Composite branched alkyl salicylhydroxamic acid collectors and their flotation applications

Abstract

The application belongs to the field of mineral flotation, and particularly discloses a composite branched alkyl salicylhydroxamic acid collector and a flotation application thereof. The composite branched alkyl salicylhydroxamic acid collector comprises formula 1A (1A), formula 1B (1B) and formula 1C (1C). The branched alkyl is introduced into the collector, so that the hydrophobic ability and the collecting ability are improved, and the separation and enrichment of strategic metal oxide minerals such as copper, iron, tin, tungsten, titanium and rare earth are improved.

Description

Technical Field

[0001] This invention relates to the field of mineral flotation, and more specifically to the field of collectors. Background Technology

[0002] Salicylic acid hydroxamic acid is a commonly used hydroxamic acid collector in mineral flotation, but its hydrophobicity is insufficient for oxide ores such as ilmenite, copper ore, cassiterite, and rare earth ores, resulting in low flotation separation and enrichment efficiency. This poor hydrophobicity leads to increased collector dosage, significantly increasing flotation costs. Therefore, introducing hydrophobic groups into the molecule of salicylic acid to improve the flotation recovery rate of valuable oxide minerals has been extensively studied. Patent document CN108554643A discloses a method for synthesizing decyl salicylic acid and its application. This invention uses decyl salicylic acid as a raw material, and after esterification and hydroxamication reactions, decyl salicylic acid is obtained, exhibiting excellent collecting ability for tungsten, tin, and rare earth ores. Patent document CN101618369A discloses a method for preparing 5-alkylsalicylic acid and its application in hematite flotation. The invention uses methyl 5-alkylsalicylate as a raw material to prepare 5-alkylsalicylic acid, which can be used in combination with fatty acids to improve the flotation recovery of hematite.

[0003] However, the alkyl salicylic acid (ester) raw material used in the existing alkyl salicylic acid process is very expensive and difficult to procure on a large scale, which actually limits the industrial application of alkyl salicylic acid. Summary of the Invention

[0004] To address the problems existing in the prior art, the primary objective of this invention is to provide a composite branched alkyl salicylic acid collector, which aims to provide a novel collector that is low in cost, easy to synthesize, and combines excellent collecting ability and selectivity.

[0005] The second objective of this invention is to provide the application of the aforementioned composite branched alkyl salicylic acid collector in flotation.

[0006] Modifying the benzene ring of salicylic acid hydroxamic acid with a hydrophobic segment promises to improve its harvesting ability, but existing methods are costly, and the harvesting selectivity needs further improvement. To address these issues, this invention provides the following improvement:

[0007] Complex branched alkyl salicylic acid collectors, including formula 1A, formula 1B and formula 1C;

[0008] Formula 1A

[0009] Formula 1B

[0010] Formula 1C;

[0011] In Formulas 1A to 1C, R is a C3 to C6 branched alkyl group; M is H, Na, K or NH4.

[0012] The composite collector described in this invention can improve the mineral collection ability and selectivity based on the synergistic effect between the components. In addition, the collector can be prepared by a simple and low-cost method.

[0013] In Formulas 1A to 1C, R is isopropyl, tert-butyl, or tert-amyl. The preferred tert-amyl group can synergistically interact with the constituent both intramolecularly and intermolecularly, contributing to further enhanced collection and selectivity.

[0014] In this invention, the R of the branched alkyl group, in combination with the aforementioned formulas 1A to 1C, can further synergistically improve the mineral's collecting ability and selectivity.

[0015] In this invention, the mass ratio of Formula 1A, Formula 1B and Formula 1C is 25~60:10~30:25~50; for example, it can be further 30~40:15~28:30~48.

[0016] In this invention, the composite collector may also contain Formula 1D;

[0017] Formula 1D

[0018] In Equation 1D, M is H, Na, K, or NH4;

[0019] In the complex branched alkyl salicylhydroxyoxime collector, the content of Formula 1D is less than 30 wt.%, and can be further 0.5~5 wt.%.

[0020] The composite branched alkyl salicylic acid hydroxyoxime collector of the present invention can be obtained by mixing the aforementioned components, or it can be prepared by the following one-pot synthesis method of the present invention without separation. The steps are as follows: Formula 2 and Formula 3 are subjected to a substitution reaction under concentrated sulfuric acid to obtain a substituted product containing Formula 4A to Formula 4C. Subsequently, the substituted product, hydroxylamine, and base are subjected to a hydroxyoxime reaction to obtain the composite branched alkyl salicylic acid hydroxyoxime collector.

