Cassiterite collecting agent and preparation method and application thereof

Abstract

The invention discloses a cassiterite collecting agent and a preparation method and application thereof, and belongs to the technical field of mineral separation. The cassiterite collecting agent is formed by coordinating and assembling the following cinnamon hydroxamic acid ligands and metal ions with the valence of more than two: # imgabs0 #, wherein M is a monovalent cation; in the formula, R is alkoxy with 1 to 5 carbon atoms or alkyl with 1 to 5 carbon atoms. The cassiterite collecting agent has very high targeted adsorption capacity on the cassiterite surface, meanwhile has excellent hydrophobic performance, particularly can achieve selective separation of cassiterite and gangue minerals such as tourmaline and garnet and enhanced flotation recovery of fine-fraction cassiterite under the condition of very low dosage, and is low in preparation cost, good in performance, simple in process and suitable for industrial production. The method is of great significance in improving efficient comprehensive recovery of cassiterite resources and is beneficial to further popularization and application.

Description

Technical Field

[0001] The invention relates to a collector, in particular to a cassiterite collector, and also to a preparation method and application thereof, belonging to the technical field of mineral processing. Background Art

[0002] As an important strategic mineral resource, tin has the characteristics of stable chemical properties and corrosion resistance. It is widely used in emerging industries such as electronic appliances, alloy materials, and new energy. It is a key raw material in the fields of military, aerospace, and atomic energy. my country is rich in tin resources, and its reserves and production rank first in the world, but it is also the largest consumer of tin metal. In recent years, with the continuous development of science and technology, the reserves of tin resources in major tin-producing countries, including China, have declined rapidly.

[0003] Cassiterite is the main raw material for extracting tin resources. It is easy to re-select and recycle due to its high specific gravity. Most of the cassiterite in the world is produced by placer tin deposits. This part of tin resources is often recovered by gravity separation or gravity flotation. However, my country's cassiterite resources are mainly primary cassiterite, mainly refractory tin ores. This part of tin ore often has many and complex associated components and fine embedded particles. In addition, cassiterite itself is brittle and easily produces a large amount of secondary tin ore mud during the grinding process. Traditional gravity separation technology is difficult to achieve efficient recovery of such tin resources. A large amount of fine cassiterite is lost in the tailings, resulting in a serious waste of tin resources.

[0004] With the increasing depletion of high-quality tin resources, more and more researchers are focusing on the enhanced re-selection of complex and difficult-to-select tin tailings, such as low-grade and fine-grained tin tailings. At the same time, with the continuous development of complex and difficult-to-select tin resources, gangue minerals such as tourmaline and garnet, which have similar floatability to cassiterite, have also become the main obstacle to cassiterite enrichment. However, traditional collectors with N, O, and P as functional groups often have low flotation efficiency, making it difficult to achieve effective separation and enrichment of cassiterite and gangue minerals, resulting in low comprehensive recovery rate and low concentrate grade.

[0005] Chinese patent (CN112973972A) discloses a cassiterite flotation collector, which uses 4-(tert-butyl)-benzihydroxamic acid as a flotation collector to improve the cassiterite grade and recovery rate, but does not disclose its specific flotation index. Chinese patent (CN117960391A) discloses a composite metal coordinated hydroxamic acid collector, which is formed by the coordination of hydroxamic acid collector and at least two metal ions. It mentions that the composite metal coordinated hydroxamic acid collector can be used as a cassiterite collector, but does not disclose its specific flotation index. Chinese patent (CN110721816A) discloses a hydroxamic acid-organophosphate multi-ligand metal complex collector and its preparation method and application. The hydroxamic acid-organophosphate multi-ligand metal complex collector is obtained by coordination reaction between hydroxamic acid-phosphate multi-ligand composite micelles prepared from hydroxamic acid salts and organophosphates and metal ions, and further discloses that it can be used for cassiterite flotation, and it can obtain ideal flotation indicators. For example, in specific embodiment 1, for cassiterite ore with a SnO2 grade of 0.57% and main gangue minerals such as quartz, fluorite and garnet, a concentrate with a SnO2 grade of 49.67% can be obtained after flotation, and the SnO2 operation recovery rate is 84.39%. However, the hydroxamic acid-organophosphate multi-ligand metal complex collector requires the use of multiple organic ligands at the same time, while phosphonic acid collectors are toxic and easily cause environmental pollution problems, and their synthesis cost is relatively high, and the existing flotation process is almost no longer used. Summary of the invention

[0006] The invention aims to solve the problem of low flotation efficiency caused by poor floatability of fine cassiterite and difficulty in separation from gangue minerals in the prior art.

