High-purity xanthate flotation collecting agent and preparation method and application thereof

Abstract

The invention belongs to the technical field of flotation collectors, and relates to a high-purity xanthate flotation collector and a preparation method and application thereof. The preparation method comprises the following steps: by taking excessive alcohol as a reaction raw material and a solvent, adding methylbenzene and dichloromethane as auxiliary solvents, then adding caustic alkali and carbon disulfide, and fully stirring and reacting in a reaction kettle; part of the solvent is removed through first ternary azeotropy, and then generated moisture is removed through second ternary azeotropy; and the high-purity xanthate flotation collecting agent is prepared and obtained through ultrasonic induced crystallization. The method provided by the invention has the technical advantages of high safety, mild reaction, few side reactions, convenience in operation and the like, and the xanthogenate prepared by the method has the characteristics of high purity and small taste, and has a remarkable industrialization prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of flotation collectors and relates to a high-purity xanthate flotation collector and a preparation method and application thereof. Background Art

[0002] Xanthate, also known as xanthate or dithiocarbonate, has a structural formula of RO-(C=S)-SM, where R is a hydrocarbon group with different carbon chains or a modified hydrocarbon group with carbon chains, and M is usually a Na or K ion. Xanthate, as an important flotation agent, has been widely used in the ore flotation industry for nearly a hundred years, and is mainly used as a flotation collector for polymetallic sulfide ores such as copper, lead, and zinc, playing a vital role.

[0003] There are many methods for making xanthate, and the three most commonly used synthesis methods are aqueous solution method, diluent method and alcohol water method. The first technology is the aqueous solution method, which is to prepare xanthate by reacting 40% sodium hydroxide aqueous solution, ethanol and carbon disulfide, and can sustainably produce high-quality xanthate products. However, this technology has some defects, such as slow reaction speed and low work efficiency. The second technology is the diluent method, which is a method of replacing the solvent water in the sodium hydroxide aqueous solution with organic solvents such as gasoline, diesel, and ether. This method can use the compatibility of carbon disulfide and solvents to increase the contact area of ​​the reactants, thereby improving production efficiency and product quality. The third alcohol water method is similar to the first method. First, solid powdered sodium hydroxide is dissolved in a certain proportion of water to prepare a sodium hydroxide aqueous solution, but the difference is that an excess of ethanol is added later to make a sodium ethanol solution, and finally CS is slowly added dropwise. 2 A mixed reaction is performed to prepare the yellow medicine product. However, all three methods have some common problems, such as the long drying process and high energy consumption, which leads to increased production costs. In addition, the side reaction sodium dithiocarbonate accounts for a large proportion in the reaction, which seriously affects the product quality and leads to a low content.

[0004] Combined with the principle of xanthate synthesis, the solvent process has good technical advantages and can improve product quality and product yield. This is similar to the diluent method mentioned above, but the removal of the solvent in this method is particularly critical, so the choice of solvent becomes the key. Patent CN108787177A uses excess carbon disulfide and adds dichloromethane as a solvent to report a method and system for preparing xanthate by a slurry method, and obtains a high-quality, stable-performance xanthate product. However, only dichloromethane is added as a solvent in this patent, and the binary azeotropic ratio of dichloromethane and water is 98.5%:1.5%, which brings out less water, so the drying is not thorough. The boiling point of dichloromethane is very low and it is very volatile, so there are still defects such as incomplete product drying and low effective content. At the same time, the use of excessive carbon disulfide increases the danger of this process.