[0021] Formula 2

[0022] Formula 3

[0023] .

[0024] In this invention, based on the combination of the substitution reaction and the hydroxyoxime reaction, the composite collector can be obtained without separation. In addition, the raw materials of the preparation method of this invention are all inexpensive commodities, and the synthesis conditions are easy to achieve.

[0025] In this invention, during the substitution reaction, the molar ratio of Formula 2, Formula 3, and concentrated sulfuric acid is 1:1~3:1~4; more specifically, it can be 1:1~2:2~3.5.

[0026] The temperature for the substitution reaction is 0℃~15℃, and the reaction time is 1~5 hours;

[0027] Preferably, the molar ratio of Formula 2 and hydroxylamine is 1:1.1~2.1; more preferably, it can be 1:1.1~1.3.

[0028] Preferably, the temperature of the hydroxyoximation reaction is 0℃~50℃; the reaction time is 2~4 hours.

[0029] In this invention, the base can be MOH, wherein M includes Na, K or NH4.

[0030] Preferably, the molar ratio of Formula 2 and the base is 1:2~3; more preferably, it can be 1:2~2.2.

[0031] In this invention, a composite collector in which M is Na, K or NH4 is prepared by the aforementioned hydroxyoxime reaction.

[0032] Furthermore, acidification can be performed after the hydroxyoximation reaction as needed. This allows for the preparation of a composite collector with M = H.

[0033] The present invention also provides an application of a composite branched alkyl salicylhydroxyoxime acid collector, which is used as a collector for the flotation of metal oxide ores.

[0034] In this invention, the metal oxide ore includes oxide ore of at least one metallic element selected from rare earth, iron, copper, tungsten, tin, zinc, lead, titanium, tantalum, niobium, aluminum, manganese, chromium, and cobalt; preferably, it includes at least one selected from ilmenite, cassiterite, bastnaesite, and malachite.

[0035] In this invention, the pH of the flotation pulp is 1.5~10.5, preferably 5~9; further, it can be 7±0.5. The composite collector described in this invention has wide pH adaptability, and can still achieve excellent target ore recovery and selectivity, especially under relatively green near-neutral flotation conditions.

[0036] In this invention, based on the weight of the ore fed to the flotation, the dosage of the composite branched alkyl salicylhydroxyoxime collector is 100~2000g / t, preferably 200~500g / t.

[0037] For example, the concentration of the collector in the slurry can be 1~10×10⁻⁶. -5 M; further, it can be 1.5~7.5×10 -5 M.

[0038] The flotation method of the present invention includes, for example, the following steps:

[0039] Step (1): Prepare mineral slurry by crushing and mixing the ore;

[0040] Step (2): Add flotation reagents to the slurry from step (1) for flotation, and filter to collect concentrate and tailings; the flotation reagents include the flotation collectors.

[0041] Beneficial effects

[0042] The composite collector described in this invention can synergistically improve the mineral collection rate and selectivity.

[0043] The composite collector described in this invention can be easily prepared using simple methods and low-cost raw materials, resulting in low cost and excellent performance of the synthesized product. Attached Figure Description

[0044] Figure 1 and Figure 2 To synthesize the isolated 5-isopropylsalicylic acid in Example 1 1 HNMR spectra and 13 CNMR spectrum.

[0045] Figure 3 and Figure 4 This is the synthesis of 5-tert-butylsalicylic acid isolated in Example 2. 1 HNMR spectra and 13 CNMR spectrum.

[0046] Figure 5 and Figure 6 This is the 5-tert-pentylsalicylic acid isolated in Synthesis Example 3. 1 HNMR spectra and 13 CNMR spectrum. Detailed Implementation

[0047] The following embodiments are intended to further illustrate the content of the present invention, but not to limit the scope of protection of the present invention. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0048] The flotation method described in this invention, except for the use of the collector described in this invention, has all other operations and parameters that are well known. For example, the steps of using the flotation collector for flotation include:

[0049] Step (1): The ore is crushed and mixed to obtain a slurry;

[0050] Step (2): Add flotation reagents to the slurry from step (1) for flotation, and collect the flotation concentrate and tailings; the flotation reagents include the alkyl salicyl hydroxyoxime collector.

[0051] In this invention, the conversion rate of the substitution reaction and the content of the components can be determined by GC. Furthermore, the hydroxyoximation reaction has a high conversion rate, exceeding 99%.

[0052] In this invention, the pH adjuster can be a commonly used component in the industry for adjusting the pH of the flotation process; for example, the alkali can be at least one of sodium hydroxide and sodium carbonate. The acid can be at least one of hydrochloric acid and sulfuric acid.

