A flotation reagent system for selectively inhibiting coal series kaolinite lattice type iron titanium impurities and a flotation separation method thereof

Abstract

The present application relates to the technical field of coal-based kaolinite flotation purification, and particularly relates to a flotation reagent system for selective inhibition of lattice type iron and titanium impurities in coal-based kaolinite and a flotation separation method thereof. The flotation reagent system comprises a metal salt activator, an amine oxime small molecule inhibitor and a cationic collector. In view of the problems that lattice type iron and titanium impurities are difficult to be effectively removed in the existing coal-based kaolinite purification process, the conventional flotation reagent has poor selectivity, and the flotation separation efficiency is low, the present application enhances the selective adsorption and complexation of the reagent on the iron and titanium active centers through the synergistic effect between the metal salt activator and the amine oxime small molecule inhibitor, thereby improving the difference in surface properties and the difference in flotation behavior between the lattice type iron and titanium impurities and the kaolinite, achieving effective selective inhibition of the lattice type iron and titanium impurities, and promoting the selective separation and purification of the kaolinite mineral in the flotation process, and improving the purity of the coal-based kaolinite concentrate and the flotation efficiency.

Description

Technical Field

[0001] This invention relates to the field of flotation purification technology for coal-series kaolinite, specifically to a flotation reagent system for selectively suppressing lattice-type iron-titanium impurities in coal-series kaolinite and its flotation separation method. Background Technology

[0002] Coal-series kaolinite is an important associated mineral resource generated during coal mining and washing, typically stockpiled in large quantities as solid waste. Through appropriate purification, it can be transformed into a high-value-added mineral raw material, widely used in ceramics, papermaking, rubber and plastic fillers, refractory materials, and functional materials. With the increasing demand for high-purity kaolinite from high-end industries, developing efficient and green coal-series kaolinite purification technologies is of great significance for comprehensive resource utilization and environmental protection.

[0003] Coal-series kaolinite often contains impurities such as iron and titanium, some of which exist in a finely disseminated state or in a lattice-like form within the kaolinite particles or on their surface. These lattice-type iron-titanium impurities show little difference from kaolinite in terms of surface charge, wettability, and flotation behavior, making their separation in flotation systems difficult. Conventional inorganic dispersants or polymeric inhibitors are insufficient to achieve high-selectivity separation. Therefore, effectively removing lattice-type iron-titanium impurities from coal-series kaolinite is a crucial technical challenge that urgently needs to be addressed in the purification of coal-series kaolinite.

[0004] Flotation technology remains the most widely used mineral separation method in kaolinite purification due to its advantages of large processing capacity, mature technology, and good economics. Current technologies mostly employ cationic collector systems for kaolinite flotation, such as amine collectors like dodecylamine and hexadecyltrimethylammonium chloride, combined with dispersants or inhibitors like sodium hexametaphosphate, sodium silicate, or starch to regulate the pulp system and remove free gangue minerals such as quartz, mica, and carbonates. However, this type of reagent system mainly relies on the differences in surface properties between different minerals for separation, and its selective separation capability for lattice-type iron-titanium impurities in coal-series kaolinite is limited.

[0005] Existing research also includes technical solutions that improve flotation performance through compound collector systems. For example, Chinese patent application CN118807988A discloses a combined collector system composed of dodecylamine, sodium oleate, and acetic acid, used for reverse flotation separation of lithium chlorite and kaolinite in clay-type lithium ores, thereby achieving pre-enrichment of lithium minerals. This method enhances mineral collection capacity through the synergistic effect of different types of collectors and has certain application value in the separation of clay minerals. However, this type of method mainly targets the differences in flotation behavior between different minerals, and its separation effect on iron and titanium impurities existing in lattice form in coal-associated kaolinite remains limited.

[0006] On the other hand, amylopectin compounds are a class of small organic molecules containing both amino and oxime functional groups. They possess strong metal ion complexing and hydrogen bonding abilities, and have a certain application basis in the fields of selective metal ion coordination and mineral surface regulation. Existing technologies have disclosed general synthetic methods for preparing amylopectin compounds by reacting cyano compounds with hydroxylamine, and their applications in some mineral flotation systems (such as quartz or magnetite flotation systems) have been reported in the literature. However, for the specific separation target of lattice-type iron-titanium impurities in coal-associated kaolinite, there is still a lack of relevant technical solutions for selectively suppressing iron-titanium impurities using amylopectin small molecules.

