阅读说明：本技术 一种高氟氯次氧化锌渣的处理方法 (Method for treating high fluorine chlorine secondary zinc oxide slag ) 是由 周惠 余承红 周康根 吴班 姜科 高峰 胡舜聪 潘希贤 彭佳乐 张剑峰 于 2020-12-28 设计创作，主要内容包括：本发明提供了一种高氟氯次氧化锌渣的处理方法,包括：S1)将高氟氯次氧化锌渣用水洗涤,得到洗渣与洗水；S2)将所述洗渣、锌电解废液与含硫酸溶液混合搅拌后,过滤,得到含硫酸锌溶液与残渣；S3)将所述硫酸锌溶液降温结晶,得到硫酸锌与结晶母液。与现有技术相比,本发明先用水清洗次氧化锌废渣,可预先除去部分次氧化锌中的氟氯,为后续硫酸锌结晶的氟氯纯度控制打下基础；然后将水洗后的次氧化锌洗渣与锌电解废液、含硫酸溶液混合搅拌并控制温度提高溶液中的硫酸锌的饱和度,为后续硫酸锌的诱导结晶析出打下基础；最后通过降温诱导结晶产生的硫酸锌结晶物颗粒粗大、纯度高,仅有少量氟氯吸附于结晶表面,可以满足回用质量要求。(The invention provides a method for treating high fluorine chlorine secondary zinc oxide slag, which comprises the following steps: s1) washing the high fluorine chlorine zinc hypoxide slag with water to obtain washing slag and washing water; s2) mixing and stirring the washing slag, the zinc electrolysis waste liquid and the sulfuric acid-containing solution, and filtering to obtain a zinc sulfate-containing solution and residues; s3) cooling and crystallizing the zinc sulfate solution to obtain zinc sulfate and a crystallization mother solution. Compared with the prior art, the method has the advantages that the waste residue of the zinc hypoxide is washed by water, so that part of fluorine and chlorine in the zinc hypoxide can be removed in advance, and a foundation is laid for controlling the purity of the fluorine and chlorine in the subsequent zinc sulfate crystallization; then mixing and stirring the washed secondary zinc oxide washing slag, zinc electrolysis waste liquid and sulfuric acid-containing solution, controlling the temperature to improve the saturation of zinc sulfate in the solution, and laying a foundation for the subsequent induced crystallization precipitation of the zinc sulfate; and finally, zinc sulfate crystal particles generated by cooling induced crystallization are large and have high purity, and only a small amount of fluorine and chlorine are adsorbed on the surface of the crystal, so that the recycling quality requirement can be met.)

1. A method for treating high fluorine chlorine zinc hypoxide slag is characterized by comprising the following steps:

s1) washing the high fluorine chlorine zinc hypoxide slag with water to obtain washing slag and washing water;

s2) mixing and stirring the washing slag, the zinc electrolysis waste liquid and the sulfuric acid-containing solution, and filtering to obtain a zinc sulfate-containing solution and residues;

s3) cooling and crystallizing the zinc sulfate solution to obtain zinc sulfate and a crystallization mother solution.

2. The process according to claim 1, wherein the high fluorine chlorine zinc hypoxide slag in step S1) comprises Zn, O, Pb, F, Cl and S; wherein the mass fraction of Zn is 15-60%; the mass fraction of O is 10-40%; the mass fraction of Pb is 0-3%; the mass fraction of F is 0.2-6%; the mass fraction of Cl is 0.3-6%; the mass fraction of S is 0-20%;

the concentration of zinc in the zinc electrolysis waste liquid in the step S2) is 120-180 g/L; the concentration of sulfate radicals is 180-265 g/L; the concentration of the fluorine ions is 20-350 mg/L; the concentration of the chloride ion is 20-500 mg/L.

3. The treatment method according to claim 1, wherein the mass ratio of the high fluorine chlorine secondary zinc oxide slag to water is 1: (2-10); the washing time is 0.5-2 h.

4. The treatment method according to claim 1, wherein the volume ratio of the washing slag to the zinc electrolysis waste liquid in the step S2) is 1: (5-20).

5. The treatment method as claimed in claim 1, wherein the mass fraction of sulfuric acid in the sulfuric acid-containing solution in the step S2) is 30-60%; the volume ratio of the washing slag to the sulfuric acid-containing solution is 1: (0.4 to 1).

6. The treatment method according to claim 1, wherein the pH value of the solution obtained by mixing the slag washing, the zinc electrolysis waste liquid and the sulfuric acid-containing solution in the step S2) is 0.5-2; the temperature of mixing and stirring is 45-70 ℃; the mixing and stirring time is 0.5-4 h; the filtering temperature is 45-70 ℃; the aperture of the filtration is 5-50 μm.

7. The treatment method as claimed in claim 1, wherein the temperature of the temperature-reducing crystallization in the step S3) is 0-25 ℃; the time for cooling and crystallizing is 2-10 h.

8. The treatment method as claimed in claim 1, wherein after cooling and crystallizing in the step S3), filtering is carried out to obtain zinc sulfate and crystallization mother liquor; the aperture of the filtration is 0.2-1 mm.

