Method for preparing high-purity zinc sulfide from activated zinc oxide

Abstract

The invention discloses a method for preparing high-purity zinc sulfide by using activated zinc oxide, which comprises the following specific steps: 1) adding activated zinc oxide into a dilute sulfuric acid solution, heating, stirring and filtering to prepare a zinc sulfate solution; (2) dropwise adding dilute sulphuric acid into the sodium sulfide solution, introducing N2 to pressurize, desulfurizing and dehydrating the generated mixed gas of hydrogen sulfide and N2, introducing the mixed gas into the bottom of the zinc sulfate solution to react while stirring, designing a container filled with zinc sulfate into three-stage series connection, after dropwise adding is finished, turning off N2, continuously stirring, after stirring is finished, standing to precipitate zinc, and then carrying out centrifugal suction filtration to obtain zinc sulfide; 3) adding deionized water to wash zinc sulfide to obtain a wet zinc sulfide product; 4, the wet zinc sulfide product is put into a vacuum drying furnace to be dried, then the dried zinc sulfide is crushed into powder through an N2 airflow crusher, and the industrial high-purity zinc sulphide is obtained.According to the method, the complicated process of zinc sulfate refining and sulfide purifying is omitted, and the generated zinc sulfide product is high in purity, few in impurity and extremely low in raw material loss.

Description

Technical Field

[0001] The invention belongs to the technical field of zinc sulfide preparation, and specifically relates to a method for preparing high-purity zinc sulfide by utilizing active zinc oxide. Background Art

[0002] Zinc sulfide is easy to disperse, not easy to agglomerate, has a neutral white color, and has good optical properties. It is often used as a component of thermosetting plastics, thermoplastics, reinforced fiberglass, flame retardants, artificial rubber and dispersants. It is widely used in semiconductors, pigments, photoluminescent devices, solar cells, infrared detectors, optical fiber communications, etc.

[0003] In the prior art, the production and preparation process of zinc sulfide is complicated. Due to insufficient purification and separation and oxidation during storage, zinc sulfide powder usually contains a small amount of sulfate, and the conversion rate of zinc sulfide is about 50%, which is very low. The particles are coarse and the particle size is uneven. Moreover, since hydrogen sulfide gas is highly toxic, there are huge safety hazards in production. In addition, the emission of "three wastes" is large, and the harm to the environment is too serious, making it difficult to develop production and increase output, and facing a very serious sewage treatment problem. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for preparing high-purity zinc sulfide using active zinc oxide, which can fully utilize the combination reaction between sulfide and zinc ions in water and greatly avoid the probability of hydrogen sulfide leakage. The specific steps are as follows:

[0005] 1) Preparation of zinc sulfate solution: Add active zinc oxide to the prepared dilute sulfuric acid solution, heat and stir to fully dissolve it, then add sodium acetate to adjust the pH of the solution, then add activated carbon for decolorization and adsorption, filter, and obtain zinc sulfate solution;

[0006] 2) Preparation of sodium sulfide solution: Add water to industrial sodium sulfide to prepare a qualified sodium sulfide solution;

[0007] 3) Zinc precipitation: dilute sulfuric acid is slowly added dropwise to a closed container containing sodium sulfide solution, and N2 is introduced to pressurize the container. The generated hydrogen sulfide and N2 mixed gas is desulfurized and dehydrated, and then introduced to the bottom of a closed container containing zinc sulfate for reaction while stirring. The container containing zinc sulfate is designed to be three-stage series. After the addition of dilute sulfuric acid is completed, N2 is turned off and stirring is continued. After the stirring is completed, the zinc is allowed to settle and then centrifuged and filtered. The filter cake is zinc sulfide;

[0008] 4) Washing: Add deionized water to wash the filter cake, wash twice to obtain wet zinc sulfide product;

[0009] 5) Drying: placing the obtained wet zinc sulfide product in a vacuum drying oven for drying;

[0010] 6) Crushing: Use N2 air flow crusher to crush the dried zinc sulfide into powder to obtain industrial high-purity zinc sulfide.

[0011] Preferably, in step 1), the concentration of the dilute sulfuric acid solution is 0.5 mol / L, the mass ratio of zinc oxide, dilute sulfuric acid solution, sodium acetate and activated carbon is 20-30:700-800:8-12:1, and the heating temperature is 50-60°C.

[0012] Preferably, the concentration of the qualified sodium sulfide solution in step 2) is 20%.

[0013] Preferably, in step 3), the concentration of dilute sulfuric acid is 2 mol / L, and the mass ratio of dilute sulfuric acid to sodium sulfide solution is 1:2-3.

