Zinc hydrometallurgy process

Abstract

The invention belongs to the technical field of metallurgical engineering, and provides a zinc hydrometallurgy process which comprises the following steps: S1, ball-milling slurrying: zinc calcine enters a ball-milling process, is ball-milled by clear water, is added with a slurrying agent, and is uniformly stirred to obtain slurry; s2, continuous leaching: enabling the slurry to enter a continuous leaching process, adjusting the pH value, and carrying out solid-liquid separation to obtain a leachate and leaching residues; s3, oxidation impurity removal: introducing ozone into the leachate to react for a period of time, adding lime, adjusting the pH value, reacting for a period of time, and carrying out solid-liquid separation to obtain filtrate and filter residues I; s4, purification is conducted, specifically, the filtrate is subjected to a reaction through a purifier containing zinc particles, purified liquid is obtained, and when the content of lead in the purified liquid is smaller than 0.005 g / L, the content of cadmium in the purified liquid is smaller than 0.002 g / L, and the content of copper in the purified liquid is smaller than 0.002 g / L, solid-liquid separation is conducted to obtain pure zinc filtrate and filter residues II; s5, electrolysis is conducted, specifically, the pure zinc filtrate enters an electrolysis procedure, and a zinc sheet and an electrolyte are obtained; and S6, casting: casting the zinc sheet, and cooling to obtain a zinc ingot.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical engineering, and in particular relates to a hydrometallurgical zinc smelting process. Background Art

[0002] Zinc is an important nonferrous metal raw material. The existing zinc smelting methods mainly include pyrometallurgical zinc smelting and hydrometallurgical zinc smelting, among which hydrometallurgy is the main zinc smelting method.

[0003] Hydrometallurgy is a process of extracting zinc from zinc ore through chemical reactions. It mainly uses acid or alkaline solutions to react with zinc in the ore, and then obtains metallic zinc through separation and purification. Its basic principle is to use the chemical reaction of zinc compounds in solution to extract zinc from its ore through a series of physical and chemical separation processes. Although the existing hydrometallurgy process has a high zinc leaching rate and high impurity separation efficiency, it still has problems such as high cost and difficulty in purification.

[0004] Therefore, how to develop a hydrometallurgical zinc smelting process with high leaching rate and high efficiency is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The object of the present invention is to provide a hydrometallurgical zinc smelting process to solve one of the technical problems mentioned in the background technology.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A hydrometallurgical zinc smelting process comprises the following steps:

[0008] S1. Ball milling: The zinc roasted sand enters the ball milling process, is ball milled with clean water, and then a slurry is added. After being stirred evenly, a slurry is obtained.

[0009] S2, continuous leaching: the slurry enters the continuous leaching process, the pH value is adjusted to 5.0-6.0, the solid-liquid separation is carried out, and the leaching liquid and the leaching residue are obtained;

[0010] S3, oxidative removal: ozone is introduced into the leaching solution, reacted for 10 to 20 minutes, lime is added, the pH value is adjusted to 5.0 to 6.0, reacted for 40 to 50 minutes, solid-liquid separation is performed, and filtrate and residue I are obtained;

[0011] S4, purification: the filtrate is reacted in a purifier containing zinc particles for 35-40 minutes to obtain a purified liquid. When the lead, cadmium and copper in the purified liquid are less than 0.005 g / L, 0.002 g / L and 0.002 g / L, the solid-liquid separation is performed to obtain a pure zinc filtrate and a filter residue II;

[0012] S5, electrolysis: the pure zinc filtrate enters the electrolysis process to obtain zinc flakes and electrolyte, and the electrolyte enters the evaporation concentration process, centrifugally separates, and obtains calcium chloride, ammonium chloride and electrolysis tail liquid;

[0013] S6. Melting and casting: Melting and casting the zinc sheets, cooling them, and obtaining zinc ingots.

[0014] Preferably, the preparation steps of zinc roasted sand in S1 are as follows:

[0015] The secondary zinc oxide and zinc-containing waste slag are put into a rotary kiln for calcination, and then pass through a preheating zone and a reaction zone in sequence, and then are cooled and ball-milled to obtain zinc roasted sand.

[0016] Preferably, the zinc content of the secondary zinc oxide is 45% to 65%, and the zinc content of the zinc-containing waste slag is 30% to 45%.

[0017] Preferably, the temperature of the preheating zone is 300-800° C., and the length of the preheating zone is 10-15 m; the temperature of the reaction zone is 800-1500° C., and the length of the reaction zone is 15-20 m.

