Staged desulfurization method for high-sulfur bauxite

Abstract

The invention relates to the technical field of bauxite matter treatment, in particular to a stage desulfurization method for high-sulfur bauxite. The weight m1 of the sulfur element of the high-sulfur bauxite and the weight m2 of the high-sulfur bauxite meet the relational expression: m1: m2 is greater than or equal to 0.03; the stage desulfurization method comprises the following steps: grinding high-sulfur bauxite to obtain high-sulfur bauxite powder; mixing an acidic flotation reagent with the high-sulfur bauxite powder to obtain primary raw ore pulp; carrying out primary flotation desulfurization on the primary raw ore pulp to obtain a primary middling mixed solution; concentrating the primary middling mixed solution to obtain a secondary middling mixed solution; and a deep desulfurization agent is mixed with the secondary middling mixed liquor, then secondary flotation desulfurization is conducted on the secondary middling mixed liquor, and aluminum concentrate is obtained. According to the stage desulfurization method, the surface active sites of sulfur-containing particles in the high-sulfur bauxite can be increased through cooperation of the acidic flotation desulfurizer and the deep desulfurization agent, and finally the aluminum concentrate with the sulfur element weight content smaller than or equal to 0.4% is obtained.

Description

Technical Field

[0001] The present application relates to the technical field of bauxite processing, and in particular to a staged desulfurization method for high-sulfur bauxite. Background Art

[0002] Bauxite is an important raw material for the production of alumina, and the sulfur in bauxite has an adverse effect on the production process and product quality of alumina. Therefore, high-sulfur bauxite needs to be desulfurized before using it as a raw material to produce alumina.

[0003] At present, most high-sulfur bauxite uses flotation desulfurization or a combination of gravity separation and flotation desulfurization to remove sulfur from high-sulfur bauxite. However, high-sulfur bauxite has a high sulfur content and most high-sulfur bauxite has a high degree of pyrite oxidation. These characteristics will cause the surface active sites of the sulfur-containing particles in the high-sulfur bauxite to be covered by hydrophilic substances, which will affect the combination of the desulfurization collector with the surface active sites of the sulfur-containing particles in the high-sulfur bauxite, resulting in unsatisfactory desulfurization effect.

[0004] At present, the desulfurization technology of high-sulfur bauxite includes: (1) A flotation desulfurization method of high-sulfur bauxite, comprising the following steps: adding lime during the grinding process of the raw ore of high-sulfur bauxite to control the pH of the slurry of the high-sulfur bauxite to be within the range of 6 to 8, and then adding an activator, a collector and a frother to the slurry of the high-sulfur bauxite in sequence to float the slurry of the high-sulfur bauxite. (2) A desulfurization method of high-sulfur bauxite, comprising the following steps: obtaining high-sulfur bauxite; grinding the high-sulfur bauxite, and then mixing the ground material with water to obtain a slurry; adjusting the pH of the slurry to alkaline to obtain an adjusted slurry; stirring and mixing the adjusted slurry with a dispersant, a flocculant, a collector and a frother in sequence to obtain a mixed slurry; flotating the mixed slurry to obtain a prefabricated alumina concentrate and a sulfur concentrate; mixing the prefabricated alumina concentrate with an oxidant to obtain an alumina concentrate. (3) A method for combined refloatation and desulfurization of high-sulfur bauxite, comprising grinding the high-sulfur bauxite slurry, and then separating pyrite and re-selected aluminum concentrate from the ground high-sulfur bauxite slurry by re-selection; flotation desulfurization of the obtained re-selected aluminum concentrate, or flotation desulfurization of the re-selected aluminum concentrate after coarse and fine classification, respectively, to obtain a foam product and an underflow product; the obtained foam product is combined with the pyrite to form a comprehensive sulfur concentrate, and the obtained underflow product is the aluminum concentrate. (4) A method for step-by-step flotation desulfurization of high-sulfur bauxite, the method comprising: a first step of performing desulfurization roughing to separate sulfide middlings and aluminum concentrate, a second step of performing desulfurization flotation on the sulfide middling obtained from the first step of desulfurization roughing to further separate sulfur rough concentrate and aluminum concentrate, and the two parts of aluminum concentrate are combined to form a comprehensive aluminum concentrate. Summary of the invention

[0005] The present application provides a staged desulfurization method for high-sulfur bauxite to solve the following technical problem: how to increase the surface active sites of sulfur-containing particles in high-sulfur bauxite.

[0006] In a first aspect, the present application provides a staged desulfurization method for high-sulfur bauxite, wherein the weight m1 of the sulfur element in the high-sulfur bauxite and the weight m2 of the high-sulfur bauxite satisfy the relationship: m1:m2≥0.03; the staged desulfurization method comprises:

[0007] Grinding high-sulfur bauxite to obtain high-sulfur bauxite powder;

[0008] Mixing an acidic flotation agent with the high-sulfur bauxite powder to mineralize the high-sulfur bauxite powder to obtain a primary raw ore pulp;

[0009] The primary raw ore pulp is subjected to primary flotation desulfurization to obtain a primary intermediate ore mixed liquid;

[0010] Concentrating the primary intermediate ore mixed solution to obtain a secondary intermediate ore mixed solution;

[0011] The deep desulfurization agent is mixed with the secondary middlings mixed liquor, and then the secondary middlings mixed liquor is subjected to secondary flotation desulfurization to obtain aluminum concentrate.

[0012] Optionally, the weight m3 of the acidic flotation reagent and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0013] m3:m4=(0.5:1000)~(5:1000).

[0014] Optionally, the acidic flotation reagent comprises an acidic regulator, a first alkyl xanthate and pine oil, wherein the acidic regulator comprises sulfuric acid and / or hydrochloric acid;

[0015] The first alkyl xanthate comprises at least one of the following:

[0016] Ethyl xanthate, butyl xanthate and amyl xanthate.