9. The processing method of claim 1, further comprising:

s4) mixing the crystallization mother liquor, and removing chlorine and fluorine by ion exchange to obtain purified mother liquor; the purified mother liquor is used for replacing the zinc electrolysis waste liquor in the step S2).

10. The process of claim 9, wherein the ion exchange dechlorination employs a strong base anion exchange resin; the pH value of the calcium sulfate during defluorination is 5-10, and the calcium-fluorine ratio is 0.5-3.

Technical Field

The invention belongs to the technical field of heavy metal smelting, and particularly relates to a treatment method of high fluorine chlorine secondary zinc oxide slag.

Background

China is a big zinc smelting country, and wet (electrolytic) zinc smelting is one of the main smelting methods. A large amount of zinc hypoxide waste residues can be produced in the zinc smelting process by an electrolytic method, the zinc hypoxide waste residues contain heavy metals such as Pb, Zn and the like and non-metals such as F, Cl, S and the like, and zinc electrolytic waste liquid with similar components to the zinc hypoxide waste residues and waste acid containing a large amount of sulfuric acid can be produced in the zinc smelting process by a wet method.

The waste residue of the secondary zinc oxide contains a large amount of zinc elements, for example, the waste of zinc can be reduced by recycling, the environment protection is also facilitated, and how to treat fluorine and chlorine contained in the high fluorine and chlorine-containing secondary zinc oxide residue is one of the key points and difficulties. The prior method for treating fluorine and chlorine in the waste residue of the secondary zinc oxide mainly comprises the following steps: removing fluorine and chlorine by a chemical precipitation method and an alkali washing method, reducing pressure and evaporating, and removing fluorine and chlorine by pyrogenic roasting, etc.

The traditional chemical precipitation method mainly comprises pre-removal, such as silver salt dechlorination and calcium hydroxide defluorination, and the method is simple to operate and has huge consumption cost. In order to reduce the cost, some of the new methods adopt a leaching method, such as an alkali washing method, wherein part of fluorine and chlorine can be removed by alkali washing, then chloride ions are removed by methods of depositing iron, cuprous and the like, and then zinc is leached by an acid solution. However, the alkaline washing consumes more soda ash, and the simple washing removal efficiency does not reach the standard for qualified electrolyte, so that the method needs to be combined with the subsequent process, and the method is complex in procedure and difficult to operate.

Therefore, the method has important significance for finding an effective and simple treatment technology of the waste residue of the secondary zinc oxide, reducing the recovery cost of the secondary zinc oxide and improving the purity of the recovered secondary zinc oxide.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a method for treating high fluorine chlorine zinc hypoxide slag, which has the advantages of low cost, simple process and capability of recovering zinc sulfate products with higher purity.

The invention provides a method for treating high fluorine chlorine secondary zinc oxide slag, which comprises the following steps:

s1) washing the high fluorine chlorine zinc hypoxide slag with water to obtain washing slag and washing water;

s2) mixing and stirring the washing slag, the zinc electrolysis waste liquid and the sulfuric acid-containing solution, and filtering to obtain a zinc sulfate-containing solution and residues;

s3) cooling and crystallizing the zinc sulfate solution to obtain zinc sulfate and a crystallization mother solution.

Preferably, the high fluorine chlorine zinc hypoxide slag in the step S1) comprises Zn, O, Pb, F, Cl and S; wherein the mass fraction of Zn is 15-60%; the mass fraction of O is 10-40%; the mass fraction of Pb is 0-3%; the mass fraction of F is 0.2-6%; the mass fraction of Cl is 0.3-6%; the mass fraction of S is 0-20%;

the concentration of zinc in the zinc electrolysis waste liquid in the step S2) is 120-180 g/L; the concentration of sulfate radicals is 180-265 g/L; the concentration of the fluorine ions is 20-350 mg/L; the concentration of the chloride ion is 20-500 mg/L.

Preferably, the mass ratio of the high fluorine chlorine zinc hypoxide slag to the water is 1: (2-10); the washing time is 0.5-2 h.

Preferably, the volume ratio of the washing slag to the zinc electrolysis waste liquid in the step S2) is 1: (5-20).

Preferably, the mass fraction of the sulfuric acid in the sulfuric acid-containing solution in the step S2) is 30-60%; the volume ratio of the washing slag to the sulfuric acid-containing solution is 1: (0.4 to 1).

Preferably, the pH value of the solution obtained by mixing the slag washing, the zinc electrolysis waste liquid and the sulfuric acid-containing solution in the step S2) is 0.5-2; the temperature of mixing and stirring is 45-70 ℃; the mixing and stirring time is 0.5-4 h; the filtering temperature is 45-70 ℃; the aperture of the filtration is 5-50 μm.

Preferably, the temperature for cooling and crystallizing in the step S3) is 0-25 ℃; the time for cooling and crystallizing is 2-10 h.

Preferably, after cooling and crystallizing in the step S3), filtering to obtain zinc sulfate and a crystallization mother liquor; the aperture of the filtration is 0.2-1 mm.

Preferably, the method further comprises the following steps:

s4) mixing the crystallization mother liquor, and removing chlorine and fluorine by ion exchange to obtain purified mother liquor; the purified mother liquor is used for replacing the zinc electrolysis waste liquor in the step S2).