[0018] Preferably, the slurrying agent in S1 is the electrolytic tail liquid obtained by evaporating and concentrating the electrolyte obtained in S5, and the solid-liquid ratio is 1-1.5:5.5-6.

[0019] Preferably, the continuous leaching process in S2 includes primary leaching and secondary leaching, wherein the primary leaching temperature is 60-65°C and the time is 2.5-3h; the secondary leaching temperature is 60-65°C and the time is 2-2.5h.

[0020] Preferably, the leaching agent in the continuous leaching step in S2 is an ammonium chloride solution, the concentration of the ammonium chloride solution is 250-260 g / L, and the solid-liquid ratio of the slurry to the leaching agent is 1-1.5:10-15.

[0021] Preferably, the leaching solution obtained in S2 contains 40-45 g / L Zn, 1-1.5 g / L Pb, 0.2-0.5 g / L Fe, 0.1-0.2 g / L Cd, and NH4 + 75~80g / L.

[0022] Preferably, the amount of lime added in S3 is 1% to 1.5% of the weight of the leachate.

[0023] Preferably, in the electrolysis process in S5, a graphite plate is used as an anode, an aluminum plate is used as a cathode, the current density is 200-450A, the temperature is 40-45°C, and the electrolysis time is 34-36h.

[0024] Preferably, the melting and casting temperature in S6 is 450-550°C.

[0025] Preferably, the solid-liquid separation method used in the above steps is filter press.

[0026] Beneficial effects of the present invention:

[0027] The zinc roasted sand used in the present invention is calcined by placing zinc oxide and zinc-containing waste slag in a rotary kiln. The reaction materials form a flow from the kiln tail (preheating zone, 300-800°C) to the kiln head (reaction zone, 800-1500°C) as the rotary kiln rotates. In the preheating zone, the reaction materials are initially agglomerated due to high humidity to form large particles. In the process of moving to the kiln head, the reaction materials are gradually dehydrated and preheated to 800°C. When the materials reach the reaction zone, chlorides and fluorides in the reaction materials are volatilized at a temperature of 800-1500°C, thereby removing chlorine and fluorine in the zinc roasted sand. Finally, the reaction materials enter a cooling system from a kiln head discharge port, and are ball-milled after cooling to obtain the zinc roasted sand. The zinc roasted sand obtained by the method has been subjected to oxidative roasting, and further provides a wet method for improving the leaching rate of raw zinc in zinc smelting.

[0028] The ball milling used in the present invention is all wet ball milling and is carried out in a completely closed process, so no waste gas and dust are generated during the ball milling process, and the process has good environmental friendliness.

[0029] The present invention uses the electrolytic tail liquid obtained by evaporating and concentrating the electrolyte generated in the electrolysis process as a slurrying agent after wet ball milling. The electrolytic tail liquid is highly acidic and contains a variety of metal ions, among which the zinc ion content is relatively high. If it is directly discharged, it will cause serious pollution to the environment. Therefore, the present invention recycles the electrolytic tail liquid, collects it and uses it as a solvent used in ball milling, and then can be used as a leaching medium with acid in the leaching process, which can not only reduce the amount of acid used in the wet zinc smelting process and reduce costs, but also promote the recovery and utilization of valuable metals in the leached residue and improve economic efficiency.

[0030] The hydrometallurgical zinc smelting process provided by the present invention optimizes the process flow, improves resource recovery rate and economic benefits, has low cost, is suitable for industrial production, and simultaneously obtains a high-quality zinc product with excellent leaching effect and direct recovery rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] Figure 1 The present invention discloses a process flow chart of a hydrometallurgical zinc smelting process. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0034] However, unnecessary detailed descriptions may be omitted. For example, repeated descriptions of well-known matters may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the following description is provided for those skilled in the art to fully understand the present application and is not intended to limit the subject matter described in the claims.

[0035] The zinc roasted sand used in the embodiments and comparative examples of the present invention is prepared by the following steps:

[0036] Subzinc oxide (containing 45% to 65% zinc) and zinc-containing waste slag (containing 30% to 45% zinc) are put into a rotary kiln for calcination reaction. The reaction materials form a flow as the rotary kiln rotates and move from the kiln tail to the kiln head. The rotary kiln is divided into a preheating zone and a reaction zone. The temperature at the kiln tail is in the range of 300 to 800°C (called the preheating zone), and the preheating zone is 10 to 15m long; the temperature at the kiln head is in the range of 800 to 1500°C (called the reaction zone), and the reaction zone is 15 to 20m long. Then the kiln enters the cooling system for cooling and ball milling to obtain zinc roasted sand.

