Efficient flotation process for minerals

Abstract

The invention relates to a flotation process of ilmenite, belongs to the technical field of flotation, and solves the problems of poor ilmenite collecting effect, poor selectivity and the like in the existing method. According to the ilmenite flotation process, the collecting agent of a specific structure is selected, the collecting agent has a hydroximido and carboxyl structure at the same time, the number of polar groups in the collecting agent is small, meanwhile, raw ore is subjected to microwave pretreatment in flotation, the surface of ilmenite is activated through microwave pretreatment, and the surface of the ilmenite is activated through microwave pretreatment; the reactive activity of active sites on the mineral surface is enhanced, the content of Fe < 3 + > on the surface of the ilmenite is increased, a chemical reaction between hydroximido and carboxyl in the collecting agent and the surface of the ilmenite is promoted, the flotation separation efficiency of the ilmenite is improved, and the collecting property, selectivity and recovery rate of the ilmenite are improved.

Description

Technical Field

[0001] The invention relates to the technical field of flotation, in particular to a flotation process of ilmenite. 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 have 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 collection properties, but it is difficult to achieve efficient separation of the two. Arsonic acid and phosphoric acid collectors have certain collectors and selectivities, 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 in ilmenite flotation processes due to their excellent flotation performance. However, the collectivity and selectivity of hydroxamic acid collectors containing only one functional group are still insufficient, making it difficult to achieve selective separation of low-grade ilmenite and gangue minerals. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a flotation process for ilmenite to solve at least one of the problems of poor ilmenite capture effect, poor selectivity, low recovery rate, etc. in the existing one-rough-one-fine flotation method.

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

[0006] A flotation process for ilmenite, comprising the following steps: subjecting the raw ore to microwave pretreatment, cooling it, and then adding it to a first flotation tank for a first flotation to obtain a coarse concentrate, and adding the coarse concentrate to a second flotation tank for a second flotation to obtain an ilmenite concentrate;

[0007] In the first flotation, the collector is added twice, and the mass ratio of the first and second additions is 0.5-2:

[0008] The chemical structural formula of the collector is shown in formula (I):

[0009]

[0010] Wherein, R is an alkyl group.

[0011] Furthermore, the microwave power in the microwave pretreatment is 500-800W, and the treatment time is 120-180s.

[0012] Furthermore, sulfuric acid and a frother are added during the first flotation and the second flotation.

[0013] Furthermore, R is octyl or decyl.

[0014] Furthermore, the raw ore is calcium-magnesium-rich ilmenite, and the gangue minerals are forsterite and / or calcite.

[0015] Furthermore, the collector is prepared by the following method:

[0016] (1) dissolving an ester compound and a catalyst in a dispersant, and then adding a halogenated alkane to carry out a substitution reaction to obtain an ester compound with a branched chain;

[0017] (2) dissolving the hydroxylamine salt and the alkali in methanol, dispersing and dissolving by ultrasonication, adding the branched ester compound, heating to carry out hydroxyl oximation reaction, adjusting the pH, filtering, and drying to obtain the collector.

[0018] Furthermore, in step (1), the ester compound is dimethyl malonate or diethyl malonate;

[0019] The catalyst is one of sodium hydride, sodium ethoxide, sodium methoxide, sodium cyanoborohydride, sodium hexamethyldisilazide, potassium hexamethyldisilazide or lithium hexamethyldisilazide;

[0020] The dispersant is methanol or ethanol;

[0021] The halogenated alkane is one of normal chloroalkane, normal bromoalkane or normal iodoalkane.

[0022] Furthermore, in step (2), the hydroxylamine salt is one of hydroxylamine hydrochloride, hydroxylamine carbonate or hydroxylamine sulfate.

[0023] Furthermore, in step (2), the heating temperature is 30 to 60°C.