[0017] Optionally, the weight m5 of the deep desulfurization agent and the dry weight m6 of the secondary middling mixed liquor satisfy the relationship:

[0018] m5:m6=(2:1000)~(6:1000).

[0019] Optionally, the deep desulfurization agent includes an alkaline regulator, a second alkyl xanthate and pine oil, wherein the alkaline regulator includes sodium hydroxide and / or potassium hydroxide;

[0020] The second alkyl xanthate comprises at least one of the following:

[0021] Ethyl xanthate, butyl xanthate and amyl xanthate.

[0022] Optionally, the weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0023] m7:m4=(0.75:1)~(0.90:1); the particle size of the fine-grained material is ≤0.074mm;

[0024] The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship:

[0025] m8:m9=(0.20:1)~(0.30:1).

[0026] Optionally, the dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0027] m10:m11=(0.35:1)~(0.40:1).

[0028] Optionally, the time of the primary flotation desulfurization is 8 minutes to 21 minutes;

[0029] The time of the secondary flotation desulfurization is 4 minutes to 12 minutes.

[0030] Optionally, the pH value of the primary raw ore slurry is 2 to 6;

[0031] The pH value of the secondary flotation desulfurization is 8-13.

[0032] Optionally, the staged desulfurization method further comprises:

[0033] The primary raw ore pulp is subjected to primary flotation desulfurization to obtain a primary middling ore mixed liquid and a primary sulfur concentrate respectively;

[0034] Concentrating the primary intermediate ore mixed solution to obtain a secondary intermediate ore mixed solution;

[0035] Mixing the deep desulfurization agent with the secondary middlings mixed solution, and then performing secondary flotation desulfurization on the secondary middlings mixed solution to obtain aluminum concentrate and secondary sulfur concentrate respectively;

[0036] The primary sulfur concentrate and the secondary sulfur concentrate are combined to obtain a sulfur concentrate.

[0037] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0038] The present application provides a staged desulfurization method for high-sulfur bauxite. Since the weight m1 of the sulfur element in the high-sulfur bauxite and the weight m2 of the high-sulfur bauxite satisfy the relationship: m1:m2≥0.03, it means that the high-sulfur bauxite contains a large amount of sulfur element. A large amount of hydrophilic substances will be formed on the surface of the high-sulfur bauxite with a high sulfur content. These hydrophilic substances will adhere to the surface of the high-sulfur bauxite, reducing the surface active sites of the sulfur-containing particles in the high-sulfur bauxite. In view of this difficulty, the staged desulfurization method first uses an acidic flotation desulfurizer and an alkaline flotation desulfurizer on the surface of the high-sulfur bauxite to remove the hydrophilicity of the alkaline flotation desulfurizer. The substances undergo an acid-base neutralization reaction to separate these hydrophilic alkaline substances from the surface of high-sulfur bauxite, thereby exposing the surface active sites of the sulfur-containing particles in the bauxite; in addition, the use of deep desulfurization agents can remove some hydrophilic salt substances on the surface of the sulfur-containing particles, exposing active sites, which helps the agents to bind to the sulfur-containing particles, so as to facilitate the floating of sulfur-containing substances in the secondary middling mixture, thereby further improving the desulfurization efficiency. Therefore, the desulfurization method at this stage can effectively increase the surface active sites of the sulfur-containing particles in the bauxite through acid flotation combined with deep desulfurization. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0041] Figure 1 A schematic flow chart of a staged desulfurization method for high-sulfur bauxite provided in an embodiment of the present application;

[0042] Figure 2 A detailed schematic diagram of a staged desulfurization method for high-sulfur bauxite provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0044] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be understood as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range; in addition, whenever a numerical range is indicated in this document, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0045] In this document, the terms "including" and "comprising" mean "including but not limited to". Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0046] It should be noted that, with respect to the prior arts (1), (2) and (3) described in the background art, the inventors have found that high-sulfur bauxite has a high sulfur content and most high-sulfur bauxite has the characteristics of a high degree of pyrite oxidation. These characteristics will cause the surface active sites of the sulfur-containing particles in the high-sulfur bauxite to be covered by hydrophilic substances, thereby affecting the binding of the desulfurization collector with the surface active sites of the sulfur-containing particles in the high-sulfur bauxite, resulting in unsatisfactory desulfurization effect.

[0047] Figure 1 A schematic flow chart of a staged desulfurization method for high-sulfur bauxite provided in an embodiment of the present application is shown by way of example;

[0048] like Figure 1 As shown, the embodiment of the present application provides a staged desulfurization method for high-sulfur bauxite, wherein the weight m1 of the sulfur element in the high-sulfur bauxite and the weight m2 of the high-sulfur bauxite satisfy the relationship: m1:m2≥0.03; the staged desulfurization method comprises:

[0049] S1. Grinding the high-sulfur bauxite to obtain high-sulfur bauxite powder;

[0050] S2. mixing an acidic flotation agent with the high-sulfur bauxite powder to mineralize the high-sulfur bauxite powder to obtain a primary raw ore slurry;

[0051] S3. The primary raw ore pulp is subjected to a flotation desulfurization to obtain a secondary ore mixed solution;

[0052] S4. The primary ore mixture is concentrated to obtain a secondary ore mixture;

[0053] S5. Mixing the deep desulfurization agent with the secondary middling mixed liquor, and then performing secondary flotation desulfurization on the secondary middling mixed liquor to obtain aluminum concentrate.

[0054] It should be noted that the mineralization process can be carried out by stirring, and stirring can improve the contact between the acidic flotation agent and the high-sulfur bauxite powder.