[0037] The present invention provides a hydrometallurgical zinc smelting process, comprising the following steps:

[0038] S1. Ball milling:

[0039] The zinc roasted sand enters the ball milling process, and after being ball milled with clean water, a slurrying agent is added. The slurrying agent is the electrolytic tail liquid obtained by evaporating and concentrating the electrolyte obtained in S5, and the solid-liquid ratio is 1-1.5:5.5-6 to obtain a slurry;

[0040] S2. Continuous leaching:

[0041] The slurry enters the continuous leaching process, the leaching agent is ammonium chloride solution (concentration is 250-260g / L), the solid-liquid ratio of slurry to leaching agent is 1-1.5:10-15, and the leachate is controlled to contain 40-45g / L Zn, 1-1.5g / L Pb, 0.2-0.5g / L Fe, 0.1-0.2g / L Cd, and NH4 + 75~80g / L, adjust the pH value to 5.0~6.0, enter the filter press section, use plate and frame filter press to separate solid and liquid, and obtain leachate and leach residue;

[0042] The above continuous leaching process includes primary leaching and secondary leaching. The temperature of the primary leaching is 60-65°C and the time is 2.5-3 hours. The temperature of the secondary leaching is 60-65°C and the time is 2-2.5 hours. The filter residue obtained after the secondary leaching is returned to the rotary kiln as a raw material for producing zinc roasted sand.

[0043] The basic principle is: zinc roasted sand reacts with ammonium chloride to form zinc ammonium complex, and other trace impurities in the raw materials (lead, copper, cadmium, thallium, etc.) also undergo similar reactions; the main chemical reactions in the leaching section are as follows:

[0044] ZnO+2NH4Cl=Zn(NH3)2Cl2+H2O

[0045] MeO+2NH4Cl=Me(NH3)2Cl2+H2O

[0046] CaO+2NH4Cl=CaCl2+2NH3+H2O

[0047] The pH of the slurry in the leaching section is 5.0-6.0, which is weakly acidic, so the NH3 produced in the leaching section will basically not overflow.

[0048] S3, oxidation removal:

[0049] Ozone is introduced into the leaching solution, and the reaction lasts for 10 to 20 minutes. Lime is added in an amount of 1% to 1.5% of the weight of the leaching solution. The pH value is adjusted to 5.0 to 6.0, and the reaction lasts for 40 to 50 minutes. The leaching solution enters the filter press section for solid-liquid separation to obtain filtrate and filter residue I. The filtrate enters the purification process, and the filter residue I is returned to the roasting workshop as a raw material to produce zinc roasted sand;

[0050] The basic principle is: using oxidants to remove Fe 2+ Oxidized to Fe 3+ , As is oxidized to negatively charged AsO4 3- colloid, and then under alkaline conditions, Fe 3+ The positively charged Fe(OH)3 colloid is formed and co-precipitated with the negatively charged colloid. The oxidation process is mainly to remove iron, arsenic and other substances. The reaction process is as follows:

[0051] 2O 3+ 2Fe 2+ =2Fe 3+ +3O 2-

[0052] [Fe(OH)3] m ·nFe 3+ +nAsO4 3- =m[Fe(OH)3]·nFeAsO4

[0053] S4. Purification:

[0054] The filtrate is reacted in a purifier filled with zinc particles for 35 to 40 minutes to obtain a purified liquid. When the lead, cadmium and copper in the purified liquid are less than 0.005 g / L, 0.002 g / L and 0.002 g / L, the purified liquid enters the filter press section for solid-liquid separation to obtain a pure zinc filtrate and filter residue II.

[0055] The basic principle is: according to the activity of the metal, zinc can replace metal impurities (Cr, Co, Cd, Ni, Sn, Pb, Cu, Hg, Ag, Au) with weaker activity than zinc, thereby removing the relevant metal impurities. The reaction process is as follows:

[0056] Me(NH3)2Cl2+Zn=Me↓+Zn(NH3)2Cl2

[0057] S5. Electrolysis:

[0058] The pure zinc filtrate enters the electrolysis process, using a graphite plate as an anode and an aluminum plate as a cathode, with a current density of 200-450A, a temperature of 40-45°C, and an electrolysis time of 34-36h to obtain zinc flakes and electrolyte; the electrolyte enters the evaporation and concentration process, and is centrifuged to obtain calcium chloride, ammonium chloride and electrolysis tail liquid;

[0059] The basic principle is: under the action of direct current, zinc-ammonium complex decomposes into zinc and ammonium chloride solution, zinc adheres to the aluminum plate, zinc is precipitated at the cathode during electrolysis, and ammonia decomposes at the anode to release nitrogen. Therefore, ammonia water must be used to supplement ammonium and balance acidity during electrolysis.