[0005] Therefore, how to synthesize xanthate more efficiently, safely and with higher quality is an issue that needs to be addressed urgently. Summary of the invention

[0006] In view of the above-mentioned related technical problems, the present invention provides a high-purity xanthate flotation collector and a preparation method and application thereof. The method for preparing xanthate provided by the present invention uses excess alcohol as a reaction raw material and solvent, and simultaneously adds dichloromethane or toluene as an auxiliary solvent, and adopts an ultrasonic induced crystallization method to prepare high-purity xanthate. The obtained product has high purity, low water content, and few impurities, and the process operation is simple and the energy consumption is low.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A preparation method of a high-purity xanthate flotation collector, the preparation method comprising: using excess alcohol as a reaction raw material and solvent, adding toluene and dichloromethane as auxiliary solvents, then adding caustic soda and carbon disulfide, and fully stirring the reaction in a reactor; removing part of the solvent through a first ternary azeotrope, and then removing the generated water through a second ternary azeotrope; and preparing the high-purity xanthate flotation collector by ultrasonic-induced crystallization.

[0009] Furthermore, the preparation method comprises the following steps:

[0010] (1) Alcohol, toluene and dichloromethane are mixed in a reaction kettle to obtain a mixed solvent, caustic soda is added to the mixed solvent, and carbon disulfide is added dropwise under closed conditions and room temperature while stirring to react; wherein the molar ratio of alcohol, caustic soda and carbon disulfide is (2-4):(1-1.02):(1-1.02); the mass ratio of alcohol, dichloromethane and toluene is: (74-120):85:(6-10);

[0011] (2) After the reaction is completed, adjusting the temperature and pressure of the reactor to allow toluene, dichloromethane and unreacted alcohol to undergo a first ternary azeotrope, and removing and recovering a portion of the mixed solvent; adjusting the temperature and pressure of the reactor again to allow toluene, dichloromethane and water to undergo a second ternary azeotrope, and removing water;

[0012] (3) lowering the temperature in the reactor, turning on the ultrasonic device, and using an ultrasonic induced crystallization method to perform ultrasonic crystallization on the material in the reactor to obtain a high-purity xanthate flotation collector.

[0013] Furthermore, the alcohol is a C2-C5 fatty alcohol; the C2-C5 fatty alcohol includes any one or more combinations of ethanol, n-propanol / isopropanol, n-butanol / isobutanol, n-pentanol, isopentanol, and neopentyl alcohol.

[0014] Furthermore, the caustic alkali is sodium hydroxide or potassium hydroxide, and the caustic alkali is in powder or granular form;

[0015] After adding caustic soda and carbon disulfide, the reaction temperature ranges from 30°C to 50°C; the reaction time is 1 to 5 hours.

[0016] Furthermore, in step (2), the mass of the recovered mixed solvent is 20 to 70% of the mass of the mixed solvent initially fed.

[0017] Furthermore, the conditions for the first ternary azeotropic mixture are: normal pressure, temperature of 48.5-63.5°C, and the first ternary azeotropic mixture ends when the alcohol content in the system is less than 5‰; the conditions for the second ternary azeotropic mixture are: normal pressure, temperature of 80.5-83.5°C, and the second ternary azeotropic mixture ends when the water content in the system is less than 5‰.

[0018] Furthermore, the conditions for ultrasonic induced crystallization are: temperature -10 to 20°C, ultrasonic power 100W to 10000W; and crystallization time 2h to 10h.

[0019] Furthermore, the conditions for ultrasonic induced crystallization are: temperature 0-5°C; ultrasonic power 100W-6000W, and crystallization time 3-6h.

[0020] A high-purity xanthate flotation collector, wherein the purity of the high-purity xanthate flotation collector is ≥95% and the water content is ≤2%.

[0021] Furthermore, the high-purity xanthate flotation collector is used for flotation of sulfide ores.

[0022] Beneficial technical effects of the present invention:

[0023] The method provided by the present invention adopts a mixed solvent method combined with an ultrasonic induced crystallization method to prepare xanthate, thereby obtaining a high-purity xanthate product, which is easy to realize industrialization; the present invention adopts a solvent method, thereby avoiding the formation of sodium dithiocarbonate by carbon disulfide and sodium hydroxide under the action of water, which brings about a bad smell.