Preferably, the ion exchange dechlorination adopts strong base type anion exchange resin; the pH value of the calcium sulfate during defluorination is 5-10, and the calcium-fluorine ratio is 0.5-3.

The invention provides a method for treating high fluorine chlorine secondary zinc oxide slag, which comprises the following steps: s1) washing the high fluorine chlorine zinc hypoxide slag with water to obtain washing slag and washing water; s2) mixing and stirring the washing slag, the zinc electrolysis waste liquid and the sulfuric acid-containing solution, and filtering to obtain a zinc sulfate-containing solution and residues; s3) cooling and crystallizing the zinc sulfate solution to obtain zinc sulfate and a crystallization mother solution. Compared with the prior art, the method has the advantages that the waste residue of the zinc hypoxide is washed by water, so that part of fluorine and chlorine in the zinc hypoxide can be removed in advance, and a foundation is laid for controlling the purity of the fluorine and chlorine in the subsequent zinc sulfate crystallization; then mixing and stirring the washed secondary zinc oxide washing slag, zinc electrolysis waste liquid and sulfuric acid-containing solution, controlling the temperature to improve the saturation of zinc sulfate in the solution, and laying a foundation for the subsequent induced crystallization precipitation of the zinc sulfate; and finally, zinc sulfate crystal particles generated by cooling induced crystallization are large and have high purity, only a small amount of fluorine and chlorine is adsorbed on the surface of the crystal, so that the recycling quality requirement can be met, and the fluorine and chlorine in the crystallization mother liquor are simply treated, so that the fluorine ion concentration is reduced to 350mg/L, and when the chlorine ion concentration is reduced to 500mg/L, the zinc electrolysis waste liquor can be replaced for recycling.

According to the invention, the zinc sulfate is crystallized by utilizing the change relation between the solubility of the zinc sulfate and the temperature, the recovery rate of the zinc sulfate is effectively improved, and the particle size of a crystal is improved by adopting cooling induction crystallization according to the relation between the particle size of the crystal and the purity, and the content of fluorine and chlorine adsorbed by the crystal is reduced. Compared with the prior art, the method for treating the high fluorine chlorine zinc hypoxide slag has simple and convenient operation, and can recover the zinc in the slag in the form of high-purity zinc sulfate crystals only by the steps of filtering, crystallizing and the like; the recovery cost is low, the concentration of fluorine ions and the concentration of chloride ions in the zinc sulfate solution obtained after the zinc sulfate crystal is dissolved are lower than 30mg/L and 50mg/L, and the electrolysis requirements can be directly met (the concentration of fluorine ions and the concentration of chloride ions in zinc electrolyte are lower than 30mg/L and 200mg/L respectively in general production); the crystallization mother liquor can be recycled only by simple fluorine-chlorine treatment and open circuit, and the concentration of fluorine ions is lower than 350mg/L and the concentration of chlorine ions is lower than 500mg/L after treatment.

Drawings

FIG. 1 is a schematic view of the treatment process of high fluorine chlorine zinc hypoxide slag provided by the invention;

FIG. 2 is a flow chart of a treatment process of the high fluorine chlorine zinc hypoxide slag in comparative example 2 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides a method for treating high fluorine chlorine secondary zinc oxide slag, which comprises the following steps: s1) washing the high fluorine chlorine zinc hypoxide slag with water to obtain washing slag and washing water; s2) mixing and stirring the washing slag, the zinc electrolysis waste liquid and the sulfuric acid-containing solution, and filtering to obtain a zinc sulfate-containing solution and residues; s3) cooling and crystallizing the zinc sulfate solution to obtain zinc sulfate and a crystallization mother solution.

Referring to fig. 1, fig. 1 is a schematic view of a treatment process of high fluorine chlorine zinc hypoxide slag provided by the invention.

The present invention is not particularly limited in terms of the source of all raw materials, and may be commercially available.

The high fluorine chlorine secondary zinc oxide slag to be treated by the invention comprises Zn, O, Pb, F, Cl and S; wherein, the mass fraction of Zn is 15-60%, more preferably 15-58%; the mass fraction of O is 10-40%, more preferably 20-40%, still more preferably 20-30%, most preferably 20-26%; the mass fraction of Pb is 0-3%, more preferably 0-2%, still more preferably 0-1%, still more preferably 0.001-0.05%, still more preferably 0.005-0.02%, most preferably 0.017%; the mass fraction of F is 0.2-6%, preferably 0.2-4%, more preferably 0.2-2%, more preferably 0.5-1%, most preferably 0.68%; the mass fraction of Cl is 0.3-6%, preferably 0.3-4%, more preferably 0.3-2%, more preferably 0.3-1%, most preferably 0.36%; the mass fraction of S is 0 to 20%, preferably 0 to 15%, more preferably 2 to 10%, more preferably 5 to 8%, and most preferably 7.5%.