[0007] Therefore, developing a flotation reagent system that can selectively suppress lattice-type iron and titanium impurities in coal-series kaolinite while maintaining good floatability of kaolinite under weakly alkaline slurry conditions through the synergistic effect of metal salt pre-regulation and ammonia oxime small molecules is of great significance for improving the purification efficiency and comprehensive utilization value of coal-series kaolinite. Summary of the Invention

[0008] The purpose of this invention is to address the problems of ineffective removal of lattice-type iron and titanium impurities, poor selectivity of conventional flotation reagents, and low flotation separation efficiency in the purification process of coal-series kaolinite. This invention provides a flotation reagent system and flotation separation method for selectively suppressing lattice-type iron and titanium impurities in coal-series kaolinite. The flotation reagent system includes a metal salt activator, a metallo-oxime small molecule inhibitor, and a cationic collector. Through the synergistic effect between the metal salt activator and the metallo-oxime small molecule inhibitor, the surface active sites of iron and titanium impurities in coal-series kaolinite can be directionally regulated, enhancing the selective adsorption and complexation of iron and titanium active centers by the reagent. This improves the difference in surface properties and flotation behavior between lattice-type iron and titanium impurities and kaolinite, achieving effective selective suppression of lattice-type iron and titanium impurities. Furthermore, it promotes the selective separation and purification of kaolinite minerals during flotation, improving the purity and flotation efficiency of coal-series kaolinite concentrate.

[0009] The technical solution of the present invention is as follows: A flotation reagent system for the flotation separation of lattice-type iron-titanium impurities in coal-series kaolinite, the flotation reagent system comprising: Metal salt activators; small molecule inhibitors of ethionine oximes; Cationic collector.

[0010] Furthermore, the amylopectin small molecule inhibitor is prepared by reacting a nitrile precursor with hydroxylamine; the amylopectin small molecule inhibitor contains one or more amylopectin groups.

[0011] This invention introduces for the first time a small molecule compound containing one or more metallo-oxime groups into the flotation separation system for lattice-type iron-titanium impurities in coal-series kaolinite, and establishes a synergistic inhibition mechanism suitable for this type of complex mineral sample by combining it with metal salt pretreatment. Under weakly alkaline conditions, this system preferentially acts on iron-titanium-containing active sites, enhancing the hydrophilicity of the lattice-type iron-titanium impurity surface, while the kaolinite bulk mineral maintains a good flotation response, thereby improving separation selectivity.

[0012] Furthermore, the small molecule inhibitors of the amylopyrime class used in this invention are preferably small molecule compounds containing 1-3 amylopyrime groups, wherein the amylopyrime small molecule inhibitors are selected from one or more of 3-amino-3-oxime propane (ADO), 1,3-diamino-1,3-dioxime propane (DADO), and 1,3-diamino-1,2,3-trioxime propane (TADO).

[0013] This invention synthesizes three small molecule inhibitors of the amylopectin class containing different numbers of amylopectin groups. The amylopectin class small molecule inhibitors are prepared by chemical reaction using nitrile precursors (preferably acrylonitrile, malononitrile, or 2-oximemalononitrile), hydroxylamine hydrochloride, and sodium hydroxide as raw materials to obtain solid powder formulations of 3-amino-3-oxime propane (ADO), 1,3-diamino-1,3-dioxime propane (DADO), and 1,3-diamino-1,2,3-trioxime propane (TADO).

[0014] The preferred molar ratio of the nitrile precursor to hydroxylamine hydrochloride and sodium hydroxide is 1:(1-1.5):(1-1.5); further, the preferred molar ratio of the nitrile precursor to hydroxylamine hydrochloride and sodium hydroxide is 1:1.2:1.2.

