the surface of sulfur-containing impurities into hydrophobic S8 and S8 groups. 0 The substances significantly improve its floatability. Comparison of Examples 1 and 6 & 7 shows that both the temperature and time of the oxidation reaction affect the degree of reaction between the oxidant and the sulfide ore surface; the optimal reaction temperature is 55–85 °C, and the optimal reaction time is 2–6 h.

[0067] In summary, this invention employs a combined oxidation-flotation process, leveraging the hydrophobicity of sulfide mineral surfaces through oxidation to achieve deep removal of sulfur-containing impurities. The sulfur removal effect is excellent, enabling the deep removal of trace amounts of sulfide minerals from fluorite concentrate. The method proposed in this invention reduces the sulfur impurity content in fluorite at the source, effectively alleviating the problem of elemental sulfur blockage during fluorite acid production.

[0068] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for removing sulfur from a mixed fluorite ore, characterized in that, Includes the following steps: S1. The mixed fluorite ore is pulped to obtain the first slurry; S2. Adjust the pH of the first slurry to acidic to obtain the second slurry; S3. The second slurry is mixed with an oxidant and a catalyst to carry out an oxidation reaction. After solid-liquid separation, an oxidized fluorite mixture is obtained. The oxidant is at least one of persulfate and peroxymonosulfate, and the catalyst is a soluble silver salt. S4. The oxidized fluorite mixture is subjected to flotation 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 amount of oxidant used is 80~150 g / t of raw ore, and the amount of catalyst used is 8~20 g / t of raw ore.

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

6. 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. The oxidized fluorite mixture is pulped to obtain a third pulp; S4.

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

3. The flotation reagent is mixed with the fourth slurry, and after flotation, desulfurized fluorite is obtained.

7. The method for removing sulfur from fluorite mixed ore according to claim 6, characterized in that, In step S4.1, the mass concentration of the third slurry is 20-35%.

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

9. The method for removing sulfur from fluorite mixed ore according to claim 6, 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 raw ore, and the amount of the frother is 15~45 g / t.

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