[0007] The first object of the present invention is to provide a cassiterite collector, which has excellent flotation performance for cassiterite, and in particular can efficiently and highly selectively enrich low-grade, fine-grained cassiterite minerals, and realize the selective separation of cassiterite from gangue minerals such as tourmaline and garnet.

[0008] The second object of the present invention is to provide a method for preparing a cassiterite collector, which has the advantages of simple operation, high yield, easy availability of raw materials, low cost, and is conducive to expanding production.

[0009] The third object of the present invention is to provide an application of a cassiterite collector, which is used for cassiterite flotation and exhibits the characteristics of strong collecting ability and good selectivity, and can greatly improve the grade and recovery rate of tin concentrate, especially for low-grade and fine-grained cassiterite minerals, and can still obtain good flotation indicators, thereby overcoming the problems of the existing complex and difficult tin to be effectively floated, separated and enriched, low comprehensive recovery rate, and low concentrate grade.

[0010] In order to achieve the above technical purpose, the present invention provides a cassiterite collector, which is assembled by coordination of cinnamic hydroxamic acid ligands and divalent or higher metal ions:

[0011] The cinnamic hydroxamic acid ligand has a molecular structure of Formula 1:

[0012]

[0013]

[0014] in,

[0015] M is a monovalent cation;

[0016] R is a C1-C5 alkoxy group or a C1-C5 alkyl group.

[0017] In the cinnamic hydroxamic acid ligands of the present invention, R can be selected from an alkyl group or an alkoxy group. On the one hand, R acts as an electron-donating group to adjust the coordination and chelating ability of the hydroxamic acid group. On the other hand, R acts as a hydrophobic group to improve the hydrophobic modification of minerals. R can be selected from a short-chain alkyl group, such as a C1-C5 alkyl group. When the number of carbon atoms exceeds 3, it can be a straight-chain alkyl group or a branched alkyl group. Specific examples include methyl, ethyl, propyl, isobutyl, etc. R can be selected from an alkoxy group, such as a C1-C5 alkoxy group. The alkyl group in the alkoxy group is specifically methyl, ethyl, propyl, isobutyl, etc. The substitution position of R on the benzene ring in the cinnamic hydroxamic acid ligand is further preferably the ortho or para position of the hydroxamic acid group. The ortho or para R group can more effectively adjust the coordination and chelating ability of the hydroxamic acid group.

[0018] The cassiterite collector of the present invention is based on the traditional metal ion-benzohydroxamic acid complex collector, based on the principle of the electronic effect of the substituent of the conjugated system, and the structure of the benzohydroxamic acid ligand is improved and designed. The key to the structural improvement design is to use the carbon-carbon double bond to extend the conjugated system, and at the same time modify the electron-donating group on the conjugated system. The combination of the two can use the electron-pushing effect to increase the electron density of the hydroxamic group and improve the coordination and chelating ability of the hydroxamic acid group. More specifically, the present invention designs a carbon-carbon double bond between the benzene ring and the hydroxamic acid group, which can be connected with the benzene ring to form p-π conjugation, so that the six-membered conjugated system of the benzene ring itself is further expanded, the electronic configuration in the entire hydroxamic acid molecule is more stable, the group electronegativity is higher, and thus it has stronger activity and chemical reactivity. The electron-donating group introduced on the benzene ring can strengthen the bonding ability of the chelating hydroxyl oxygen and oxime oxygen in the organic ligand structure with the polar metal group through the synergistic effect of conjugation and electronic effect. At the same time, the alkoxy or alkyl group has excellent hydrophobic properties, and the hydrophobic ability can be easily adjusted by the chain length, which is conducive to compensating for the insufficient foaming ability of the collector caused by the benzene ring as a non-polar group. The collector formed by the assembly of cinnamic hydroxamic acid ligands and metal ions can target cassiterite and has a more advantageous selective collection ability, especially can strengthen the flotation recovery of fine-grained cassiterite. Compared with metal ion-benzohydroxamic acid complexes, it has a larger adsorption capacity and is more conducive to the dehydroxylation of the cassiterite surface, strengthening the hydrophilicity difference between the target mineral cassiterite and the surface of gangue minerals such as tourmaline and garnet, which can greatly improve the comprehensive recovery rate of cassiterite resources.

[0019] As a preferred solution, the divalent or higher metal ions include Pb 2+ , Cu 2+ 、Zn 2+ , Mn 2+ , Ca 2+ Mg 2+ , Fe 2+ 、Al 3+ or Fe 3+ At least one of the following. Different divalent or higher metal ions have different coordination abilities with cinnamic hydroxamic acid ligands, and the three-dimensional structure of the complex formed by assembly will also be different. More preferably, Pb 2+ , the electron configuration of the divalent lead ion is [Xe]4f 14 5d 10 6s 2 The electrons in its d and f orbitals cannot effectively shield the s electrons in the valence layer, making its role in coordination and regulation of assembly at the mineral flotation interface particularly significant.