[0024] In the method of the present invention, adding a mixed solvent can more effectively disperse the reaction amount. The addition of toluene and dichloromethane as a mixed solvent plays the role of a reaction medium, so heat exchange is promoted and the side reaction of carbon disulfide reacting with an alkali to generate sodium dithiocarbonate is reduced; in addition, the participation of dichloromethane is conducive to the evaporation of alcohol, and toluene and dichloromethane are ternary azeotropic with alcohol and water respectively, taking away unreacted alcohol and generated water. Therefore, the method provided by the present invention can better control product quality, is conducive to obtaining high-purity xanthate, and is easy to realize industrial production.

[0025] The method of the invention has the technical advantages of high safety, mild reaction, few side reactions, convenient operation, etc. The xanthate prepared by the method has the characteristics of high purity and small taste, and has significant industrial prospects. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention. All "parts" in the present invention represent "parts by weight".

[0027] Example 1

[0028] A method for preparing a high-purity xanthate flotation collector, the method comprising:

[0029] (1) 92 parts of ethanol, 85 parts of dichloromethane and 10 parts of toluene are mixed in a reactor to obtain a mixed solvent, sodium hydroxide (99%) is added to the mixed solvent, and carbon disulfide (99%) is added dropwise at room temperature under sufficient stirring, and a condensing device is started at the same time. The dropping time is controlled to be 1 hour. As the reaction proceeds, the temperature of the material in the reactor increases. At this time, the reaction temperature is controlled at 30 to 35° C. and the reaction is kept warm for 3 hours. At this time, the product in the reactor is in a slurry state; wherein the molar ratio of ethanol, sodium hydroxide and carbon disulfide is 2:1.02:1.02;

[0030] (2) adjusting the temperature and pressure of the reaction kettle to allow toluene, dichloromethane and unreacted alcohol to undergo a first ternary azeotrope, and removing and recovering a portion of the mixed solvent; adjusting the temperature and pressure of the reaction kettle again to allow toluene, dichloromethane and water to undergo a second ternary azeotrope, and removing water;

[0031] In this embodiment, the conditions for the first ternary azeotropic mixture are: normal pressure, temperature 48.5°C, and after a period of time, the alcohol content in the ternary azeotropic mixture is measured to be 2.5‰, and the first ternary azeotropic mixture ends; the conditions for the second ternary azeotropic mixture are: normal pressure, temperature 82°C, and after a period of time, the water content in the ternary azeotropic mixture is measured to be 2‰, and the second ternary azeotropic mixture ends;

[0032] (3) Transfer the reaction liquid of the material after the reaction in step (2) to an ultrasonic crystallizer, adjust the power to 200 W, then reduce the temperature in the crystallizer to 0° C., turn on the ultrasonic device, and ultrasonically induce crystallization for 3 hours. Then transfer it to a centrifuge and centrifuge to dry it to obtain a high-purity sodium ethyl xanthate product. Filter the obtained solvent and return it to be reused as the mother liquor.

[0033] Analysis shows that the purity of the sodium ethyl xanthate product prepared in this embodiment can reach 98.5%, the free alkali is less than 0.06%, the moisture content is only 1.2%, the product yield is 91.2%, and the purity is much higher than the existing non-ferrous metal industry standard.

[0034] Example 2

[0035] A method for preparing a high-purity xanthate flotation collector, the method comprising:

[0036] (1) 120 parts of isopropanol, 85 parts of dichloromethane and 10 parts of toluene are mixed in a reactor to obtain a mixed solvent, sodium hydroxide (99%) is added to the mixed solvent, and carbon disulfide (99%) is added dropwise at room temperature under sufficient stirring, and a condensing device is started at the same time. The dropping time is controlled to be 1 hour. As the reaction proceeds, the temperature of the material in the reactor increases. At this time, the reaction temperature is controlled at 30 to 35° C. and the reaction is kept warm for 3 hours. At this time, the product in the reactor is in a slurry state; wherein the molar ratio of isopropanol, sodium hydroxide and carbon disulfide is 2:1.02:1.02;

