Method for treating and reusing wastewater from the production of alkyl xanthate propylene

Abstract

The present invention belongs to the technical field of chemical wastewater recycling, and specifically relates to a method for treating and reusing wastewater produced by alkyl xanthate propylene ester, comprising the following steps: oxidizing the wastewater produced by alkyl xanthate propylene ester; standing to separate the aqueous phase and the organic phase, adjusting the pH value of the organic phase of the oxidized wastewater, and then merging the aqueous phase and the organic phase; evaporating and desalting the wastewater, collecting the condensed water after desalting; and reusing the condensed water as dissolved water in the production process of isopropyl ethyl thiocarbamate. The present invention can purify the wastewater produced by alkyl xanthate propylene ester, and can reuse the treated wastewater for the reproduction of isopropyl ethyl thiocarbamate.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical wastewater recycling, and specifically relates to a method for treating and recycling wastewater produced by alkyl xanthate propene. Background Art

[0002] Isoamyl xanthate propylene ester product belongs to the third generation of ester beneficiation reagents, is an excellent collector for non-ferrous metal sulfide ores, is an efficient, low-toxic and environmentally friendly green flotation reagent, and has a large market demand. However, a large amount of wastewater is generated during the production process. Based on the annual output of 800 tons of isoamyl xanthate propylene ester, the amount of wastewater generated is about 2,800 tons. The wastewater has a strong garlic smell, which seriously pollutes the production environment, brings great difficulties to wastewater discharge and environmental protection treatment, and is usually difficult to be treated by conventional evaporation and desalination and then biological methods. According to the test, in addition to water, the main inorganic matter in the wastewater is sodium chloride (content is about 10%), and other main organic substances include sodium isoamyl xanthate, allyl chloride, allyl mercaptan, isopentanol, and isoamyl xanthate propylene ester, all of which have low contents. It is determined that the substance that produces the foul odor is an allyl mercaptan compound. Therefore, it is necessary to treat the production wastewater of isoamyl xanthate propylene ester. The problems currently faced by the treatment of this wastewater are as follows:

[0003] First, it is necessary to solve the problem that the strong smell of allyl mercaptan remaining in the isopentyl xanthate propylene ester wastewater makes it difficult to carry out conventional evaporation treatment;

[0004] Second, it is necessary to solve the problem that the isopentyl xanthate propylene ester wastewater cannot be reused in production. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for treating and reusing wastewater from the production of alkyl xanthate propylene.

[0006] The present invention is achieved by providing a method for treating and reusing wastewater from the production of alkyl xanthate propylene ester, comprising the following steps:

[0007] 1) Oxidizing the alkyl xanthate production wastewater;

[0008] 2) leaving the oxidized wastewater to stand for a certain period of time until the organic phase and the aqueous phase are separated, separating the organic phase, adjusting the pH value of the organic phase, and then combining the organic phase with the aqueous phase;

[0009] 3) evaporating and desalting the wastewater treated in step 2), and collecting the desalted condensed water;

[0010] 4) The condensed water in step 3) is reused as dissolved water in the production process of isopropyl ethylthiocarbamate.

[0011] Preferably, in step 1), UV / O 3The combined method is used to oxidize the wastewater from the production of alkyl xanthate acrylate.

[0012] More preferably, in step 2), the pH value of the organic phase of the wastewater is adjusted with an aqueous solution of a strongly alkaline substance.

[0013] More preferably, the strong alkaline substance is one of sodium carbonate, sodium hydroxide and caustic potash.

[0014] Further preferably, in step 2), the oxidized wastewater is allowed to stand for 15-30 days, and the pH value of the organic phase is adjusted to pH ≥ 8.

