A method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite

Abstract

The present invention discloses a method for flotation desulfurization and desiliconization of high-sulfur, high-silicon bauxite. The method comprises grinding and slurrying the bauxite to obtain a pulp; adjusting the pulp to a pH of 9.5 to 10.5, and then performing reverse flotation desulfurization using a xanthate compound, a hydroxamic acid compound, and a non-polar oil as a collector I and a sulfate as an activator to obtain a sulfur concentrate and desulfurized tailings; adjusting the desulfurized tailings to a pH of 9.5 to 10.5, and then performing forward flotation desiliconization using a fatty acid soap compound and a hydroxamic acid compound as a collector II to obtain a bauxite concentrate and tailings; and adjusting the bauxite concentrate to a pH of 9.5 to 10.5, and then adding a silicate inhibitor and a sulfide ore inhibitor to perform beneficiation to obtain a bauxite concentrate and beneficiated tailings. The present invention achieves desulfurization and desiliconization of high-sulfur, high-silicon bauxite, resulting in a high-purity sulfur concentrate, a high aluminum-silicon ratio, a low sulfur content, and a high alumina recovery rate.

Description

Technical Field

[0001] The present invention relates to the field of mineral processing and flotation, and in particular to a method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite. Technical Background

[0002] Bauxite is the primary raw material for alumina production. Currently, over 90% of the world's alumina is produced through the Bayer process. With the rapid development of my country's aluminum industry, high-grade, low-sulfur bauxite resources are becoming increasingly depleted, gradually failing to meet the production requirements of the alumina industry. Therefore, accelerating the comprehensive utilization of low-grade, high-sulfur, high-silicon bauxite is urgent.

[0003] Low-grade, high-sulfur bauxite generally refers to bauxite with a sulfur content exceeding 0.8%. The ore also has a high silicon content and a low aluminum-silicon ratio (1 to 4), making its comprehensive utilization difficult. The main sulfur-containing minerals in bauxite are pyrite, marcasite, and pyrite, while the main silicon-containing minerals are kaolinite, illite, chlorite, montmorillonite, and quartz. Without pretreatment for desulfurization and desiliconization of low-grade, high-sulfur, high-silicon bauxite, the silicon-containing minerals in the bauxite will decompose and dissolve during the Bayer process, forming sodium-silicon slag. The sulfur-containing minerals will also enter the Bayer process solution during the dissolution process, increasing alkali and aluminum consumption, increasing chemical losses in the Bayer process, and causing equipment corrosion, increased alkali consumption, and difficulty in settling the dissolved red mud, all of which affect the normal production of alumina. Therefore, the Bayer process generally requires the sulfur content in the bauxite to be less than 0.3% and the aluminum-silicon ratio to be greater than 8.

[0004] To increase the aluminum-silicon ratio of bauxite and reduce its sulfur content to provide suitable bauxite raw material for the Bayer process, the bauxite must be pretreated for desulfurization and desiliconization before the Bayer process. Flotation is a simple, low-cost, low-pollution, and highly efficient removal method. Flotation desulfurization is based on the difference in surface electrical properties between sulfur-containing minerals and silicate minerals such as diaspore and kaolinite. Desulfurization pretreatment is achieved by adding flotation reagents such as inhibitors, activators, and collectors. Flotation desiliconization is based on the difference in surface electrical properties between diaspore and siliceous gangue minerals such as quartz and kaolinite. By adding flotation reagents such as regulators, inhibitors, and collectors, the flotation difference between diaspore and siliceous gangue minerals is further amplified, thereby achieving flotation enrichment of bauxite.

[0005] However, due to the partial oxidation of sulfur-containing minerals in bauxite, close association with other minerals, and insufficient monomer dissociation, current bauxite reverse flotation desulfurization processes suffer from low desulfurization efficiency. Furthermore, due to the fine particle size of some silicate minerals, which are easily entrained during flotation, the direct flotation desiliconization process for bauxite suffers from low desiliconization efficiency, low bauxite recovery rate, and low aluminum-silicon ratio in the concentrate, limiting the comprehensive utilization of low-grade, high-sulfur bauxite. Furthermore, some bauxite flotation processes are conducted under acidic conditions, causing severe corrosion to equipment and environmental damage. Therefore, it is necessary to develop a clean and effective flotation desulfurization and desiliconization method for high-sulfur, high-silicon bauxite. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention provides a method for flotation desulfurization and desiliconization of high-sulfur, high-silicon bauxite. This method utilizes a combination of reverse flotation desulfurization and forward flotation desiliconization, combined with a special collector and inhibitor combination, to achieve comprehensive utilization of low-grade, high-sulfur, high-silicon bauxite. The resulting bauxite concentrate has a high aluminum-silicon ratio, low sulfur content, and high bauxite recovery. This method also has the advantages of low reagent consumption, low reagent cost, and minimal environmental impact.