[0020] As a preferred embodiment, the monovalent cation is H + , K + 、Na+ or NH4 + These cations are introduced during the alkalization or acidification process of the cinnamic hydroxamic acid ligands, and have little effect on the coordination and chelating ability of the cinnamic hydroxamic acid ligands.

[0021] As a preferred scheme, the coordination molar ratio of the cinnamic hydroxamic acid ligand to the divalent or higher metal ion is (1-16): (1-4). Under the appropriate coordination molar ratio conditions, the complex collector formed by pre-coordination assembly is more conducive to adsorption on the terminal oxygen atom formed by hydroxylation on the hydrophilic cassiterite surface; when the metal ion ratio is too high, the competitive adsorption caused by its own hydration will inhibit the floating of cassiterite, and will also lead to non-selective activation of silicate gangue minerals such as tourmaline and garnet. The coordination molar ratio of the cinnamic hydroxamic acid ligand to the divalent or higher metal ion is further preferably (4-12): (1-2).

[0022] The present invention also provides a method for preparing a cassiterite collector, which comprises the following steps:

[0023] 1) reacting a cinnamic acid compound with an acyl chloride reagent to obtain a cinnamoyl chloride compound;

[0024] The cinnamic acid compound has a molecular structure of Formula 2:

[0025]

[0026] The cinnamoyl chloride compound has a molecular structure of Formula 3:

[0027]

[0028] 2) subjecting a cinnamoyl chloride compound to a hydroximation reaction with hydroxylamine in the presence of triethylamine to obtain a cinnamoyl hydroxamic acid triethylamine salt compound; the cinnamoyl hydroxamic acid triethylamine salt compound is dissolved in an alkali solution, or the cinnamoyl hydroxamic acid triethylamine salt compound is dissolved in an alkali solution and then acidified to obtain a cinnamoyl hydroxamic acid ligand;

[0029] The cinnamic hydroxamic acid triethylamine salt compound has a structure of formula 4;

[0030]

[0031] Wherein, R is a C1-C5 alkoxy group or a C1-C5 alkyl group;

[0032] 3) The cinnamic hydroxamic acid ligand is subjected to coordination reaction with divalent or higher metal ions in a solution to obtain the product.

[0033] The synthesis process of the cassiterite collector of the present invention is as follows: first, a cinnamic hydroxamic acid compound is synthesized by using an "acyl chloride-hydroxylamine method"; more specifically, the carboxylic acid of the cinnamic acid compound is chlorinated by using an acyl chloride reagent, and the acyl chloride can be reacted with hydroxylamine under alkaline conditions to be converted into a hydroxamic acid group; secondly, a "template effect" of a divalent or higher metal ion is utilized to coordinate and assemble with a cinnamic hydroxamic acid ligand to form a metal ion-cinnamic hydroxamic acid complex; more specifically, the hydroxyl oxygen and oxime oxygen in the cinnamic hydroxamic acid ligand are utilized to coordinate with a divalent The above metal ions undergo chelation to form a stable "O,O" five-membered ring. At the same time, the hydroxide in the aqueous solution also participates in the coordination assembly to form a metal-based colloidal collector that regularly connects hydroxyl and hydroxamic acid ligands with metal ions as nodes. The collector has a more complex spatial network structure and a larger colloidal particle size. It has excellent flotation performance, which is beneficial to improving the surface roughness of the target mineral, strengthening the hydrophilicity difference with the gangue mineral, promoting the collision and adhesion probability with nanobubbles, and improving the grade and recovery rate of the flotation concentrate.

[0034] As a preferred solution, the molar ratio of the cinnamic acid compound to the acyl chloride reagent is 1:(1-1.5). Using an appropriate excess of the acyl chloride reagent can increase the conversion rate of the cinnamic acid compound. The common acyl chloride reagent is thionyl chloride.

[0035] As a more preferred scheme, the conditions of the acyl chloride reaction are: temperature of 45-65°C, reaction time of 0.5-2h, DMF is used as a catalyst, and the amount of DMF is 1-20% of the molar amount of the cinnamic acid compound. When DMF (N,N-dimethylformamide) is used as a catalyst, DMF will attack thionyl chloride to form an intermediate, and then remove a portion of sulfur dioxide to form an active Vilsmeier reagent. The reagent is a weak electrophilic species with a structure similar to that of a haloimide cation salt. The active Vilsmeier reagent is attacked by carboxylic acid to generate an acyl-DMF complex intermediate, in which the acyl part is connected to the nitrogen atom of DMF, and the resulting intermediate further reacts to remove DMF and hydrogen chloride to generate acyl chloride, and DMF is regenerated and re-enters the cycle. The preferred amount of DMF used in the present invention is 5-10% of the molar ratio of p-methoxycinnamic hydroxamic acid. Under the preferred reaction conditions, the process of the acyl chloride reaction can be significantly accelerated, which is conducive to improving the yield of the product.

