Quaternary ammonium cation modified cellulose, preparation method thereof and application of quaternary ammonium cation modified cellulose as chalcopyrite inhibitor

Abstract

The invention discloses quaternary ammonium cation modified cellulose, a preparation method thereof and application of the quaternary ammonium cation modified cellulose as a chalcopyrite inhibitor, and belongs to the technical field of mineral separation. The molecular structural formula of the quaternary ammonium cation modified cellulose is as follows: # imgabs0 #, R1, R2 and R3 are independently selected from hydrogen or quaternary ammonium salt groups, and at least one of R1, R2 and R3 is a quaternary ammonium salt group; the chalcopyrite flotation inhibitor has a selective inhibition effect on chalcopyrite flotation and is particularly suitable for flotation separation of metal sulfide ores (such as molybdenite and galena) and chalcopyrite.

Description

Technical Field

[0001] The present invention relates to a modified cellulose, in particular to a quaternary ammonium cation modified cellulose, and also relates to a preparation method of the quaternary ammonium cation modified cellulose and its application as a chalcopyrite depressant, belonging to the technical field of mineral processing. Background Art

[0002] Flotation is an important means for the enrichment of low-grade ores. Among them, the selectivity of flotation reagents directly affects the mineral separation effect. In terms of chalcopyrite depression, traditional inorganic depressants such as sulfides and cyanides have problems such as high toxicity and high dosage, while organic depressants face limitations such as complex synthesis and high cost. At present, the main chalcopyrite depressants include sodium sulfide, sodium thioglycolate, sodium thiosulfate, etc.

[0003] Cellulose and modified cellulose have environmental protection and biodegradability, high-efficiency charge neutralization ability and interfacial modification effect as flotation reagents. As a high-molecular compound with unique structure and properties, it can achieve selective adsorption through the interaction between the groups it carries and the mineral surface, improving the flotation effect; its low dosage, wide pH adaptability and low toxicity characteristics make it superior to traditional synthetic reagents in mineral flotation and reduce secondary pollution at the same time.

[0004] For example, Chinese Patent (CN116159680A) discloses the use of nano-cellulose as a serpentine depressant for the flotation of copper-nickel ores, with high recovery rates of copper and nickel metals and low magnesium oxide content in the concentrate, and can achieve efficient enrichment of pentlandite and chalcopyrite in copper-nickel ores. Another example is that Chinese Patent (CN105331421A) discloses carboxymethyl cellulose as a desulfurization depressant for coal flotation, Chinese Patent (CN103817011A) discloses a composition of carboxymethyl cellulose as a carbonaceous material depressant for the separation of nickel-molybdenum minerals and carbonaceous materials, Chinese Patent (CN1010844110A) discloses a composition of carboxymethyl cellulose as a layered silicate depressant in the flotation process of sulfide ores, Chinese Patent (CN103386367A) discloses sodium carboxymethyl cellulose as a depressant for magnesium-containing ore gangue minerals such as talc, etc. The technologies disclosed in these patents all use anion-modified carboxymethyl cellulose as a depressant for gangue minerals. So far, there has been little research on the application of cation-modified cellulose in mineral flotation, especially in terms of chalcopyrite depression, and there has been no systematic report. Summary of the Invention

[0005] Aiming at the technical problems existing in the prior art, the first object of the present invention is to provide a quaternary ammonium cation modified cellulose, which has a selective inhibitory effect on the flotation of chalcopyrite and is particularly suitable for the flotation separation of molybdenite and galena from chalcopyrite.

[0006] The second object of the present invention is to provide a method for synthesizing quaternary ammonium cation-modified cellulose, which has the advantages of simple process, mild reaction conditions, environmental protection, safety, simple post-treatment, and less waste generation, and meets the requirements of large-scale production.

[0007] The third object of the present invention is to provide an application of quaternary ammonium cation-modified cellulose. When used as an inhibitor of chalcopyrite, it can be used for the flotation separation of molybdenite, galena and other metal sulfide ores from chalcopyrite, and has the characteristics of low inhibitor concentration, wide applicable pH range, and good inhibition effect.