[0014] Preferably, in step 3), the N2 introduction rate is 1-1.5 L / min, and the pressure after pressurization is ≤0.1 MPa.

[0015] Preferably, in step 3), the dilute sulfuric acid is added dropwise for 2-3 hours, the zinc precipitation time is 2-3 hours, and the stirring time is continued for 1-2 hours.

[0016] Preferably, the material-liquid ratio of washing in step 4) is 1:9-12.

[0017] Preferably, in step 5), the drying temperature is 100-110° C. and the drying time is 4-6 hours.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] Compared with the traditional process for producing zinc sulfide, the method of the invention saves the complicated process of zinc sulfate refining and sulfide purification, and the generated zinc sulfide product has high purity, few impurities, and almost zero raw material loss; the hydrogen sulfide generated in the middle is used as the synthetic raw material of zinc sulfide, and the purification process and cost of sulfide are saved; the hydrogen sulfide tail gas absorption tower is only used as an emergency, and the protective measures for hydrogen sulfide leakage are added, which reduces the safety risk and reduces the risk of hydrogen sulfide gas generated in the production process of zinc sulfide, and the risk of personnel poisoning and environmental pollution caused by hydrogen sulfide leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic flow diagram of the steps of the method of the present invention. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Example 1

[0023] 1) Preparation of qualified zinc sulfate solution: Take 1L of deionized water, slowly add 47.5g of sulfuric acid while stirring, then weigh 40g of active zinc oxide and add it to dilute sulfuric acid, heat and stir to 60°C to dissolve, then continue to add 10g of sodium acetate to dissolve, adjust the pH to 5.0, then add 1.5g of activated carbon for decolorization and adsorption, filter, the filtrate is the qualified zinc sulfate solution, put it into a 3L four-necked reaction bottle;

[0024] 2) Gas production: Put 155g of industrial 60% sodium sulfide into another 3L reaction bottle, add 1L of water and mix, introduce nitrogen, and set the gas volume to 1L / min. After 3 minutes, use a dropping funnel to slowly drip 2mol / L dilute sulfuric acid into the sodium sulfide solution, adjust the dripping speed, and the whole dripping process takes 2h;

[0025] 3) Zinc precipitation: The N2 and hydrogen sulfide mixed gas is scrubbed and desulfurized with a saturated sodium sulfide solution, and then dehydrated with industrial calcium chloride before entering the zinc sulfate reaction bottle. Bubbling and stirring are performed, and white turbidity is generated. As the reaction proceeds, the feed liquid slowly turns into milky white. After the sulfuric acid is added, the nitrogen is stopped and stirring is continued for 30 minutes. The first reaction bottle is stopped and allowed to stand for 30 minutes for aging. For the next batch of reactions, the 2# and 3# reaction bottles are placed in the front position, and new zinc sulfate qualified solution is placed in the original 3# reaction bottle to continue the zinc precipitation reaction.

[0026] 4) Washing: Filter the zinc precipitated liquid by suction, and wash the filter cake with 10 times the amount of deionized water for 2 times to obtain wet zinc sulfide;

[0027] 5) Drying and crushing: Put the wet zinc sulfide into a vacuum drying oven, dry it at 105°C for 5 hours, and use a N2 air flow crusher to crush the dried zinc sulfide into powder to obtain white powdery high-purity zinc sulfide.

[0028] Example 2

[0029] 1) Preparation of qualified zinc sulfate solution: Take 1L of deionized water, slowly add 50g of sulfuric acid while stirring, then weigh 45g of active zinc oxide and add it to dilute sulfuric acid, heat and stir to 60°C to dissolve, then continue to add 11g of sodium acetate to dissolve, adjust the pH to 5.5, then add 1.3g of activated carbon for decolorization and adsorption, filter, the filtrate is the qualified zinc sulfate solution, put it into a 3L four-necked reaction bottle;

[0030] 2) Gas production: Put 150g of industrial 60% sodium sulfide into another 3L reaction bottle, add 1L of water and mix, introduce nitrogen, and set the gas volume to 1L / min. After 3 minutes, use a dropping funnel to slowly drip 2mol / L dilute sulfuric acid into the sodium sulfide solution, adjust the dripping speed, and the whole dripping process takes 2h;

[0031] 3) Zinc precipitation: The N2 and hydrogen sulfide mixed gas is scrubbed and desulfurized with a saturated sodium sulfide solution, and then dehydrated with industrial calcium chloride before entering the zinc sulfate reaction bottle. Bubbling and stirring are performed, and white turbidity is generated. As the reaction proceeds, the feed liquid slowly turns into milky white. After the sulfuric acid is added, the nitrogen is stopped and stirring is continued for 30 minutes. The first reaction bottle is stopped and allowed to stand for 40 minutes for aging. For the next batch of reactions, the 2# and 3# reaction bottles are placed in the front position, and new zinc sulfate qualified solution is placed in the original 3# reaction bottle to continue the zinc precipitation reaction.