[0037] (2) adjusting the temperature and pressure of the reaction kettle to allow toluene, dichloromethane and unreacted alcohol to undergo a first ternary azeotrope, and removing and recovering a portion of the mixed solvent; adjusting the temperature and pressure of the reaction kettle again to allow toluene, dichloromethane and water to undergo a second ternary azeotrope, and removing water;

[0038] In this embodiment, the conditions for the first ternary azeotropic mixture are: normal pressure, temperature 50°C, after a period of time, the alcohol content in the ternary azeotropic mixture is measured to be 2‰, and the first ternary azeotropic mixture ends; the conditions for the second ternary azeotropic mixture are: normal pressure, temperature 83.5°C, after a period of time, the water content in the ternary azeotropic mixture is measured to be 2.7‰, and the second ternary azeotropic mixture ends;

[0039] (3) The material is transferred to the reaction liquid in an ultrasonic crystallizer, and the power is adjusted to 1000 W. At this time, the temperature in the crystallizer is lowered to 0°C, and the ultrasonic device is turned on to induce crystallization for 3 hours. The product is then transferred to a centrifuge and centrifuged to obtain a high-purity sodium isopropyl xanthate product. The solvent obtained by filtration is returned and reused as the mother liquor.

[0040] Analysis shows that the purity of sodium isopropyl xanthate product can reach 96.6%, the free alkali is less than 0.1%, the moisture content is only 1.3%, the product yield is 90.6%, and the purity is much higher than the existing non-ferrous metal industry standards.

[0041] Example 3

[0042] A method for preparing a high-purity xanthate flotation collector, the method comprising:

[0043] (1) 120 parts of isobutyl alcohol, 85 parts of dichloromethane and 6 parts of toluene are mixed in a reactor to obtain a mixed solvent, sodium hydroxide (99%) is added to the mixed solvent, and carbon disulfide (99%) is added dropwise at room temperature under sufficient stirring, and a condensing device is started at the same time. The dropping time is controlled to be 1 hour. As the reaction proceeds, the temperature of the material in the reactor increases. At this time, the reaction temperature is controlled at 35 to 40° C. and the reaction is kept warm for 4 hours. At this time, the product in the reactor is in a slurry state; wherein the molar ratio of isobutyl alcohol, sodium hydroxide and carbon disulfide is 1.6:1.02:1.02;

[0044] (2) adjusting the temperature and pressure of the reaction kettle to allow toluene, dichloromethane and unreacted alcohol to undergo a first ternary azeotrope, and removing and recovering a portion of the mixed solvent; adjusting the temperature and pressure of the reaction kettle again to allow toluene, dichloromethane and water to undergo a second ternary azeotrope, and removing water;

[0045] In this embodiment, the conditions for the first ternary azeotropic mixture are: normal pressure, temperature 63.5°C, and after a period of time, the alcohol content in the ternary azeotropic mixture is measured to be 2.3‰, and the first ternary azeotropic mixture ends; the conditions for the second ternary azeotropic mixture are: normal pressure, temperature 83°C, and after a period of time, the water content in the ternary azeotropic mixture is measured to be 2.5‰, and the second ternary azeotropic mixture ends;

[0046] (3) Transfer the reaction liquid to an ultrasonic crystallizer, adjust the power to 3000 W, then lower the temperature in the crystallizer to 0-5°C, turn on the ultrasonic device, and ultrasonically induce crystallization for 4 hours. Then transfer the product to a centrifuge, centrifuge and dry to obtain a high-purity sodium isobutyl xanthate product. Filter the obtained solvent and return it to be reused as the mother liquor.

[0047] Analysis shows that the purity of sodium isobutyl xanthate product can reach 95.8%, the free alkali is less than 0.12%, the moisture content is only 1.4%, the product yield is 91.6%, and the purity is much higher than the existing non-ferrous metal industry standards.