[0036] As a preferred solution, the molar ratio of the cinnamic acid compound to hydroxylamine is 1:(1-2). As a more preferred solution, the conditions of the hydroxyoximation reaction are: triethylamine is used to maintain the pH at 8.0-12.0, the reaction temperature is 0-50°C, and the reaction time is 1-3h. Chloroform is used as a solvent for the hydroxyoximation reaction. Triethylamine can mainly maintain the pH environment of the reaction system. Alkaline conditions help to increase the reactivity of the carbonyl carbon, making it more receptive to the nucleophilic attack of the nitrogen atom in hydroxylamine. At the same time, alkaline conditions are not conducive to the formation of by-products such as amides, which is conducive to improving the purity of the hydroxyoximation modified product.

[0037] The alkali solution of the present invention can be an inorganic alkali solution such as sodium hydroxide solution, potassium hydroxide solution, ammonia water, etc.

[0038] The acidification of the present invention can adopt conventional inorganic acids, such as hydrochloric acid, sulfuric acid and the like.

[0039] The divalent or higher metal ions of the present invention are mainly provided by soluble metal salts, such as nitrates, sulfates, and chlorides.

[0040] The invention also provides an application of a cassiterite collector, which is used for cassiterite mineral flotation.

[0041] As a preferred solution, the tin ore is ground and pre-treated by impurity removal, the pH of the pulp is adjusted to alkaline, and flotation is performed using a flotation agent including the cassiterite collector to obtain a tin concentrate; the tin ore is a low-grade, fine-grained cassiterite mineral.

[0042] As a preferred solution, the flotation includes one roughing selection, two or more cleaning selections and one or more scavenging selections.

[0043] As a more preferred scheme, the reagent system for roughing is: the dosage of cassiterite collector is 400-1000g / t, and the dosage of 2# oil frother is 30-60g / t; the reagent system for fine selection is: the dosage of salinized water glass inhibitor is 10-100g / t, and the salinized water glass is formed by mixing aluminum sulfate and water glass, and the mass ratio of aluminum sulfate to water glass is 1:(2-4); the reagent system for scavenging is: the dosage of cassiterite collector is 50-500g / t, and the dosage of 2# oil frother is 10-40g / t; wherein, the mass of cassiterite collector is measured according to the mass of cinnamic hydroxamic acid compounds contained therein. Under the preferred flotation reagent system, the flotation efficiency of cassiterite, especially fine-grained cassiterite, can be effectively enhanced, and the grade and recovery rate of the final concentrate can be improved.

[0044] The salted water glass of the present invention is a conventional inhibitor for cassiterite flotation in the prior art.

[0045] Compared with the existing technology, the beneficial technical effects brought by the present invention are as follows:

[0046] (1) The cassiterite collector provided by the present invention has a strong selective collection ability for cassiterite, and has good hydrophobicity and strong foaming ability, and can achieve efficient flotation separation of cassiterite and gangue minerals such as tourmaline and garnet.

[0047] (2) Compared with the conventional benzohydroxamic acid ligands, the cinnamic hydroxamic acid ligands in the cassiterite collector provided by the present invention extend the conjugated system and modify the power-donating group on the conjugated system. Through the conjugation effect and the electronic effect, the electron density of the hydroxyoxime group is higher and the chelating ability is stronger, which is beneficial to increase the adsorption amount of the collector on the cassiterite surface and improve the flotation efficiency of cassiterite.

[0048] (3) The cassiterite collector provided by the present invention has a low dosage during use, is non-toxic and pollution-free, is beneficial to reducing the cost of mineral processing, and has excellent flotation performance for fine-grained cassiterite. It can enhance the flotation recovery of fine-grained cassiterite at a lower dosage, thereby improving the grade and recovery rate of the final tin concentrate.

[0049] (4) The cassiterite collector provided by the present invention is used in a cassiterite flotation separation method, which is simple to operate and is applicable to the enhanced reselection of various primary cassiterites and tin tailings, etc., and is conducive to further promotion and use.

[0050] (5) The preparation method of the cassiterite collector provided by the present invention has high yield, few impurities, easy-to-obtain raw materials, low cost, and is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the p-methoxycinnamic acid ligand prepared in Example 1.