[0007] In order to achieve the above technical objectives, the present invention provides a method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite, which comprises grinding and slurrying the bauxite to obtain a pulp; adjusting the pH of the pulp to 9.5-10.5, and then performing reverse flotation desulfurization using a xanthate compound, a hydroxamic acid compound, and a non-polar oil as a collector I and a sulfate as an activator to obtain a sulfur crude concentrate and a desulfurized tailing; adjusting the pH of the desulfurized tailing to 9.5-10.5, and then performing forward flotation desiliconization using a fatty acid soap compound and a hydroxamic acid compound as a collector II to obtain a bauxite crude concentrate and tailings; and adjusting the pH of the bauxite crude concentrate to 9.5-10.5, adding a silicate inhibitor and a sulfide ore inhibitor to perform concentration to obtain a bauxite concentrate and a concentrated tailings.

[0008] The technical solution of the present invention is aimed at the mineral composition of low-grade high-sulfur and high-silicon bauxite. The key is to first separate the sulfur concentrate and the desulfurized tailings through reverse flotation desulfurization with a special collector I, wherein the collector I is composed of xanthate compounds, hydroxamic acid compounds and non-polar oils. The xanthate compounds can be effectively adsorbed on the surface of the monomer-dissociated sulfur-containing minerals, achieving effective hydrophobicity of the sulfur-containing minerals, and then supplemented with non-polar oils to achieve effective floating of the sulfur-containing minerals. In addition to existing in the form of monomer dissociation, the sulfur-containing minerals in the high-sulfur bauxite are also closely associated with the oxidized minerals in the form of intergrowths, and some sulfide mineral surfaces are oxidized. Although most of the easily floated pyrite can be removed by simply adding xanthate compounds and non-polar oils, it is impossible to achieve deep removal of sulfur in the high-sulfur bauxite. Therefore, the addition of hydroxamic acid compounds can assist xanthate compounds and non-polar oils to effectively hydrophobically float sulfur-containing minerals that are surface-oxidized or partially oxidized and not monomerically dissociated, thereby achieving deep desulfurization of high-sulfur bauxite. At the same time, the addition of hydroxamic acid compounds is beneficial to the subsequent positive flotation desiliconization of bauxite, reducing the amount of collector used in subsequent processes and reducing the cost of reagents. Secondly, the sulfur crude concentrate can be subjected to multiple rounds of selection to obtain a high-purity sulfur concentrate to meet the application of industrial production. The desulfurized tailings are further desiliconized by positive flotation under the synergistic effect of collector II containing fatty acid soap compounds and hydroxamic acid compounds to separate the silicon component in the bauxite, thereby obtaining a bauxite crude concentrate and tailings. The synergistic mechanism of the fatty acid soap compounds and hydroxamic acid compounds in collector II is that the addition of fatty acid soap compounds can make the surface of diaspore hydrophobic and float, but the addition of such agents will also make the flotation foam sticky and difficult to defoam, resulting in problems such as large entrainment of silicon-containing minerals, large flotation volume, and difficulty in subsequent treatment during the flotation process, thereby reducing the desiliconization efficiency of bauxite and the recovery rate of bauxite; and the addition of hydroxamic acid compounds can, on the one hand, assist fatty acid soap compounds, enhance their collection performance for diaspore, and improve the recovery rate of bauxite; on the other hand, the addition of hydroxamic acid compounds can effectively regulate the flotation foam, reduce the entrainment of silicon-containing minerals during the flotation process, and improve the aluminum-silicon ratio of the flotation bauxite concentrate. Finally, the resulting bauxite concentrate utilizes silicate and sulfide inhibitors to effectively suppress the presence of silicate and sulfide minerals in the concentrate. This, after beneficiation, significantly improves the bauxite grade and effectively removes sulfide minerals, resulting in a bauxite concentrate with a high aluminum-silicon ratio and low sulfur content. Furthermore, the entire process of the present invention is carried out under weakly alkaline conditions, which not only ensures the stability of the flotation process and reduces flotation reagent usage and costs, but also creates a clean and environmentally friendly flotation environment, preventing serious corrosion to equipment and environmental damage.