[0024] Furthermore, in step (2), the base is one of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] (1) In the ilmenite flotation process of the present invention, a collector with a specific structure is selected. The collector of the present invention has both a hydroxyoxime structure and a carboxyl structure. The number of polar groups in the collector is small. At the same time, the raw ore is subjected to microwave pretreatment during flotation. The microwave pretreatment activates the surface of the ilmenite, enhances the reactivity of the active sites on the mineral surface, and improves the Fe 3+The content of the iodine is promoted to chemically react with the hydroxyoxime group and the carboxyl group in the collector and the surface of the ilmenite, thereby improving the flotation separation efficiency of the ilmenite. In the process of the present invention, a specific collector is used and the raw ore is pretreated with microwaves. In the first flotation, the collector is dosed twice to increase the contact probability between the collector and the mineral surface, thereby improving the capture and selectivity of the ilmenite, as well as the concentrate grade and recovery rate, and can reduce the amount of the collector.

[0027] (2) The two polar groups of the collector molecule prepared by the present invention, the hydroxyoxime group and the carboxyl group, are combined to form a multi-dentate chelating solid-affinic group, which can improve the matching chelating ability between the collector solid-affinic group and the metal ions. The hydroxyoxime group forms a stable chelating ring with the surface active site of the raw ore treated with microwaves, while the carboxyl group rotates flexibly, which not only reduces the inductive effect and steric hindrance between the two polar groups, but also promotes the molecular association through intermolecular hydrogen bonding, thereby enhancing the overall adsorption stability of the collector molecule on the mineral surface and improving the capture and selectivity of the collector molecule.

[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 flotation process of ilmenite, comprising the following steps: subjecting the raw ore to microwave pretreatment, cooling it, and then adding it to a first flotation tank for a first flotation to obtain a coarse concentrate, and adding the coarse concentrate to a second flotation tank for a second flotation to obtain an ilmenite concentrate;

[0035] In the first flotation, the collector is added twice, and the mass ratio of the first and second additions is 0.5-2, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2:

[0036] The chemical structural formula of the collector is shown in formula (I):

[0037]

[0038] Wherein, R is an alkyl group.

[0039] Compared with the prior art, the ilmenite flotation process of the present invention selects a collector with a specific structure. The collector of the present invention has both a hydroxyoxime group and a carboxyl group structure, and the number of polar groups in the collector is small. At the same time, the raw ore is subjected to microwave pretreatment during flotation, and the microwave pretreatment activates the surface of the ilmenite, enhances the reactivity of the active sites on the mineral surface, and improves the Fe 3+ The content of the collector is promoted to chemically react with the hydroxyoxime group and the carboxyl group in the collector and the surface of the ilmenite, thereby improving the flotation separation efficiency of the ilmenite. In the process of the present invention, a specific collector is used and the raw ore is pretreated with microwaves. In the first flotation, the collector is dosed twice to increase the collision probability between the collector and the mineral surface, thereby improving the collectability and selectivity of the ilmenite, as well as the concentrate grade and recovery rate, and can reduce the amount of the collector.

[0040] In a specific embodiment, the microwave power in the microwave pretreatment is 500-800 W, for example, 500 W, 550 W, 600 W, 650 W, 700 W, 750 W, 800 W, and the treatment time is 120-180 s, for example, 120 s, 130 s, 140 s, 150 s, 160 s, 170 s, 180 s.

[0041] In a specific embodiment, sulfuric acid and a frother are also added during the first flotation and the second flotation.

[0042] Preferably, the foaming agent is methyl isobutyl carbinol.

[0043] Preferably, sulfuric acid is added to make the pH of the slurry equal to 4-5.

[0044] Preferably, the collector is dissolved in water, the mineral is dispersed in water, sulfuric acid is added to make the pH of the slurry be 4-5, and then a small amount of frother is added to perform the first flotation or the second flotation.

[0045] Specifically, the two flotation times are the same, and only sulfuric acid and frother are added in the second flotation.

[0046] 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.

[0047] Preferably, the raw ore is placed in a corundum magnetic boat and subjected to microwave pretreatment in a microwave oven, and the temperature is lowered by a cold quenching method.

[0048] Preferably, the raw ore is calcium-magnesium-rich ilmenite, the gangue minerals are forsterite and / or calcite, and the TiO2 grade in the raw ore is ≤12%.

[0049] In a specific embodiment, the collector is prepared by the following method:

[0050] (1) dissolving an ester compound and a catalyst in a dispersant, and then adding a halogenated alkane to carry out a substitution reaction to obtain an ester compound with a branched chain;

[0051] (2) dissolving the hydroxylamine salt and the alkali in methanol, dispersing and dissolving by ultrasonication, adding the branched ester compound, heating to carry out hydroxyl oximation reaction, adjusting the pH, filtering, and drying to obtain the collector.