[0052] Figure 2 This is the carbon nuclear magnetic resonance spectrum of the p-methoxycinnamic hydroxamic acid ligand prepared in Example 1.

[0053] Figure 3 The flotation test results of Example 3 are shown below.

[0054] Figure 4 This is a flotation process flow chart of Example 4. DETAILED DESCRIPTION

[0055] The following examples are further detailed descriptions of the present invention, but are not intended to limit the scope of the claims of the present invention. Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0056] Example 1

[0057] Preparation of lead ion-p-methoxycinnamic acid complex:

[0058] 100 ml of chloroform was added as a solvent in a three-necked flask, and 17.818 g of p-methoxycinnamic acid (0.1 mol) with a purity of 98% was added under stirring. After the solution was dissolved, 13.087 g of thionyl chloride (0.11 mol) with a purity of 99.5% and 0.3655 g of DMF (0.005 mol) with a purity of 99.8% were added dropwise to the flask respectively, and a circulating condensation reflux system was opened, and the reaction was carried out at 50° C. for 1 hour, and the solvent was evaporated under reduced pressure to obtain the acyl chloride product. After the acyl chloride product was dissolved in 50 ml of chloroform, 8.3388 g of hydroxylamine hydrochloride (0.12 mol) with a purity of 99% was slowly added, and the pH of the reaction system was adjusted to 10.0 with triethylamine, and the circulating condensation reflux system was opened, and the reaction was carried out at 15° C. for 2 hours, and the solvent was evaporated under reduced pressure to obtain the hydroxamate modified product. After dissolving the hydroximation modified product in 50 ml of a sodium hydroxide solution with a molar concentration of 1 mol / L, concentrated hydrochloric acid was added dropwise to the reaction system under stirring at room temperature to adjust the pH of the reaction system to 5.0. After the addition was completed, the product was precipitated under low temperature and filtered to recover the precipitated light yellow solid, which was the crude product of p-methoxycinnamic acid. The crude product can be further purified by cooling and crystallizing in a hot ethanol solution. Its nuclear magnetic resonance 1H NMR and 13C NMR were respectively Figure 1 and Figure 2 .

[0059] Under stirring conditions, 0.125 mol of lead nitrate is added to 1 L of a 1.0 mol / L p-methoxycinnamic hydroxamic acid solution, and the reaction is carried out for 3 minutes to obtain the lead ion-p-methoxycinnamic hydroxamic acid complex collector.

[0060] Example 2

[0061] Preparation of copper ion-p-methoxycinnamic hydroxamic acid complex:

[0062] 80 ml of chloroform was added as a solvent in a three-necked flask, and 8.909 g of p-methoxycinnamic acid (0.05 mol) with a purity of 98% was added under stirring. After the solution was dissolved, 7.1382 g of thionyl chloride (0.06 mol) with a purity of 99.5% and 0.3655 g of DMF (0.005 mol) with a purity of 99.8% were added dropwise to the flask respectively, and a circulating condensation reflux system was opened, and the reaction was carried out at 60° C. for 1 h, and the solvent was evaporated under reduced pressure to obtain the acyl chloride product. After the acyl chloride product was dissolved in 40 ml of chloroform, 4.1694 g of hydroxylamine hydrochloride (0.06 mol) with a purity of 99% was slowly added, and the pH of the reaction system was adjusted to 9.0 with triethylamine, and the circulating condensation reflux system was opened, and the reaction was carried out at room temperature for 1.5 h, and the solvent was evaporated under reduced pressure to obtain the hydroxamate modified product. After dissolving the hydroximation modified product in 30 ml of an ammonia solution with a molar concentration of 1 mol / L, concentrated hydrochloric acid is added dropwise to the reaction system while stirring to adjust the pH of the reaction system to 4.0. After the addition is completed, a light-colored solid precipitated under low temperature conditions is the crude product of p-methoxycinnamic acid. The crude product can be further purified by recrystallization from ethanol / water.

[0063] 0.125 mol of copper sulfate was added to 1 L of 1.0 mol / L p-methoxycinnamic hydroxamic acid solution under stirring conditions, and the mixture was reacted for 3 minutes to obtain the cassiterite flotation collector.

[0064] The flotation collectors used in the following specific examples are all prepared by this method.

[0065] Example 3

[0066] Flotation behavior of cassiterite of different particle sizes under the new flotation collector system:

[0067] The dosage of the new flotation collector (Pb-PMCA) described in Example 1 was 1.0×10 -4 mol / L, the pH of the flotation pulp was adjusted with hydrochloric acid / sodium hydroxide, the dosage of the foaming agent methyl isobutyl carbinol (MIBC) was 12.5μL / L, the N2 flow rate was 300mL / min, and the flotation operation was performed on pure cassiterite with a particle size of -0.074~+0.038mm and -0.038mm, respectively, and the flotation time was 3min. The specific test results are shown in Figure 3 .