[0009] The inventors have discovered that the process of reverse flotation desulfurization and forward flotation desiliconization adopted in the present invention obtains sulfur concentrate and bauxite coarse ore in steps. This not only realizes the comprehensive utilization of low-grade, high-sulfur, and high-silicon bauxite, but also maximizes the recovery rate of bauxite compared to the simultaneous desiliconization and desulfurization process in the prior art.

[0010] As a preferred solution, the reagent used to adjust the pH of the present invention is sodium carbonate and / or sodium hydroxide, and the amount used relative to the original ore is 200-1000g / t. The present invention can not only adjust the slurry pH by adding sodium carbonate and / or sodium hydroxide, but also eliminate Ca in the slurry. 2+ Mg 2+ , improve the selectivity of the collector and reduce the dosage of the collector.

[0011] As a preferred solution, the grinding time is 10 to 20 minutes, the grinding fineness is -200 mesh (-0.074 mm), and the mineral mass accounts for 80 to 90%. The slurry concentration is 25 to 40 wt%. The purpose of grinding the bauxite ore in the present invention is to achieve effective monomer dissociation of silicon-containing minerals such as bauxite and kaolinite, and sulfur-containing minerals such as pyrite, thereby facilitating the subsequent flotation separation process. The purpose of slurrying the grinding product is to adjust the slurry's physical properties such as viscosity, hydraulic flow characteristics, and solid content, thereby improving the slurry's flotation environment.

[0012] As a preferred solution, the sulfate is copper sulfate and / or lead sulfate, and the amount used relative to the original ore is 1000-2000 g / t. The activator selected in the present invention is allowed to react with the slurry to be treated for 1-5 minutes, which can change the surface composition of the mineral and promote the interaction between the collector and the mineral surface.

[0013] As a preferred solution, the mass ratio of xanthate compounds, hydroxamic acid compounds and non-polar oils in the collector I is (4-20): (1-5): (0.2-0.5). In the technical solution of the present invention, the desulfurization efficiency of bauxite and the recovery rate of bauxite can be balanced and controlled by the ratio of xanthate compounds, hydroxamic acid compounds and non-polar oils in the collector I. Xanthate compounds are the main collectors of sulfide ores. When their content is too low, the desulfurization rate will be low; when their content is too high, the cost of the reagent will be high. However, when the addition amount of hydroxamic acid compounds is too low, it is impossible to deeply remove the surface-oxidized or partially oxidized sulfur-containing minerals in the bauxite, resulting in a low desulfurization rate; and when the addition amount of hydroxamic acid compounds is too high, the excessive hydroxamic acid compounds will capture useful minerals such as bauxite, reducing the recovery rate of bauxite. When the non-polar oil dosage is too low, its effect on enhancing the deep desulfurization of bauxite is poor; when the dosage is too high, it will assist the hydroxamic acid collector, increasing the collection effect of bauxite and causing bauxite loss. A further preferred mass ratio of xanthate compound, hydroxamic acid compound, and non-polar oil is (10-20):(1-5):(0.2-0.5).

[0014] As a preferred solution, the xanthate compound in the collector I is selected from at least one of butyl xanthate, isobutyl xanthate, amyl xanthate, isopentyl xanthate, and butylamine black medicine, and the amount relative to the original ore is 500 to 1500 g / t; butyl xanthate is further preferred.

[0015] As a preferred solution, the hydroxamic acid compound in the collector I is selected from at least one of benzohydroxamic acid, carboxymethylhydroxamic acid, and alkylhydroxamic acid, and the amount thereof is 100 to 300 g / t relative to the original ore; more preferably, benzohydroxamic acid is used.

[0016] As a preferred solution, the non-polar oil in the collector I is selected from at least one of pine oil, methyl isobutyl carbinol, and pine oil, and the amount used relative to the original ore is 10 to 40 g / t, and pine oil is more preferably used.

[0017] By further optimizing the collector of xanthate compounds, hydroxamic acid compounds and non-polar oil combination, the sulfur-containing minerals in bauxite that are monomer dissociated, surface oxidized or partially oxidized, or have insufficient monomer dissociation can be effectively removed through the combination of agents, thereby achieving effective removal of sulfur-containing minerals in bauxite.