[0052] In a specific embodiment, in step (1), the ester compound is dimethyl malonate or diethyl malonate;

[0053] The catalyst is one of sodium hydride, sodium ethoxide, sodium methoxide, sodium cyanoborohydride, sodium hexamethyldisilazide, potassium hexamethyldisilazide or lithium hexamethyldisilazide;

[0054] The dispersant is methanol or ethanol;

[0055] The halogenated alkane is one of normal chloroalkane, normal bromoalkane or normal iodoalkane.

[0056] In a specific embodiment, in step (2), the hydroxylamine salt is one of hydroxylamine hydrochloride, hydroxylamine carbonate or hydroxylamine sulfate.

[0057] In a specific embodiment, in step (2), the heating temperature is 30-60°C, for example, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C.

[0058] In a specific embodiment, in step (2), the base is one of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.

[0059] The collector of the invention is prepared by substitution reaction and hydroxyoximation reaction, and the preparation method is simple and easy to operate.

[0060] The two polar groups of the hydroxyoxime group and the carboxyl group in the collector molecule prepared by the present invention are combined to form a multi-dentate chelating solid-philic group, which can improve the matching chelating ability between the collector solid-philic group and the metal ion. The hydroxyoxime group forms a stable chelating ring with the surface active site of the raw ore treated with microwaves, and the carboxyl group rotates flexibly, which not only reduces the inductive effect and steric hindrance between the two polar groups, but also promotes the molecular association through the intermolecular hydrogen bonding effect of the carboxyl group, thereby enhancing the adsorption stability of the collector molecule as a whole on the mineral surface, and improving the capture and selectivity of the collector molecule.

[0061] 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.

[0062] The technical solution of the present invention is further explained below in conjunction with specific embodiments.

[0063] Example 1

[0064] A flotation process of ilmenite in this embodiment comprises the following steps: pre-treating the raw ore with microwaves in a 600W microwave oven for 160 seconds, cooling the raw ore with a cold quenching method, dispersing the pre-treated raw ore in water, adding the raw ore to a first flotation tank for a first flotation to obtain a coarse concentrate, and adding the coarse concentrate to a second flotation tank for a second flotation to obtain an ilmenite concentrate;

[0065] The collector was added twice in the first flotation, with the mass ratio of the first to the second addition being 2:1. Sulfuric acid and frother (5 μL) were added in both the first and second flotations, but no collector was added in the second flotation. Sulfuric acid was added in the first flotation to make the pulp pH = 5, and sulfuric acid was added in the second flotation to make the pulp pH = 4.

[0066] The structural formula of the collector of this embodiment is as follows:

[0067]

[0068] The preparation method of the collector of the present embodiment is as follows:

[0069] (1) Weigh diethyl malonate (16.02 g), sodium ethoxide and 1-bromooctane in a molar ratio of 1:1.1:1.1, disperse diethyl malonate and sodium ethoxide in ethanol and mix them evenly, first react at 60°C in a 250 mL round-bottom flask for 1.5 h, then slowly dropwise add 1-bromooctane, and quickly raise the temperature to 100°C and heat to react for 8 h. After the reaction is completed, remove ethanol by rotary distillation, and then extract with saturated sodium chloride solution 4 to 6 times.

[0070] (2) Octylmalonate (5.00 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:4.2:8.6, and hydroxylamine hydrochloride and NaOH were respectively dissolved in 40 mL of a mixed solution of water and methanol (water: methanol = 3:1), ultrasonically dispersed and dissolved, and then mixed and stirred in an ice-water bath for 0.5 h to allow hydroxylamine to be fully freed. Octylmalonate was then added, and the temperature was raised to 40° C. for reaction for 14 h to obtain 2-N-hydroxyamide-sodium dodecanoate.

[0071] (3) Acidify the solution with 1.0 mol / L hydrochloric acid to adjust the pH to 5-6, filter, and obtain a white solid as a crude product of 2-N-hydroxyamide-decanoic acid. Disperse the crude product of 2-N-hydroxyamide-decanoic acid in ethyl acetate, filter with a sand core funnel to remove the ethyl acetate, dry, and grind to obtain a relatively pure product of 2-N-hydroxyamide-decanoic acid (i.e., collector).