[0053] Synthesis example 1

[0054] 90 g (0.6 mol) of methyl salicylate and 55 g (0.915 mol) of isopropanol were added to a 1 L three-necked flask equipped with a stirrer and a thermometer. The mixture was stirred until homogeneous and cooled to 0-5 °C. Then, 176.5 g (1.8 mol) of concentrated sulfuric acid was added at 5-10 °C, and the mixture was stirred at this temperature until the gas phase (GC) monitoring showed that methyl salicylate was <5%, approximately 3.5 h. The reaction was then stopped to obtain an oily mixture of isopropyl salicylate. The mixture contained 32.31% (GC) of 5-isopropyl salicylate, 15.28% (GC) of 3-isopropyl salicylate, 45.30% (GC) of 3,5-diisopropyl salicylate, and 3.27% (GC) of methyl salicylate. Subsequently, 0.66 mol of hydroxylamine hydrochloride was added below 10 °C, followed by the addition of 50.4 g (1.26 mol) of sodium hydroxide in portions. The mixture was stirred for 15 min, heated to 30 °C, and maintained at this temperature for 4 h. The reaction was then acidified with hydrochloric acid and the solvent removed by vacuum distillation, yielding a brownish-red solid mixture of isopropyl salicylic acid containing 5-isopropyl salicylic acid, 3,5-diisopropyl salicylic acid, 5-isopropyl salicylic acid, and salicylic acid (SHA). The overall yield of the hydroxamic acid mixture was 96.15%, calculated based on the molar amount of methyl salicylate. The crude isopropyl salicylic acid mixture was labeled ISHA and used as a collector for metal oxide ores in subsequent flotation. The nuclear magnetic resonance spectrum of 5-isopropyl salicylic acid in the mixture after separation and purification is shown in the figure below. Figure 1 and Figure 2 .

[0055] Synthesis example 2

[0056] 120 g (0.8 mol) of methyl salicylate and 0.88 mol of tert-butanol were added to a 1 L three-necked flask equipped with a stirrer and thermometer. The mixture was stirred until homogeneous and then cooled to 0-5 °C. Subsequently, 157 g (1.6 mol) of concentrated sulfuric acid was added at 5-10 °C, and the mixture was stirred at this temperature until the gas phase (GC) monitoring showed that methyl salicylate was <5%, a total of approximately 4 hours. The reaction was then stopped, yielding an oily mixture of tert-butyl salicylate. The mixture contained 38.60% (GC) of 5-tert-butyl salicylate, 25.28% (GC) of 3-tert-butyl salicylate, 30.30% (GC) of 3,5-di-tert-butyl salicylate, and 2.01% (GC) of methyl salicylate. Subsequently, 61.15 g (0.88 mol) of hydroxylamine hydrochloride was added below 10 °C, followed by 67.2 g (1.68 mol) of sodium hydroxide in portions. The mixture was stirred for 15 min, heated to 30 °C, and maintained at this temperature for 4 h. The reaction was then acidified with hydrochloric acid and the solvent removed by vacuum distillation, yielding a brownish-red solid mixture of tert-butylsalicylic acid containing 5-tert-butylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 5-tert-butylsalicylic acid, and salicylic acid. The resulting crude tert-butylsalicylic acid mixture was labeled TBSHA and used as a collector for metal oxide ores in subsequent flotation. The nuclear magnetic resonance spectrum of 5-tert-butylsalicylic acid in the mixture after separation and purification is shown below. Figure 3 and Figure 4 .

[0057] Synthesis example 3

[0058] 90 g (0.6 mol) of methyl salicylate and 158 g (1.8 mol) of tert-amyl alcohol were added to a 1 L three-necked flask equipped with a stirrer and a thermometer. The mixture was stirred until homogeneous and then cooled to 0-5 °C. Subsequently, 177 g (1.8 mol) of concentrated sulfuric acid was added at 5-10 °C, and the reaction was stirred at this temperature until the gas phase (GC) monitoring showed that methyl salicylate was <5%, which took approximately 3 hours. The reaction was then stopped to obtain an oily mixture of tert-amyl salicylate. The mixture contained 34.20% (GC) of 5-tert-amyl salicylate, 15.65% (GC) of 3-tert-amyl salicylate, 42.38% (GC) of 3,5-di-tert-amyl salicylate, and 1.68% (GC) of methyl salicylate. Subsequently, 0.66 mol of hydroxylamine hydrochloride was added below 10°C, followed by the addition of 50.4 g (1.26 mol) of sodium hydroxide in portions. The mixture was stirred for 15 min, heated to 30°C, and maintained at this temperature for 4 h. The reaction was then acidified with hydrochloric acid and the solvent removed by vacuum distillation, yielding a brownish-red solid mixture of tert-amyl salicylic acid containing 5-tert-amyl salicylic acid, 3,5-di-tert-amyl salicylic acid, 5-tert-amyl salicylic acid, and salicylic acid. The resulting crude tert-amyl salicylic acid mixture was labeled TASHA and used as a collector for metal oxide ores in subsequent flotation. The nuclear magnetic resonance spectrum of 5-tert-amyl salicylic acid in the mixture after separation and purification is shown below. Figure 5 and Figure 6 .