[0032] 4) Washing: Filter the zinc precipitated liquid by suction, and wash the filter cake with 10 times the amount of deionized water for 2 times to obtain wet zinc sulfide;

[0033] 5) Drying and crushing: Put the wet zinc sulfide into a vacuum drying oven, dry it at 100°C for 5 hours, and use a N2 air flow crusher to crush the dried zinc sulfide into powder to obtain white powdery high-purity zinc sulfide.

[0034] Example 3

[0035] 1) Preparation of qualified zinc sulfate solution: Take 1L of deionized water, slowly add 55g of sulfuric acid while stirring, then weigh 45g of active zinc oxide and add it to dilute sulfuric acid, heat and stir to 60°C to dissolve, then continue to add 11g of sodium acetate to dissolve, adjust the pH to 5.0, then add 1.6g of activated carbon for decolorization and adsorption, filter, the filtrate is the qualified zinc sulfate solution, put it into a 3L four-necked reaction bottle;

[0036] 2) Gas production: Put 155g of industrial 60% sodium sulfide into another 3L reaction bottle, add 1L of water and mix, introduce nitrogen, and set the gas volume to 1L / min. After 3 minutes, use a dropping funnel to slowly drip 2mol / L dilute sulfuric acid into the sodium sulfide solution, adjust the dripping speed, and the whole dripping process takes 2h;

[0037] 3) Zinc precipitation: The N2 and hydrogen sulfide mixed gas is scrubbed and desulfurized with a saturated sodium sulfide solution, and then dehydrated with industrial calcium chloride before entering the zinc sulfate reaction bottle. Bubbling and stirring are performed, and white turbidity is generated. As the reaction proceeds, the feed liquid slowly turns into milky white. After the sulfuric acid is added, the nitrogen is stopped and stirring is continued for 30 minutes. The first reaction bottle is stopped and allowed to stand for 30 minutes for aging. For the next batch of reactions, the 2# and 3# reaction bottles are placed in the front position, and new zinc sulfate qualified solution is placed in the original 3# reaction bottle to continue the zinc precipitation reaction.

[0038] 4) Washing: Filter the zinc precipitated liquid by suction, and wash the filter cake with 10 times the amount of deionized water for 2 times to obtain wet zinc sulfide;

[0039] 5) Drying and crushing: Put the wet zinc sulfide into a vacuum drying oven, dry it at 105°C for 5 hours, and use a N2 air flow crusher to crush the dried zinc sulfide into powder to obtain white powdery high-purity zinc sulfide.

[0040] Example 4

[0041] 1) Preparation of qualified zinc sulfate solution: Take 1L of deionized water, slowly add 40g of sulfuric acid while stirring, then weigh 35g of active zinc oxide and add it to dilute sulfuric acid, heat and stir to 60°C to dissolve, then continue to add 8g of sodium acetate to dissolve, adjust the pH to 5.5, then add 1g of activated carbon for decolorization and adsorption, filter, the filtrate is the qualified zinc sulfate solution, put it into a 3L four-necked reaction bottle;

[0042] 2) Gas production: Put 155g of industrial 60% sodium sulfide into another 3L reaction bottle, add 1L of water and mix, introduce nitrogen, and set the gas volume to 1L / min. After 3 minutes, use a dropping funnel to slowly drip 2mol / L dilute sulfuric acid into the sodium sulfide solution, adjust the dripping speed, and the whole dripping process takes 2h;

[0043] 3) Zinc precipitation: The N2 and hydrogen sulfide mixed gas is scrubbed and desulfurized with a saturated sodium sulfide solution, and then dehydrated with industrial calcium chloride before entering the zinc sulfate reaction bottle. Bubbling and stirring are performed, and white turbidity is generated. As the reaction proceeds, the feed liquid slowly turns into milky white. After the sulfuric acid is added, the nitrogen is stopped and stirring is continued for 30 minutes. The first reaction bottle is stopped and allowed to stand for 30 minutes for aging. For the next batch of reactions, the 2# and 3# reaction bottles are placed in the front position, and new zinc sulfate qualified solution is placed in the original 3# reaction bottle to continue the zinc precipitation reaction.