[0055] It should be noted that after the primary intermediate ore mixture is concentrated, not only a secondary intermediate ore mixture but also a supernatant can be obtained, and the obtained supernatant can be used as a wetting agent for grinding.

[0056] In some optional embodiments, the weight m3 of the acidic flotation reagent and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0057] m3:m4=(0.5:1000)~(5:1000);

[0058] In these embodiments, the weight m3 of the acidic flotation agent and the total weight m4 of the high-sulfur bauxite powder can satisfy the relationship: m3:m4=(0.5:1000)~(5:1000), which can promote the addition of a sufficient amount of acidic flotation agent into the high-sulfur bauxite powder. The sufficient amount of acidic flotation agent will undergo an acid-base neutralization reaction with the hydrophilic alkaline substances on the surface of the high-sulfur bauxite, so that these hydrophilic alkaline substances are separated from the surface of the high-sulfur bauxite, thereby exposing the surface active sites of the sulfur-containing particles in the high-sulfur bauxite.

[0059] The weight m3 of the acidic flotation agent and the total weight m4 of the high-sulfur bauxite powder can satisfy the relationship: m3:m4=(0.5:1000), (1:1000), (1.5:1000), (2.5:1000), (3:1000), (3.5:1000), (4:1000), (4.5:1000) or (5:1000).

[0060] In some optional embodiments, the acidic flotation reagent includes an acidic regulator, a first alkyl xanthate and pine oil, wherein the acidic regulator includes sulfuric acid and / or hydrochloric acid;

[0061] The first alkyl xanthate comprises at least one of the following:

[0062] ethyl xanthate, butyl xanthate, and amyl xanthate;

[0063] In these embodiments, the acidic flotation reagent may include an acidic regulator, an alkyl xanthate and pine oil. In addition, the acidic regulator may include sulfuric acid and / or hydrochloric acid; and the alkyl xanthate may include at least one of ethyl xanthate, butyl xanthate and amyl xanthate. The acidic regulator in the acidic flotation reagent undergoes an acid-base neutralization reaction with the hydrophilic alkaline substance on the surface of the high-sulfur bauxite, thereby exposing the surface active sites of the sulfur-containing particles in the high-sulfur bauxite, and then the alkyl xanthate and pine oil are used to float these sulfur-containing particles.

[0064] It should be noted that the acidic flotation agent may also include copper sulfate and / or ferrous sulfate and / or sodium hexametaphosphate.

[0065] In some optional embodiments, the weight m5 of the deep desulfurization agent and the dry weight m6 of the secondary middling mixed liquor satisfy the relationship:

[0066] m5:m6=(2:1000)~(6:1000);

[0067] In these embodiments, the weight m5 of the deep desulfurization agent and the dry weight m6 of the secondary middling ore mixture can satisfy the relationship: m5:m6=(2:1000)~(6:1000), which can promote the secondary middling ore mixture to have a sufficient amount of deep desulfurization agent. The sufficient amount of deep desulfurization agent can expose the surface active sites of the sulfur-containing particles and adsorb them, thereby promoting the floating of sulfur-containing substances in the secondary middling ore mixture.

[0068] The weight m5 of the deep desulfurization agent and the dry weight m6 of the secondary middling ore mixed liquor can satisfy the relationship: m5:m6=(2:1000), (2.5:1000), (3:1000), (3.5:1000), (4:1000), (4.5:1000), (5:1000), (5.5:1000) or (6:1000)

[0069] In some optional embodiments, the deep desulfurization agent includes an alkaline regulator, a second alkyl xanthate and pine oil, wherein the alkaline regulator includes sodium hydroxide and / or potassium hydroxide;

[0070] The second alkyl xanthate comprises at least one of the following:

[0071] ethyl xanthate, butyl xanthate, and amyl xanthate;

[0072] In these embodiments, the deep desulfurization agent may include an alkaline regulator, a second alkyl xanthate and pine oil, and the alkaline regulator may include sodium hydroxide and / or potassium hydroxide, and the second alkyl xanthate may include at least one of ethyl xanthate, butyl xanthate and amyl xanthate. The deep desulfurization agent may expose and adsorb the surface active sites of the sulfur-containing particles to further improve the desulfurization efficiency.

[0073] It should be noted that the alkaline regulator may also include sodium carbonate and potassium carbonate.

[0074] In some optional embodiments, the weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0075] m7:m4=(0.75:1)~(0.90:1); the particle size of the fine-grained material is ≤0.074mm;

[0076] The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship:

[0077] m8:m9=(0.20:1)~(0.30:1);

[0078] In these embodiments, the weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder can satisfy the relationship: m7:m4=(0.75:1)-(0.90:1), and the particle size of the fine-grained material is ≤0.074 mm, which can promote the presence of sufficient fine-grained material in the high-sulfur bauxite powder, and the sufficient fine-grained material can fully contact with the acidic flotation reagent, so as to promote the acidic flotation reagent to contact the surface of the high-sulfur bauxite. The hydrophilic substances can fully undergo acid-base neutralization reaction, so that these hydrophilic substances can be separated from the surface of the high-sulfur bauxite to expose the surface active sites of the sulfur-containing particles in the high-sulfur bauxite; in addition, the dry weight m8 of the primary raw ore pulp and the total weight m9 of the primary raw ore pulp can satisfy the relationship: m8:m9=(0.20:1)~(0.30:1), so as to promote the acidic flotation agent and the high-sulfur bauxite to fully desulfurize, thereby improving the grade of the aluminum concentrate.

[0079] The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder can satisfy the relationship: m7:m4=0.75:1, 0.80:1, 0.85:1 or 0.90:1.