Washing the high fluorine chlorine secondary zinc oxide slag with water to obtain washing slag and washing water; the water is preferably tap water; the mass ratio of the high fluorine chlorine secondary zinc oxide slag to water is preferably 1: (2-10); the washing time is preferably 0.5-2 h, and more preferably 1-1.5 h; the purpose of washing is to primarily remove fluorine and chlorine in the slag, if the solid-liquid ratio of the high fluorine-chlorine secondary zinc oxide slag to water is higher than 1:2, the removal rate of fluorine and chlorine in the slag is too low, so that the subsequent zinc sulfate crystallization purity is influenced; if the solid-to-liquid ratio of the high fluorine-chlorine secondary zinc oxide slag to water is lower than 1:10, the water consumption is overlarge, and the obtained fluorine-containing chlorine washing water is overlarge, so that the washing water treatment load is increased.

Mixing and stirring the washing slag, the zinc electrolysis waste liquid and the sulfuric acid-containing solution; by the step, zinc in the washing slag can be converted into a saturated zinc sulfate solution; the concentration of zinc in the zinc electrolysis waste liquid is preferably 120-180 g/L, more preferably 120-160 g/L, still more preferably 130-160 g/L, still more preferably 140-160 g/L, and most preferably 150-160 g/L; in some embodiments provided by the present invention, the concentration of zinc in the zinc electrolysis waste liquid is preferably 160 g/L; in some embodiments provided by the present invention, the concentration of zinc in the zinc electrolysis waste liquid is preferably 155 g/L; in other embodiments provided by the present invention, the concentration of zinc in the zinc electrolysis waste liquid is preferably 150 g/L; the concentration of the sulfate radical is preferably 180-265 g/L, more preferably 180-250 g/L, and further preferably 180-240 g/L; in some embodiments provided herein, the concentration of sulfate is preferably 240 g/L; in some embodiments provided herein, the concentration of sulfate is preferably 230 g/L; in other embodiments provided herein, the sulfate concentration is preferably 226 g/L; the concentration of the fluorine ions is preferably 20-350 mg/L, more preferably 20-200 mg/L, further preferably 20-100 mg/L, further preferably 20-50 mg/L; the concentration of the chloride ions is preferably 20-500 mg/L, more preferably 20-400 mg/L, still more preferably 20-200 mg/L, still more preferably 20-100 mg/L, still more preferably 20-50 mg/L; the volume ratio of the washing slag to the zinc electrolysis waste liquid is preferably 1: (5-20), more preferably 1: (5-15), and more preferably 1: (7-14); if the solid-liquid ratio of the washing slag to the zinc electrolysis waste liquid is higher than 1: 5, the supersaturation degree of the zinc sulfate-containing solution is too high, so that the insoluble zinc sulfate is too much to cause waste, and if the solid-to-liquid ratio of the washing slag to the zinc electrolysis waste liquid is lower than 1:20, the supersaturation degree of the zinc sulfate-containing solution is too low, and the zinc sulfate cannot reach the saturation condition; in some embodiments provided by the present invention, the volume ratio of the washing slag to the zinc electrolysis waste liquid is preferably 1: 14; in some embodiments provided by the present invention, the volume ratio of the washing slag to the zinc electrolysis waste liquid is preferably 1: 7; in some embodiments provided by the present invention, the volume ratio of the washing slag to the zinc electrolysis waste liquid is preferably 1: 8.

the mass concentration of the sulfuric acid in the sulfuric acid-containing solution is preferably 30-60%; if the mass fraction of the sulfuric acid is lower than 30%, the zinc concentration in the obtained zinc sulfate-containing solution is too low, and the zinc sulfate cannot reach the saturation condition, if the mass fraction of the sulfuric acid is higher than 60%, the supersaturation degree of the obtained zinc sulfate-containing solution is too high, and the insoluble zinc sulfate is excessive, so that waste is caused; the volume ratio of the washing slag to the sulfuric acid-containing solution is preferably 1: (0.4 to 1), more preferably 1: (0.44-0.88); in some embodiments provided herein, the volume ratio of the washing slag to the sulfuric acid-containing solution is preferably 1: 0.44; in some embodiments provided herein, the volume ratio of the washing slag to the sulfuric acid-containing solution is preferably 1: 0.45 of; in some embodiments provided herein, the volume ratio of the washing slag to the sulfuric acid-containing solution is preferably 1: 0.88; in other embodiments provided by the present invention, the volume ratio of the washing slag to the sulfuric acid-containing solution is preferably 1: 0.672 parts of the total weight of the mixture; .

The pH value of the solution obtained by mixing the washing slag, the zinc electrolysis waste liquid and the sulfuric acid-containing solution is preferably 0.5-2; the mixing and stirring temperature is preferably 45-70 ℃, and more preferably 45-60 ℃; the mixing and stirring time is preferably 0.5-4 h, more preferably 1-4 h, and further preferably 2-4 h. The pH value of the mixing and stirring is controlled to ensure that zinc in the secondary zinc oxide slag is converted into zinc sulfate, and if the pH value of the mixing and stirring is lower than 0.5, sulfuric acid is wasted; if the pH value of the mixed stirring is higher than 2, the proportion of converting the zinc into the zinc sulfate in the washing slag is reduced, and the recovery rate of the zinc sulfate is reduced.