[0018] As a preferred embodiment, the mass ratio of the fatty acid soap compound to the hydroxamic acid compound in the collector II is (3-6):1. When the mass ratio of the fatty acid soap compound to the hydroxamic acid compound is too high, that is, when the amount of the hydroxamic acid compound added is too low, the process of the hydroxamic acid compound assisting the fatty acid soap compound in collecting bauxite has problems such as large entrainment, difficulty in defoaming, and low aluminum-silicon ratio, resulting in poor effect. When the mass ratio of the fatty acid soap compound to the hydroxamic acid compound is too low, that is, when the amount of the hydroxamic acid compound added is too high, the Al2O3 grade in the bauxite coarse concentrate will be significantly reduced.

[0019] As a preferred solution, the fatty acid soap compound in the collector II is at least one of sodium oleate, oleic acid, saponified oleic acid, sodium dodecyl sulfonate, and sodium dodecyl sulfate, and the amount relative to the original ore is 300-1000 g / t; more preferably, saponified oleic acid.

[0020] As a preferred solution, the hydroxamic acid compound in the collector II is at least one of benzohydroxamic acid, carboxymethylhydroxamic acid, and alkylhydroxamic acid, and the amount thereof is 80 to 200 g / t relative to the raw ore. Benzohydroxamic acid is more preferred.

[0021] As a preferred solution, the sulfide ore inhibitor is selected from at least one of lime, sodium sulfide, sodium sulfite and sodium hydrosulfide, and the amount used relative to the original ore is 30 to 200 g / t; more preferably, lime and / or sodium sulfite.

[0022] As a preferred solution, the silicate inhibitor is selected from at least one of sodium hexametaphosphate, sodium fluorosilicate, and sodium silicate, and the amount used relative to the original ore is 50 to 200 g / t. Sodium hexametaphosphate is more preferred.

[0023] As a preferred solution, the reverse flotation desulfurization process includes one roughing step and at least one scavenging step.

[0024] As a preferred solution, the flotation reagent system for roughing in the reverse flotation desulfurization process is: sulfate 1000-2000g / t, xanthate compounds 500-1500g / t, hydroxamic acid compounds 100-300g / t, and non-polar oil 10-40g / t.

[0025] As a preferred solution, the dosage of the flotation reagent in the scavenging flotation reagent system in the reverse flotation desulfurization process is 2 / 5 to 1 / 2 of that in the roughing flotation desulfurization process.

[0026] As a preferred solution, the direct flotation desiliconization process includes one roughing step and at least one scavenging step.

[0027] As a preferred solution, the flotation reagent system for roughing in the direct flotation desiliconization process is: 300-1000 g / t of fatty acid soap compounds and 80-200 g / t of hydroxamic acid compounds.

[0028] As a preferred solution, the dosage of the flotation reagent system for scavenging in the direct flotation desiliconization process is 2 / 5 to 1 / 2 of that for roughing in the direct flotation desiliconization process.

[0029] As a preferred solution, the forward flotation, reverse flotation and concentration are all carried out under an environment with a stirring speed of 1700-2400 r / min. The present invention can fully disperse the flotation pulp through strong stirring, so that the flotation reagent and the pulp can fully react.

[0030] The present invention provides a method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite, which specifically comprises the following steps:

[0031] (1) Grinding and slurrying the high-sulfur and high-silicon bauxite ore to obtain a slurry with appropriate particle size and concentration;

[0032] (2) Adding appropriate amounts of pH adjuster, activator and combined collector to the slurry to be treated in sequence, and allowing them to act on the slurry to be treated for a period of time, and then undergoing a roughing and a scavenging process under weak alkalinity and strong stirring conditions to obtain desulfurized tailings and sulfur coarse concentrate, and the middlings are returned to the previous process in sequence;

[0033] (3) adding an appropriate amount of pH adjuster to the sulfur concentrate obtained in the second step, and allowing it to react with the slurry to be treated for a period of time, and then performing five rounds of concentration under weak alkalinity and strong stirring conditions to obtain sulfur concentrate and concentrated tailings, and the concentrated tailings are sequentially returned to the previous process;

[0034] (4) Adding appropriate amounts of pH adjuster and combined collector to the desulfurized tailings obtained in the second step, and allowing them to react with the slurry to be treated for a period of time, and then undergoing a roughing and a scavenging process under weak alkalinity and strong stirring conditions to obtain bauxite coarse concentrate and tailings, and the middlings are returned to the previous process in sequence;

