Flotation process for high-selectivity titanium minerals

Abstract

The invention relates to a high-selectivity ilmenite flotation process, belongs to the technical field of flotation, and aims to solve at least one of the problems of poor ilmenite selectivity, poor collecting performance and the like in the conventional flotation method. According to the ilmenite flotation process, the collecting agent of a specific structure is selected, the two hydroximido groups and the two imino groups are introduced into the same molecular structure, and the binding capacity between the collecting agent and metal ions can be improved through a solid-loving group composed of the two hydroximido groups; the adsorption stability of the whole collector molecules on the surface of the mineral is enhanced, and the collecting performance and selectivity of the collector molecules are improved; meanwhile, a plasma pretreatment method is adopted for the raw ore, the surface structure of the ore is changed, impurities on the surface of the ore are reduced, the reaction activity of the surface of the ore is enhanced, and the surface property difference between the ilmenite and forsterite is improved, so that collecting agent molecules can chemically react with the surface of the ilmenite under the weak acid condition, and the flotation separation efficiency of the ilmenite is improved; and the consumption of sulfuric acid is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of flotation, in particular to a highly selective ilmenite flotation process. Background Art

[0002] my country has rich reserves of titanium resources, accounting for about 28% of the world's total reserves. Ilmenite is the main source of titanium resources in my country, mainly distributed in Panzhihua and Xichang areas of Sichuan. my country's ilmenite resources show the characteristics of "more poor ores, fewer rich ores, and fine particle size", making it difficult to achieve efficient sorting, restricting the further utilization of titanium resources. Flotation is an important method for achieving efficient sorting of fine-grained mineral resources. Due to the similar surface properties of the target minerals and gangue minerals, traditional fatty acid collectors have good capture properties, but it is difficult to achieve efficient separation of the two. Arsonic acid and phosphoric acid collectors have certain capture properties and selectivity, but there are problems such as environmental pollution. Therefore, it is necessary to develop environmentally friendly and highly selective flotation collectors.

[0003] In recent years, hydroxamic acid collectors have attracted extensive attention due to their excellent flotation performance, but the functional groups of the collectors have poor selectivity and poor collection performance. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a highly selective ilmenite flotation process to solve at least one of the problems of the existing one-rough-one-fine flotation method, such as poor ilmenite selectivity, poor collection performance, and low recovery rate.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A highly selective ilmenite flotation process comprises the following steps:

[0007] (1) The raw ore is subjected to plasma pretreatment, and sodium oleate is added to perform the first flotation desliming to obtain deslimed tailings;

[0008] (2) adding a collector having a structural formula (I) to the desludging tailings under weakly acidic conditions to perform a second flotation to obtain a coarse ilmenite concentrate;

[0009] (3) subjecting the ilmenite rough concentrate to a third flotation to obtain an ilmenite concentrate;

[0010] Wherein, the collector shown in formula (I) is as follows:

[0011] R is an alkyl group.

[0012] Furthermore, in step (1), the power of the plasma pretreatment is 60-100 W, the treatment time is 3-8 min, and the treatment gas flow rate is 200-500 mL / min.

[0013] Furthermore, the plasma pretreatment uses a plasma treatment gas, and the plasma treatment gas is a mixture of argon and oxygen in a volume ratio of 1:1 to 3.

[0014] Furthermore, a frother is added in the first flotation desliming, and sulfuric acid is added in the second and third flotations.

[0015] Furthermore, the R is an alkyl group having 8 to 10 carbon atoms.

[0016] Furthermore, in step (2), the amount of collector added is 300-600 g / t.

[0017] Furthermore, the collector is prepared by the following method:

[0018] (a) dissolving glutamic acid in a methanol solution containing NaOH, adding a halogenated alkane to carry out a substitution reaction, and then acidifying with hydrochloric acid to generate a 2-(alkyl) glutaric acid with an imino group and a branched chain;

[0019] (b) dissolving the acyl chloride in methanol to obtain a mixed solution, adding 2-(alkyl) glutaric acid having an imino group and a branched chain into the mixed solution for reaction to obtain methyl 2-(alkyl) glutarate;

[0020] (c) dissolving hydroxylamine salt and alkali in methanol, dispersing and dissolving by ultrasonication, adding 2-(alkyl) glutaric acid methyl ester, heating and performing hydroxyl oximation reaction, adjusting the pH value to 5-6, filtering and drying to obtain the collector.

[0021] Furthermore, in step (a), the halogenated alkane is a chloroalkane, a bromoalkane or an iodinated alkane.