The main reaction of mixing and stirring is shown as formula (1) and formula (2):

Zn₂O+10H₂O+2H₂SO₄＝2ZnSO₄·6H₂o type (1)

ZnO+5H₂O+H₂SO₄＝ZnSO₄·6H₂O type (2)

Mixing and stirring, and filtering to obtain a zinc sulfate-containing solution and residues; the filtering temperature is preferably 45-70 ℃, and more preferably 45-60 ℃; can guarantee through the control mixing stirring and filterable temperature that zinc sulfate solution reaches the maximum solubility, the high temperature or low excessively can cause zinc sulfate solubility to descend, leads to the zinc sulfate rate of recovery to reduce. The aperture of the filtration is preferably 5-50 μm, more preferably 10-50 μm, and still more preferably 10-30 μm; insoluble residue in the separable secondary zinc oxide sediment through filtering, because of the residue is thinner, if the filter aperture is too big then insoluble heavy metal in the residue and ash content get into the filtrating, influence the quality of zinc sulfate crystallization, if the filter aperture undersize then filter speed slows down, calorific loss increases.

Cooling and crystallizing the zinc sulfate solution; the temperature of the cooling crystallization is preferably 0-25 ℃, more preferably 10-25 ℃, and further preferably 20-25 ℃; the cooling crystallization time is preferably 2-10 h, more preferably 4-8 h, and still more preferably 6 h. According to the invention, the zinc sulfate crystal can be obtained by cooling crystallization by utilizing the change rule of zinc sulfate solubility along with temperature; the main reaction of cooling crystallization is shown as formula (3):

ZnO·6H₂O+H₂O＝ZnSO₄·7H₂o type (3)

After cooling crystallization, preferably filtering to obtain zinc sulfate and crystallization mother liquor; because the particle size of zinc sulfate crystallization is great, in order to guarantee the effective separation of crystallization and mother liquor, the preferred 0.2 ~ 1mm of aperture of filteration.

According to the invention, the mother liquid after purification is obtained after ion exchange dechlorination and calcium sulfate defluorination of the crystallization mother liquid; the purified mother liquor is used for replacing the zinc electrolysis waste liquor in the step S2). The ion exchange dechlorination preferably adopts strong base type anion exchange resin, more preferably styrene series macroporous strong base type anion exchange resin; further preferred is a D201 resin; the pH value of the calcium sulfate during defluorination is preferably 5-10, more preferably 5-8, still more preferably 5-6, and most preferably 5.5; the calcium-fluorine ratio is preferably 0.5 to 3, more preferably 0.5 to 2, and still more preferably 0.5 to 1. Wherein, the main reaction of the calcium sulfate for removing fluorine is shown as a formula (4):

CaSO₄+2F^-＝CaF₂+SO₄ ^2-↓ (4)

After the chlorine and the calcium sulfate are removed by ion exchange, the fluorine ion concentration in the crystallization mother liquor is lower than 350mg/L and the chlorine ion concentration is lower than 500mg/L, so that the recycling requirement of the crystallization mother liquor is met, the obtained purified mother liquor can be recycled to replace the zinc electrolysis waste liquor in the step S2), the zinc electrolysis waste liquor is stopped from being added, and the steps S3) and S4) are continuously repeated, thereby realizing the closed cycle of the mother liquor.

According to the invention, the washing water obtained in step S1) is preferably mixed with a crystallization mother liquor and then subjected to ion exchange dechlorination and calcium sulfate defluorination treatments.

The method firstly uses water to clean the waste residue of the zinc hypoxide, can remove part of fluorine and chlorine in the zinc hypoxide in advance, and lays a foundation for controlling the purity of the fluorine and chlorine in the subsequent zinc sulfate crystallization; then mixing and stirring the washed secondary zinc oxide washing slag, zinc electrolysis waste liquid and sulfuric acid-containing solution, controlling the temperature to improve the saturation of zinc sulfate in the solution, and laying a foundation for the subsequent induced crystallization precipitation of the zinc sulfate; and finally, zinc sulfate crystal particles generated by cooling induced crystallization are large and have high purity, only a small amount of fluorine and chlorine is adsorbed on the surface of the crystal, so that the recycling quality requirement can be met, and the fluorine and chlorine in the crystallization mother liquor are simply treated, so that the fluorine ion concentration is reduced to 350mg/L, and when the chlorine ion concentration is reduced to 500mg/L, the zinc electrolysis waste liquor can be replaced for recycling.

According to the invention, the zinc sulfate is crystallized by utilizing the change relation between the solubility of the zinc sulfate and the temperature, the recovery rate of the zinc sulfate is effectively improved, and the particle size of a crystal is improved by adopting cooling induction crystallization according to the relation between the particle size of the crystal and the purity, and the content of fluorine and chlorine adsorbed by the crystal is reduced. Compared with the prior art, the method for treating the high fluorine chlorine zinc hypoxide slag has simple and convenient operation, and can recover the zinc in the slag in the form of high-purity zinc sulfate crystals only by the steps of filtering, crystallizing and the like; the recovery cost is low, the concentration of fluorine ions in the zinc sulfate solution obtained after the zinc sulfate crystal is dissolved is lower than 30mg/L, the concentration of chloride ions is lower than 50mg/L, and the electrolysis requirements can be directly met (the concentration of fluorine ions in zinc electrolyte is lower than 30mg/L and the concentration of chloride ions is lower than 200mg/L in general production). The crystallization mother liquor can be recycled only by simple fluorine-chlorine treatment and open circuit, and the concentration of fluorine ions is lower than 350mg/L and the concentration of chlorine ions is lower than 500mg/L after treatment.