[0035] (5) Add appropriate amounts of pH adjuster, silicate inhibitor, and sulfide ore inhibitor to the bauxite coarse concentrate obtained in the fourth step in sequence, and allow them to act with the slurry to be treated for a period of time. Perform two bauxite concentrations under weak alkalinity and strong stirring conditions to obtain bauxite concentrate and concentrated tailings. The concentrated tailings are returned to the previous process in sequence.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The present invention provides a flotation desulfurization and desiliconization method for high-sulfur, high-silicon bauxite. The entire process is carried out under weak alkaline conditions and strong agitation, ensuring the stability of the flotation process and reducing the amount of flotation reagents and flotation costs. The present invention utilizes a combined reverse flotation desulfurization process by adding a combined collector I (xanthate compound, hydroxamic acid compound, and non-polar oil) in a specific ratio. The three reagents act in combination and are added all at once. This combination of three reagents effectively removes sulfur-containing minerals that are monomerically dissociated, non-monomerically dissociated, surface-oxidized, or partially oxidized from the bauxite, enhancing the efficient and deep removal of sulfur-containing minerals and simplifying the process flow. A high-purity sulfur concentrate can be obtained from the crude sulfur concentrate after five rounds of cleaning. The desulfurized tailings are then combined with a fatty acid soap compound and a hydroxamic acid compound in appropriate ratios. After a single roughing and a single scavenging, a crude bauxite concentrate is obtained. This removes the silicon component from the bauxite while ensuring a high recovery rate. At the same time, sodium sulfite, lime, and other chemicals are added to the bauxite crude concentrate to effectively suppress sulfur-containing minerals, and sodium hexametaphosphate and other chemicals are added to effectively suppress silicate minerals. After two rounds of concentration, a bauxite concentrate with a high aluminum-silicon ratio and low sulfur is obtained. The present invention has high industrial application value and a simple process flow, requires a small amount of chemicals, has low chemical costs, has little environmental harm, and has a wide range of applications, conforming to the concept of green environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The present invention is a process flow chart of a method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite. DETAILED DESCRIPTION

[0039] The following examples are provided to illustrate the present invention but are not intended to limit the scope of the present invention. Without departing from the spirit and substance of the present invention, modifications or substitutions made to the steps or conditions of the method of the present invention are within the scope of the present invention.

[0040] Example 1

[0041] (1) Bauxite ore (Al2O3, SiO2, and S contents of 57.77%, 15.83%, and 2.75%, respectively) was ground in a conical ball mill for 18 min to a fineness of -200 mesh (85%). The ground slurry was placed in a flotation tank and slurried with an appropriate amount of water to a slurry concentration of 35 wt%.

[0042] (2) Sodium carbonate (1000 g / t relative to the original ore dosage) is added to the flotation tank in sequence to adjust the pH value to 9.5, and copper sulfate (1500 g / t relative to the original ore dosage) is added to activate the sulfur-containing minerals, and each of them is reacted with the flotation pulp for 3 minutes. Subsequently, butyl xanthate (1000 g / t relative to the original ore dosage), benzohydroxamic acid (200 g / t), and pine oil (20 g / t) are added to the flotation tank at one time, and are reacted with the flotation pulp for 3 minutes. Subsequently, aeration is performed for 1 minute and scraping for 4 minutes to perform a roughing process to obtain a sulfur concentrate and a roughing tailing. Then, a scavenging process is performed by maintaining the pulp pH at 9.5 and reducing the reagent dosage by half to obtain a scavenging concentrate and a desulfurized tailing. The scavenging concentrate is returned to the previous process.

[0043] (3) Sodium carbonate (200 g / t relative to the original ore) was added to the sulfur concentrate to maintain a pH of 9.5, and the concentrate was allowed to react with the flotation pulp for 3 minutes, followed by aeration for 1 minute and scraping for 2 minutes for five rounds of concentration to obtain a high-purity sulfur concentrate.

[0044] (4) Sodium carbonate (300 g / t relative to the original ore dosage) is added to the desulfurized tailings in sequence to adjust the pH value to 9.5, and the solution is reacted with the flotation pulp for 3 minutes. Subsequently, oleic acid (400 g / t relative to the original ore dosage) and benzohydroxamic acid (100 g / t) are added to the flotation tank at one time, and the solution is reacted with the flotation pulp for 3 minutes. A roughing process is then performed by aerating for 1 minute and scraping for 4 minutes to obtain a bauxite concentrate and a roughing tailing. Then, a scavenging process is performed by maintaining the slurry pH at 9.5 and halving the reagent dosage to obtain a scavenged concentrate and tailings. The scavenged concentrate is returned to the previous process.