[0022] Furthermore, in step (b), the reaction temperature is 20-35° C., and the reaction time is 16-20 h.

[0023] Furthermore, in step (c), the heating temperature is 40-60° C. and the reaction time is 4-6 hours.

[0024] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0025] (1) In the ilmenite flotation process of the present invention, a collector with a specific structure is selected, and two hydroxyoxime groups and an imino group are introduced into the same molecular structure. The solid-affinity group composed of the two hydroxyoxime groups can improve the binding ability between the collector and the metal ions; while one hydroxyoxime group forms a stable chelate ring with the surface active site, the other hydroxyoxime group can rotate flexibly, which not only reduces the inductive effect and steric hindrance between the two polar groups, but also improves the matching performance of the molecule with the double active sites on the surface of ilmenite. In addition, the imino group and in the carbon chain of the collector molecule can promote the association between the collector molecules through hydrogen bonding; the adsorption stability of the collector molecule as a whole on the mineral surface is enhanced, and the capture and selectivity of the collector molecule are improved;

[0026] (2) The method of the present invention also uses a plasma pretreatment method for the raw ore, which can change the surface structure of the mineral, reduce impurities on the mineral surface, enhance the reaction activity of the mineral surface, improve the difference in surface properties between ilmenite and forsterite, and allow the collector molecules to react chemically with the ilmenite surface under weakly acidic conditions, thereby improving the flotation separation efficiency of ilmenite and reducing the amount of sulfuric acid used.

[0027] (3) The method of the present invention adopts the flotation pre-desliming method under natural pH conditions to effectively reduce the influence of gangue mudification on the flotation of ilmenite, reduce the probability of adsorption of collectors on the surface of gangue minerals, thereby improving the flotation efficiency of minerals, improving the concentrate grade and recovery rate, and reducing the consumption of reagents.

[0028] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0030] Figure 1 This is the infrared spectrum of the collector prepared in Example 1 of the present invention;

[0031] Figure 2 The mass spectrum of the collector prepared in Example 1 of the present invention;

[0032] Figure 3 This is the nuclear magnetic resonance image of the collector prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0034] A specific embodiment of the present invention discloses a highly selective ilmenite flotation process, comprising the following steps:

[0035] (1) The raw ore is subjected to plasma pretreatment, and sodium oleate is added to perform the first flotation desliming to obtain deslimed tailings;

[0036] (2) adding a collector having a structural formula (I) to the desludging tailings under weakly acidic conditions to perform a second flotation to obtain a coarse ilmenite concentrate;

[0037] (3) subjecting the ilmenite rough concentrate to a third flotation to obtain an ilmenite concentrate;

[0038] Wherein, the collector shown in formula (I) is as follows:

[0039] R is an alkyl group.

[0040] Compared with the prior art, the invention selects a collector with a specific structure in the ilmenite flotation process, introduces two hydroxyoxime groups and an imino group into the same molecular structure, and the solid-affinity group composed of the two hydroxyoxime groups can improve the binding ability between the collector and the metal ion; one hydroxyoxime group forms a stable chelate ring with the surface active site while the other hydroxyoxime group can rotate flexibly, which not only reduces the inductive effect and steric hindrance between the two polar groups, but also improves the matching performance of the molecule and the double active sites on the surface of the ilmenite; in addition, the imino group and in the carbon chain of the collector molecule can promote the association between the collector molecules through hydrogen bonding; the adsorption stability of the collector molecule as a whole on the mineral surface is enhanced, and the capture and selectivity of the collector molecule are improved; at the same time, a plasma pretreatment method is adopted for the raw ore, which can change the mineral surface structure, reduce impurities on the mineral surface, enhance the mineral surface reaction activity, improve the difference in surface properties of ilmenite and forsterite, and enable the collector molecule to react chemically with the ilmenite surface under weakly acidic conditions, thereby improving the flotation separation efficiency of the ilmenite and reducing the amount of sulfuric acid used. In addition, the flotation pre-desliming method under natural pH conditions can effectively reduce the impact of gangue mudification on ilmenite flotation, reduce the probability of collector adsorption on the surface of gangue minerals, thereby improving mineral flotation efficiency, improving concentrate grade and recovery rate, and reducing reagent consumption.

[0041] In a specific embodiment, in step (1), the power of the plasma pretreatment is 60-100 W, for example, 60 W, 65 W, 70 W, 75 W, 80 W, 85 W, 90 W, 95 W, 100 W, the treatment time is 3-8 min, for example, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, and the treatment gas flow rate is 200-500 mL / min, for example, 200 mL / min, 250 mL / min, 300 mL / min, 350 mL / min, 400 mL / min, 450 mL / min, 500 mL / min.