[0080] The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry can satisfy the relationship: m8:m9=0.20:1, 0.21:1, 0.22:1, 0.23:1, 0.24:1, 0.25:1, 0.26:1, 0.27:1, 0.28:1, 0.29:1 or 0.30:1.

[0081] It should be noted that when the dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship m8:m9<0.20:1, the efficiency of the primary flotation desulfurization will be reduced; when the dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship m8:m9>0.30:1, the inclusion amount of the desulfurization foam will increase, thereby reducing the grade of the final sulfur concentrate.

[0082] In some optional embodiments, the dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0083] m10:m11=(0.35:1)~(0.40:1);

[0084] In these embodiments, the dry weight m10 of the secondary medium ore mixture and the total weight m11 of the secondary medium ore mixture can satisfy the relationship: m10:m11=(0.35:1)~(0.40:1), indicating that the secondary medium ore mixture contains a sufficient amount of desulfurized high-sulfur bauxite powder to promote sufficient secondary desulfurization and increase the mass concentration of the secondary medium ore in the secondary medium ore mixture, thereby promoting the floating of sulfur-containing substances in the secondary medium ore mixture.

[0085] The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture may satisfy the relationship: m9:m10=0.35:1, 0.36:1, 0.37:1, 0.38:1, 0.39:1 or 0.40:1.

[0086] It should be noted that, when the dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship: m10:m11<0.35:1, the weight content of the high-sulfur bauxite powder in the secondary intermediate ore mixture after desulfurization is too low, which will reduce the efficiency of secondary flotation desulfurization; when the dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship: m10:m11>0.40:1, the weight content of the high-sulfur bauxite powder in the secondary intermediate ore mixture after desulfurization is too high, and excessive desulfurized high-sulfur bauxite powder will increase the inclusion amount of desulfurization foam during the secondary flotation desulfurization process, thereby reducing the grade of the final sulfur concentrate.

[0087] In some optional embodiments, the time of the primary flotation desulfurization is 8 min to 21 min;

[0088] The secondary flotation desulfurization time is 4min to 12min;

[0089] In these embodiments, the time of the primary flotation desulfurization can be 8 minutes to 21 minutes, which can promote the primary flotation desulfurization to be fully carried out, so as to promote the acidic flotation agent and the hydrophilic alkaline substances on the surface of the high-sulfur bauxite to fully carry out the acid-base neutralization reaction, thereby promoting these hydrophilic alkaline substances to separate from the surface of the high-sulfur bauxite to expose the surface active sites of the sulfur-containing particles in the high-sulfur bauxite; in addition, the time of the secondary flotation desulfurization can be 4 minutes to 12 minutes, which can promote the secondary flotation desulfurization to be fully carried out, so that the flotation of sulfur-containing substances in the secondary middlings mixed liquor can be increased by the deep desulfurizer, so as to further improve the desulfurization efficiency.

[0090] The time for the primary flotation desulfurization can be 8 min, 10 min, 12 min, 14 min, 16 min, 18 min or 21 min.

[0091] The time for the secondary flotation desulfurization can be 4 minutes, 6 minutes, 8 minutes, 10 minutes or 12 minutes.

[0092] In some optional embodiments, the pH of the primary raw ore slurry is 2 to 6;

[0093] The pH value of the secondary flotation desulfurization is 8-13.

[0094] In these embodiments, the pH value of the primary raw ore slurry can be 2 to 6, within which the acidic flotation agent can be prompted to fully undergo an acid-base neutralization reaction with the hydrophilic substances on the surface of the high-sulfur bauxite, thereby prompting these hydrophilic substances to detach from the surface of the high-sulfur bauxite to expose the surface active sites of the sulfur-containing particles in the high-sulfur bauxite; in addition, the pH value of the secondary flotation desulfurization can be 8 to 13, which can prompt the deep desulfurization agent to fully expose the surface active sites of the sulfur-containing particles and adsorb to these exposed surface active sites, so as to improve the flotation of sulfur-containing substances in the secondary middling ore mixture, thereby further improving the desulfurization efficiency.

[0095] The pH of the primary ore slurry can be 2, 3, 4, 5 or 6.

[0096] The pH value of the secondary flotation desulfurization can be 8, 9, 10, 11, 12 or 13.

[0097] It should be noted that, when the pH value of the primary raw ore slurry is less than 2, the primary raw ore slurry with too low pH value will corrode the flotation desulfurization equipment and increase the cost of primary flotation desulfurization; when the pH value of the primary raw ore slurry is greater than 6, the primary raw ore slurry with too high pH value will hardly improve the surface properties of the high-sulfur bauxite powder in the primary raw ore slurry, thereby failing to promote the acidic flotation agent to fully react with the hydrophilic substances on the surface of the high-sulfur bauxite to undergo acid-base neutralization reaction, and thus failing to expose the surface active sites of the sulfur-containing particles in the high-sulfur bauxite.

[0098] It should be noted that when the pH value of secondary flotation desulfurization is less than 8, the secondary flotation desulfurization with too low pH value will make it difficult for the deep desulfurization agent to expose the surface active sites of the sulfur-containing particles, making it difficult to increase the flotation of sulfur-containing substances in the secondary middlings mixture through the deep desulfurization agent; when the pH value of secondary flotation desulfurization is greater than 13, the secondary flotation desulfurization ash with too high pH value will increase the cost of secondary flotation desulfurization.