[0059] Obviously, the preparation process of the alkyl salicylic acid collector provided by the present invention is simple, efficient, has a high yield, and low cost, and is a commercially valuable preparation route.

[0060] Flotation Example 1: Flotation Separation of Ilmenite and Titanium Spodumene

[0061] The chemical compositions of pure ilmenite and pyroxene minerals are shown in Table 1. Add 1 g each of 0.074-0.038 mm ilmenite and pyroxene to a beaker and stir in 200 mL of water until evenly dispersed. While stirring, add the pH adjuster and collector sequentially (where the concentration of salicylic acid SHA is 1.5 × 10⁻⁶). -3 The concentration of ISHA, TBSHA, or TASHA is 7.5 × 10 mol / L. - 5 mol / L) and foaming agent methyl isobutyl methanol MIBC (1.5×10 -4 (mol / L) and stirred for 2 min, 3 min and 1 min respectively. After stirring, the slurry was brought to a final volume of 220 mL and transferred to a Hallimond tube for flotation for 4 min.

[0062]

[0063] The flotation separation results of ilmenite and titanopyroxene under a pulp environment of pH=7.0±0.2 are shown in Table 2.

[0064]

[0065] Table 2 shows that the low-dosage alkyl salicylic acid collectors ISHA, TBSHA, and TASHA achieved better flotation performance than the high-dosage SHA (salicylic acid), significantly improving TiO2 recovery and TiO2 grade in titanium concentrate. TASHA, in particular, demonstrated superior performance.

[0066] Flotation Example 2: Separation of Ilmenite and Olivine by Flotation

[0067] The pure mineral chemical compositions of ilmenite and olivine are shown in Table 3. The mixed ore during flotation consisted of ilmenite and olivine, with a SHA concentration of 1 × 10⁻⁶. -3 The concentration of ISHA, TBSHA, or TASHA is 1.5 × 10 mol / L. -5 mol / L, with other conditions the same as in Flotation Example 1.

[0068]

[0069] The flotation separation results of ilmenite and olivine under a pulp environment of pH=7.0±0.2 are shown in Table 4.

[0070]

[0071] As shown in Table 4, the low-dosage alkyl salicylic acid collectors ISHA, TBSHA, and TASHA achieved higher TiO2 recovery rates than the high-dosage SHA, indicating a significant improvement in the collecting capacity of the branched alkyl salicylic acid collectors.

[0072] Flotation Example 3: Flotation Separation of Cassiterite and Calcite

[0073] The chemical compositions of pure cassiterite and calcite are shown in Table 5. During flotation, the mixed ore consisted of cassiterite and calcite, with a SHA concentration of 2 × 10⁻⁶. -3 mol / L, the concentration of ISHA, TBSHA or TASHA is 5×10 -5 mol / L, with other conditions the same as in Flotation Example 1.

[0074]

[0075] Table 6 shows the flotation separation results of cassiterite and calcite under a pulp environment of pH=7.0±0.2. It indicates that the SnO2 flotation recovery and grade of cassiterite concentrate obtained by low dosage of alkyl salicylhydroxyoxime collectors ISHA, TBSHA and TASHA are higher than those obtained by high dosage of SHA. This shows that alkyl salicylhydroxyoxime collectors not only have strong collecting ability but also good selectivity when flotating cassiterite.

[0076]

[0077] Flotation Example 4: Flotation Separation of Fluorocarbonate Cerium Ore and Calcite

[0078] The chemical compositions of pure bastnaesite and calcite are shown in Table 7. The mixed ore during flotation consisted of bastnaesite and calcite, with a SHA concentration of 1.5 × 10⁻⁶. -3 mol / L, the concentration of ISHA, TBSHA or TASHA is 5×10 -5 mol / L, flotation pulp pH=8.0±0.2, other conditions are the same as in flotation example 1.