[0042] In a specific embodiment, the plasma pretreatment uses a plasma treatment gas, and the plasma treatment gas is a mixture of argon and oxygen in a volume ratio of 1:1 to 3.

[0043] It should be noted that if there is only argon gas and no oxygen, the plasma cleaning machine only has the function of cleaning surface impurities. When there is oxygen, the surface oxidation of ilmenite can be made more hydrophilic, and the divalent iron ions are oxidized to trivalent iron ions, which is more conducive to the adsorption of collectors. The surface oxidation of forsterite (gangue) is more hydrophilic, and the surface properties of the two minerals obtained after the final pretreatment are more different, which is conducive to flotation. The volume ratio of the present invention is selected to ensure that ilmenite is not over-oxidized, so that its surface oxidation degree is too large, and hydrophilicity is enhanced. If over-oxidation can make both mineral surfaces have strong hydrophilicity, the difference is reduced. Therefore, the feeding ratio of oxygen is controlled.

[0044] In a specific embodiment, a frother is added in the first flotation desliming, and sulfuric acid is added in the second and third flotations.

[0045] Preferably, the foaming agent is methyl isobutyl carbinol.

[0046] Specifically, in step (1), the pretreated raw ore is dispersed in water, and sodium oleate and a frother are added to perform the first flotation desliming;

[0047] Specifically, the addition amount of sodium oleate is 600-800 g / t, for example, 600 g / t, 650 g / t, 700 g / t, 750 g / t, 800 g / t.

[0048] In step (2), a collector is added to the desludging tailings to be evenly dispersed, sulfuric acid is added to adjust the pH value to 6 to 6.5, and a second flotation is performed to obtain a coarse ilmenite concentrate;

[0049] Specifically, the amount of collector added is 300-600 g / t, for example, 300 g / t, 350 g / t, 400 g / t, 450 g / t, 500 g / t, 550 g / t, 600 g / t.

[0050] In step (3), sulfuric acid is added to the crude ilmenite concentrate to adjust the pH value to 6-6.5, and a third flotation is performed to obtain an ilmenite concentrate.

[0051] In a specific embodiment, R is an alkyl group with 8-10 carbon atoms, preferably, R is an octyl group or a decyl group. When R is an alkyl group with 8-10 carbon atoms, the collector has better capture and selectivity, and low or high carbon atoms will affect the capture and selectivity.

[0052] It should be noted that the raw ore in the present invention is calcium-magnesium-rich ilmenite, the gangue mineral is forsterite or calcite, and the TiO2 grade in the raw ore is ≤13%.

[0053] In a specific embodiment, the collector is prepared by the following method:

[0054] (a) dissolving glutamic acid in a methanol solution containing NaOH, adding a halogenated alkane to carry out a substitution reaction, and then acidifying with hydrochloric acid to generate a 2-(alkyl) glutaric acid with an imino group and a branched chain;

[0055] (b) dissolving the acyl chloride in methanol to obtain a mixed solution, adding 2-(alkyl) glutaric acid having an imino group and a branched chain into the mixed solution for reaction to obtain methyl 2-(alkyl) glutarate;

[0056] (c) dissolving hydroxylamine salt and alkali in methanol, dispersing and dissolving by ultrasonication, adding 2-(alkyl) glutaric acid methyl ester, heating and performing hydroxyl oximation reaction, adjusting the pH value to 5-6, filtering and drying to obtain the collector.

[0057] In a specific embodiment, in step (a), the halogenated alkane is a chloroalkane, a bromoalkane or an iodinated alkane.

[0058] Specifically, in step (a), the molar ratio of the alkyl halide to glutamic acid is 1:0.7-0.8, for example, 1:0.7, 1:0.71, 1:0.72, 1:0.73, 1:0.74, 1:0.75, 1:0.76, 1:0.77, 1:0.78, 1:0.79, 1:0.8, and hydrochloric acid is added to a pH value of 5.

[0059] In a specific embodiment, in step (b), the reaction temperature is 20-35°C, for example, 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 35°C, and the reaction time is 16-20h, for example, 16h, 16.5h, 17h, 17.5h, 18h, 18.5h, 19h, 19.5h, 20h.

[0060] Specifically, in step (b), the molar ratio of the 2-(alkyl) glutaric acid having an imino group and a branched chain to the acyl chloride is 1:2 to 2.5, for example, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, 1:2.5.