[0008] To achieve the above technical objects, the present invention provides a quaternary ammonium cation-modified cellulose, which has the following molecular structural formula:

[0009]

[0010] Among them,

[0011] R1, R2 and R3 are independently selected from hydrogen or a quaternary ammonium salt group, and at least one of R1, R2 and R3 is a quaternary ammonium salt group;

[0012] The structural formula of the quaternary ammonium salt group is as follows:

[0013]

[0014] Among them, R is a bonding group;

[0015] R4, R5 and R6 are independently selected from C1-C4 alkyl groups;

[0016] m / (m + n) = 0.18 - 0.9.

[0017] In the molecular structure of the quaternary ammonium cation-modified cellulose of the present invention, R is a bonding group, that is, the bonding group for grafting the quaternary ammonium salt group onto the cellulose main chain, which can be a C1-C 10 hydrocarbon chain or a C2-C 10 hydrocarbon-oxygen chain. The C1-C 10 hydrocarbon chain can be a saturated hydrocarbon chain, that is, an alkane chain. It can also be an unsaturated hydrocarbon chain, for example, the main chain contains at least one alkenyl or alkynyl group. The C2-C 10 hydrocarbon-oxygen chain can be a hydrocarbon-oxygen chain containing an ether oxygen bond, a hydroxyl substituent, an ester group, etc. Specific examples are: -CH2-CH(OH)-CH2-, -CH(OH)-CH2-, -(CH2)3-CH=CH-CH2-, -CH2-CH(CH3)C(=O)-O-CH2-CH2- and other groups. The bonding group mainly plays a bonding role and has relatively little influence on the activity of the quaternary ammonium salt active group.

[0018] The quaternary ammonium cation modified cellulose of the present invention has a positively charged -N + (CH3)3 group preferentially adsorbs on the negatively charged hydroxylated layer formed due to oxidation on the surface of chalcopyrite (CuFeS2) to form a hydrophilic film on the surface of chalcopyrite, thereby inhibiting the interaction between chalcopyrite and the collector. Molybdenite (MoS2) is naturally hydrophobic and has a neutral surface potential, and galena (PbS) has different hydrolysis characteristics, resulting in weak adsorption competition. Therefore, the quaternary ammonium cation modified cellulose can selectively inhibit chalcopyrite and efficiently flotation separate molybdenite and galena concentrates. 2+

[0019] In the molecular structure of the quaternary ammonium cation modified cellulose of the present invention, m / (m + n) = 0.18 - 0.9. The higher the proportion of m, the more the content of the quaternary ammonium salt group, thus affecting its inhibitory effect on chalcopyrite.

[0020] The present invention also provides a preparation method of the quaternary ammonium cation modified cellulose, which includes the following steps:

[0021] 1) Alkalize cellulose to obtain alkalized cellulose;

[0022] 2) Carry out an etherification reaction between the alkalized cellulose and a halogenated organic quaternary ammonium salt, an alkenyl - containing organic quaternary ammonium salt or an epoxy - containing organic quaternary ammonium salt to obtain the product.

[0023] As a preferred scheme, the alkalization process is as follows: Cellulose and sodium hydroxide are in an alcohol - water mixed solution at a temperature of 25 - 60 °C for 10 - 30 minutes.

[0024] As a preferred scheme, the concentration of sodium hydroxide in the alcohol - water mixed solution is 0.1 - 1 mol / L.

[0025] As a preferred scheme, the molar ratio of cellulose to sodium hydroxide is 1:(1.0 - 10.0), where cellulose is measured by the molar amount of its sugar units. The structural formula of the sugar unit is as follows:

[0026]

[0027] As a preferred scheme, the molar ratio of cellulose to the halogenated organic quaternary ammonium salt is 1:

[0028] (1.0 - 4.0), where cellulose is measured by the molar amount of its sugar units.

[0029] As a preferred scheme, the conditions for the etherification reaction are: temperature is 70 - 90 °C and time is 1 - 1.5 hours.