[0015] Further preferably, step 4) specifically comprises the following steps:

[0016] 401) taking a certain amount of condensed water in step 3), dissolving chloroacetic acid, and obtaining a chloroacetic acid aqueous solution;

[0017] 402) neutralizing the chloroacetic acid aqueous solution obtained in step 401) with soda ash, and adding a certain amount of isopropyl xanthate to react after neutralization;

[0018] 403) adding monoethylamine to the reaction solution obtained in step 402) at a certain temperature to carry out aminolysis reaction, and then standing for a certain time until the organic phase and the aqueous phase are fully separated, and separating the upper organic phase, which is isopropyl ethyl thiocarbamate;

[0019] 404) using the aqueous phase separated in step 403) as a mineral processing inhibitor.

[0020] Further preferably, in step 402), the chloroacetic acid aqueous solution is neutralized with soda ash to a pH between 7 and 8.

[0021] More preferably, in step 403), the content of monoethylamine is 70%.

[0022] More preferably, the alkyl xanthate propylene ester is isopentyl xanthate propylene ester.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] The invention provides a method for treating and reusing wastewater produced by alkyl xanthate propylene ester. Firstly, the wastewater produced by alkyl xanthate propylene ester can be purified and treated, and secondly, the treated wastewater can be reused for the reproduction of isopropyl ethyl thiocarbamate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0027] The invention provides a method for treating and reusing wastewater from the production of alkyl xanthate propylene ester. After the wastewater from the production of alkyl xanthate propylene ester is purified, it is used for the reproduction of isopropyl ethyl thiocarbamate. After the wastewater is purified, it also contains trace amounts of isopentanol and sodium isopentanol xanthate. Isopentyl alcohol has strong foaming properties and can be used as a foaming agent for non-ferrous metal beneficiation in a flotation process. Sodium isopentanol xanthate is an excellent collector for sulfide ores and can also be used as a reaction raw material to undergo an esterification reaction with a sodium chloroacetate solution to generate sodium isopentanol xanthate acetate, which then reacts with monoethylamine to generate isopentanol ethyl thiocarbamate. Isopentyl ethyl thiocarbamate also belongs to the alkyl ethyl thiocarbamate series of products and has a similar collecting effect to isopropyl ethyl thiocarbamate. Therefore, the wastewater from the production of alkyl xanthate propylene ester treated by the method is used for the reproduction of isopropyl ethyl thiocarbamate, which has a positive effect on beneficiation.

[0028] Embodiment 1,

[0029] 1) 5000 g of isopentyl xanthate propylene ester wastewater was subjected to UV / O 3 Combined with advanced oxidation to remove allyl mercaptan and some other organic matter in wastewater;

[0030] 2) the wastewater after the combined oxidation treatment in step 1) is allowed to stand for 15-30 days to fully separate the organic phase from the aqueous phase, the upper organic phase is separated, and its pH value is adjusted to pH ≥ 8 with a 35% sodium hydroxide aqueous solution to remove isoamyl alcohol and allyl alcohol produced by oxidation of allyl chloride, so as to generate an aqueous solution containing sodium isoamyl alcohol and sodium allyl alcohol, and the aqueous solution is combined with the separated lower aqueous phase;

[0031] 3) evaporating and desalting the liquid obtained in step 2), and collecting the desalted condensed water;

[0032] 4) taking 1600 g of condensed water obtained after desalination, dissolving 440 g of chloroacetic acid without adding fresh water, to obtain a chloroacetic acid aqueous solution;

[0033] 5) neutralizing the chloroacetic acid aqueous solution obtained in step 4) with soda ash to a pH value between 7 and 8 to obtain a sodium chloroacetate aqueous solution, adding 840 g of sodium isopropyl xanthate to the sodium chloroacetate aqueous solution under stirring to react and generate an isopropyl xanthate sodium acetate aqueous solution;

[0034] 6) Slowly adding 300 g of 70% monoethylamine to the aqueous solution of sodium isopropyl xanthate acetate obtained in step 5) to carry out aminolysis reaction to generate a mixture of isopropyl ethyl thiocarbamate and sodium thioglycolate; standing the mixture obtained in the step for separation for 48-84 hours to allow the two phases to be fully separated, and after the two phases are separated, the organic phase is isopropyl ethyl thiocarbamate and the aqueous phase is sodium thioglycolate;

[0035] 7) Sampling and analyzing the isopropyl ethyl thiocarbamate obtained in step 6), the content of which is 95.53%, and can be directly used as a flotation collector for copper sulfide ore, and the sodium thioglycolate in the aqueous phase can be used as an inhibitor for copper-molybdenum separation after further processing.