[0061] In a specific embodiment, in step (c), the heating temperature is 40-60°C, for example, 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, and the reaction time is 4-6h, for example, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5.0h, 5.2h, 5.4h, 5.6h, 5.8h, 6h.

[0062] Specifically, in step (c), the molar ratio of 2-(alkyl)glutaric acid methyl ester, hydroxylamine salt and base is 1:2-2.5:4-5, for example, 1:2:4, 1:2.1:4.2, 1:2.2:4.4, 1:2.3:4.6, 1:2.4:4.8, 1:2.5:5.

[0063] The collector of the present invention not only has two hydroxyoxime groups, which have excellent capture and selectivity, but also has three carbon atoms between the two hydroxyoxime groups, which makes the collector molecule have certain flexibility, and the two polar functional groups can be adjusted through the spatial distribution of the active sites to match the active sites on the mineral surface in a better way. In addition, the imino groups in the molecules can be bridged to each other through hydrogen bonding, so that the collector molecules are stably arranged on the mineral surface in a network structure, thereby improving the hydrophobicity of the mineral surface.

[0064] The flotation method of the present invention can be used not only for ilmenite, but also for the flotation of phosphate ore, rutile, fluorite, tungsten ore and the like.

[0065] The technical solution of the present invention is further explained below in conjunction with specific embodiments.

[0066] Example 1

[0067] A highly selective ilmenite flotation process of this embodiment comprises the following steps:

[0068] (1) Plasma pretreatment of the raw ore, wherein the raw ore is ilmenite, the plasma treatment power is 60 W, the treatment time is 8 min, the treatment gas flow rate is 200 mL / min, and the plasma treatment uses a treatment gas, which is a mixture of argon and oxygen in a volume ratio of 1:1;

[0069] The pretreated raw ore is dissolved in water, and 800 g / t sodium oleate and 1 drop of frother are added to carry out the first flotation desliming to obtain deslimed tailings;

[0070] (2) adding 500 g / t of collector to the desludging tailings to disperse them evenly, adding sulfuric acid to adjust the pH value to 6-6.5, and performing a second flotation to obtain a coarse ilmenite concentrate;

[0071] (3) adding sulfuric acid to the ilmenite crude concentrate to adjust the pH value to 6-6.5, and performing a third flotation to obtain an ilmenite concentrate;

[0072] Wherein, the collector structural formula of this embodiment is as follows:

[0073]

[0074] Wherein, the preparation method of the collector of this embodiment is as follows:

[0075] (a) 1-Bromooctane (10 g) and glutamic acid were weighed in a molar ratio of 1:0.7, glutamic acid was dissolved in a methanol solution containing NaOH (pH = 10.3-10.8), 1-Bromooctane was added, and the mixture was heated to 45°C (control the reaction pH>10) for 5 h. After the reaction, 1.0 mol / L HCl was added to adjust the pH of the resulting mixture to 5, the white precipitate was filtered and washed with a mixture of acetone and water, and then crystallized twice in an equal mixture of ethanol and water to obtain 2-(octylamino)glutaric acid.

[0076] (b) Weighing 2-(octylamine) glutaric acid (10 g) and acetamide in a molar ratio of 1:2, dissolving acetamide in methanol, stirring for 5 minutes, then adding 2-(octylamine) glutaric acid to the mixed solution, and then reacting at 20-35° C. for 16-20 hours to obtain 2-(octylamine) glutaric acid methyl ester;

[0077] (c) 2-(octylamine) glutaric acid methyl ester (5 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:2 to 2.5:4 to 5, and hydroxylamine hydrochloride and NaOH were dissolved in 40 mL of methanol, respectively, and ultrasonically dispersed and dissolved. After mixing, the mixture was stirred in an ice-water bath for 0.5 h to fully free the hydroxylamine, and then 2-(octylamine) glutaric acid methyl ester was added, and the temperature was raised to 40° C. and reacted for 6 h to obtain 2-(octylamine)-N,N'-dicarboxylic acid. Sodium hydroxypentanediamine; acidify the solution with 1.0 mol / L hydrochloric acid to adjust the pH value of the solution to 5-6, filter to obtain a crude product of 2-(octylamine)-N,N'-dihydroxypentanediamine, disperse the crude product of 2-(octylamine)-N,N'-dihydroxypentanediamine in a 15% acetic acid solution, filter with a sand core funnel to remove the 15% acetic acid solution, and dry to obtain a pure product of 2-(octylamine)-N,N'-dihydroxypentanediamine (collector).