In order to further explain the invention, the following will describe in detail the treatment method of high fluorine chlorine zinc hypoxide slag provided by the invention with reference to the examples.

The strong base anion exchange resin used in the examples is a styrene macroporous type D201.

Example 1

The high fluorine chlorine zinc hypoxide waste residue comprises the following components:

58% of Zn, 26% of O, 0.017% of Pb, 0.68% of F, 0.36% of Cl and 7.5% of S.

The zinc electrolysis waste liquid comprises the following components:

the concentration of zinc is 160g/L, the concentration of sulfate radical is 240g/L, the concentration of fluorinion is 20mg/L, and the concentration of chlorion is 20 mg/L.

S1, mixing the components according to a solid-liquid ratio of 1:2, 40g of zinc hypoxide waste residue and 80mL of tap water are mixed, washed for 1 hour and filtered to obtain 57.1mL of washing residue and 62.9mL of washing water.

Through detection, the concentration of fluorine ions in the washing water is 550mg/L, and the concentration of chlorine ions in the washing water is 1215 mg/L.

S2, mixing 57.1mL of washing slag, 400mL of zinc electrolysis waste liquid and 25.2mL of sulfuric acid-containing solution with the sulfuric acid concentration of 60%, heating at 45 ℃ for 4h, and filtering with filter paper with the pore diameter of 10 μm to obtain 388mL of zinc sulfate-containing solution and 91g of residue.

The Zn concentration of the obtained zinc sulfate-containing solution is 196g/L by detection.

S3, performing induced crystallization on the zinc sulfate-containing solution, cooling to 25 ℃, performing induced crystallization for 6 hours, and filtering by using a rapid funnel with the aperture of 0.2mm to obtain 43g of zinc sulfate crystals and 371mL of crystallization mother liquor.

The detection shows that the concentration of Zn in the crystallization mother liquor is 169g/L, the concentration of fluorine ions is 530mg/L, and the concentration of chlorine ions is 331 mg/L.

S4, mixing the crystallization mother liquor and washing water to obtain 434mL fluorine-chlorine-containing solution, performing ion exchange dechlorination by using D201 resin (styrene macroporous strong base anion exchange resin) to remove chlorine and fluorine by using calcium sulfate, wherein the calcium-fluorine ratio is 0.5, the pH value is 5.5, mixing and stirring for 1h to obtain purified mother liquor.

The detection shows that the concentration of chlorine ions in the mother liquor is reduced to 200mg/L and the concentration of fluorine ions is reduced to 306mg/L after purification.

S5, returning the purified mother liquor to S2.

The mass fraction of fluorine in the zinc sulfate crystal of S3 is detected to be 0.005%, the mass fraction of chlorine is detected to be 0.006%, and the crystal is calculated to be used for preparing a zinc sulfate electrolyte with the zinc content of 120g/L, the fluorine ion concentration in the electrolyte can be reduced to 22.4mg/L (lower than 30mg/L), and the chlorine ion concentration can be reduced to 25.2mg/L (lower than 50 mg/L). It is demonstrated that the zinc sulfate crystal product obtained in example 1 can be recycled as a zinc electrolysis raw material.

Example 2

The high fluorine chlorine zinc hypoxide waste residue comprises the following components:

58% of Zn, 26% of O, 0.017% of Pb, 0.68% of F, 0.36% of Cl and 7.5% of S.

The zinc electrolysis waste liquid comprises the following components:

the concentration of zinc is 155g/L, the concentration of sulfate radical is 230g/L, the concentration of fluorinion is 20mg/L, and the concentration of chlorion is 20 mg/L.

S1, mixing the components according to a solid-liquid ratio of 1:10, 40g of zinc hypoxide waste residue and 400mL of tap water are mixed, washed for 1 hour and filtered to obtain 56mL of washing residue and 384mL of washing water.

Through detection, the fluorine ion concentration of the washing water is 378mg/L, and the chlorine ion concentration is 552 mg/L.

S2, mixing 56mL of washing slag, 400mL of zinc electrolysis waste liquid and 25.2mL of sulfuric acid-containing solution with the sulfuric acid concentration of 60%, heating at 60 ℃ for 4h, and filtering with filter paper with the pore diameter of 30 μm to obtain 378mL of zinc sulfate-containing solution and 78g of residue.

The Zn concentration in the zinc sulfate-containing solution is 206g/L by detection.

S3, performing induced crystallization on the zinc sulfate-containing solution, cooling to 25 ℃, performing induced crystallization for 6 hours, and filtering by using a quick funnel with the aperture of 1mm to obtain 65.3g of zinc sulfate crystals and 306mL of crystallization mother liquor.