[0036] Embodiment 2,

[0037] 1) 5000 g of isopentyl xanthate propylene ester wastewater was subjected to UV / O 3 Combined with advanced oxidation to remove allyl mercaptan and some other organic matter in wastewater;

[0038] 2) the wastewater after the combined oxidation treatment in step 1) is allowed to stand for 15-30 days to fully separate the organic phase from the aqueous phase, the upper organic phase is separated, and its pH value is adjusted to pH ≥ 8 with a 35% sodium hydroxide aqueous solution to remove isoamyl alcohol and allyl alcohol produced by oxidation of allyl chloride, so as to generate an aqueous solution containing sodium isoamyl alcohol and sodium allyl alcohol, and the aqueous solution in the step is combined with the separated lower aqueous phase;

[0039] 3) evaporating and desalting the liquid obtained in step 2), and collecting the desalted condensed water;

[0040] 4) 800 g of condensed water obtained after desalination is mixed with fresh water in a weight ratio of condensed waste water: fresh water = 1:1 to dissolve chloroacetic acid to obtain a chloroacetic acid aqueous solution;

[0041] 5) The chloroacetic acid aqueous solution obtained in step 4) is neutralized with soda ash to a pH of 7-8 to obtain a sodium chloroacetate aqueous solution, and 840 g of sodium isopropyl xanthate is added to the sodium chloroacetate aqueous solution under stirring to react to produce an isopropyl xanthate sodium acetate aqueous solution.

[0042] 6) Slowly adding 300 g of 70% monoethylamine to the aqueous solution of sodium isopropyl xanthate acetate obtained in step 5) to carry out aminolysis reaction to generate a mixture of isopropyl ethylthiocarbamate and sodium thioglycolate; allowing the mixture to stand for separation for 48-84 hours to allow the two phases to be fully separated;

[0043] 7) After the two phases in step 6) are separated, the organic phase is isopropyl ethyl thiocarbamate; the aqueous phase is sodium thioglycolate. The isopropyl ethyl thiocarbamate obtained in step 7) is sampled and analyzed, and the content is 96.04%, which can be directly used as a flotation collector for copper sulfide ore, and the sodium thioglycolate in the aqueous phase can be used as an inhibitor for copper-molybdenum separation after further processing.

[0044] Embodiment 3,

[0045] 1) 5000 g of isopentyl xanthate propylene ester wastewater was subjected to UV / O3 combined advanced oxidation to remove allyl mercaptan and some other organic matter in the wastewater;

[0046] 2) the wastewater after the combined oxidation treatment in step 1) is allowed to stand for 15-30 days to fully separate the organic phase from the aqueous phase, the upper organic phase is separated, and its pH value is adjusted to pH ≥ 8 with a 35% sodium hydroxide aqueous solution to remove isoamyl alcohol and allyl alcohol produced by oxidation of allyl chloride, so as to generate an aqueous solution containing sodium isoamyl alcohol and sodium allyl alcohol; the aqueous solution is combined with the separated lower aqueous phase;

[0047] 3) evaporating and desalting the liquid obtained in step 2), and collecting the desalted condensed water;

[0048] 4) 533 g of the condensed wastewater obtained after desalination was mixed with fresh water in a weight ratio of condensed wastewater: fresh water = 1:2 to dissolve chloroacetic acid to obtain a chloroacetic acid aqueous solution;

[0049] 5) neutralizing the chloroacetic acid aqueous solution obtained in step 4) with soda ash to make its pH = 7-8 to obtain a sodium chloroacetate aqueous solution, adding 840 g of sodium isopropyl xanthate to the sodium chloroacetate aqueous solution under stirring to react and generate an isopropyl xanthate sodium acetate aqueous solution;