[0078] The infrared spectrum of the collector prepared in this example is as follows Figure 1 As shown in the mass spectrum Figure 2 As shown, the NMR images are Figure 3 shown.

[0079] Example 2

[0080] The highly selective ilmenite flotation process of this embodiment is the same as that of Example 1, except that the plasma treatment power is 80 W, the treatment time is 5.5 min, the treatment gas flow rate is 350 mL / min, and the treatment gas is a mixture of argon and oxygen in a volume ratio of 1:2.

[0081] Wherein, the preparation method of the collector of this embodiment is as follows:

[0082] (a) 1-Bromooctane (10 g) and glutamic acid were weighed in a molar ratio of 1:0.75, glutamic acid was dissolved in a methanol solution containing NaOH (pH = 10.3-10.8), 1-Bromooctane was added, and the mixture was heated to 55°C (control the reaction pH>10) for 4.5 hours. After the reaction, 1.0 mol / L HCl was added to adjust the pH of the resulting mixture to 5, the white precipitate was filtered and washed with a mixture of acetone and water, and then crystallized twice in an equal mixture of ethanol and water to obtain 2-(octylamino)glutaric acid.

[0083] (b) 2-(octylamino)glutaric acid (10 g) and acetamide were weighed in a molar ratio of 1:2.25, acetamide was first dissolved in methanol, stirred for 5 min, and then 2-(octylamino)glutaric acid was added to the mixed solution, followed by reaction at 27° C. for 18 h to obtain 2-(octylamino)glutaric acid methyl ester;

[0084] (c) 2-(Octylamine) glutaric acid methyl ester (5 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:2.25:4.5, and hydroxylamine hydrochloride and NaOH were dissolved in 40 mL of methanol, respectively, and ultrasonically dispersed and dissolved. After mixing, the mixture was stirred in an ice-water bath for 1.0 h to fully free the hydroxylamine, and then 2-(Octylamine) glutaric acid methyl ester was added, and the temperature was raised to 50° C. for 5 h to obtain 2-(Octylamine)-N,N'-dihydro-1-nitropropane. Sodium hydroxypentanediamine; acidify the solution with 1.0 mol / L hydrochloric acid to adjust the pH value of the solution to 5-6, filter to obtain a crude product of 2-(octylamine)-N,N'-dihydroxypentanediamine, disperse the crude product of 2-(octylamine)-N,N'-dihydroxypentanediamine in a 15% acetic acid solution, filter with a sand core funnel to remove the 15% acetic acid solution, and dry to obtain a pure product of 2-(octylamine)-N,N'-dihydroxypentanediamine (collector).

[0085] The collector prepared in this example was also tested in Example 1, and the results were basically the same. Due to limited space, they are not listed one by one.

[0086] The highly selective ilmenite flotation process of this embodiment is the same as that of Example 1, except that the plasma treatment power is 100 W, the treatment time is 8 min, the treatment gas flow rate is 500 mL / min, and the treatment gas is a mixture of argon and oxygen in a volume ratio of 1:3.

[0087] Wherein, the preparation method of the collector of this embodiment is as follows:

[0088] (a) 1-Bromooctane (10 g) and glutamic acid were weighed in a molar ratio of 1:0.8, glutamic acid was dissolved in a methanol solution containing NaOH (pH = 10.3-10.8), 1-Bromooctane was added, and the mixture was heated to 65°C (control the reaction pH>10) for 4 hours. After the reaction, 1.0 mol / L HCl was added to adjust the pH of the resulting mixture to 5, and the white precipitate was filtered and washed with a mixture of acetone and water, and then crystallized twice in an equal mixture of ethanol and water to obtain 2-(octylamino)glutaric acid.

[0089] (b) 2-(octylamino)glutaric acid (10 g) and acetamide were weighed in a molar ratio of 1:2.5, acetamide was first dissolved in methanol, stirred for 5 min, and then 2-(octylamino)glutaric acid was added to the mixed solution, followed by reaction at 35° C. for 16 h to obtain 2-(octylamino)glutaric acid methyl ester;

[0090] (c) 2-(octylamine) glutaric acid methyl ester (5 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:2.5:5, and hydroxylamine hydrochloride and NaOH were respectively dissolved in 40 mL of methanol, ultrasonically dispersed and dissolved, and then mixed and stirred in an ice-water bath for 1.5 h to fully free hydroxylamine, and then 2-(octylamine) glutaric acid methyl ester was added, and the temperature was raised to 60° C. and reacted for 4 h to obtain 2-(octylamine)-N,N'-dihydroxypentanediamine sodium; 1.0 mol / L hydrochloric acid was used to acidify the solution to adjust the pH to 5-6, and filtered to obtain a crude product of 2-(octylamine)-N,N'-dihydroxypentanediamine, and the crude product of 2-(octylamine)-N,N'-dihydroxypentanediamine was dispersed in a 15% acetic acid solution, and the 15% acetic acid solution was removed by filtering with a sand core funnel, and dried to obtain a pure product of 2-(octylamine)-N,N'-dihydroxypentanediamine (collector).