[0030] The halogenated organic quaternary ammonium salt involved in the present invention has the following molecular structure:​

[0031]

[0032] Among them, X is a halogen substituent, R is a bonding group, and R4, R5, and R6 are independently selected from C1-C4 alkyl groups; specifically, X is, for example, a chlorine substituent or a bromine substituent. Specific examples of the halogenated organic quaternary ammonium salt include: 3-chloro-2-hydroxypropyltrimethylammonium chloride. The halogenated organic quaternary ammonium salt and alkalized cellulose mainly form ether bonds through a substitution reaction.

[0033] The alkenyl-containing organic quaternary ammonium salt involved in the present invention has the following molecular structure:

[0034] Among them, R8 is methyl or hydrogen; R7 can be a C1-C8 hydrocarbon chain or a C2-C8 hydrocarbon-oxygen chain; R4, R5, and R6 are independently selected from C1-C4 alkyl groups. Specific examples of the alkenyl-containing organic quaternary ammonium salt include: dimethyldiallylammonium chloride, methacryloyloxyethyltrimethylammonium chloride, and the like. The alkenyl-containing organic quaternary ammonium salt and alkalized cellulose mainly form ether bonds through an addition reaction.

[0035] The epoxy group-containing organic quaternary ammonium salt involved in the present invention has the following molecular structure:

[0036] Among them, R9 can be a C1-C8 hydrocarbon chain or a C2-C8 hydrocarbon-oxygen chain; R4, R5, and R6 are independently selected from C1-C4 alkyl groups. Specific examples of the epoxy group-containing organic quaternary ammonium salt include: bis(2,3-epoxypropyl)trimethylammonium chloride, and the like. The epoxy group-containing organic quaternary ammonium salt and alkalized cellulose mainly form ether bonds through a ring-opening addition reaction.

[0037] The present invention takes the formation of ether bonds between a halogenated organic quaternary ammonium salt and alkalized cellulose through a substitution reaction as an example for specific illustration. The reaction formula is as follows:

[0038]

[0039] R1, R2, and R3 are independently selected from hydrogen or a quaternary ammonium salt group, and at least one of R1, R2, and R3 is a quaternary ammonium salt group;

[0040] The structural formula of the quaternary ammonium salt group is as follows:

[0041]

[0042] R is a bonding group;

[0043] R4, R5, and R6 are independently selected from C1-C4 alkyl groups;

[0044] m / (m + n) = 0.18 - 0.90.

[0045] The present invention also provides an application of quaternary ammonium cation modified cellulose, which is used as a chalcopyrite depressant for mineral flotation.

[0046] As a preferred embodiment, the quaternary ammonium cation modified cellulose is used as a chalcopyrite depressant for the flotation separation of chalcopyrite from other metal sulfide ores.

[0047] The quaternary ammonium cation modified cellulose of the present invention can selectively act on the surface of chalcopyrite, thereby realizing its selective inhibition effect, and can be used for the efficient flotation separation of metal sulfide ores such as molybdenite and galena from chalcopyrite.

[0048] As a preferred embodiment, the other metal sulfide ores include chalcopyrite, molybdenite and / or galena.

[0049] As a preferred embodiment, during the flotation separation process, the pH value of the pulp is adjusted to 4.0 - 10.0. The quaternary ammonium cation modified cellulose is applicable to a wide pH range. The pH value is adjusted using hydrochloric acid or sodium hydroxide.

[0050] As a preferred embodiment, the concentration of the quaternary ammonium cation modified cellulose in the pulp is 100 - 500 mg / L.

[0051] As a preferred embodiment, the concentration of kerosene in the pulp is 5 - 150 mg / L.

[0052] As a preferred embodiment, the concentration of the foaming agent in the pulp is 1 - 3×10 -4 mol / L.

[0053] The application process of the quaternary ammonium cation modified cellulose of the present invention: Take 220 mL of deionized water and 2 g of metal sulfide ore to prepare a pulp. Then stir at 600 rpm for 1 min, add a pH adjuster and stir for 2 min, add the quaternary ammonium cation modified cellulose and stir for 3 min, then add a metal sulfide ore collector (kerosene) and stir for 3 min, and finally add a foaming agent (methyl isobutyl carbinol) and stir for 1 min. Let it stand for 1 min, transfer it to a single bubble tube for aerated flotation for 3 min, and after suction filtration to obtain concentrate and tailings, dry and weigh them.