[0045] (5) Sodium carbonate (200 g / t relative to the original ore) was added to the bauxite concentrate to adjust the pH to 9.5-10, sodium hexametaphosphate (50 g / t relative to the original ore), and sodium sulfite (30 g / t relative to the original ore) were added in sequence, and the mixture was reacted with the flotation slurry for 3 minutes. Subsequently, the mixture was aerated for 1 minute and scraped for 3 minutes to perform two concentrations, obtaining bauxite concentrate and concentrated tailings. The concentrated tailings were returned to the previous process.

[0046] After steps (1) to (4), high-purity sulfur concentrate and bauxite crude concentrate can be obtained. The purity of the sulfur concentrate is 90%, and the Al2O3, SiO2, and S contents in the bauxite crude concentrate are 62.91%, 11.21%, and 0.72%, respectively. After step (5), the Al2O3, SiO2, and S contents in the bauxite concentrate are 69.65%, 5.62%, and 0.25%, respectively, and the bauxite recovery rate is about 83%. It can be seen that the further inhibitor effect and flotation in step (5) can significantly improve the Al2O3 grade of the bauxite concentrate and reduce the S content, while ensuring a high bauxite recovery rate.

[0047] Example 2

[0048] Step (1) is the same as in Example 1;

[0049] (2) Sodium carbonate (1000 g / t relative to the original ore dosage) is added to the flotation tank in sequence to adjust the pH value to 9.5, and copper sulfate (1500 g / t relative to the original ore dosage) is added to activate the sulfur-containing minerals, and each of them is reacted with the flotation pulp for 3 minutes. Subsequently, butyl xanthate (1000 g / t relative to the original ore dosage), benzohydroxamic acid (250 g / t), and pine oil (10 g / t) are added to the flotation tank at one time, and are reacted with the flotation pulp for 3 minutes. Subsequently, aeration is performed for 1 minute and scraping for 4 minutes to perform a roughing operation to obtain a sulfur concentrate and a roughing tailing. Then, a scavenging operation is performed by maintaining the pulp pH at 9.5 and reducing the reagent dosage by half to obtain a scavenging concentrate and a desulfurized tailing. The scavenging concentrate is returned to the previous process.

[0050] Step (3) is the same as in Example 1;

[0051] (4) Sodium carbonate (300 g / t relative to the original ore dosage) is added to the desulfurized tailings in sequence to adjust the pH value to 9.5, and the solution is reacted with the flotation pulp for 3 minutes. Subsequently, 400 g / t of saponified oleic acid and 80 g / t of benzohydroxamic acid relative to the original ore dosage are added to the flotation tank at one time, and the solution is reacted with the flotation pulp for 3 minutes. Subsequently, aeration is performed for 1 minute and scraping for 4 minutes to perform a roughing process to obtain bauxite rough concentrate and roughing tailings. Then, a scavenging process is performed by maintaining the slurry pH at 9.5 and halving the reagent dosage to obtain scavenged concentrate and tailings. The scavenged concentrate is returned to the previous process.

[0052] Step (5) is the same as in Example 1.

[0053] After steps (1) to (4), high-purity sulfur concentrate and bauxite concentrate can be obtained. The purity of the sulfur concentrate is 91%, and the Al2O3, SiO2, and S contents in the bauxite concentrate are 62.42%, 11.43%, and 0.70%, respectively. After step (5), the Al2O3, SiO2, and S contents in the bauxite concentrate are 68.98%, 5.94%, and 0.23%, respectively, and the bauxite recovery rate is about 82%.

[0054] Example 3

[0055] This embodiment is compared with embodiment 2 only in step (4) in which collector II is replaced by oleic acid saponified in an amount of 500 g / t and benzohydroxamic acid 100 g / t relative to the original ore, and the other steps and conditions are the same.

[0056] After steps (1) to (4), high-purity sulfur concentrate and bauxite concentrate can be obtained. The purity of the sulfur concentrate is 91%, and the Al2O3, SiO2, and S contents in the bauxite concentrate are 61.92%, 12.23%, and 0.69%, respectively. After step (5), the Al2O3, SiO2, and S contents in the bauxite concentrate are 68.25%, 6.42%, and 0.24%, respectively, and the bauxite recovery rate is about 84%.

[0057] Example 4

[0058] Compared with Example 3, this example only replaces the inhibitor in step (5) with 80 g / t of sodium hexametaphosphate and 50 g / t of sodium sulfite relative to the original ore, and the other steps and conditions are the same.