Through detection, the concentration of Zn in the crystallization mother liquor is 167g/L, the concentration of fluorine ions is 552mg/L, and the concentration of chlorine ions is 346 mg/L.

S4, mixing the crystallization mother liquor with washing water to obtain 762mL of fluorine-and chlorine-containing solution, performing ion exchange dechlorination by using D201 resin (styrene macroporous strong base anion exchange resin) to remove chlorine and fluorine by using calcium sulfate, wherein the calcium-fluorine ratio is 0.5, the pH value is 5.5, mixing and stirring for 1h to obtain purified mother liquor.

The concentration of chlorine ions in the mother liquor after purification is detected to be reduced to 218mg/L, and the concentration of fluorine ions is detected to be reduced to 327 mg/L.

S5, returning the purified filtrate to S2.

The mass fraction of fluorine and the mass fraction of chlorine of the zinc sulfate crystal obtained in S3 are detected to be 0.006% and 0.008%, and the concentration of fluorine ions in the electrolyte can be reduced to 26.9mg/L (lower than 30mg/L) and the concentration of chlorine ions can be reduced to 33.6mg/L (lower than 50mg/L) by calculating the mass fraction of the fluorine and the mass fraction of the chlorine in the zinc sulfate crystal prepared by using the crystal to prepare a zinc sulfate electrolyte with the zinc content of 120 g/L. It is proved that the zinc sulfate crystal product obtained in example 2 can be reused as zinc electrolysis raw material.

Example 3

The high fluorine chlorine zinc hypoxide waste residue comprises the following components:

58% of Zn, 26% of O, 0.017% of Pb, 0.68% of F, 0.36% of Cl and 7.5% of S.

The zinc electrolysis waste liquid comprises the following components:

the concentration of zinc is 160g/L, the concentration of sulfate radical is 240g/L, the concentration of fluorinion is 20mg/L, and the concentration of chlorion is 20 mg/L.

S1, mixing the components according to a solid-liquid ratio of 1:2, 20g of zinc hypoxide waste residue and 40mL of tap water are mixed, washed for 1 hour and filtered to obtain 28.6mL of washing residue and 31.4mL of washing water.

Through detection, the fluorine ion concentration of the mixed washing water is 552mg/L, and the chlorine ion concentration is 1203 mg/L.

S2, mixing 28.6mL of washing slag, 400mL of zinc electrolysis waste liquid and 25.2mL of sulfuric acid-containing solution with the sulfuric acid concentration of 60%, heating at 45 ℃ for 4h, and filtering with filter paper with the pore diameter of 30 μm to obtain 392mL of zinc sulfate-containing solution and 36g of residue.

The Zn concentration of the zinc sulfate-containing solution is detected to be 175 g/L.

S3, performing induced crystallization on the zinc sulfate-containing solution, cooling to 25 ℃, performing induced crystallization for 6 hours, and filtering by using a rapid funnel with the aperture of 0.2mm to obtain 15g of zinc sulfate crystals and 387mL of crystallization mother liquor.

Through detection, the concentration of Zn in the crystallization mother liquor is 166g/L, the concentration of fluorine ions is 522mg/L, and the concentration of chlorine ions is 315 mg/L.

S4, mixing the crystallization mother liquor with washing water to obtain 424mL fluorine-chlorine-containing solution, performing ion exchange dechlorination by using strong-base anion exchange resin, performing calcium sulfate defluorination, wherein the calcium-fluorine ratio is 0.5, the pH value is 5.5, mixing and stirring for 1h to obtain purified mother liquor.

The concentration of chlorine ions in the mother liquor after purification is detected to be reduced to 108mg/L, and the concentration of fluorine ions is detected to be reduced to 305 mg/L.

S5, returning the purified mother liquor to S2.

The detection proves that the mass fraction of fluorine in the zinc sulfate crystal obtained in S3 is 0.004%, the mass fraction of chlorine is 0.005%, and the calculation proves that when the crystal is used for preparing the zinc sulfate electrolyte with the zinc content of 120g/L, the fluorine ion concentration in the electrolyte can be reduced to 17.9mg/L (lower than 30mg/L), and the chlorine ion concentration can be reduced to 21mg/L (lower than 50 mg/L). It is demonstrated that the zinc sulfate crystal product obtained in example 3 can be recycled as a zinc electrolysis raw material.

Example 4

The high fluorine chlorine zinc hypoxide waste residue comprises the following components:

58% of Zn, 26% of O, 0.017% of Pb, 0.68% of F, 0.36% of Cl and 7.5% of S.

The zinc electrolysis waste liquid comprises the following components:

the concentration of zinc is 150g/L, the concentration of sulfate radical is 226g/L, the concentration of fluorinion is 20mg/L, and the concentration of chlorion is 20 mg/L.

S1, mixing the components according to a solid-liquid ratio of 1:2, mixing 40g of zinc hypoxide waste residue and 80mL of tap water, washing for 1 hour, and filtering to obtain 50mL of washing residue and 70mL of washing water.

Through detection, the concentration of the fluorine ions in the mixed washing water is 548mg/L, and the concentration of the chlorine ions is 1189 mg/L.