[0054] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0055] The synthesis method of the quaternary ammonium cation modified cellulose provided by the present invention has the advantages of mild reaction conditions, simple operation, high conversion rate, environmental protection and safety, simple post-treatment, and less waste generation.

[0056] The quaternary ammonium cation modified cellulose provided by the present invention can be used as a chalcopyrite inhibitor for the efficient flotation separation of molybdenite, galena and chalcopyrite. Its optimal flotation conditions are that the inhibition concentration of cationic cellulose is relatively low, the applicable pulp pH value range is relatively wide, and it has broad application prospects. Description of the Drawings

[0057] Figure 1 It is the ultraviolet spectrum of 2,3-epoxypropyltrimethylammonium chloride.

[0058] Figure 2 It is the ultraviolet spectrum of quaternary ammonium cation modified cellulose CGC.

[0059] Figure 3 It is the infrared spectrum of quaternary ammonium cation modified cellulose CGC.

[0060] Figure 4 It is the ultraviolet spectrum of 3-chloro-2-hydroxypropyltrimethylammonium chloride.

[0061] Figure 5 It is the ultraviolet spectrum of quaternary ammonium cation modified cellulose CAC.

[0062] Figure 6 It is the infrared spectrum of quaternary ammonium cation modified cellulose CAC.

[0063] Figure 7 It is the infrared spectrum of quaternary ammonium cation modified cellulose CDC.

[0064] Figure 8 It is the relationship diagram of the influence of pH on the performance of quaternary ammonium cation modified cellulose in inhibiting galena / chalcopyrite.

[0065] Figure 9 It is the relationship diagram of the influence of pH on the performance of quaternary ammonium cation modified cellulose in inhibiting molybdenite / chalcopyrite. Detailed Embodiments

[0066] The technical solutions of the present invention will be described in detail below through specific embodiments, but the following specific embodiments do not limit the protection scope of the claims of the present invention.

[0067] In the following embodiments, unless otherwise specified, the reagents used are all commercially available products. The concentrations or contents in each embodiment are all mass percentages.

[0068] The cellulose of the present invention is a commercially available microcrystalline cellulose product: CAS: 9004-34-6.

[0069] Example 1

[0070] Weigh 0.01 mol of cellulose, 30 g of isopropanol, 0.4 g of sodium hydroxide, and 90 mL of water. After mixing, stir for half an hour, set the temperature at 60 °C, and the rotation speed at 400 rpm. Subsequently, add 0.04 mol of 2,3-epoxypropyltrimethylammonium chloride (GC). Its ultraviolet spectrum is shown in Figure 1 , stir and react for 1 hour, set the temperature at 80 °C, and the rotation speed at 400 rpm. After centrifuging the prepared product solution, dry the lower-layer solid in an oven to obtain a white solid inhibitor (CGC). The ultraviolet spectrum of the obtained product is shown in Figure 2 , and the infrared spectrum is shown in Figure 3 .

[0071] Cellulose itself is insoluble in water. The raw materials before the reaction and the products after the reaction were characterized by ultraviolet spectroscopy respectively. Figure 1 and Figure 2 The peak positions in them changed significantly, indicating the formation of new products. The wavelength shifted by 18 nm, indicating changes in the hydrogen bonds or polar environment around the chromophore groups in the raw materials, resulting in a blue shift. The infrared spectrum Figure 3 The broad peak near 3382 cm-1 belongs to the O-H stretching vibration; the C-H stretching vibration on the cellulose chain is at 2902 cm-1. There is an asymmetric bending vibration of C-H at 1476 cm-1, which is a strong characteristic peak of the quaternary ammonium group. It shows that the quaternary ammonium salt group has been successfully grafted onto the cellulose.