[0060] Anode reaction: Ammonia decomposition occurs to produce nitrogen gas, and the reaction is as follows:

[0061] 〔(NH3)2Cl2〕 2- =N2↑+6H + +6Cl -

[0062] 6H + +6NH3=6NH4 +

[0063] Cathode reaction:

[0064] 〔Zn(NH3)2〕 2+ +2e=Zn+2NH3

[0065] Overall electrolysis reaction:

[0066] 3〔Zn(NH3)2〕Cl2+2NH3=3Zn+N2↑+6NH4Cl

[0067] S6, Melting and Casting:

[0068] The zinc sheets are placed in a melting and casting furnace for melting and casting at a temperature of 450-550°C, and then cooled to obtain zinc ingots.

[0069] A small amount of zinc slag will be produced on the upper layer of the molten zinc liquid, and smoke will be discharged from the zinc molten electric furnace. The main components are smoke dust (ZnO, ammonium chloride), etc., which are collected by cyclone and bag negative pressure and returned to the continuous leaching section for use.

[0070] Example 1

[0071] A hydrometallurgical zinc smelting process comprises the following steps:

[0072] S1. Ball milling:

[0073] The zinc roasted sand enters the ball milling process, and after being ball milled with clean water, a slurrying agent is added. The slurrying agent is the electrolytic tail liquid obtained by evaporating and concentrating the electrolyte obtained in S5, and the solid-liquid ratio is 1:5.5 to obtain a slurry;

[0074] S2, continuous leaching: the slurry enters the continuous leaching process, the leaching agent is ammonium chloride solution (concentration is 250g / L), the solid-liquid ratio of slurry to leaching agent is 1:10, and the leachate is controlled to contain 40-45g / L Zn, 1-1.5g / L Pb, 0.2-0.5g / L Fe, 0.1-0.2g / L Cd, and NH4 + 75~80g / L, adjust the pH value to 5.0, enter the filter press section, use plate and frame filter press to separate solid and liquid, and obtain leachate and leach residue;

[0075] The above continuous leaching process includes primary leaching and secondary leaching, wherein the primary leaching temperature is 60°C and the time is 2.5 hours; the secondary leaching temperature is 60°C and the time is 2 hours, and the filter residue obtained after the secondary leaching is returned to the rotary kiln as a raw material for producing zinc roasted sand;

[0076] S3, oxidation removal: ozone is introduced into the leachate, reacted for 10 minutes, lime is added, the amount of lime added is 1% of the weight of the leachate, the pH value is adjusted to 5.0, the reaction is carried out for 40 minutes, and the leachate enters the filter press section for solid-liquid separation to obtain filtrate and filter residue I. The filtrate enters the purification process, and the filter residue I is returned to the roasting workshop as a raw material to produce zinc roasted sand;

[0077] S4, purification: the filtrate is reacted in a purifier filled with zinc particles for 35 minutes to obtain a purified liquid. When the lead, cadmium and copper in the purified liquid are less than 0.005g / L, 0.002g / L and 0.002g / L, it enters the filter press section for solid-liquid separation to obtain pure zinc filtrate and filter residue II;

[0078] S5, electrolysis: the pure zinc filtrate enters the electrolysis process, using a graphite plate as an anode and an aluminum plate as a cathode, with a current density of 200A, a temperature of 40°C, and an electrolysis time of 36 hours to obtain zinc flakes and electrolyte; the electrolyte enters the evaporation and concentration process, and is centrifuged to obtain calcium chloride, ammonium chloride and electrolysis tail liquid;

[0079] S6. Melting and casting: Melting and casting the zinc sheets at a temperature of 450° C., cooling, and obtaining zinc ingots.

[0080] Example 2

[0081] The only difference from Example 1 is that the solid-liquid ratio of zinc roasted sand to slurrying agent in step S1 is different:

[0082] S1. Ball milling:

[0083] The zinc roasted sand enters the ball milling process, and after being ball milled with clean water, a slurrying agent is added. The slurrying agent is the electrolytic tail liquid obtained by evaporating and concentrating the electrolyte obtained in S5, and the solid-liquid ratio is 1:6 to obtain a slurry.