S2, mixing 50mL of washing slag, 400mL of zinc electrolysis waste liquid and 33.6mL of sulfuric acid-containing solution with the sulfuric acid concentration of 45%, heating at 45 ℃ for 4h, and filtering with filter paper with the pore diameter of 30 μm to obtain 365mL of zinc sulfate-containing solution and 85g of residue.

The Zn concentration of the zinc sulfate-containing solution is 189g/L through detection.

S3, performing induced crystallization on the zinc sulfate-containing solution, cooling to 25 ℃, performing induced crystallization for 6 hours, and filtering by using a rapid funnel with the aperture of 0.2mm to obtain 37g of zinc sulfate crystals and 347mL of crystallization mother liquor.

Through detection, the concentration of Zn in the crystallization mother liquor is 168g/L, the concentration of fluorine ions is 528mg/L, and the concentration of chlorine ions is 306 mg/L.

S4, mixing the crystallization mother liquor and washing water to obtain 417mL fluorine-chlorine-containing solution, performing ion exchange dechlorination by using D201 resin (styrene macroporous strong base type anion exchange resin) to remove chlorine and fluorine by using calcium sulfate, wherein the calcium-fluorine ratio is 0.5, the pH value is 5.5, mixing and stirring for 1h to obtain purified mother liquor.

The concentration of chloride ions in the mother liquor after purification is detected to be reduced to 215mg/L, and the concentration of fluoride ions is detected to be reduced to 296 mg/L.

S5, returning the purified filtrate to S2.

The detection proves that the mass fraction of fluorine in the zinc sulfate crystal obtained in S3 is 0.005%, the mass fraction of chlorine is 0.007%, and the calculation proves that when the crystal is used for preparing a zinc sulfate electrolyte with the zinc content of 120g/L, the fluorine ion concentration in the electrolyte can be reduced to 23mg/L (lower than 30mg/L), and the chlorine ion concentration can be reduced to 28mg/L (lower than 50 mg/L). It is demonstrated that the zinc sulfate crystal product obtained in example 4 can be recycled as a zinc electrolysis raw material.

Comparative example 1

The zinc hypoxide and zinc electrolysis waste liquid were the same as in example 1.

The procedure of example 1 was followed except that the solid-to-liquid ratio of S1 was changed in accordance with the solid-to-liquid ratio of 1:1 mixing 40g of zinc hypoxide with 40mL of tap water, the mixed washing water is difficult to stir, and the residual washing water is too little to collect because the zinc hypoxide absorbs water.

It is proved that S1 has a solid-liquid ratio higher than 1:2, the washing effect cannot be achieved.

Comparative example 2

The process flow diagram is shown in figure 2.

The zinc hypoxide and zinc electrolysis waste liquid were the same as in example 1.

The procedure of example 1 was followed except that the step of S1 was eliminated.

The mass fraction of fluorine and the mass fraction of chlorine in the zinc sulfate crystal obtained in S3 are respectively 0.017% and 0.0106%, and the zinc sulfate electrolyte with the zinc content of 120g/L is prepared by using the crystal through calculation, wherein the fluorine ion concentration in the electrolyte is reduced to 76.8mg/L, and the chlorine ion concentration is reduced to 47.9 mg/L. The requirements of the zinc electrolyte on the concentration of fluorine ions below 30mg/L and the concentration of chlorine ions below 200mg/L for recycling are not met.

The removal of S1 proves that the fluorine and chlorine contents of the zinc sulfate crystal in S3 can not reach the reuse standard of zinc electrolyte.

Comparative example 3

The procedure of example 1 was followed except that S2 was changed to heating at 90 deg.C, the Zn concentration of the S2 zinc sulfate-containing solution was reduced to 176g/L, and the amount of precipitated zinc sulfate crystals in S3 was reduced to 12 g.

The solubility of zinc sulfate is reduced when the heating temperature of S2 is too high, and the crystallization amount of zinc sulfate precipitated from S3 is reduced.

Comparative example 4

The procedure of example 1 was followed, except that the solid-to-liquid ratio of S2 washing slag to zinc electrolysis waste liquid was less than 1:20, and that 400mL of zinc electrolysis waste liquid containing 4g of secondary zinc oxide washing slag was added to S2, whereby S3 did not cause precipitation of zinc sulfate crystals.

The solid-to-liquid ratio of the S2 washing slag to the zinc electrolysis waste liquid is lower than 1:20, the zinc concentration in the S2 zinc sulfate-containing solution is 163g/L, the zinc concentration is not saturated, and S3 cannot separate out zinc sulfate crystals.

Comparative example 5

The zinc hypoxide and zinc electrolysis waste liquid were the same as in example 1.

The procedure of example 1 was followed, except that S2 was not added with sulfuric acid and the washing slag and the zinc electrolysis waste liquid were mixed at a pH of about 3, whereby the Zn concentration of the S2 zinc sulfate-containing solution was reduced to 162g/L, the Zn concentration was not saturated, and S3 was free from crystal precipitation.

The S2 reaction pH value is over high, the zinc hypoxide in the S2 washing slag is not dissolved, and S3 is not crystallized and precipitated.