[0050] 6) Slowly adding 300 g of 70% monoethylamine to the aqueous solution of sodium isopropyl xanthate acetate obtained in step 5) to carry out aminolysis reaction to generate a mixture of isopropyl ethylthiocarbamate and sodium thioglycolate; allowing the mixture to stand for separation for 48-84 hours to allow the two phases to be fully separated;

[0051] 7) After the two phases in step 6) are separated, the organic phase is isopropyl ethyl thiocarbamate; the aqueous phase is sodium thioglycolate. Sampling and analysis of isopropyl ethyl thiocarbamate show a content of 96.49%, which can be directly used as a flotation collector for copper sulfide ores, and the sodium thioglycolate in the aqueous phase can be used as an inhibitor for copper-molybdenum separation after further processing.

Claims

1. Treatment and reuse method of wastewater from the production of alkyl xanthate propylene ester, It is characterized in that The steps include: 1) Oxidation of alkyl xanthate production wastewater; 2) The oxidized wastewater is allowed to stand for a certain period of time until the organic phase and the aqueous phase are separated, the organic phase is separated, the pH value of the organic phase is adjusted, the oxidized wastewater is allowed to stand to fully separate the organic phase and the aqueous phase, the upper organic phase is separated, and its pH value is adjusted to pH ≥ 8 with a 35% sodium hydroxide aqueous solution to remove isoamyl alcohol and allyl alcohol produced by oxidation of allyl chloride, so as to generate an aqueous solution containing sodium isoamyl alcohol and sodium allyl alcohol, and then the aqueous solution is combined with the separated lower aqueous phase; 3) evaporating and desalting the wastewater treated in step 2), and collecting the desalted condensed water; 4) The condensed water in step 3) is reused as dissolved water in the production process of isopropyl ethylthiocarbamate, which specifically includes the following steps: 401) taking a certain amount of condensed water in step 3), dissolving chloroacetic acid, and obtaining a chloroacetic acid aqueous solution; 402) neutralizing the chloroacetic acid aqueous solution obtained in step 401) with soda ash, and adding a certain amount of isopropyl xanthate to react after neutralization; 403) adding monoethylamine to the reaction solution obtained in step 402) at a certain temperature to carry out aminolysis reaction, and then standing for a certain time until the organic phase and the aqueous phase are fully separated, and separating the upper organic phase, which is isopropyl ethyl thiocarbamate; 404) The aqueous phase separated in step 403) is used as a mineral processing inhibitor.

2. The method for treating and reusing wastewater from the production of alkyl xanthate propylene according to claim 1, It is characterized in that In step 1), use UV / O 3 The combined method is used to oxidize the wastewater from the production of alkyl xanthate acrylate.

3. The method for treating and reusing wastewater from the production of alkyl xanthate propene according to claim 1, It is characterized in that In step 2), the pH value of the organic phase of the wastewater is adjusted with an aqueous solution of a strongly alkaline substance.

4. The method for treating and reusing wastewater from the production of alkyl xanthate propene according to claim 3, It is characterized in that The strong alkaline substance is one of sodium carbonate, sodium hydroxide and caustic potash.

5. The method for treating and reusing wastewater from the production of alkyl xanthate propene according to claim 1, It is characterized in that In step 2), the oxidized wastewater is allowed to stand for 15-30 days, and the pH value of the organic phase is adjusted to pH ≥ 8.

6. The method for treating and reusing wastewater from the production of alkyl xanthate propene according to claim 1, It is characterized in that In step 402), the aqueous solution of chloroacetic acid is neutralized with soda ash to a pH between 7 and 8.

7. The method for treating and reusing wastewater from the production of alkyl xanthate propylene ester according to claim 1, It is characterized in that In step 403), the content of monoethylamine is 70%.

8. The method for treating and reusing wastewater produced by alkyl xanthate propene according to any one of claims 1 to 7, It is characterized in that The alkyl xanthate propylene ester is isopentyl xanthate propylene ester.

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