[0099] Figure 2 The detailed process diagram of a stage desulfurization method of high-sulfur bauxite provided in an embodiment of the present application is exemplarily shown;

[0100] In some optional embodiments, such as Figure 2 As shown, the stage desulfurization method also includes:

[0101] S301. subjecting the primary raw ore pulp to a flotation desulfurization to obtain a primary intermediate ore mixed liquid and a primary sulfur concentrate;

[0102] S401. The primary ore mixture is concentrated to obtain a secondary ore mixture;

[0103] S501. Mixing the deep desulfurization agent with the secondary middlings mixed solution, and then performing secondary flotation desulfurization on the secondary middlings mixed solution to obtain aluminum concentrate and secondary sulfur concentrate respectively;

[0104] S601. combining the primary sulfur concentrate and the secondary sulfur concentrate to obtain a sulfur concentrate;

[0105] In these embodiments, the primary sulfur concentrate obtained by the primary flotation desulfurization and the secondary sulfur concentrate obtained by the secondary flotation are combined and processed to recover the sulfur element in the high-sulfur bauxite to obtain a higher-grade sulfur concentrate product.

[0106] The present application is further described below in conjunction with specific examples. The experimental methods in the following examples that do not specify specific conditions are usually measured according to industry standards; if there are no corresponding industry standards, they are carried out according to common international standards, conventional conditions, or conditions recommended by the manufacturer.

[0107] Example 1

[0108] like Figure 2 As shown, a staged desulfurization method for high-sulfur bauxite, the weight of sulfur element m1 of the high-sulfur bauxite and the weight of the high-sulfur bauxite m2 satisfy the relationship: m1:m2=0.0833; the staged desulfurization method includes:

[0109] S1. Grinding the high-sulfur bauxite to obtain high-sulfur bauxite powder;

[0110] S2. mixing an acidic flotation agent with high-sulfur bauxite powder to mineralize the high-sulfur bauxite powder to obtain a primary raw ore slurry;

[0111] S301. The primary raw ore pulp is subjected to a flotation desulfurization to obtain a primary intermediate ore mixed liquid and a primary sulfur concentrate;

[0112] S401. The primary ore mixture is concentrated to obtain a secondary ore mixture;

[0113] S501. The deep desulfurization agent is mixed with the secondary middlings mixed solution, and then the secondary middlings mixed solution is subjected to secondary flotation desulfurization to obtain aluminum concentrate and secondary sulfur concentrate, respectively;

[0114] S601. Combine the primary sulfur concentrate and the secondary sulfur concentrate to obtain sulfur concentrate.

[0115] The weight of the acidic flotation reagent m3 and the total weight of the high-sulfur bauxite powder m4 satisfy the relationship:

[0116] m3:m4=4.71:1000.

[0117] The types and proportions of acid flotation reagents are:

[0118] Sulfuric acid:copper sulfate:sodium hexametaphosphate:butyl xanthate:pinenol oil=40:1:0.8:4:1.3.

[0119] The weight of deep desulfurization agent m5 and the dry weight of secondary ore mixed liquor m6 satisfy the relationship:

[0120] m5:m6=5.77:1000.

[0121] The types and proportions of deep desulfurization agents are:

[0122] Sodium hydroxide: sodium carbonate: butyl xanthate: pine oil = 35:20:2:0.7.

[0123] The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0124] m7:m4=0.90:1; particle size of fine-grained materials ≤0.074mm;

[0125] The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship:

[0126] m8:m9=0.2018:1.

[0127] The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0128] m10:m11=0.3715:1.

[0129] The time for one flotation desulfurization is 21 minutes;

[0130] The time for secondary flotation desulfurization is 12 minutes.

[0131] The pH of the primary ore slurry is 2;

[0132] The pH value of secondary flotation desulfurization is 13.

[0133] Example 2

[0134] Based on the contents disclosed in Example 1, the following modifications are further made:

[0135] The weight m1 of sulfur element in high-sulfur bauxite and the weight m2 of high-sulfur bauxite satisfy the relationship: m1:m2=0.0607.

[0136] The weight of the acidic flotation reagent m3 and the total weight of the high-sulfur bauxite powder m4 satisfy the relationship:

[0137] m3:m4=3.53:1000.

[0138] The types and proportions of acid flotation reagents are:

[0139] Sulfuric acid: copper sulfate: sodium hexametaphosphate: butyl xanthate: pine oil = 30: 0.8: 0.5: 3: 1.

[0140] The weight of deep desulfurization agent m5 and the dry weight of secondary ore mixed liquor m6 satisfy the relationship:

[0141] m5:m6=3.77:1000.

[0142] The types and proportions of deep desulfurization agents are:

[0143] Potassium hydroxide:potassium carbonate:butyl xanthate:pineol oil=20:15:2:0.7.

[0144] The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0145] m7:m4=0.8632:1; the particle size of fine-grained materials is ≤0.074mm;

[0146] The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship:

[0147] m8:m9=0.2369:1.

[0148] The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0149] m10:m11=0.3598:1.

[0150] The time for one flotation desulfurization is 12 minutes;

[0151] The time for secondary flotation desulfurization is 6 minutes.

[0152] The pH of the primary ore slurry is 3;

[0153] The pH value of secondary flotation desulfurization is 10.5.

[0154] Example 3

[0155] Based on the contents disclosed in Example 1, the following modifications are further made:

[0156] The weight m1 of sulfur element in high-sulfur bauxite and the weight m2 of high-sulfur bauxite satisfy the relationship: m1:m2=0.0680.

[0157] The weight of the acidic flotation reagent m3 and the total weight of the high-sulfur bauxite powder m4 satisfy the relationship:

[0158] m3:m4=3.27:1000.

[0159] The types and proportions of acid flotation reagents are:

[0160] Hydrochloric acid: ferrous sulfate: sodium hexametaphosphate: ethyl xanthate: amyl xanthate: pine oil = 20:5:1:2:3:1.7.

[0161] The weight of deep desulfurization agent m5 and the dry weight of secondary ore mixed liquor m6 satisfy the relationship:

[0162] m5:m6=3.83:1000.