[0048] Example 4

[0049] A method for preparing a high-purity xanthate flotation collector, the method comprising:

[0050] (1) 110 parts of isoamyl alcohol, 85 parts of dichloromethane and 6 parts of toluene are mixed in a reactor to obtain a mixed solvent, sodium hydroxide (99%) is added to the mixed solvent, and carbon disulfide (99%) is added dropwise at room temperature under sufficient stirring, and a condensing device is started at the same time. The dropping time is controlled to be 1 hour. As the reaction proceeds, the temperature of the material in the reactor increases. At this time, the reaction temperature is controlled at 40 to 45° C. and the reaction is kept warm for 4 hours. At this time, the product in the reactor is in a slurry state; wherein the molar ratio of isoamyl alcohol, sodium hydroxide and carbon disulfide is 1.24:1:1;

[0051] (2) adjusting the temperature and pressure of the reaction kettle to allow toluene, dichloromethane and unreacted alcohol to undergo a first ternary azeotrope, and removing and recovering a portion of the mixed solvent; adjusting the temperature and pressure of the reaction kettle again to allow toluene, dichloromethane and water to undergo a second ternary azeotrope, and removing water;

[0052] In this embodiment, the conditions for the first ternary azeotropic mixture are: normal pressure, temperature 60°C; the conditions for the second ternary azeotropic mixture are: normal pressure, temperature 85°C;

[0053] (3) The material is transferred to the reaction liquid in an ultrasonic crystallizer, and the power is adjusted to 6000 W. At this time, the temperature in the crystallizer is lowered to 0-5°C, and the ultrasonic device is turned on to induce crystallization for 4 hours. The product is then transferred to a centrifuge and centrifugally dried to obtain a high-purity sodium isopentyl xanthate product. The solvent obtained by filtration is returned to be reused as the mother liquor.

[0054] Analysis shows that the purity of sodium isopentyl xanthate product can reach 95.6%, the free base is less than 0.12%, the moisture content is only 1.5%, the product yield is 90.8%, and the purity is much higher than the existing non-ferrous metal industry standards.

[0055] Example 5

[0056] A method for preparing a high-purity xanthate flotation collector, the method comprising:

[0057] (1) 74 parts of isobutanol, 46 parts of ethanol, 85 parts of dichloromethane and 10 parts of toluene are mixed in a reactor to obtain a mixed solvent, sodium hydroxide (99%) is added to the mixed solvent, and carbon disulfide (99%) is added dropwise at room temperature under sufficient stirring, and a condensing device is started at the same time. The dropping time is controlled to be 1 hour. As the reaction proceeds, the temperature of the material in the reactor increases. At this time, the reaction temperature is controlled at 35 to 40° C. and the reaction is kept warm for 4 hours. At this time, the product in the reactor is in a slurry state; wherein the molar ratio of isobutanol, ethanol, sodium hydroxide and carbon disulfide is 1:1:1:1;

[0058] (2) adjusting the temperature and pressure of the reaction kettle to allow toluene, dichloromethane and unreacted alcohol to undergo a first ternary azeotrope, and removing and recovering a portion of the mixed solvent; adjusting the temperature and pressure of the reaction kettle again to allow toluene, dichloromethane and water to undergo a second ternary azeotrope, and removing water;

[0059] In this embodiment, the conditions for the first ternary azeotropic mixture are: normal pressure, temperature 55°C, and after a period of time, the alcohol content in the ternary azeotropic mixture is measured to be 2.6‰, and the first ternary azeotropic mixture ends; the conditions for the second ternary azeotropic mixture are: normal pressure, temperature 80.5°C, and after a period of time, the water content in the ternary azeotropic mixture is measured to be 2‰, and the second ternary azeotropic mixture ends;

[0060] (3) Transfer the reaction liquid to an ultrasonic crystallizer and adjust the power to 1000 W. Then, lower the temperature in the crystallizer to 0-5°C, turn on the ultrasonic device, and ultrasonically induce crystallization for 4 hours. Then, transfer the mixture to a centrifuge and centrifuge to dry the mixture to obtain a high-purity mixed sodium xanthate product. Filter the obtained solvent and return it to the mother liquor for reuse.