[0072] Example 2

[0073] Weigh 0.01 mol of cellulose, 30 g of isopropanol, 0.4 g of sodium hydroxide, and 90 mL of water. After mixing, stir for 10 minutes, set the temperature at 25 °C, and the rotation speed at 400 rpm. Subsequently, add 3-chloro-2-hydroxypropyltrimethylammonium chloride (CTA). Its ultraviolet spectrum is shown in Figure 4 . Stir and react for 1 hour, set the temperature at 80 °C, and the rotation speed at 400 rpm. After centrifuging and separating the prepared product solution, dry the lower-layer solid in an oven to obtain a white solid inhibitor (CAC). The ultraviolet spectrum of the obtained product is shown in Figure 5 , and the infrared spectrum is shown in Figure 6 .

[0074] The raw materials before the reaction and the products after the reaction were characterized by ultraviolet spectroscopy respectively. Figure 4 and Figure 5 The peak positions in them changed significantly, indicating the formation of new products. The wavelength shifted by 32 nm, indicating changes in the hydrogen bonds or polar environment around the chromophore groups in the raw materials, resulting in a blue shift. The infrared spectrum Figure 6 The broad peak near 3402 cm-1 belongs to the O-H stretching vibration; there is an asymmetric bending vibration of C-H at 1481 cm-1, which is a strong characteristic peak of the quaternary ammonium group. It shows that the quaternary ammonium salt group has been successfully grafted onto the cellulose.

[0075] Figure 7 It is the infrared spectrum of cationic cellulose with the bonding group -(CH2)3-CH=CH-CH2-. The broad peak near 3356 cm-1 in the figure belongs to the O-H stretching vibration; the C-H stretching vibration on the cellulose chain is at 2902 cm-1. The C-H asymmetric bending vibration at 1461 cm-1 corresponds to the strong characteristic peak of the quaternary ammonium group, indicating that the quaternary ammonium salt group has been successfully grafted onto the cellulose.

[0076] Example 3

[0077] Study on the flotation performance of the (CGC) inhibitor prepared in Example 1 on single minerals. Take 220 mL of deionized water and 2 g of metal sulfide ore (chalcopyrite / galena) to prepare a pulp. Then stir at 600 rpm for 1 min, add a pH adjuster (such as sodium hydroxide) to adjust to the set pH and stir for 2 min, add quaternary ammonium cation-modified cellulose, stir at an inhibitor concentration of 200 mg / L in the pulp for 3 min, then add a metal sulfide ore collector (kerosene), stir at a collector concentration of 30 mg / L in the pulp for 3 min, and finally add a foaming agent (methyl isobutyl carbinol), stir at a foaming agent concentration of 1.5×10 -4 mol / L for 1 min. Let it stand for 1 min, transfer it to a single-bubble tube for aerated flotation for 3 min, filter by suction to obtain concentrate and tailings, and then dry and weigh.

[0078] The inhibitor shown in Example 1 of the present invention has good inhibitory ability on chalcopyrite and weak inhibitory ability on galena; when the inhibitor concentration is 200 mg / L and pH = 10, the flotation recovery rate of the inhibitor in Example 1 for chalcopyrite is 24.85%, and the flotation recovery rate for galena is 83.87%. For specific conditions, see Figure 8 .

[0079] From Figure 8 As can be seen from the figure, the (CGC) inhibitor shown in Example 1 of the present invention maintains good inhibitory ability on chalcopyrite in the entire pH value range (4 - 10); when the pH value is 10, the inhibitory ability of the inhibitor on chalcopyrite and galena differs greatly, and it is possible to achieve the separation of chalcopyrite - galena. Thus, it can be seen that the cationic cellulose flotation inhibitor shown in Example 1 has good selectivity.

[0080] Example 4

[0081] Study on the flotation performance of the (CGC) inhibitor prepared in Example 1. Take 220 mL of deionized water and 2 g of metal sulfide ore (chalcopyrite / molybdenite) to prepare a pulp. Then stir at 600 rpm for 1 min, add a pH adjuster (such as sodium hydroxide) to adjust to the set pH and stir for 2 min, add quaternary ammonium cation-modified cellulose, stir at an inhibitor concentration of 200 mg / L in the pulp for 3 min, then add a collector for metal sulfide ore (kerosene), stir at a collector concentration of 30 mg / L in the pulp for 3 min, and finally add a foaming agent (methyl isobutyl carbinol), stir at a foaming agent concentration of 1.5×10 -4 mol / L for 1 min. Let it stand for 1 min, transfer it to a single-bubble tube for aerated flotation for 3 min, filter by suction to obtain concentrate and tailings, and then dry and weigh them.