[0163] The types and proportions of deep desulfurization agents are:

[0164] Sodium hydroxide: sodium carbonate: ethyl xanthate: amyl xanthate: pine oil = 15:20:0.5:2:0.8

[0165] The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0166] m7:m4=0.8213:1; particle size of fine-grained materials ≤0.074mm;

[0167] The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship:

[0168] m8:m9=0.2458:1.

[0169] The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0170] m10:m11=0.3818:1.

[0171] The time for one flotation desulfurization is 18 minutes;

[0172] The time for secondary flotation desulfurization is 9 minutes.

[0173] The pH of the primary ore slurry is 4;

[0174] The pH value of secondary flotation desulfurization is 10.

[0175] Example 4

[0176] Based on the contents disclosed in Example 1, the following modifications are further made:

[0177] The weight m1 of sulfur element in high-sulfur bauxite and the weight m2 of high-sulfur bauxite satisfy the relationship: m1:m2=0.0402.

[0178] The weight of the acidic flotation reagent m3 and the total weight of the high-sulfur bauxite powder m4 satisfy the relationship:

[0179] m3:m4=1.5:1000.

[0180] The types and proportions of acid flotation reagents are:

[0181] Sulfuric acid: hydrochloric acid: ferrous sulfate: sodium hexametaphosphate: butyl xanthate: pine oil = 2:3:0.5:1:3:1.

[0182] The weight of deep desulfurization agent m5 and the dry weight of secondary ore mixed liquor m6 satisfy the relationship:

[0183] m5:m6=2.07:1000.

[0184] The types and proportions of deep desulfurization agents are:

[0185] Potassium hydroxide:potassium carbonate:butyl xanthate:pineol oil=4:10:5:1.7.

[0186] The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0187] m7:m4=0.7869:1; the particle size of fine-grained materials is ≤0.074mm;

[0188] The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship:

[0189] m8:m9=0.2756:1.

[0190] The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0191] m10:m11=0.3921:1.

[0192] The time for one flotation desulfurization is 10 minutes;

[0193] The time for secondary flotation desulfurization is 4 minutes.

[0194] The pH of the primary ore slurry is 5;

[0195] The pH value of secondary flotation desulfurization is 9.

[0196] Example 5

[0197] Based on the contents disclosed in Example 1, the following modifications are further made:

[0198] The weight m1 of sulfur element in high-sulfur bauxite and the weight m2 of high-sulfur bauxite satisfy the relationship: m1:m2=0.0366.

[0199] The weight of the acidic flotation reagent m3 and the total weight of the high-sulfur bauxite powder m4 satisfy the relationship:

[0200] m3:m4=0.73:1000.

[0201] The types and proportions of acid flotation reagents are:

[0202] Sulfuric acid: copper sulfate: sodium hexametaphosphate: butyl xanthate: pine oil = 3: 0.5: 0.5: 2.5: 0.8.

[0203] The weight of deep desulfurization agent m5 and the dry weight of secondary ore mixed liquor m6 satisfy the relationship:

[0204] m5:m6=2.55:1000.

[0205] The types and proportions of deep desulfurization agents are:

[0206] Sodium hydroxide: sodium carbonate: butyl xanthate: pine oil = 2.8:20:2:0.7.

[0207] The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0208] m7:m4=0.7869:1; the particle size of fine-grained materials is ≤0.074mm;

[0209] The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship:

[0210] m8:m9=0.2756:1.

[0211] The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0212] m10:m11=0.3921:1.

[0213] The time for one flotation desulfurization is 8 minutes;

[0214] The time for secondary flotation desulfurization is 4 minutes.

[0215] The pH of the primary ore slurry is 6;

[0216] The pH value of secondary flotation desulfurization is 8.

[0217] Comparative Example 1

[0218] Based on the contents disclosed in Example 1, the following modifications are further made:

[0219] Using the prior art (1) described in the background art, high-sulfur bauxite in which the weight m1 of sulfur element and the weight m2 of high-sulfur bauxite satisfy the relationship: m1:m2=0.0833 is processed.

[0220] Grinding high-sulfur bauxite and adding lime during the grinding process to obtain a grinding product; wherein the weight m11 of the fine-grained material in the grinding product and the total weight m12 of the grinding product satisfy the relationship: m11:m12=0.83:1, the pH value of the grinding product is 8; the particle size of the fine-grained material is ≤0.074 mm;

[0221] The ground products are then subjected to closed-circuit flotation desulfurization in a "one roughing, three scavenging, three concentrating" mode to obtain aluminum concentrate and sulfur concentrate respectively.

[0222] Comparative Example 2

[0223] Based on the contents disclosed in Example 1, the following modifications are further made:

[0224] Using the prior art (2) described in the background art, high-sulfur bauxite in which the weight m1 of sulfur element and the weight m2 of high-sulfur bauxite satisfy the relationship: m1:m2=0.0833 is processed.

[0225] The high-sulfur bauxite is ground, and the particle size of the ground high-sulfur bauxite powder is ≤400 meshes. The high-sulfur bauxite powder is then mixed with water to obtain a slurry with a weight concentration of 10%.

[0226] The pH of the slurry was adjusted to 9 using CaO to obtain an adjusted slurry.

[0227] The adjusted ore pulp is first stirred and mixed with sodium hexametaphosphate, and then the mixed solution obtained by the first stirring and mixing is second stirred and mixed with aluminum sulfate, and then the mixed solution obtained by the second stirring and mixing is third stirred and mixed with butyl xanthate, and then the mixed solution obtained by the third stirring and mixing is fourth stirred and mixed with pine oil to obtain a mixed ore pulp; wherein the rotation speed of the first stirring is 2400 rpm, and the time of the first stirring is 5 minutes; the rotation speed of the second stirring is 1000 rpm, and the time of the second stirring is 12 minutes.