[0068] Control experimental group:

[0069] Flotation behavior of cassiterite of different particle sizes in conventional Pb-BHA complex collector system:

[0070] The dosage of conventional Pb-BHA complex collector is 1.0×10 -4mol / L, the pH of the flotation pulp was adjusted with hydrochloric acid / sodium hydroxide, the dosage of frother methyl isobutyl carbinol (MIBC) was 12.5μL / L, the N2 flow rate was 300mL / min, and the flotation operation was performed on pure cassiterite with a particle size of -0.074~+0.038mm and -0.038mm, respectively, and the flotation time was 3min. Figure 3 It can be seen from the flotation test results shown that the flotation collector of the present invention can greatly improve the flotation recovery rate of cassiterite, especially fine-grained cassiterite, at the same dosage. In the most suitable range of pH 9.0 to 10.0, the flotation efficiency is the highest, and the recovery rate is significantly increased from 40% to more than 90%.

[0071] Example 4

[0072] The process of the present invention is used to treat a low-grade fine-grained cassiterite gravity separation tailings in Guangxi, and the flotation collector of Example 1 is used for the gravity separation tailings to strengthen the re-selection. The specific process flow is shown in Figure 4 The main gangue minerals of the gravity separation tailings are tourmaline and quartz, with contents of 49.73% and 33.06% respectively, followed by iron oxides and pyrite, with contents of 5.96% and 3.84% respectively. Sn is mainly present in the form of cassiterite, with a low overall content of 0.16%, and is mainly distributed in the fine-grained products of -0.015mm particle size, as shown in Table 1 below.

[0073] Table 1 Grain size composition and tin distribution results of gravity separation tailings

[0074]

[0075] First, a Slon-100 periodic pulsating high-gradient magnetic separator was used to remove magnetic impurities under a magnetic field strength of 1.2T. The iron tailings were desulfurized and flotated with 100g / t copper sulfate as an activator, 200g / t butyl xanthate as a collector, and 30g / t 2# oil as a frother. The desulfurized tailings were first adjusted to a pH of 10.0 by sodium carbonate, and 600g / t of the collector described in Example 1 and 50g / t of 2# oil as a frother were added. After aeration and slurry mixing for 5 minutes, cassiterite roughing was performed; 200g / t of collector and 20g / t of 2# oil were added for scavenging; saline water glass Al-SBL was added as an inhibitor (the mass ratio of aluminum sulfate to water glass was 1:2) for the concentrating operation, and the total amount of saline water glass Al-SBL used for concentrating was 100g / t; the middlings were returned to the previous flotation operation in sequence. After four rounds of concentration, a tin concentrate containing 11.32% Sn was obtained, with a recovery rate of 63.59%.

[0076] Table 2 Flotation test results of Example 4

[0077]

[0078] Control experimental group:

[0079] Under stirring conditions, 0.125 mol of lead nitrate was added to 1 L of 1.0 mol / L benzohydroxamic acid solution and reacted for 3 minutes to obtain a Pb-BHA complex collector.

[0080] The control group is used for comparison with Example 4. The iron removal and desulfurization in the control group are consistent with Example 4. The only difference is that the conventional Pb-BHA complex collector is used for roughing. The desulfurized tailings are first adjusted to pH 10.0 by sodium carbonate, and 1000g / t of Pb-BHA complex collector and 60g / t of 2# oil are added as a foaming agent. After aeration and slurry stirring for 5 minutes, the cassiterite roughing operation is carried out; 400g / t of Pb-BHA complex collector and 30g / t of 2# oil are added for scavenging operation; salinized water glass Al-SBL is added as an inhibitor (the mass ratio of aluminum sulfate to water glass is 1:2) for the concentrating operation, and the total amount of salinized water glass Al-SBL used for concentrating is 100g / t. After four times of concentrating, a tin concentrate containing 9.77% Sn is obtained, and the recovery rate is 58.46%. It can be seen from the flotation test results that the flotation collector of the present invention can achieve higher flotation efficiency at a lower dosage, which is beneficial to the efficient flotation enrichment of fine-grained cassiterite. The grade of tin concentrate is increased from 9.77% to 11.32%, and the recovery rate is increased from 58.46 to 63.59%, which is of great significance to ensuring the sustainable development of tin resources.