[0059] After steps (1) to (4), high-purity sulfur concentrate and bauxite concentrate can be obtained. The purity of the sulfur concentrate is 91%, and the Al2O3, SiO2, and S contents in the bauxite concentrate are 61.92%, 12.23%, and 0.69%, respectively. After step (5), the Al2O3, SiO2, and S contents in the bauxite concentrate are 69.68%, 4.97%, and 0.18%, respectively, and the bauxite recovery rate is about 80%.

[0060] Comparative Example 1

[0061] The only difference between this comparative example and Example 1 is that sodium hexametaphosphate and sodium sulfite inhibitors are not added in step (5), and the remaining steps and conditions are the same.

[0062] After steps (1) to (4), a high-purity sulfur concentrate and a low-sulfur bauxite concentrate with a high aluminum-silicon ratio can be obtained. The purity of the sulfur concentrate is 90%, and the Al2O3, SiO2, and S contents in the bauxite crude concentrate are 62.89%, 11.36%, and 0.71%, respectively; the Al2O3, SiO2, and S contents in the bauxite concentrate are 62.91%, 11.21%, and 0.71%, respectively, and the bauxite recovery rate is 88%. Compared with Example 1, when no inhibitor is added in step (5), the SiO2 and S contents in the bauxite concentrate do not decrease significantly compared with the bauxite crude concentrate, and the Al2O3 grade does not increase further.

[0063] Comparative Example 2

[0064] The only difference between this comparative example and Example 1 is that in step (4), the collector II is oleic acid saponified in an amount of 400 g / t relative to the original ore, and benzohydroxamic acid is not added. The remaining steps and conditions are the same.

[0065] After steps (1) to (5), high-purity sulfur concentrate and low-sulfur bauxite concentrate can be obtained. The purity of the sulfur concentrate is 90%, and the Al2O3, SiO2, and S contents in the bauxite concentrate are 65.46%, 8.68%, and 0.26%, respectively. The bauxite recovery rate is about 77%. Compared with Example 1, when only fatty acid soap compounds are used in the direct flotation desiliconization process in this comparative example, although the sulfur content in the bauxite concentrate does not change, the Al2O3 grade decreases, the SiO2 content increases, and the bauxite recovery rate decreases significantly. This is because when only fatty acid soap compounds are used in the direct flotation process, the flotation entrainment amount is large, and the foam is sticky and difficult to defoam, resulting in a large amount of silicate minerals such as kaolinite and chlorite being entrained in the bauxite concentrate, resulting in a significant decrease in the grade of Al2O3 and the aluminum-silicon ratio in the bauxite concentrate.

[0066] Comparative Example 3

[0067] The difference between this comparative example and Example 1 is that in step (2), the collector I is replaced by 1000 g / t butyl xanthate and 20 g / t pine oil relative to the original ore amount, and benzohydroxamic acid is not added. The other steps and conditions are the same.

[0068] After steps (1) to (4), high-purity sulfur concentrate and bauxite crude concentrate can be obtained. The purity of the sulfur concentrate is 91%, and the Al2O3, SiO2, and S contents in the bauxite crude concentrate are 60.68%, 12.26%, and 1.24%, respectively. After step (5), the Al2O3, SiO2, and S contents in the bauxite concentrate are 67.24%, 6.65%, and 0.69%, respectively, and the bauxite recovery rate is about 84%. It can be seen that when benzohydroxamic acid is not added to the collector I in step (2), the Al2O3 grade in the bauxite crude concentrate decreases and the S content is high. This is because when the addition amount of the hydroxamic acid compound is too low, the surface-oxidized or partially oxidized sulfur-containing minerals in the bauxite cannot be deeply removed, resulting in a low desulfurization rate.

[0069] Comparative Example 4

[0070] The difference between this comparative example and Example 1 is that in step (2), the collector I is replaced by 1000 g / t butyl xanthate, 500 g / t benzohydroxamic acid, and 40 g / t pine oil relative to the original ore dosage, and the other steps and conditions are the same.

[0071] After steps (1) to (4), high-purity sulfur concentrate and bauxite crude concentrate can be obtained. The purity of the sulfur concentrate is 85%, and the Al2O3, SiO2, and S contents in the bauxite crude concentrate are 57.71%, 14.53%, and 0.94%, respectively. After step (5), the Al2O3, SiO2, and S contents in the bauxite concentrate are 65.33%, 7.48%, and 0.57%, respectively, and the bauxite recovery rate is about 77%. This shows that when the benzohydroxamic acid content in the collector I is too high, the excessive hydroxamic acid compounds will capture useful minerals such as bauxite, reducing the grade of Al2O3 in the bauxite concentrate and simultaneously reducing the bauxite recovery rate.