[0091] The collector prepared in this example was also tested in Example 1, and the results were basically the same. Due to limited space, they are not listed one by one.

[0092] Example 4

[0093] The flotation process of a highly selective ilmenite in this embodiment is the same as that in Example 1, except that the structural formula of the collector is as follows:

[0094]

[0095] The preparation method of the collector of the present embodiment is as follows:

[0096] (a) 1-Bromodecane (10 g) and glutamic acid were weighed in a molar ratio of 1:0.7, glutamic acid was dissolved in a methanol solution containing NaOH (pH = 10.3-10.8), 1-bromooctane was added, and the mixture was heated to 55°C (control the reaction pH>10) for 4.5 hours. After the reaction, 1.0 mol / L HCl was added to adjust the pH of the resulting mixture to 5, the white precipitate was filtered and washed with a mixture of acetone and water, and then crystallized twice in an equal mixture of ethanol and water to obtain 2-(octylamino)glutaric acid.

[0097] (b) 2-(decylamino)glutaric acid (10 g) and acetamide were weighed in a molar ratio of 1:2, acetamide was first dissolved in methanol, stirred for 5 min, and then 2-(decylamino)glutaric acid was added to the mixed solution, followed by reaction at 20° C. for 20 h to obtain methyl 2-(octylamino)glutarate;

[0098] (c) 2-(Decylamine) glutaric acid methyl ester (5 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:2:4, and hydroxylamine hydrochloride and NaOH were respectively dissolved in 40 mL of methanol, ultrasonically dispersed and dissolved, and then mixed and stirred in an ice-water bath for 0.5 h to fully free hydroxylamine, and then 2-(Decylamine) glutaric acid methyl ester was added, and the temperature was raised to 40°C for reaction for 6 h to obtain 2-(Decylamine)-N,N'-dihydroxypentanediamine sodium; 1.0 mol / L hydrochloric acid was used to acidify the solution to adjust the pH to 5-6, and filtered to obtain a crude product of 2-(Decylamine)-N,N'-dihydroxypentanediamine, and the crude product of 2-(Decylamine)-N,N'-dihydroxypentanediamine was dispersed in a 15% acetic acid solution, and the 15% acetic acid solution was removed by filtering with a sand core funnel, and dried to obtain a relatively pure product of 2-(Decylamine)-N,N'-dihydroxypentanediamine.

[0099] Example 5

[0100] The highly selective ilmenite flotation process of this embodiment is the same as that of Example 4, except that the plasma treatment power is 80 W, the treatment time is 5.5 min, the treatment gas flow rate is 350 mL / min, and the treatment gas is a mixture of argon and oxygen in a volume ratio of 1:2.

[0101] The preparation method of the collector of the present embodiment is as follows:

[0102] (a) 1-Bromodecane (10 g) and glutamic acid were weighed in a molar ratio of 1:0.75, glutamic acid was dissolved in a methanol solution containing NaOH (pH = 10.3-10.8), 1-bromooctane was added, and the mixture was heated to 55°C (control the reaction pH>10) for 4.5 hours. After the reaction, 1.0 mol / L HCl was added to adjust the pH of the resulting mixture to 5, the white precipitate was filtered and washed with a mixture of acetone and water, and then crystallized twice in an equal mixture of ethanol and water to obtain 2-(octylamino)glutaric acid.