[0061] Analysis shows that the mixed sodium xanthate product contains less than 0.16% free alkali, only 1.5% water content, and the product yield is 91.3%.

[0062] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high-purity xanthate flotation collector, characterized in that: The preparation method comprises: using excess alcohol as a reaction raw material and solvent, adding toluene and dichloromethane as auxiliary solvents, then adding caustic soda and carbon disulfide, and fully stirring the reaction in a reactor; removing part of the solvent through a first ternary azeotropic process, and then removing the generated water through a second ternary azeotropic process; and preparing a high-purity xanthate flotation collector by using ultrasonic induced crystallization.

2. The method for preparing a high-purity xanthate flotation collector according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Alcohol, toluene and dichloromethane are mixed in a reaction kettle to obtain a mixed solvent, caustic soda is added to the mixed solvent, and carbon disulfide is added dropwise under closed conditions and room temperature while stirring to react; wherein the molar ratio of alcohol, caustic soda and carbon disulfide is (2-4):(1-1.02):(1-1.02); the mass ratio of alcohol, dichloromethane and toluene is: (74-120):85:(6-10); (2) After the reaction is completed, adjusting the temperature and pressure of the reactor to allow toluene, dichloromethane and unreacted alcohol to undergo a first ternary azeotrope, and removing and recovering a portion of the mixed solvent; adjusting the temperature and pressure of the reactor again to allow toluene, dichloromethane and water to undergo a second ternary azeotrope, and removing water; (3) lowering the temperature in the reactor, turning on the ultrasonic device, and using an ultrasonic induced crystallization method to perform ultrasonic crystallization on the material in the reactor to obtain a high-purity xanthate flotation collector.

3. The method for preparing a high-purity xanthate flotation collector according to claim 1, characterized in that: The alcohol is a C2-C5 fatty alcohol; the C2-C5 fatty alcohol includes any one or more combinations of ethanol, n-propanol / isopropanol, n-butanol / isobutanol, n-pentanol, isopentanol, and neopentyl alcohol.

4. The method for preparing a high-purity xanthate flotation collector according to claim 1, characterized in that: The caustic alkali is sodium hydroxide or potassium hydroxide, and the caustic alkali is in powder or granular form; After adding caustic soda and carbon disulfide, the reaction temperature ranges from 30°C to 50°C; the reaction time is 1 to 5 hours.

5. The method for preparing a high-purity xanthate flotation collector according to claim 2, characterized in that: In step (2), the mass of the recovered mixed solvent is 20 to 70% of the mass of the mixed solvent initially fed.

6. The method for preparing a high-purity xanthate flotation collector according to claim 1, characterized in that: The conditions for the first ternary azeotropic mixture are: normal pressure, temperature of 48.5-63.5°C, and the first ternary azeotropic mixture ends when the alcohol content in the system is less than 5‰; the conditions for the second ternary azeotropic mixture are: normal pressure, temperature of 80.5-83.5°C, and the second ternary azeotropic mixture ends when the water content in the system is less than 5‰.

7. The method for preparing a high-purity xanthate flotation collector according to claim 2, characterized in that: The conditions for ultrasonic induced crystallization are: temperature -10 to 20°C, ultrasonic power 100W to 10000W; crystallization time is 2h to 10h.

8. The method for preparing a high-purity xanthate flotation collector according to claim 7, characterized in that: The conditions for ultrasonic induced crystallization are: temperature 0-5°C; ultrasonic power 100W-6000W; crystallization time 3-6h.

9. A high-purity xanthate flotation collector, characterized in that: The high-purity xanthate flotation collector is prepared by the method described in any one of claims 1 to 8, and the purity of the high-purity xanthate flotation collector is ≥ 95%, and the moisture content is ≤ 2%.

10. The use of a high-purity xanthate flotation collector according to claim 9, characterized in that: The high-purity xanthate flotation collector is used for flotation of sulfide ores.