[0081] Table 3 Flotation test results of control experiment

[0082]

[0083] Example 5

[0084] The process method of the present invention is used to treat a copper-tin complex polymetallic ore in Hunan, and the flotation collector of Example 2 is used for the enhanced flotation of cassiterite. The Sn grade of the original ore of the copper-tin deposit is about 0.18%, and the main gangue minerals are calcite, fluorite, quartz and garnet, accounting for more than 60%. After crushing and grinding, the original ore meets the mass content of -200 mesh particle size of 75%, and then a drum wet magnetic separator is used to remove iron weakly under the condition of a magnetic field intensity of 0.6T. After the non-magnetic product is concentrated by a thickener, 200g / t copper sulfate is used as an activator, 150g / t yellow medicine and 50g / t ethyl thiocyanate are used as collectors, and 20g / t 2# oil is used as a frother for desulfurization flotation. The desulfurized tailings were first adjusted to a pH of 9.5 by carbonate ore, and 450 g / t of the collector described in Example 2 and 40 g / t of frother 2# oil were added. After aeration and slurry mixing for 5 minutes, cassiterite roughing was performed; 150 g / t of collector and 10 g / t of 2# oil were added for scavenging; and 150 g / t of saline water glass Al-SBL (1:2) was added for concentrating. The total amount of the concentrating salt was 150 g / t. After three times of concentrating, the tin concentrate obtained contained 10.33% Sn and had a recovery rate of 72.72%.

[0085] Table 4 Flotation test results of Example 5

[0086]

[0087] Control group

[0088] Under stirring conditions, 0.125 mol of copper sulfate was added to 1 L of 1.0 mol / L benzohydroxamic acid solution and reacted for 3 minutes to obtain a Cu-BHA complex collector.

[0089] The control experimental group is used for comparison with Example 5. The crushing, grinding, iron removal, desulfurization and other processes in the control experimental group are consistent with Example 5. The pH of the desulfurized tailings is adjusted to 9.5 by sodium carbonate, and 600g / t of Cu-BHA complex collector and 40g / t of frother 2# oil are added. After aeration and slurry mixing for 5 minutes, cassiterite roughing operation is carried out; 200g / t of Cu-BHA complex collector and 10g / t of 2# oil are added for scavenging; the total amount of salted water glass Al-SBL (1:2) added for selection is 150g / t. The tin concentrate obtained after three selections contains Sn7.14% and the recovery rate is 64.74%. It can be seen from the flotation test results that the cassiterite flotation collector of the present invention has a higher tin grade and recovery rate, and the amount is less than that of conventional benzohydroxamic acid, and the ore dressing cost is lower, which is conducive to further promotion and application.

[0090] Table 5 Flotation test results of control experimental group

[0091]

[0092]

[0093] Example 6

[0094] The process of the present invention is used to treat a tungsten-tin polymetallic ore in Hunan, and the flotation collector of Example 1 is used for the enhanced flotation of cassiterite in tungsten tailings. The Sn grade of the original tungsten-tin polymetallic ore is 0.12%, and most of it exists in the form of cassiterite, and the gangue is mainly garnet, calcium fluoride and calcium carbonate. This part of cassiterite mainly exists in the form of fine particles. Due to its poor floatability and slow flotation rate, it falls into the tailings under the action of the inhibitor that has been carefully selected many times in the previous tungsten flotation process. The pH value of the tungsten tailings was readjusted to 9.5 by carbonate ore, and 500 g / t of the collector described in Example 1 and 30 g / t of frother 2# oil were added. After aeration and slurry mixing for 5 minutes, cassiterite roughing was carried out; 200 g / t of collector and 10 g / t of 2# oil were added for scavenging; and 120 g / t of saline water glass Al-SBL (1:2) was added for concentrating. The tin concentrate obtained after two concentrating operations contained 6.93% Sn and had a recovery rate of 74.79%.

[0095] Table 6 Flotation test results of Example 6

[0096]

[0097] Control group

[0098] Under stirring conditions, 0.125 mol of lead nitrate was added to 1 L of 1.0 mol / L p-methoxybenzohydroxamic acid solution and reacted for 3 minutes to obtain a Pb-PMOB complex collector.

[0099] The control experimental group is used for comparison with Example 6, and the only difference is that different collectors are used. The tungsten tailings are first adjusted to a pH of 9.5 through carbonate ore, and 500 g / t of Pb-PMOB collector and 30 g / t of frother 2# oil are added. After aeration and slurry mixing for 5 minutes, cassiterite roughing operation is carried out; 200 g / t of collector and 10 g / t of 2# oil are added for scavenging; the total amount of salted water glass Al-SBL (1:2) added for concentrating is 120 g / t. After two concentrating operations, the tin concentrate obtained contains 3.52% Sn and the recovery rate is 35.21%. It can be seen from the flotation test results that the flotation efficiency of the collector using p-methoxybenzohydroxamic acid as a ligand is not high, with more than 60% of tin tailing and only about 3.5% of the concentrate grade. The flotation performance of the collector of the present invention is relatively advantageous, with both the grade and recovery rate of tin being relatively high. This also shows that the collector of the present invention has a stronger selective capture ability for cassiterite, and can achieve enhanced flotation recovery of low-grade and difficult-to-select cassiterite resources.