[0072] The infrared spectrum of the collector prepared in this example is as follows Figure 1 As shown, 1211cm -1 The absorption peak at 1625cm belongs to the non-conjugated CN bond absorption band; -1 The absorption peak at 1630 cm is attributed to the bending vibration of the primary amine NH; -1 The absorption peak at 1526cm is attributed to the C=O stretching vibration in the amide group; -1 The absorption peak at is attributed to the NH bending vibration in the amide group.

[0073] The mass spectrum of the collector prepared in this example is as follows Figure 2 As shown, the molecular weight M of 2-N-hydroxyamide-decanoic acid is 231.29 (C 11 H 21 O4N), the measured molecular weight of sodium addition is 254.13 (C 11 H 21 O4N+Na).

[0074] The nuclear magnetic resonance image of the collector prepared in this example is as follows Figure 3 shown.

[0075] Example 2

[0076] The flotation process of ilmenite in this embodiment is the same as that in Embodiment 1, except that the collector is added twice in the first flotation, and the mass ratio of the first and second additions is 1:2.

[0077] The preparation method of the collector of the present embodiment is as follows:

[0078] (1) Weigh diethyl malonate (16.02 g), sodium ethoxide and 1-bromooctane in a molar ratio of 1:1.1:1.25, disperse diethyl malonate and sodium ethoxide in ethanol and mix them evenly, first react at 70°C in a 250 mL round-bottom flask for 1 h, then slowly dropwise add 1-bromooctane, and quickly raise the temperature to 110°C, heat and react for 7 h, remove ethanol by rotary distillation after the reaction, and then extract with saturated sodium chloride solution 4 to 6 times,

[0079] (2) Octylmalonate (5.00 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:4.35:8.8, and hydroxylamine hydrochloride and NaOH were respectively dissolved in 40 mL of a mixed solution of water and methanol (water: methanol = 3:1), ultrasonically dispersed and dissolved, and then mixed and stirred in an ice-water bath for 1.0 h to allow hydroxylamine to be fully freed. Octylmalonate was then added, and the temperature was raised to 45° C. for reaction for 12 h to obtain 2-N-hydroxyamide-sodium dodecanoate.

[0080] (3) Acidify the solution with 1.0 mol / L hydrochloric acid to adjust the pH to 5-6, filter, and obtain a white solid as a crude product of 2-N-hydroxyamide-decanoic acid. Disperse the crude product of 2-N-hydroxyamide-decanoic acid in ethyl acetate, filter with a sand core funnel to remove the ethyl acetate, dry, and grind to obtain a relatively pure product of 2-N-hydroxyamide-decanoic acid (i.e., collector).

[0081] Example 3

[0082] The flotation process of ilmenite in this embodiment is the same as that in Embodiment 1, except that the collector is added twice in the first flotation, and the mass ratio of the first and second additions is 1:1.

[0083] The preparation method of the collector of the present embodiment is as follows:

[0084] (1) Weigh diethyl malonate (16.02 g), sodium ethoxide and 1-bromooctane in a molar ratio of 1:1.1:1.4, disperse diethyl malonate and sodium ethoxide in ethanol and mix them evenly, first react at 80°C in a 250 mL round-bottom flask for 0.5 h, then slowly dropwise add 1-bromooctane, and quickly raise the temperature to 120°C, heat and react for 6 h, remove ethanol by rotary distillation after the reaction, and then extract with saturated sodium chloride solution 4 to 6 times,

[0085] (2) Octylmalonate (5.00 g), hydroxylamine hydrochloride and NaOH were weighed in a molar ratio of 1:4.5:9.0, and hydroxylamine hydrochloride and NaOH were respectively dissolved in 40 mL of a mixed solution of water and methanol (water: methanol = 3:1), ultrasonically dispersed and dissolved, and then mixed and stirred in an ice-water bath for 1.5 h to fully free hydroxylamine, and then octylmalonate was added, and the temperature was raised to 50° C. for reaction for 10 h to obtain 2-N-hydroxyamide-sodium dodecanoate.