[0103] (b) 2-(Decylamino)glutaric acid (10 g) and acetamide were weighed at a molar ratio of 1:2.25, acetamide was first dissolved in methanol, stirred for 5 min, and then 2-(Decylamino)glutaric acid was added to the mixed solution, followed by reaction at 27° C. for 18 h to obtain 2-(octylamino)glutaric acid methyl ester;

[0104] (c) 2-(Decylamine) glutaric acid methyl ester (5 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:2.25:4.5, and hydroxylamine hydrochloride and NaOH were respectively dissolved in 40 mL of methanol, ultrasonically dispersed and dissolved, and then mixed and stirred in an ice-water bath for 1.0 h to fully free hydroxylamine, and then 2-(Decylamine) glutaric acid methyl ester was added, and the temperature was raised to 50° C. and reacted for 5 h to obtain 2-(Decylamine)-N,N'-dihydroxypentanediamine sodium; 1.0 mol / L hydrochloric acid was used to acidify the solution to adjust the pH to 5-6, and filtered to obtain a crude product of 2-(Decylamine)-N,N'-dihydroxypentanediamine, and the crude product of 2-(Decylamine)-N,N'-dihydroxypentanediamine was dispersed in a 15% acetic acid solution, and the 15% acetic acid solution was removed by filtering with a sand core funnel, and dried to obtain a relatively pure product of 2-(Decylamine)-N,N'-dihydroxypentanediamine.

[0105] Example 6

[0106] The highly selective ilmenite flotation process of this embodiment is the same as that of Example 4, except that the plasma treatment power is 100 W, the treatment time is 8 min, the treatment gas flow rate is 500 mL / min, and the treatment gas is a mixture of argon and oxygen in a volume ratio of 1:3.

[0107] The preparation method of the collector of the present embodiment is as follows:

[0108] (a) 1-Bromodecane (10 g) and glutamic acid were weighed in a molar ratio of 1:0.8, glutamic acid was dissolved in a methanol solution containing NaOH (pH = 10.3-10.8), 1-bromooctane was added, and the mixture was heated to 65°C (control the reaction pH>10) for 4 hours. After the reaction, 1.0 mol / L HCl was added to adjust the pH of the resulting mixture to 5, and the white precipitate was filtered and washed with a mixture of acetone and water, and then crystallized twice in an equal mixture of ethanol and water to obtain 2-(octylamino)glutaric acid.

[0109] (b) 2-(Decylamino)glutaric acid (10 g) and acetamide were weighed in a molar ratio of 1:2.5, acetamide was first dissolved in methanol, stirred for 5 min, and then 2-(Decylamino)glutaric acid was added to the mixed solution, followed by reaction at 35° C. for 16 h to obtain 2-(octylamino)glutaric acid methyl ester;

[0110] (c) 2-(Decylamine) glutaric acid methyl ester (5 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:2.5:5, and hydroxylamine hydrochloride and NaOH were respectively dissolved in 40 mL of methanol, ultrasonically dispersed and dissolved, and then mixed and stirred in an ice-water bath for 1.5 h to fully free hydroxylamine, and then 2-(Decylamine) glutaric acid methyl ester was added, and the temperature was raised to 60° C. and reacted for 4 h to obtain 2-(Decylamine)-N,N'-dihydroxypentanediamine sodium; 1.0 mol / L hydrochloric acid was used to acidify the solution to adjust the pH to 5-6, and filtered to obtain a crude product of 2-(Decylamine)-N,N'-dihydroxypentanediamine, and the crude product of 2-(Decylamine)-N,N'-dihydroxypentanediamine was dispersed in a 15% acetic acid solution, and the 15% acetic acid solution was removed by filtering with a sand core funnel, and dried to obtain a relatively pure product of 2-(Decylamine)-N,N'-dihydroxypentanediamine.

[0111] Comparative Example 1

[0112] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that in step (1), the step of plasma pretreatment of the raw ore is removed.

[0113] Comparative Example 2

[0114] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that in step (1), the first flotation desliming step is removed.

[0115] Comparative Example 3

[0116] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that in step (1), the plasma pretreatment power is 100 W, the treatment time is 10 min, the gas flow rate is 600 mL / min, and the argon:oxygen ratio is 1:5.

[0117] Comparative Example 4

[0118] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that the structural formula of the collector is as follows:

[0119]

[0120] Test Example 1

[0121] The flotation processes of Examples 1-6 and Comparative Examples 1-4 were respectively adopted, and specifically, the raw ore was an actual ilmenite ore with a grade of 12.54% for flotation. 200 g of actual ilmenite ore was weighed in each group and dissolved in 0.5 L of water. The time for the first flotation desliming, the second flotation and the third flotation was the same, and each flotation time was 5 min. A frother was added and stirred for 5 min, and the scraping time was 5 min. The flotation results are shown in Table 1.