[0100] Table 7 Flotation test results of control experimental group

[0101]

Claims

1. A cassiterite collector, characterized in that: It is assembled by cinnamic hydroxamic acid ligands coordinated with divalent or higher metal ions: The cinnamic hydroxamic acid ligand has a molecular structure of Formula 1: in, M is a monovalent cation; R is a C1-C5 alkoxy group or a C1-C5 alkyl group.

2. A cassiterite collector according to claim 1, characterized in that: The divalent or higher metal ions include Pb 2+ , Cu 2+ 、Zn 2+ , Mn 2+ , Ca 2+ Mg 2+ , Fe 2+ 、Al 3+ or Fe 3+ At least one of the following; The monovalent cation is H + , K + 、Na + or NH4 + .

3. A cassiterite collector according to claim 1 or 2, characterized in that: The coordination molar ratio of the cinnamic hydroxamic acid ligand to the divalent or higher metal ion is (1-16): (1-4).

4. The method for preparing a cassiterite collector according to any one of claims 1 to 3, characterized in that: The following steps are involved: 1) reacting a cinnamic acid compound with an acyl chloride reagent to obtain a cinnamoyl chloride compound; The cinnamic acid compound has a molecular structure of Formula 2: The cinnamoyl chloride compound has a molecular structure of Formula 3: 2) subjecting a cinnamoyl chloride compound to a hydroximation reaction with hydroxylamine in the presence of triethylamine to obtain a cinnamoyl hydroxamic acid triethylamine salt compound; the cinnamoyl hydroxamic acid triethylamine salt compound is dissolved in an alkali solution, or the cinnamoyl hydroxamic acid triethylamine salt compound is dissolved in an alkali solution and then acidified to obtain a cinnamoyl hydroxamic acid ligand; the cinnamoyl hydroxamic acid triethylamine salt compound has a structure of Formula 4; Wherein, R is a C1-C5 alkoxy group or a C1-C5 alkyl group; 3) The cinnamic hydroxamic acid ligand is subjected to coordination reaction with divalent or higher metal ions in a solution to obtain the product.

5. The method for preparing a cassiterite collector according to claim 4, characterized in that: The molar ratio of the cinnamic acid compound to the acyl chloride reagent is 1:(1-1.5); and / or; The molar ratio of the cinnamic acid compound to hydroxylamine is 1:(1-2).

6. A method for preparing a cassiterite collector according to claim 4 or 5, characterized in that: The conditions of the acyl chlorination reaction are: temperature of 45-65°C, reaction time of 0.5-2h, DMF as catalyst, and the amount of DMF is 1-20% of the molar amount of the cinnamic acid compound; The conditions of the hydroxamination reaction are: using triethylamine to maintain the pH at 8.0-12.0, the reaction temperature at 0-50° C., and the reaction time at 1-3 h.

7. The use of a cassiterite collector according to any one of claims 1 to 3, characterized in that: Used for cassiterite flotation.

8. The use of a cassiterite collector according to claim 7, characterized in that: After the tin ore is ground and pre-treated by impurity removal, the pH of the pulp is adjusted to alkaline, and flotation is performed using a flotation agent including the cassiterite collector to obtain a tin concentrate; the tin ore is a low-grade, fine-grained cassiterite mineral.

9. The use of a cassiterite collector according to claim 8, characterized in that: The flotation comprises one roughing selection, two or more cleaning selections and one or more scavenging selections.

10. The use of a cassiterite collector according to claim 9, characterized in that: The reagent system for roughing is: the dosage of cassiterite collector is 400-1000g / t, and the dosage of 2# oil foaming agent is 30-60g / t; The selected reagent system is as follows: the dosage of the salted water glass inhibitor is 10-100 g / t, the salted water glass is formed by mixing aluminum sulfate and water glass, and the mass ratio of aluminum sulfate to water glass is 1:(2-4); The reagent system for the sweeping selection is as follows: the dosage of the cassiterite collector is 50-500 g / t, and the dosage of the 2# oil foaming agent is 10-40 g / t; The mass of the cassiterite collector is measured according to the mass of the cinnamic hydroxamic acid compound contained therein.

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