[0086] (3) Acidify the solution with 1.0 mol / L hydrochloric acid to adjust the pH to 5-6, filter, and obtain a white solid as a crude product of 2-N-hydroxyamide-decanoic acid. Disperse the crude product of 2-N-hydroxyamide-decanoic acid in ethyl acetate, filter with a sand core funnel to remove the ethyl acetate, dry, and grind to obtain a relatively pure product of 2-N-hydroxyamide-decanoic acid (i.e., collector).

[0087] Example 4

[0088] The flotation process of ilmenite in this embodiment is the same as that in embodiment 3, except that the structural formula of the collector is as follows:

[0089]

[0090] The collector of this embodiment is prepared by the following method:

[0091] (1) Diethyl malonate (16.02 g), sodium ethoxide and 1-bromodecane were weighed in a molar ratio of 1:1.1:1.1, diethyl malonate and sodium ethoxide were dispersed in ethanol and mixed evenly, and the mixture was first heated at 60°C in a 250 mL round-bottom flask for 1.5 h, and then 1-bromodecane was slowly added dropwise, and the temperature was quickly raised to 100°C and heated for 8 h. After the reaction was completed, ethanol was removed by rotary distillation, and then extracted with saturated sodium chloride solution for 4 to 6 times to obtain diethyl 2-decylmalonate product.

[0092] (2) Weigh 2-decylmalonate (5.00 g), hydroxylamine hydrochloride and NaOH in a molar ratio of 1:4.2:8.6, and dissolve hydroxylamine hydrochloride and NaOH in 40 mL of a mixed solution of water and methanol (water: methanol = 3:1), respectively, and dissolve by ultrasonic dispersion. Then, mix them and stir in an ice-water bath for 1 h to fully free hydroxylamine. Then, add 2-decylmalonate, heat to 50° C. and react for 10 h to obtain 2-N-hydroxyamide-sodium decanoate.

[0093] (3) Acidify the solution with 1.0 mol / L hydrochloric acid to adjust the pH to 4-5, filter, and obtain a white solid as a crude product of 2-N-hydroxyamide-dodecanoic acid. Disperse the crude product of 2-N-hydroxyamide-decanoic acid in ethyl acetate, filter with a sand core funnel to remove the ethyl acetate, dry, and grind to obtain a relatively pure product of 2-N-hydroxyamide-dodecanoic acid.

[0094] Example 5

[0095] The flotation process of ilmenite in this embodiment is the same as that in embodiment 4, except that the mass ratio of the collector added twice in the first flotation is 2:1.

[0096] The collector of this embodiment is prepared by the following method:

[0097] (1) Diethyl malonate (16.02 g), sodium ethoxide and 1-bromodecane were weighed in a molar ratio of 1:1.1:1.25, diethyl malonate and sodium ethoxide were dispersed in ethanol and mixed evenly, and the mixture was first heated at 70°C in a 250 mL round-bottom flask for 1.0 h, and then 1-bromodecane was slowly added dropwise, and the temperature was quickly raised to 110°C and heated for 7 h. After the reaction was completed, ethanol was removed by rotary distillation, and then extracted with saturated sodium chloride solution for 4 to 6 times to obtain diethyl 2-decyl malonate product.

[0098] (2) Weigh 2-decylmalonate (5.00 g), hydroxylamine hydrochloride and NaOH in a molar ratio of 1:4.35:8.8, and dissolve hydroxylamine hydrochloride and NaOH in 40 mL of a mixed solution of water and methanol (water: methanol = 3:1), respectively, and dissolve by ultrasonic dispersion. Then, mix them and stir in an ice-water bath for 1 h to fully free hydroxylamine. Then, add 2-decylmalonate, heat to 50° C. and react for 12 h to obtain sodium 2-N-hydroxyamide-decanoate.

[0099] (3) Acidify the solution with 1.0 mol / L hydrochloric acid to adjust the pH to 4-5, filter, and obtain a white solid as a crude product of 2-N-hydroxyamide-dodecanoic acid. Disperse the crude product of 2-N-hydroxyamide-decanoic acid in ethyl acetate, filter with a sand core funnel to remove the ethyl acetate, dry, and grind to obtain a relatively pure product of 2-N-hydroxyamide-dodecanoic acid.