[0015] The preparation steps for 3-amino-3-oxime propane (ADO), 1,3-diamino-1,3-dioxime propane (DADO), and 1,3-diamino-1,2,3-trioxime propane (TADO) are as follows: Step (1): Weigh out the nitrile precursors acrylonitrile, malononitrile or 2-oxime-malononitrile, add methanol to a round-bottom flask and mix it evenly with the nitrile precursors to obtain the reaction solution; Step (2): Add hydroxylamine hydrochloride to a 40 wt% solution of sodium hydroxide and stir the mixture in a flask at room temperature to obtain a free hydroxylamine solution. Step (3): Add the free hydroxylamine solution obtained in step (2) to the reaction solution obtained in step (1) and react at 0-30 ℃ for 2-6 h to obtain solution a; Step (4): The solution a obtained in step (3) is rotary evaporated at 30-60 °C to obtain solid substance ①; Step (5): Dissolve the solid substance ① obtained in step (4) with an appropriate amount of anhydrous methanol. The precipitated solid substance is an impurity. Filter the solution to obtain solution b. Step (6): The solution b obtained in step (5) is rotary evaporated at 30-60℃ to obtain solid substance ②; Step (7): Dry the solid substance ② obtained in step (6) in a freeze dryer to obtain the said amygdoxime small molecule inhibitor.

[0016] The small molecule inhibitors of the amylopectin class prepared by this invention have the advantages of good selectivity, strong stability, low cost and easy synthesis.

[0017] The ADO reaction synthesis route is as follows: ; The DADO reactive synthesis route is as follows: ; The TADO reaction synthesis route is as follows: .

[0018] Furthermore, the metal salt activator is a cobalt salt; the cobalt salt is preferably cobalt sulfate and its hydrate.

[0019] Furthermore, the metal salt activator is CoSO4·7H2O.

[0020] Furthermore, the cationic collector is hexadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, dodecylamine and its salts, or dodecyltrimethylammonium chloride.

[0021] Furthermore, the present invention also provides the application of the flotation reagent system described above in the flotation separation of lattice-type iron-titanium impurities in coal-series kaolinite.

[0022] Furthermore, this invention also provides a flotation separation method for lattice-type iron-titanium impurities in coal-series kaolinite, comprising the following steps: Step (1): Prepare the kaolinite ore sample from the coal series into a slurry and adjust the pH of the slurry to alkaline; Step (2): Add metal salt activator to the slurry and stir to adjust the slurry; Step (3): Add a small molecule inhibitor of amphetamine oxime to the slurry and stir to adjust the slurry; Step (4): Add a cationic collector to the slurry for flotation separation to obtain kaolinite concentrate.

[0023] Furthermore, the amount of the metal salt activator is 50-100 g / t; the amount of the amine oxime small molecule inhibitor is 20-80 g / t; the amount of the cationic collector is 400-1200 g / t; and the pH of the slurry is 8.0-10.0.

[0024] Furthermore, the amount of the metal salt activator is 75 g / t; the amount of the amine oxime small molecule inhibitor is 40 g / t; the amount of the cationic collector is 800 g / t; and the pH of the pulp is 8.5-9.5.

[0025] Furthermore, the stirring time in step (2) is 3-5 min, the stirring time in step (3) is 3-5 min, and in step (4), after adding the cationic collector, the mixture is stirred for 2-4 min and then aerated and skimmed.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The flotation reagent system provided by this invention introduces a small molecule compound containing one or more amylopectin groups into the flotation separation system of lattice-type iron-titanium impurities in coal-series kaolinite for the first time, and combines it with the pretreatment effect of metal salt activators to form a synergistic inhibition mechanism in the slurry system. Under weakly alkaline conditions, the metal salt activator can directionally regulate the active sites containing iron and titanium on the mineral surface, making it easier for amylopectin-type small molecule inhibitors to complex or adsorb with the active centers of iron and titanium, thereby preferentially acting on the surface of lattice-type iron-titanium impurities, and thus enhancing the hydrophilicity of the surface of lattice-type iron-titanium impurities; at the same time, the main kaolinite mineral can still maintain a good flotation response. Through the above synergistic effect, the surface property difference between lattice-type iron-titanium impurities and kaolinite can be effectively expanded, improving the selectivity of the flotation system, which is conducive to achieving efficient purification of coal-series kaolinite and improving the stability and separation efficiency of the flotation process. Compared with conventional inorganic inhibitors, the flotation reagent system of this invention has the advantages of low reagent dosage, clear target, high separation selectivity and good process adaptability.