[0122] Table 1

[0123]

[0124] It can be seen from the above table that, under the same other conditions, only the carbon chain length of the collector is changed. The longer the carbon chain length of the collector, the stronger the capture and the weaker the selectivity. Under the same flotation conditions, the collector with a longer carbon chain leads to a slight decrease in the grade of ilmenite and an increase in the recovery rate. Comparative Example 1 Compared with Example 1, plasma pretreatment can effectively improve the surface property difference between the target mineral and the gangue mineral, promote the selective flotation of the target mineral by the collector under weakly acidic conditions, and improve the grade of the concentrate.

[0125] Compared with Comparative Example 2, the flotation desliming process of Example 1 can remove part of the gangue impurities in the mineral in advance, reduce the slime formation of the ore pulp and its influence on the post-flotation, and promote the adsorption process of the flotation collector on the surface of the target mineral.

[0126] Compared with Comparative Example 3, Example 1 has poor flotation effect under the plasma treatment conditions of the present invention.

[0127] Compared with Example 4, the two polar groups in the bifunctional collector of the present invention have higher flexibility, making it easy to match the active sites on the surface of the mineral, making the selectivity stronger. The method of the present invention maximizes the removal efficiency of impurities in the combined pulp of gangue minerals by combining plasma pretreatment and flotation desludging process, promotes the targeted action process of the selective collector, and improves the flotation grade and recovery rate.

[0128] Test Example 2

[0129] The flotation process of Example 2 was adopted, and the method of Experimental Example 1 was followed, except that the collector in step (2) was replaced with octyl hydroxamic acid or MOH. The flotation effect is shown in Table 2.

[0130] Table 2 Flotation effect of different collectors and addition amounts on actual ilmenite ore

[0131]

[0132] According to Table 2, the collector of the present invention has a better collecting effect at a reduced dosage than octylhydroxamic acid or MOH at a high dosage, which indicates that the collector of the present invention significantly reduces the dosage of the agent.

[0133] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A highly selective ilmenite flotation process, characterized in that: The steps include: (1) The raw ore is subjected to plasma pretreatment, and sodium oleate is added to perform the first flotation desliming to obtain deslimed tailings; (2) adding a collector having a structural formula (I) to the desludging tailings under weakly acidic conditions to perform a second flotation to obtain a coarse ilmenite concentrate; (3) subjecting the ilmenite rough concentrate to a third flotation to obtain an ilmenite concentrate; Wherein, the collector shown in formula (I) is as follows: R is an alkyl group.

2. A highly selective ilmenite flotation process according to claim 1, characterized in that: In step (1), the power of the plasma pretreatment is 60-100 W, the treatment time is 3-8 min, and the treatment gas flow rate is 200-500 mL / min.

3. A highly selective ilmenite flotation process according to claim 2, characterized in that: The plasma pretreatment uses a plasma treatment gas, which is a mixture of argon and oxygen in a volume ratio of 1:1 to 3.

4. A highly selective ilmenite flotation process according to claim 1, characterized in that: A frother is added during the first flotation desliming, and sulfuric acid is added during the second and third flotations.

5. A highly selective ilmenite flotation process according to any one of claims 1 to 4, characterized in that: The R is an alkyl group having 8 to 10 carbon atoms.

6. A highly selective ilmenite flotation process according to any one of claims 1 to 4, characterized in that: In step (2), the amount of collector added is 300-600 g / t.

7. A highly selective ilmenite flotation process according to any one of claims 1 to 4, characterized in that: The collector is prepared by the following method: (a) dissolving glutamic acid in a methanol solution containing NaOH, adding a halogenated alkane to carry out a substitution reaction, and then acidifying with hydrochloric acid to generate a 2-(alkyl) glutaric acid with an imino group and a branched chain; (b) dissolving the acyl chloride in methanol to obtain a mixed solution, adding 2-(alkyl) glutaric acid having an imino group and a branched chain into the mixed solution for reaction to obtain methyl 2-(alkyl) glutarate; (c) dissolving hydroxylamine salt and alkali in methanol, dispersing and dissolving by ultrasonication, adding 2-(alkyl) glutaric acid methyl ester, heating and performing hydroxyl oximation reaction, adjusting the pH value to 5-6, filtering and drying to obtain the collector.

8. A highly selective ilmenite flotation process according to claim 7, characterized in that: In step (a), the halogenated alkane is a chloroalkane, a brominated alkane or an iodinated alkane.

9. A highly selective ilmenite flotation process according to claim 7, characterized in that: In step (b), the reaction temperature is 20-35° C. and the reaction time is 16-20 h.

10. A highly selective ilmenite flotation process according to claim 7, characterized in that: In step (c), the heating temperature is 40-60° C. and the reaction time is 4-6 hours.

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