[0228] The mixed pulp is subjected to flotation to obtain prefabricated alumina concentrate and sulfur concentrate; wherein the flotation stirring rate is 1000 rpm and the flotation stirring time is 12 minutes. The prefabricated alumina concentrate is mixed with O3 and desulfurized for 180 minutes to obtain alumina concentrate.

[0229] Comparative Example 3

[0230] Based on the contents disclosed in Example 1, the following modifications are further made:

[0231] Using the prior art (3) described in the background art, high-sulfur bauxite in which the weight m1 of sulfur element and the weight m2 of high-sulfur bauxite satisfy the relationship: m1:m2=0.0833 is processed.

[0232] Grinding high-sulfur bauxite to obtain a grinding product; wherein the weight m11 of the fine-grained material in the grinding product and the total weight m12 of the grinding product satisfy the relationship: m11:m12=0.82:1; and the particle size of the fine-grained material is ≤0.074 mm;

[0233] The grinding product is then mixed with water to obtain a high-sulfur bauxite slurry;

[0234] A shaking table is used to perform gravity separation and desulfurization on high-sulfur bauxite slurry to obtain gravity separation aluminum concentrate and gravity separation pyrite; wherein the inclination angle of the shaking table is set to 1.5°, the stroke of the shaking table is set to 14 mm, and the flushing frequency of the shaking table is set to 300 times / min;

[0235] The flotation machine is used to carry out flotation desulfurization on the re-selected aluminum concentrate. The flotation desulfurization process includes one roughing selection, three cleaning selections and three scavenging selections in sequence to obtain flotation aluminum concentrate and flotation sulfur concentrate. The obtained flotation aluminum concentrate is the final aluminum concentrate. The flotation sulfur concentrate obtained by flotation and the re-selected pyrite obtained by re-selection are combined into a comprehensive sulfur concentrate.

[0236] Comparative Example 4

[0237] Based on the contents disclosed in Example 1, the following modifications are further made:

[0238] Using the prior art (4) described in the background art, high-sulfur bauxite in which the weight m1 of sulfur element and the weight m2 of high-sulfur bauxite satisfy the relationship: m1:m2=0.0833 is processed.

[0239] The high-sulfur bauxite is ground to a grinding fineness of 75%, and then the first desulfurization roughing I is carried out. During the first desulfurization roughing I, 300 g / t of butyl xanthate and 100 g / t of frother pine oil are added to remove the sulfide middlings I. The remaining product of the flotation tank of the first desulfurization roughing I is the bauxite middlings. Then the bauxite middlings are subjected to the first desulfurization roughing II, and 100 g / t of butyl xanthate and 30 g / t of frother pine oil are added to the bauxite middlings. Pine oil is used to separate sulfide middlings Ⅱ and aluminum concentrate 2; then the sulfide middlings Ⅱ are subjected to the second step of desulfurization flotation: the sulfide middlings Ⅰ of the first step of desulfurization roughing Ⅰ and the sulfide middlings Ⅱ of the first step of desulfurization roughing Ⅱ are combined, and then 200g / t of water glass and 50g / t of butyl xanthate are added respectively to further separate the sulfur rough concentrate and aluminum concentrate 2, and then the aluminum concentrate 2 obtained by the second step of desulfurization flotation is combined with the aluminum concentrate 2 obtained by the first step of flotation to form a comprehensive aluminum concentrate.

[0240] Comparative Example 5

[0241] Based on the contents disclosed in Example 1, the following modifications are further made:

[0242] No deep desulfurization agent is added and no secondary flotation desulfurization is performed.

[0243] Comparative Example 6

[0244] Based on the contents disclosed in Example 1, the following modifications are further made:

[0245] The weight of the acidic flotation reagent m3 and the total weight of the high-sulfur bauxite powder m4 satisfy the relationship:

[0246] m3:m4=0.43:1000.

[0247] The weight of deep desulfurization agent m5 and the dry weight of secondary ore mixed liquor m6 satisfy the relationship:

[0248] m5:m6=1.9:1000.

[0249] Comparative Example 7

[0250] Based on the contents disclosed in Example 1, the following modifications are further made:

[0251] The weight of the acidic flotation reagent m3 and the total weight of the high-sulfur bauxite powder m4 satisfy the relationship:

[0252] m3:m4=5.01:1000.

[0253] The weight of deep desulfurization agent m5 and the dry weight of secondary ore mixed liquor m6 satisfy the relationship:

[0254] m5:m6=6.17:1000.

[0255] Comparative Example 8

[0256] Based on the contents disclosed in Example 1, the following modifications are further made:

[0257] The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0258] m7:m4=0.70:1.

[0259] Comparative Example 9

[0260] Based on the contents disclosed in Example 1, the following modifications are further made:

[0261] The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship:

[0262] m7:m4=1.0:1.

[0263] Comparative Example 10

[0264] Based on the contents disclosed in Example 1, the following modifications are further made:

[0265] The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0266] m10:m11=0.30:1.

[0267] Comparative Example 11

[0268] Based on the contents disclosed in Example 1, the following modifications are further made:

[0269] The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship:

[0270] m10:m11=0.50:1.

[0271] Related experiments and effect data:

[0272] The weight content of sulfur in the high-sulfur bauxite used in each embodiment and comparative example, as well as the performance parameters of the obtained aluminum concentrate and sulfur concentrate were statistically analyzed. The results are shown in Table 1.