[0027] (2) The flotation separation method provided by this invention, by sequentially adding metal salt activators, amine oxime small molecule inhibitors, and cationic collectors, and coordinating with suitable pH conditions and slurry conditioning parameters, preferentially regulates the surface active sites of iron-titanium impurities in the slurry system, thereby enhancing the difference in flotation behavior between iron-titanium impurities and kaolinite. In this method, the order of reagent addition is clear and the flotation conditions are controllable, which can effectively improve the selectivity and stability of the flotation process, thereby achieving efficient separation of coal-series kaolinite from lattice-type iron-titanium impurities and improving the purity and recovery rate of kaolinite concentrate.

[0028] (3) The flotation reagent system of the present invention is applied to the flotation separation of lattice-type iron and titanium impurities in coal-series kaolinite. It can address the problem that iron and titanium elements in coal-series kaolinite exist in the form of lattice substitution or structural bonding and are difficult to remove by conventional physical methods, thereby achieving selective inhibition and efficient separation of such impurities. By using the flotation reagent system of the present invention for flotation treatment, the iron and titanium content in kaolinite products can be significantly reduced, the product purity can be improved, and thus the application scope of coal-series kaolinite in the field of high value-added materials can be broadened. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the ball-and-stick models of ADO, DADO, and TADO obtained in this invention, where gray represents carbon atoms, white represents hydrogen atoms, blue represents nitrogen atoms, and red represents oxygen atoms; Figure 2 This is a reaction synthesis route diagram of the ADO obtained in this invention; Figure 3 This is a reaction synthesis route diagram of DADO obtained in this invention; Figure 4 This is a reaction synthesis route diagram for TADO obtained in this invention; Figure 5 The infrared spectra of ADO, DADO, and TADO obtained in Examples 4-6 of this invention are shown below. Figure 6 The ultraviolet spectra of ADO, DADO, and TADO obtained in Examples 4-6 of this invention are shown below. Figure 7 Thermogravimetric analysis diagram of ADO obtained in Example 4 of the present invention; Figure 8 Thermogravimetric analysis diagram of DADO obtained in Example 5 of the present invention; Figure 9 Thermogravimetric analysis diagram of TADO obtained in Example 6 of the present invention; Figure 10 The figures (a1) and (a2) show the flotation purification results of coal-series kaolinite under different cationic collector dosages in the three small molecule inhibition systems of the three amylopectins obtained in Examples 13-27 of this invention. Figure 11 The above figures show the flotation comparison results of the three amylopectin small molecule inhibition systems obtained in Examples 10-12 and Comparative Examples 7-18 of this invention under different pH conditions. Detailed Implementation

[0030] The technical solutions of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings. The embodiments described herein are specific implementations of the present invention, used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary, and should not be construed as limiting the implementation methods or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can employ other obvious technical solutions based on the content disclosed in the claims and specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.

[0031] Unless otherwise specified, the methods used in the following examples and comparative examples are all prior art; reagents not specifically mentioned are conventional reagents, all of which can be purchased from conventional reagent manufacturers and distributors. Information such as some raw material manufacturers and CAS numbers is as follows: The coal-series kaolinite ore sample was purchased from Anhui Jinyan Kaolin New Material Co., Ltd. The iron content of this coal-series kaolinite is 0.85%, and the titanium content is 0.45%.

[0032] 2-Oxime-malonium was prepared in-house using malononitrile, glacial acetic acid, and sodium nitrite as raw materials. Experimental method: 40 g of malononitrile, 42 g of NaNO₂, and 70.0 mL of water were added to a 0.5 L reactor and stirred at 0-10 °C. 6 mL of glacial acetic acid was slowly added, controlling the addition rate to keep the temperature below 15 °C. The reaction was carried out at room temperature for 2-3 h to obtain the target product solution. After rotary evaporation, the solid product, 2-oxime-malonium, was obtained.