[0100] Example 6

[0101] The flotation process of ilmenite in this embodiment is the same as that in embodiment 4, except that the mass ratio of the collector added twice in the first flotation is 1:2.

[0102] The collector of this embodiment is prepared by the following method:

[0103] (1) Diethyl malonate (16.02 g), sodium ethoxide and 1-bromodecane were weighed in a molar ratio of 1:1.1:1.4, diethyl malonate and sodium ethoxide were dispersed in ethanol and mixed evenly, and the mixture was first heated at 80°C in a 250 mL round-bottom flask for 0.5 h, and then 1-bromodecane was slowly added dropwise, and the temperature was quickly raised to 120°C and heated for 6 h. After the reaction was completed, ethanol was removed by rotary distillation, and then extracted with saturated sodium chloride solution for 4 to 6 times to obtain diethyl 2-decyl malonate product.

[0104] (2) Weigh 2-decylmalonate (5.00 g), hydroxylamine hydrochloride and NaOH in a molar ratio of 1:4.5:9.0, and dissolve hydroxylamine hydrochloride and NaOH in 40 mL of a mixed solution of water and methanol (water: methanol = 3:1), respectively, and dissolve by ultrasonic dispersion. Then, mix them and stir in an ice-water bath for 1 h to fully free hydroxylamine. Then, add 2-decylmalonate, heat to 50° C. and react for 14 h to obtain 2-N-hydroxyamide-sodium decanoate.

[0105] (3) Acidify the solution with 1.0 mol / L hydrochloric acid to adjust the pH to 4-5, filter, and obtain a white solid as a crude product of 2-N-hydroxyamide-dodecanoic acid. Disperse the crude product of 2-N-hydroxyamide-decanoic acid in ethyl acetate, filter with a sand core funnel to remove the ethyl acetate, dry, and grind to obtain a relatively pure product of 2-N-hydroxyamide-dodecanoic acid.

[0106] Example 7

[0107] The flotation process of ilmenite in this embodiment is the same as that in Example 1, except that the microwave power of the raw ore microwave pretreatment is 800 W and the pretreatment time is 120 s.

[0108] Example 8

[0109] The flotation process of ilmenite in this embodiment is the same as that in Example 1, except that the microwave power of the raw ore microwave pretreatment is 500 W and the pretreatment time is 180 s.

[0110] Comparative Example 1

[0111] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that the raw ore is not subjected to microwave pretreatment.

[0112] Comparative Example 2

[0113] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that the collector is added once in the first flotation instead of twice.

[0114] Comparative Example 3

[0115] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that the mass ratio of the collector added twice in the first flotation is 2:5.

[0116] Comparative Example 4

[0117] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that the mass ratio of the collector added twice in the first flotation is 2.1:1.

[0118] Comparative Example 5

[0119] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that the microwave power of the raw ore microwave pretreatment is 160 W and the pretreatment time is 180 s.

[0120] Comparative Example 6

[0121] The flotation process of ilmenite in this comparative example is the same as that in Example 1, except that 3-decanoylamino-3-hydroxycarbamoylpropionic acid is used as the collector.

[0122] Test Example 1

[0123] 2-N-hydroxyamide-decanoic acid, 3-decanoylamino-3-hydroxycarbamoyl propionic acid and sodium oleate prepared in Example 1 were respectively used as collectors to test the flotation effects of the three collectors on ilmenite single mineral, as follows: 2g of ilmenite single mineral was weighed and dispersed in a plexiglass flotation cell containing 40mL of deionized water, and the pH was adjusted to 5 with a sulfuric acid solution of appropriate concentration, and stirred for 3min; a certain amount of collector solution (specific addition amount is shown in Table 1) was added to the above flotation cell, stirred for 3min, and the flotation time was 3min. The flotation results are shown in Table 1.