[0044] 4) Washing: Filter the zinc precipitated liquid by suction, and wash the filter cake with 10 times the amount of deionized water for 2 times to obtain wet zinc sulfide;

[0045] 5) Drying and crushing: Put the wet zinc sulfide into a vacuum drying oven, dry it at 105°C for 5 hours, and use a N2 air flow crusher to crush the dried zinc sulfide into powder to obtain white powdery high-purity zinc sulfide.

[0046] The high-purity zinc sulfide of Examples 1-4 was tested, and the content of each component was tested as shown in the following table:

[0047] Example 1 Example 2 Example 3 Example 4 ZnS% 99.12 98.83 99.07 98.75 Feμg / g 53.35 53.52 53.29 53.39 Pbμg / g 0.49 0.46 0.48 4.47 Cuμg / g 0.81 0.78 0.80 0.79 Niμg / g 0.19 0.20 0.18 0.19

[0048] In step 3) of Example 1-4, a hydrogen sulfide tail gas absorption tower is installed in the zinc precipitation step for emergency use to increase the protection measures against hydrogen sulfide leakage, thereby reducing the safety risk for a second time and reducing the risk of hydrogen sulfide gas generated during the production process of zinc sulfide, and the risk of hydrogen sulfide leakage causing poisoning and environmental pollution.

[0049] The above descriptions are merely embodiments of the present invention. It should be pointed out that, for those skilled in the art, various changes, modifications, substitutions and variations can be made to these embodiments without departing from the technical principles of the present invention. These changes, modifications, substitutions and variations should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing high-purity zinc sulfide using active zinc oxide, characterized in that: The specific steps are as follows: 1) Preparation of zinc sulfate solution: Add active zinc oxide to the prepared dilute sulfuric acid solution, heat and stir to fully dissolve it, then add sodium acetate to adjust the pH of the solution, then add activated carbon for decolorization and adsorption, filter, and obtain zinc sulfate solution; 2) Preparation of sodium sulfide solution: Add water to industrial sodium sulfide to prepare qualified sodium sulfide solution; 3) Zinc precipitation: dilute sulfuric acid is slowly added dropwise to a closed container containing sodium sulfide solution, and N2 is introduced to pressurize it. The generated hydrogen sulfide and N2 mixed gas is desulfurized and dehydrated, and then introduced to the bottom of a closed container containing zinc sulfate for reaction while stirring. The container containing zinc sulfate is designed to be three-stage series. After the addition of dilute sulfuric acid is completed, N2 is turned off and stirring is continued. After stirring, the zinc is allowed to settle and then centrifuged and filtered. The filter cake is zinc sulfide; 4) Washing: Add deionized water to wash the filter cake, wash twice to obtain wet zinc sulfide product; 5) Drying: Place the obtained wet zinc sulfide product in a vacuum drying furnace for drying; 6) Crushing: Use N2 air flow crusher to crush the dried zinc sulfide into powder to obtain industrial high-purity zinc sulfide.

2. The method for preparing high-purity zinc sulfide using activated zinc oxide according to claim 1, characterized in that: In step 1), the concentration of the dilute sulfuric acid solution is 0.5 mol / L, the mass ratio of zinc oxide, dilute sulfuric acid solution, sodium acetate and activated carbon is 20-30:700-800:8-12:1, and the heating temperature is 50-60°C.

3. The method for preparing high-purity zinc sulfide using activated zinc oxide according to claim 1, characterized in that: The concentration of the qualified sodium sulfide solution in step 2) is 20%.

4. The method for preparing high-purity zinc sulfide using activated zinc oxide according to claim 1, characterized in that: In the step 3), the concentration of dilute sulfuric acid is 2 mol / L, and the mass ratio of dilute sulfuric acid to sodium sulfide solution is 1:2-3.

5. The method for preparing high-purity zinc sulfide using activated zinc oxide according to claim 1, characterized in that: In the step 3), the N2 introduction rate is 1-1.5 L / min, and the pressure after pressurization is ≤0.1 MPa.

6. The method for preparing high-purity zinc sulfide using activated zinc oxide according to claim 1, characterized in that: In the step 3), the dilute sulfuric acid is added dropwise for 2-3 hours, the zinc precipitation time is 2-3 hours, and the stirring time is continued for 1-2 hours.

7. The method for preparing high-purity zinc sulfide using activated zinc oxide according to claim 1, characterized in that: The material-liquid ratio of washing in step 4) is 1:9-12.

8. The method for preparing high-purity zinc sulfide using activated zinc oxide according to claim 1, characterized in that: In step 5), the drying temperature is 100-110° C. and the drying time is 4-6 hours.

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