[0033] Hydroxylamine hydrochloride, CAS No.: 5470-11-1; CoSO4·7H2O, CAS No.: 10124-43-3; Hexadecyltrimethylammonium bromide, CAS No.: 57-09-0; Tetradecyltrimethylammonium bromide, CAS No.: 1119-97-7; Dodecyltrimethylammonium bromide, CAS No.: 1119-94-4; Acrylonitrile, CAS No.: 107-13-1; Malonadionitrile, CAS No.: 109-77-3; Dodecylamine, CAS No.: 124-22-1; Dodecyltrimethylammonium chloride, CAS No.: 112-00-5.

[0034] This invention discloses a flotation reagent system and flotation separation method for selectively suppressing lattice-type iron-titanium impurities in coal-series kaolinite. The raw materials used in the flotation reagent system include a metal salt activator, a metallamine oxime small molecule inhibitor, and a cationic collector. Examples 1-9 of this invention describe the preparation of the metallamine oxime small molecule inhibitor, and the amounts of raw materials used are shown in the table below: Table 1. Raw material usage of the small molecule inhibitors of the amine oxime class in Examples 1-9 of this invention. The preparation methods of the methylamine oxime small molecule inhibitors of Examples 1-9 of this invention are as follows: Step (1): Weigh the nitrile precursor, add methanol to a 250 mL round-bottom flask and mix it evenly with the nitrile precursor to obtain the reaction solution; Step (2): Add hydroxylamine hydrochloride to a 40wt% solution of sodium hydroxide, stir the mixture in a 100 mL flask at room temperature for 30 min to obtain a free hydroxylamine solution; Step (3): Add the free hydroxylamine solution obtained in step (2) to the reaction solution obtained in step (1) to obtain solution a; Step (4): The solution a obtained in step (3) is rotary evaporated at 50°C to obtain solid substance ①; Step (5): Dissolve the solid substance ① obtained in step (4) with an appropriate amount of anhydrous methanol. The precipitated solid substance is an impurity. Filter the solution to obtain solution b. Step (6): Rotary evaporate the solution b obtained in step (5) at 50°C to obtain solid substance ②; Step (7): Dry the solid substance ② obtained in step (6) in a freeze dryer for 24 h; to obtain the said amygdoxime small molecule inhibitor.

[0035] like Figure 5 The infrared spectra of ADO, DADO, and TADO obtained in Examples 4-6 of this invention are shown. Due to the overlap of the stretching vibrations of OH and N-H2, the range of 3468-3324 cm⁻¹ is observed in the figures. -1 The broad, strong absorption band at this point corresponds to the stretching vibrations of OH and NH, indicating the presence of hydroxyl and amino groups in the product; and the band at 1664-1650 cm⁻¹ in the figure... -1 A characteristic absorption peak for C=N appears at [location missing]; secondly, the peak values ​​in the figure are 1057-1037 cm⁻¹. -1 The fingerprint area corresponds to the CN tensile vibration; the NO bond is located at 987-937 cm. -1 A stretching vibration peak appears at 1057-1037 cm⁻¹, while in the figure, the peak is observed at 1057-1037 cm⁻¹. -1 and 987-937 cm -1CN and NO-related vibrational peaks appeared nearby; and the infrared spectra of the three inhibitor molecules were at 3443, 1664, and 937 cm⁻¹. -1 The presence of characteristic absorption peaks indicates the presence of a -C=N-OH (-NH2) structure in the product, which in turn indicates the presence of a amine oxime functional group in the product.

[0036] and Figure 6 The UV spectra of ADO, DADO, and TADO obtained in Examples 4-6 of this invention show that the peak positions also prove that the three inhibitors contain oxime groups, further verifying the formation of the target functional group (-CN-OH).

[0037] Example 10 150 g of coal-series kaolinite ore sample was placed in a 0.5 L flotation cell. The raw ore contained 0.85% Fe and 0.45% Ti. Water was added to adjust the slurry, and the mixture was stirred at 1800 r / min for 3 min to fully wet the minerals. The pH of the slurry was adjusted to 9.0 using 1 mol / L HCl or NaOH, and stirred for 3 min. Subsequently, 75 g / t CoSO4·7H2O was added sequentially, and the mixture was stirred for 3 min; 40 g / t of the amylopectin-based small molecule inhibitor ADO obtained in Example 4 was added, and the mixture was stirred for 3 min; finally, 800 g / t hexadecyltrimethylammonium bromide was added, and the mixture was stirred for 3 min, followed by aeration and foaming for 6 min to obtain the flotation concentrate.