[0124] Table 1

[0125]

[0126] As can be seen from Table 1, when the amount of collector is low, the recovery rate of ilmenite is low. With the increase of the amount of reagent, the recovery rate of ilmenite continues to increase. When the amount of collector is 25 mg / L, the recovery rate of ilmenite with 2-N-hydroxyamide-decanoic acid as collector reaches 95.50%. The recovery rates of 3-decanoylamino-3-hydroxycarbamoyl propionic acid and sodium oleate as ilmenite collectors are 70.60% and 79.40%, respectively, which are lower than 2-N-hydroxyamide-decanoic acid. This is because the hydroxyoxime group in 2-N-hydroxyamide-decanoic acid forms a chelate ring with the titanium and iron on the surface of ilmenite, and the carboxyl group forms a chemical bond with the titanium and iron on the surface of ilmenite, so that the collector forms a stable network structure on the surface of ilmenite, thereby enhancing its capture property. 3-Decanylamino-3-hydroxycarbamoylpropionic acid interacts with the active sites on the surface of ilmenite through carboxyl and hydroxyoxime groups. The amide groups in the chain reduce the flexibility of the molecule, restrict the rotational changes of the hydroxyoxime groups in space, and reduce the adsorption of the collector on the surface of ilmenite.

[0127] Test Example 2

[0128] 2-N-hydroxyamide-decanoic acid, 3-decanoylamino-3-hydroxyaminoformyl propionic acid, and sodium oleate prepared in Example 1 were used as collectors to test the flotation effects of the three collectors on forsterite. Specifically, 2g of forsterite was weighed and dispersed in a plexiglass flotation cell containing 40mL of deionized water, and the pH was adjusted to 5 with a sulfuric acid solution of appropriate concentration, and stirred for 3min; a certain amount of collector solution (the specific amount added is shown in Table 2) was added to the above flotation cell, stirred for 3min, and the flotation time was 3min. The flotation results are shown in Table 2.

[0129] Table 2

[0130]

[0131] As can be seen from Table 2, the recovery rate of 2-N-hydroxyamide-decanoic acid on forsterite in different added amounts of collectors is low. With the increase of the dosage of the agent, the recovery rate of forsterite gradually increases. When the dosage of the collector is 25 mg / L, the recovery rate of forsterite reaches 4.55%. The recovery rates of 3-decanoylamino-3-hydroxyaminoformyl propionic acid and sodium oleate as ilmenite collectors are 31.55% and 61.36% respectively. The capture of forsterite by these two collectors is stronger than that of 2-N-hydroxyamide-decanoic acid. This is because the negative charge value of the carboxyl group of sodium oleate is high, which can be adsorbed with the magnesium site on the surface of forsterite, so it has a strong capture of forsterite. 3-decanoylamino-3-hydroxyaminoformyl propionic acid has three polar groups, the electron enrichment of the solid-philic group, and the high reaction activity, so it also has a strong capture of forsterite.

[0132] Test Example 3

[0133] 2-N-hydroxyamide-decanoic acid prepared in Example 1 and commercially available MOH were used as collectors, and the two collectors were tested for flotation of ilmenite ore with a grade of 11.54%. Specifically, 200 g of ilmenite ore with a grade of 11.54% was weighed and dispersed in a 0.5 L organic glass flotation tank, and the pH was adjusted to 5 with a sulfuric acid solution of appropriate concentration, and stirred for 5 minutes, and 600 g / t of different types of flotation collectors were added. The flotation time was 5 minutes each time, and a frother was added and stirred for 5 minutes. The scraping time was 5 minutes to obtain ilmenite concentrate. The flotation results are shown in Table 3.

[0134] Table 3

[0135]

[0136] As can be seen from Table 3, the ilmenite concentrate grade is 29.98% when the conventional MOH collector is used for flotation of ilmenite, which is 18.44% higher than the original ore, and the recovery rate is 41.15%. However, the ilmenite concentrate grade can reach 37.06% and the recovery rate can reach 64.61% when the 2-N-hydroxyamide-decanoic acid of the present invention is used as the collector for flotation of ilmenite. Therefore, the separation efficiency of ilmenite by the collector 2-N-hydroxyamide-decanoic acid of the present invention is higher.

[0137] Test Example 4

[0138] The flotation process of Examples 1-3, 7-8 and Comparative Examples 1-6 was used to flotate the actual ilmenite ore with a grade of 11.54%. 200 g of the actual ilmenite ore was weighed in each group and dissolved in 0.5 L of water. The amount of collector added was 600 g / t. The flotation time was 5 min each time. The frother was added and stirred for 5 min. The scraping time was 5 min. The flotation results are shown in Table 4.