[0072] Comparative Example 5

[0073] The only difference between this comparative example and Example 1 is that in step (4), the collector II is replaced by 400 g / t saponified oleic acid and 400 g / t benzohydroxamic acid relative to the original ore, and the other steps and conditions are the same.

[0074] After steps (1) to (4), high-purity sulfur concentrate and low-sulfur bauxite concentrate can be obtained. The purity of the sulfur concentrate is 90%, and the Al2O3, SiO2, and S contents in the bauxite concentrate are 53.85%, 14.58%, and 0.74%, respectively. After step (5), the Al2O3, SiO2, and S contents in the bauxite concentrate are 61.59%, 7.59%, and 0.24%, respectively, and the bauxite recovery rate is about 84%.

Claims

1. A method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite, characterized by: Grinding and slurrying the bauxite to obtain a pulp; adjusting the pH of the pulp to 9.5-10.5, performing reverse flotation desulfurization using a xanthate compound, a hydroxamic acid compound, and a non-polar oil as a collector I and sulfate as an activator to obtain a sulfur crude concentrate and a desulfurized tailing; adjusting the pH of the desulfurized tailing to 9.5-10.5, performing direct flotation desiliconization using a fatty acid soap compound and a hydroxamic acid compound as a collector II to obtain a bauxite crude concentrate and tailings; adjusting the pH of the bauxite crude concentrate to 9.5-10.5, adding a silicate inhibitor and a sulfide ore inhibitor to perform beneficiation to obtain a bauxite concentrate and beneficiated tailings; The mass ratio of the xanthate compound, the hydroxamic acid compound and the non-polar oil in the collector I is (4-20): (1-5): (0.2-0.5); The mass ratio of the fatty acid soap compound to the hydroxamic acid compound in the collector II is (3-6):

1.

2. The method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite according to claim 1, characterized in that: The grinding time is 10-20 minutes, and the grinding fineness is -200 mesh, and the mineral mass accounts for 80-90%; The slurry concentration is 25-40 wt%.

3. The method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite according to claim 2, characterized in that: The sulfate is copper sulfate and / or lead sulfate, and the amount used relative to the original ore is 1000-2000 g / t.

4. The method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite according to claim 1, characterized in that: The xanthate compound in the collector I is selected from at least one of butyl xanthate, isobutyl xanthate, amyl xanthate, and isopentyl xanthate, and the amount thereof relative to the original ore is 500 to 1500 g / t; The hydroxamic acid compound in the collector I is selected from at least one of benzohydroxamic acid, carboxymethylhydroxamic acid, and alkylhydroxamic acid, and the amount thereof is 100-300 g / t relative to the original ore; The non-polar oil in the collector I is selected from at least one of pine oil, methyl isobutyl carbinol, and pine oil, and the amount relative to the original ore is 10-40 g / t.

5. The method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite according to claim 4, characterized in that: The fatty acid soap compound in the collector II is at least one of sodium oleate, oleic acid, saponified oleic acid, sodium dodecyl sulfonate, and sodium dodecyl sulfate, and the amount relative to the original ore is 300-1000 g / t; The hydroxamic acid compound in the collector II is at least one of benzohydroxamic acid, carboxymethylhydroxamic acid, and alkylhydroxamic acid, and the dosage relative to the original ore is 80-200 g / t.

6. The method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite according to claim 1, characterized in that: The sulfide ore inhibitor is selected from at least one of lime, sodium sulfide, sodium sulfite, and sodium hydrosulfide, and the amount used relative to the original ore is 30-200 g / t; The silicate inhibitor is selected from at least one of sodium hexametaphosphate, sodium fluorosilicate, and sodium silicate, and the amount used relative to the original ore is 50-200 g / t.

7. The method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite according to claim 1, characterized in that: The reverse flotation desulfurization process includes one roughing selection and at least one scavenging selection; The direct flotation desiliconization process includes one roughing selection and at least one scavenging selection.

8. The method for flotation desulfurization and desiliconization of high-sulfur and high-silicon bauxite according to claim 7, characterized in that: The forward flotation, reverse flotation and concentration are all carried out under an environment with a stirring speed of 1700~2400 r / min.

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