[0038] Example 11 150 g of coal-series kaolinite ore sample was placed in a 0.5 L flotation cell. The raw ore contained 0.85% Fe and 0.45% Ti. Water was added to adjust the slurry, and the mixture was stirred at 1800 r / min for 3 min to fully wet the minerals. The pH of the slurry was adjusted to 8.0 using 1 mol / L HCl or NaOH, and stirred for 3 min. Subsequently, 50 g / t CoSO4·7H2O was added sequentially, and the mixture was stirred for 3 min; 20 g / t of the DADO small molecule inhibitor obtained in Example 5 was added, and the mixture was stirred for 3 min; finally, 400 g / t dodecylamine was added, and the mixture was stirred for 2 min, followed by aeration and foaming for 6 min to obtain the flotation concentrate.

[0039] Example 12 150 g of coal-series kaolinite ore sample was placed in a 0.5 L flotation cell. The raw ore contained 0.85% Fe and 0.45% Ti. Water was added to adjust the slurry, and the mixture was stirred at 1800 r / min for 3 min to fully wet the minerals. The pH of the slurry was adjusted to 10.0 using 1 mol / L HCl or NaOH, and stirred for 3 min. Subsequently, 100 g / t CoSO4·7H2O was added sequentially, and the mixture was stirred for 5 min. Then, 80 g / t of the TADO small molecule inhibitor obtained in Example 6 was added, and the mixture was stirred for 5 min. Finally, 1000 g / t dodecyltrimethylammonium chloride was added, and the mixture was stirred for 4 min, followed by aeration and foaming for 6 min to obtain the flotation concentrate.

[0040] Examples 13-27 The amounts of the cationic collector cetyltrimethylammonium bromide (CTAB) used in Examples 13-27 are shown in the table below. Other preparation steps are similar to those in Example 12.

[0041] Table 2. Dosage of cationic collectors in Examples 13-27 of the present invention. Comparative Examples 1-18 The differences between Comparative Examples 1-18 and the Examples are shown in the table below. Other preparation steps are similar to those in Example 12.

[0042] Table 3. Differences between Comparative Examples 1-18 and the Embodiments of the Present Invention Experimental Example 1: Thermogravimetric Analysis 1. Test subjects: ADO, DADO, and TADO obtained in Examples 4-6 of this invention. 2. Test method: Take 10 mg of solid powder ADO, DADO and TADO into the crucible of the thermogravimetric analyzer, respectively. After the instrument baseline is calibrated, place the sample crucible in the instrument and perform thermogravimetric analysis under a nitrogen atmosphere. The temperature range is room temperature to 800 ℃, and the heating rate is 10 ℃ / min. After setting the parameters, start the test. The instrument automatically records the mass-temperature data (instrument model: NETZSCH STA 449 F5 Jupiter® simultaneous thermal analyzer).

[0043] 3. Test Results: The test results are as follows Figure 7-9 The thermogravimetric analysis diagrams of ADO, DADO, and TADO obtained in Examples 4-6 of this invention are shown.

[0044] The ADO, DADO, and TADO obtained by this invention all exhibit good thermal stability under flotation conditions. Their main weight loss processes correspond to the adsorbed water removal and functional group decomposition processes, meeting the requirements for use in room temperature flotation.

[0045] The thermogravimetric diagram of ADO molecules shows that in the first stage (30-120 ℃), due to the release of adsorbed water, the cumulative weight loss rate in this range reaches 43.11%; the second stage (130-300 ℃) is the characteristic decomposition range of the ammonium oxime group, with a weight loss rate of 14.6%; the third stage (300-600 ℃) is attributed to the thermal cracking, cyclization and aromatization reactions of the polymer backbone, with a cumulative weight loss of 12.03%, of which 130 ℃ meets the flotation working conditions.

[0046] The thermogravimetric diagram of DADO molecules shows that the first stage (30-130 ℃) corresponds to the volatilization process of physically adsorbed water, with a cumulative weight loss of 2.55% in this range; the second stage (180-300 ℃) is the characteristic decomposition range of the amylopyroxime group (-C(=NOH)-NH2), with a cumulative weight loss of 6.86%; the third stage (300-600 ℃) is the thermal cracking and aromatization process of the polymer backbone, with a cumulative weight loss of 6.86%, of which 180 ℃ meets the flotation working conditions.