[0079]

[0080] The flotation separation results of bastnaesite and calcite are shown in Table 8. It shows that the low-dosage alkyl salicylhydroxyoxime collectors ISHA, TBSHA and TASHA achieved better rare earth oxide (REO) flotation recovery and grade than the high-dosage SHA, indicating that alkyl salicylhydroxyoxime collectors not only have strong collecting ability but also good selectivity when flotating bastnaesite.

[0081]

[0082] Flotation Example 5: Separation of Malachite and Calcite by Flotation

[0083] The chemical compositions of pure malachite and calcite samples are shown in Table 9. The mixed ore during flotation consisted of malachite and calcite, with a SHA concentration of 1 × 10⁻⁶. -3 mol / L, the concentration of ISHA, TBSHA or TASHA is 3×10 -5 mol / L, flotation pulp pH=8.0±0.2, other conditions are the same as in flotation example 1.

[0084]

[0085] The flotation separation results of malachite and calcite are shown in Table 10. It shows that the low-dosage alkyl salicylhydroxyoxime collectors ISHA, TBSHA and TASHA achieved better copper flotation recovery and grade than the high-dosage SHA, indicating that alkyl salicylhydroxyoxime collectors not only have strong collecting ability but also good selectivity when flotating malachite.

[0086]

[0087] Flotation Example 6: Flotation Separation of Fluorocarbonate Cerium Ore and Fluorite

[0088] The chemical compositions of pure fluorite and bastnaesite are shown in Table 11. The mixed ore during flotation consisted of bastnaesite and fluorite, with a SHA concentration of 1.5 × 10⁻⁶. -3 mol / L, the concentration of ISHA, TBSHA or TASHA is 5×10 -5 mol / L, flotation pulp pH=9.0±0.2, other conditions are the same as in flotation example 1.

[0089]

[0090] The flotation separation results of bastnaesite and fluorite are shown in Table 12. It shows that the low-dosage alkyl salicylhydroxyoxime collectors ISHA, TBSHA and TASHA achieved better REO flotation recovery and grade than the high-dosage SHA, indicating that alkyl salicylhydroxyoxime collectors not only have strong collecting ability but also good selectivity when flotating bastnaesite.

[0091]

[0092] In summary, alkyl salicylhydroxyoxime acid mixture collectors not only have a strong collecting ability for valuable metal oxide minerals, but they also have good flotation selectivity.

Claims

1. A composite branched alkyl salicylic acid collector, characterized in that, Including Equations 1A, 1B, and 1C; Formula 1A; Formula 1B; Formula 1C; In Formulas 1A to 1C, R is a C3 to C6 branched alkyl group; M is H, Na, K or NH4.

2. The composite branched alkyl salicylic acid collector as described in claim 1, characterized in that, In Formulas 1A to 1C, R is isopropyl, tert-butyl, or tert-pentyl.

3. The composite branched alkyl salicylic acid collector as described in claim 1, characterized in that, The mass ratio of Formula 1A, Formula 1B and Formula 1C is 25~60:10~30:25~50.

4. The composite branched alkyl salicylic acid collector according to any one of claims 1 to 3, characterized in that, It also allows inclusion-based 1D; Formula 1D; In Equation 1D, M is H, Na, K, or NH4; In the complex branched alkyl salicylhydroxyoxime collector, the content of Formula 1D is less than 30 wt.%.

5. The application of a composite branched alkyl salicylic acid collector, characterized in that, It is used as a collector in the flotation of metal oxide ores; The composite branched alkyl salicylic acid collector is the composite branched alkyl salicylic acid collector according to any one of claims 1 to 4.

6. The application of the composite branched alkyl salicylic acid collector as described in claim 5, characterized in that, The metal oxide minerals include oxide minerals of at least one metallic element selected from rare earth, iron, copper, tungsten, tin, zinc, lead, titanium, tantalum, niobium, aluminum, manganese, chromium, and cobalt; preferably, they include at least one selected from ilmenite, cassiterite, bastnaesite, and malachite.

7. The application of the composite branched alkyl salicylic acid collector as described in claim 5 or 6, characterized in that, The pH of the flotation pulp is 1.5 to 10.5, preferably 5 to 9.

8. The application of the composite branched alkyl salicylic acid collector as described in any one of claims 5 to 7, characterized in that, Based on the weight of the ore fed to the flotation, the dosage of the composite branched alkyl salicylic acid collector is 100~2000g / t, preferably 200~500g / t.

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