[0139] Table 4

[0140]

[0141] By comparing Comparative Example 1 in Table 4 with Example 1, after the ilmenite is pretreated by microwave, the flotation grade and recovery rate of the ilmenite are improved, and the selective adsorption capacity of the collector to the ilmenite is improved.

[0142] Comparative Example 2 Compared with Example 1, adding the collector twice can effectively improve the recovery rate and grade of ilmenite.

[0143] Compared with Example 1-3, the different proportions of the collector added twice in Comparative Example 3-4 have a great influence on the recovery rate and grade of ilmenite. When the mass ratio of the first and second additions is 0.5-2, the recovery rate and grade of ilmenite are higher. When it is not within the above range, the recovery rate and grade of ilmenite are significantly reduced.

[0144] Compared with Examples 1, 7 and 8, in Comparative Example 5, the recovery rate and grade of ilmenite are reduced under the microwave power and pretreatment time not in the present invention.

[0145] Comparative Example 6 Compared with Example 1, the recovery rate and grade of ilmenite are reduced by using 3-decanoylamino-3-hydroxyaminoformylpropionic acid as a collector. This is because 3-decanoylamino-3-hydroxyaminoformylpropionic acid acts on the active sites on the surface of ilmenite through carboxyl and hydroxyoxime groups, and the amide group in the chain not only reduces the molecular flexibility, but also limits the rotational change of the hydroxyoxime group in space, thereby reducing the adsorption of the collector on the surface of ilmenite.

[0146] The inventor has also conducted the above test on other embodiments, and the results are basically the same. Due to limited space, they are not listed one by one.

[0147] 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 flotation process for ilmenite, characterized in that: The method comprises the following steps: pre-treating the raw ore with microwaves, cooling it, and then adding it to a first flotation tank for a first flotation to obtain a coarse concentrate, and adding the coarse concentrate to a second flotation tank for a second flotation to obtain an ilmenite concentrate; In the first flotation, the collector is added twice, and the mass ratio of the first and second additions is 0.5-2: The chemical structural formula of the collector is shown in formula (I): Wherein, R is an alkyl group.

2. The flotation process of ilmenite according to claim 1, characterized in that: The microwave power in the microwave pretreatment is 500-800W, and the treatment time is 120-180s.

3. The flotation process of ilmenite according to claim 1, characterized in that: Sulfuric acid and frother are also added during the first and second flotation.

4. A flotation process for ilmenite according to any one of claims 1 to 3, characterized in that: R is octyl or decyl.

5. A flotation process for ilmenite according to any one of claims 1 to 3, characterized in that: The raw ore is calcium-magnesium-rich ilmenite, and the gangue minerals are forsterite and / or calcite.

6. A flotation process for ilmenite according to any one of claims 1 to 3, characterized in that: The collector is prepared by the following method: (1) dissolving an ester compound and a catalyst in a dispersant, and then adding a halogenated alkane to carry out a substitution reaction to obtain an ester compound with a branched chain; (2) dissolving the hydroxylamine salt and the alkali in methanol, dispersing and dissolving by ultrasonication, adding the branched ester compound, heating to carry out hydroxyl oximation reaction, adjusting the pH, filtering, and drying to obtain the collector.

7. The flotation process of ilmenite according to claim 6, characterized in that: In step (1), the ester compound is dimethyl malonate or diethyl malonate; The catalyst is one of sodium hydride, sodium ethoxide, sodium methoxide, sodium cyanoborohydride, sodium hexamethyldisilazide, potassium hexamethyldisilazide or lithium hexamethyldisilazide; The dispersant is methanol or ethanol; The halogenated alkane is one of normal chloroalkane, normal bromoalkane or normal iodoalkane.

8. The flotation process of ilmenite according to claim 6, characterized in that: In step (2), the hydroxylamine salt is one of hydroxylamine hydrochloride, hydroxylamine carbonate or hydroxylamine sulfate.

9. The flotation process of ilmenite according to claim 6, characterized in that: In step (2), the heating temperature is 30 to 60°C.

10. The flotation process of ilmenite according to claim 6, characterized in that: In step (2), the alkali is one of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.

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