[0047] The thermogravimetric diagram of TADO molecules shows that the first stage (30-120 ℃) ​​corresponds to the volatilization process of physically adsorbed water, with a cumulative weight loss of only 0.93% in this range; the second stage (150-200 ℃) involves hydroxyl and amino groups, while the 200-350 ℃ stage involves the pyrolysis and cleavage of oxime groups and carbon chains, with a cumulative weight loss of up to 36.34%; the third stage (350-600 ℃) involves the thermal decomposition and aromatization of the polymer backbone, with a cumulative weight loss of 9.77%, of which 150 ℃ meets the flotation working conditions.

[0048] Experimental Example 2: Fe and Ti Content Test 1. Test subjects: Examples 10-27 and Comparative Examples 1-18 of this invention 2. Test methods: Take 0.1 g of sample and add hydrochloric acid, nitric acid, hydrofluoric acid, and 20% hydrogen peroxide to a digestion tube. Place the tube in a microwave digester and digest at 200 °C for 2 h. Then, remove the acid in an acid-removing apparatus at 180 °C until 1-2 mL of solution remains. Dilute the remaining solution with ultrapure water to 100 mL, and filter 6-10 mL of this solution through a water filter before ICP testing. Measure the emission intensity of standard solutions (1 ppm, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 30 ppm) sequentially, and plot a concentration-intensity standard curve. The correlation coefficient of the standard curve should be greater than 0.999. After establishing the standard curve, measure the ultrapure water first to subtract background interference. Measure the emission intensity of the sample solution sequentially; the instrument will automatically calculate the concentration of each element in the sample based on the standard curve (instrument model: Agilent 5800 ICP-OES).

[0049] 3. Test Results: The experimental results of Fe and Ti content in this invention are shown in Tables 4 and 5.

[0050] Table 4. Test results of Fe and Ti content in Examples 10-27 of the present invention. Table 5. Test results of Fe and Ti content in comparative examples 1-18 of this invention. Secondly, the grade test results of this invention (iron content test of concentrate and tailings) are as follows: Figure 10 , Figure 11 As shown.

[0051] The present invention Figure 10 (a1) and (a2) demonstrate the effect of different dosages of the cationic collector CTAB on the flotation performance. As the CTAB dosage increased from 400 g / t to 1200 g / t, the concentrate impurity content of the three amylopectin small molecule inhibitors continuously increased, reaching a peak at 1200 g / t (ADO concentrate impurity content was close to 0.73%). With increasing CTAB dosage, the concentrate recovery of the three amylopectin small molecule inhibitors significantly improved, with the lowest recovery at 400 g / t (ADO around 50%, TADO close to 40%), and a peak at 1200 g / t (ADO close to 80%, TADO over 70%).

[0052] At the same CTAB dosage, the recovery rates were ranked as ADO > DADO > TADO. Within the experimental dosage range, the higher the CTAB dosage, the higher the concentrate impurity content and the higher the recovery rate. Therefore, it is necessary to select an optimal point with relatively low impurity content and suitable recovery rate. Based on this, 800 g / t was selected as the optimal collector dosage. Furthermore, at the same CTAB dosage, TADO still exhibits the best overall flotation performance, balancing low impurity content and suitable recovery rate.

[0053] That is, from Figure 10 As can be seen, with the increase of cationic collector dosage, all three amine oxime small molecule inhibitor systems showed a trend of increased tailings grade and slow change in concentrate grade, indicating that the enhancing effect of the collector mainly promoted the flotation separation process of minerals, while the inhibitor played a key selective regulation role. Among them, the TADO system showed the best separation effect, indicating that it has a stronger directional complexing ability for iron- and titanium-containing active sites.