[0082] The (CGC) inhibitor shown in Example 1 of the present invention has good inhibitory ability on chalcopyrite and weak inhibitory ability on molybdenite; under the condition of a cationic cellulose concentration of 200 mg / L and pH = 10, the flotation recovery rate of the inhibitor in Example 1 for chalcopyrite is 24.85%, and the flotation recovery rate for molybdenite is 87.68%. See the specific situation in Figure 9 .

[0083] From Figure 9 as shown, the inhibitor shown in Example 1 of the present invention maintains good inhibitory ability on chalcopyrite in the entire pH value range (4 - 10); when the pH value is 10, the inhibitory ability of the inhibitor on chalcopyrite and molybdenite differs greatly, and it is possible to achieve the separation of chalcopyrite - molybdenite. Thus, it can be seen that the flotation inhibitor prepared in Example 1 has good selectivity.

Claims

1. A quaternary ammonium cation-modified cellulose, characterized in that: It has the following molecular structural formula: Wherein, R1, R2 and R3 are independently selected from hydrogen or a quaternary ammonium salt group, and at least one of R1, R2 and R3 is a quaternary ammonium salt group; The structural formula of the quaternary ammonium salt group is as follows: R is a bonding group; R4, R5 and R6 are independently selected from C1-C4 alkyl groups; m / (m + n)=0.18-0.

9.

2. The quaternary ammonium cation-modified cellulose according to claim 1, wherein: The bonding group is a C1-C 10 hydrocarbon chain or a C2-C 10 hydrocarbon-oxygen chain.

3. The preparation method of a quaternary ammonium cation-modified cellulose according to claim 1 or 2, characterized in that: It includes the following steps: 1) Alkalize cellulose to obtain alkalized cellulose; 2) Carry out an etherification reaction between the alkalized cellulose and a halogenated organic quaternary ammonium salt, an alkenyl-containing organic quaternary ammonium salt or an epoxy group-containing organic quaternary ammonium salt to obtain the product.

4. The preparation method of a quaternary ammonium cation-modified cellulose according to claim 3, characterized in that: The alkalization process is as follows: Cellulose and sodium hydroxide are in an alcohol-water mixed solution and react at a temperature of 25-60°C for 10-30 minutes.

5. The preparation method of a quaternary ammonium cation modified cellulose according to claim 3, characterized in that: The concentration of sodium hydroxide in the alcohol-water mixed solution is from 0.1 to 1 mol / L; The molar ratio of cellulose to sodium hydroxide is 1:(1.0-10.0), wherein cellulose is measured by the molar amount of sugar units it contains.

6. The preparation method of a quaternary ammonium cation modified cellulose according to claim 3, characterized in that: The molar ratio of cellulose to the halogenated organic quaternary ammonium salt, the alkenyl-containing organic quaternary ammonium salt or the epoxy group-containing organic quaternary ammonium salt is 1:(1.0-4.0), wherein cellulose is measured by the molar amount of sugar units it contains.

7. The preparation method of a quaternary ammonium cation-modified cellulose according to claim 3 or 6, characterized in that: The conditions for the etherification reaction are: the temperature is 70-90°C and the time is 1-1.5 hours.

8. Use of a quaternary ammonium cation-modified cellulose according to claim 1 or 2, characterized in that: It is used as a chalcopyrite inhibitor for mineral flotation.

9. Use of a quaternary ammonium cation-modified cellulose according to claim 8, characterized in that: It is used as a chalcopyrite inhibitor for the flotation separation of chalcopyrite from other metal sulfide ores.

10. Use of a quaternary ammonium cation modified cellulose according to claim 9, characterized in that: The other metal sulfide ores include chalcopyrite, molybdenite and / or galena; During the flotation separation process, the pH value of the pulp is adjusted to 4.0-10.0.

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