[0273] Table 1 Performance parameters of high-sulfur bauxite raw materials, aluminum concentrate and sulfur concentrate in various embodiments and comparative examples

[0274]

[0275]

[0276] It can be seen from Table 1 that the embodiment of the present application provides a staged desulfurization method for high-sulfur bauxite. The staged desulfurization method can effectively increase the surface active sites of sulfur-containing particles in the high-sulfur bauxite by combining an acidic flotation desulfurizer with a deep desulfurization agent, so as to finally obtain an aluminum concentrate with a sulfur content of ≤0.4% by weight and a sulfur concentrate with a sulfur content of ≥36% by weight. However, according to the prior art of Comparative Examples 1 to 4, for high-sulfur bauxite with a high sulfur content, the prior art cannot reduce the sulfur content of the aluminum concentrate to below 0.4%. The main reason for this is that the high-sulfur bauxite is severely oxidized and there are hydrophilic substances on the pyrite surface of the high-sulfur bauxite, which is not conducive to the attachment of the collector in flotation desulfurization.

[0277] To summarize, the embodiment of the present application provides a stage desulfurization method for high-sulfur bauxite. In this stage desulfurization method, the high-sulfur bauxite is first ground and then subjected to a flotation desulfurization with an acidic flotation desulfurizer to obtain a primary intermediate ore and a primary sulfur concentrate. However, the sulfur content of the primary intermediate ore is still relatively high at this time. Therefore, a deep desulfurization agent is subsequently added to allow the deep desulfurization agent to expose the active sites of sulfur-containing substances in the secondary intermediate ore mixture and combine with them, which is beneficial to the floating of sulfur-containing minerals in the secondary intermediate ore mixture, so as to promote the secondary intermediate ore mixture to complete secondary desulfurization and obtain aluminum concentrate and secondary sulfur concentrate. The obtained aluminum concentrate can be used as a qualified production raw material for alumina enterprises, and then the primary sulfur concentrate and the secondary sulfur concentrate are combined into a sulfur concentrate. The obtained sulfur concentrate can be used as a raw material for sulfuric acid production to achieve comprehensive utilization of high-sulfur bauxite resources.

[0278] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown in the present application, but will conform to the widest scope consistent with the principles and novel features applied for by the present application.

Claims

1. A staged desulfurization method for high-sulfur bauxite, characterized in that: The weight m1 of the sulfur element in the high-sulfur bauxite and the weight m2 of the high-sulfur bauxite satisfy the relationship: m1:m2≥0.03; the staged desulfurization method includes: Grinding high-sulfur bauxite to obtain high-sulfur bauxite powder; Mixing an acidic flotation agent with the high-sulfur bauxite powder to mineralize the high-sulfur bauxite powder to obtain a primary raw ore pulp; The primary raw ore pulp is subjected to primary flotation desulfurization to obtain a primary intermediate ore mixed liquid; Concentrating the primary intermediate ore mixed solution to obtain a secondary intermediate ore mixed solution; The deep desulfurization agent is mixed with the secondary middling mixed liquor, and then the secondary middling mixed liquor is subjected to secondary flotation desulfurization to obtain aluminum concentrate.

2. The staged desulfurization method according to claim 1, characterized in that: The weight m3 of the acidic flotation reagent and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship: m3:m4=(0.5:1000)~(5:1000).

3. The staged desulfurization method according to claim 1 or 2, characterized in that: The acidic flotation reagent comprises an acidic regulator, a first alkyl xanthate and pine oil, wherein the acidic regulator comprises sulfuric acid and / or hydrochloric acid; The first alkyl xanthate comprises at least one of the following: Ethyl xanthate, butyl xanthate and amyl xanthate.

4. The staged desulfurization method according to claim 1, characterized in that: The weight m5 of the deep desulfurization agent and the dry weight m6 of the secondary middling mixed liquor satisfy the relationship: m5:m6=(2:1000)~(6:1000).

5. The staged desulfurization method according to claim 1 or 4, characterized in that: The deep desulfurization agent includes an alkaline regulator, a second alkyl xanthate and pine oil, wherein the alkaline regulator includes sodium hydroxide and / or potassium hydroxide; The second alkyl xanthate comprises at least one of the following: Ethyl xanthate, butyl xanthate and amyl xanthate.

6. The staged desulfurization method according to claim 1, characterized in that: The weight m7 of the fine-grained material in the high-sulfur bauxite powder and the total weight m4 of the high-sulfur bauxite powder satisfy the relationship: m7:m4=(0.75:1)~(0.90:1); the particle size of the fine-grained material is ≤0.074mm; The dry weight m8 of the primary raw slurry and the total weight m9 of the primary raw slurry satisfy the relationship: m8:m9=(0.20:1)~(0.30:1).

7. The staged desulfurization method according to claim 1, characterized in that: The dry weight m10 of the secondary intermediate ore mixture and the total weight m11 of the secondary intermediate ore mixture satisfy the relationship: m10:m11=(0.35:1)~(0.40:1).

8. The staged desulfurization method according to claim 1, characterized in that: The time of the primary flotation desulfurization is 8min to 21min; The time of the secondary flotation desulfurization is 4 minutes to 12 minutes.

9. The staged desulfurization method according to claim 1, characterized in that: The pH value of the primary raw ore slurry is 2 to 6; The pH value of the secondary flotation desulfurization is 8-13.

10. The staged desulfurization method according to claim 1, characterized in that: The stage desulfurization method also includes: The primary raw ore pulp is subjected to primary flotation desulfurization to obtain a primary middling ore mixed liquid and a primary sulfur concentrate respectively; Concentrating the primary intermediate ore mixed solution to obtain a secondary intermediate ore mixed solution; Mixing the deep desulfurization agent with the secondary middlings mixed solution, and then performing secondary flotation desulfurization on the secondary middlings mixed solution to obtain aluminum concentrate and secondary sulfur concentrate respectively; The primary sulfur concentrate and the secondary sulfur concentrate are combined to obtain a sulfur concentrate.

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