[0054] Figure 11 This graph shows the grade test results of three amylopectin-based small molecule inhibitors (ADO, DADO, and TADO) at different pH values ​​during flotation experiments. pH is a crucial factor affecting the flotation effect of this invention. Under weakly alkaline conditions (pH 8-10), the three amylopectin-based small molecule inhibitors exhibit the best inhibition effect, resulting in the lowest concentrate impurity content and optimal flotation performance. As the pH decreases (neutral → acidic), the inhibitor effect continuously deteriorates, and the impurity content in the concentrate increases; the stronger the acidity, the worse the flotation effect. Under strongly alkaline conditions (pH=11), the effect of the amylopectin-based small molecule inhibitors also deteriorates. Furthermore, under the same pH conditions, TADO shows the best overall flotation performance, followed by DADO, with ADO being the weakest.

[0055] In this invention, pH has a significant impact on flotation behavior, with the optimal separation effect observed under weakly alkaline conditions (pH 8-10). This is because, under these conditions, the active sites of iron and titanium on the mineral surface undergo hydroxylation, while the deprotonation of the oxime groups enhances coordination ability. Under the activation of metal salts, a stable surface complex structure is formed, which preferentially acts on lattice-type iron and titanium impurities, increasing their hydrophilicity and inhibiting their flotation behavior, while the kaolinite main mineral retains good floatability, ultimately achieving selective separation.

[0056] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A flotation reagent system for the flotation separation of lattice-type iron-titanium impurities in coal-series kaolinite, characterized in that, The flotation reagent system includes: Metal salt activators; small molecule inhibitors of ethionine oximes; Cationic collector.

2. The flotation reagent system for the flotation separation of lattice-type iron-titanium impurities in coal-series kaolinite as described in claim 1, characterized in that, The cyclomethicone small molecule inhibitors are prepared by reacting nitrile precursors with hydroxylamine; the cyclomethicone small molecule inhibitors contain one or more cyclomethicone groups.

3. The flotation reagent system for the flotation separation of lattice-type iron-titanium impurities in coal-series kaolinite as described in claim 1, characterized in that, The amylopyridine small molecule inhibitors are selected from one or more of 3-amino-3-oxime propane, 1,3-diamino-1,3-dioxime propane, and 1,3-diamino-1,2,3-trioxime propane.

4. The flotation reagent system for the flotation separation of lattice-type iron-titanium impurities in coal-series kaolinite as described in claim 1, characterized in that, The metal salt activator is a cobalt salt.

5. The flotation reagent system for the flotation separation of lattice-type iron-titanium impurities in coal-series kaolinite as described in claim 1, characterized in that, The cationic collector is hexadecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, dodecyltrimethylammonium bromide, dodecylamine and its salts or dodecyltrimethylammonium chloride.

6. The application of the flotation reagent system as described in claim 1 in the flotation separation of lattice-type iron and titanium impurities in coal-series kaolinite.

7. A flotation separation method for lattice-type iron-titanium impurities in coal-series kaolinite, characterized in that, Includes the following steps: Step (1): Prepare the kaolinite ore sample from the coal series into a slurry and adjust the pH of the slurry to alkaline; Step (2): Add metal salt activator to the slurry and stir to adjust the slurry; Step (3): Add a small molecule inhibitor of amphetamine oxime to the slurry and stir to adjust the slurry; Step (4): Add a cationic collector to the slurry for flotation separation to obtain kaolinite concentrate.

8. The flotation separation method for lattice-type iron-titanium impurities in coal-series kaolinite as described in claim 7, characterized in that, The dosage of the metal salt activator is 50-100 g / t; the dosage of the amine oxime small molecule inhibitor is 20-80 g / t; the dosage of the cationic collector is 400-1200 g / t; and the pH of the slurry is 8.0-10.

0.

9. The flotation separation method for lattice-type iron-titanium impurities in coal-series kaolinite as described in claim 7, characterized in that, The dosage of the metal salt activator is 75 g / t; the dosage of the amine oxime small molecule inhibitor is 40 g / t; the dosage of the cationic collector is 800 g / t; and the pH of the pulp is 8.5-9.

5.

10. The flotation separation method for lattice-type iron-titanium impurities in coal-series kaolinite as described in claim 7, characterized in that, The stirring time in step (2) is 3-5 min, the stirring time in step (3) is 3-5 min, and in step (4) after adding the cationic collector, the mixture is stirred for 2-4 min and then aerated and skimmed.

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