[0084] Example 3

[0085] The only difference compared with Example 1 is that the concentration of the ammonium chloride solution in step S2 is different:

[0086] S2, continuous leaching: the slurry enters the continuous leaching process, the leaching agent is ammonium chloride solution (concentration is 260g / L), the solid-liquid ratio of slurry to leaching agent is 1:10, and the leachate is controlled to contain Zn 40-45g / L, Pb 1-1.5g / L, Fe 0.2-0.5g / L, Cd 0.1-0.2g / L, NH4 + 75~80g / L, adjust the pH value to 5.0, enter the filter press section, use plate and frame filter press to separate solid and liquid, and obtain leachate and leach residue;

[0087] The above continuous leaching process includes primary leaching and secondary leaching, wherein the primary leaching temperature is 60°C and the time is 2.5 hours; the secondary leaching temperature is 60°C and the time is 2 hours, and the filter residue obtained after the secondary leaching is returned to the rotary kiln as a raw material for producing zinc roasted sand;

[0088] Example 4

[0089] The only difference from Example 1 is that the solid-liquid ratio of the slurry to the leaching agent in step S2 is different:

[0090] S2, continuous leaching: the slurry enters the continuous leaching process, the leaching agent is ammonium chloride solution (concentration is 250g / L), the solid-liquid ratio of slurry to leaching agent is 1:14, and the leachate is controlled to contain 40-45g / L Zn, 1-1.5g / L Pb, 0.2-0.5g / L Fe, 0.1-0.2g / L Cd, and NH4+ 75~80g / L, adjust the pH value to 5.0, enter the filter press section, use plate and frame filter press to separate solid and liquid, and obtain leachate and leach residue;

[0091] The above continuous leaching process includes primary leaching and secondary leaching, wherein the primary leaching temperature is 60°C and the time is 2.5 hours; the secondary leaching temperature is 60°C and the time is 2 hours, and the filter residue obtained after the secondary leaching is returned to the rotary kiln as a raw material for producing zinc roasted sand;

[0092] Example 5

[0093] The only difference from Example 1 is that the temperature and time of the first leaching and the second leaching in step S2 are different:

[0094] S2, continuous leaching: the slurry enters the continuous leaching process, the leaching agent is ammonium chloride solution (concentration is 250g / L), the solid-liquid ratio of slurry to leaching agent is 1:10, and the leachate is controlled to contain 40-45g / L Zn, 1-1.5g / L Pb, 0.2-0.5g / L Fe, 0.1-0.2g / L Cd, and NH4 + 75~80g / L, adjust the pH value to 5.0, enter the filter press section, use plate and frame filter press to separate solid and liquid, and obtain leachate and leach residue;

[0095] The above-mentioned continuous leaching process includes primary leaching and secondary leaching, wherein the primary leaching temperature is 65°C and the time is 23 hours; the secondary leaching temperature is 60°C and the time is 2.5 hours. The filter residue obtained after the secondary leaching is returned to the rotary kiln as a raw material for producing zinc roasted sand.

[0096] Example 6

[0097] The only difference from Example 1 is that the amount of lime added in step S3 is different:

[0098] S3, oxidation removal: ozone is introduced into the leachate, react for 10 minutes, lime is added, the amount of lime added is 1.3% of the weight of the leachate, the pH value is adjusted to 5.0, the reaction is carried out for 40 minutes, and the leachate enters the filter press section for solid-liquid separation to obtain filtrate and filter residue I. The filtrate enters the purification process, and the filter residue I is returned to the roasting workshop as a raw material for producing zinc roasted sand.

[0099] Example 7

[0100] The only difference from Example 1 is that the current density, temperature and time of electrolysis in step S5 are different:

[0101] S5. Electrolysis: The pure zinc filtrate enters the electrolysis process, using a graphite plate as an anode and an aluminum plate as a cathode, with a current density of 400A, a temperature of 43°C, and an electrolysis time of 35h to obtain zinc flakes and electrolyte; the electrolyte enters the evaporation and concentration process, and is centrifuged to obtain calcium chloride, ammonium chloride and electrolysis tail liquid.

[0102] Example 8

[0103] The only difference from Example 1 is that the melting and casting temperature in step S6 is different:

[0104] S6. Melting and casting: Melting and casting the zinc sheets at a temperature of 550° C., cooling, and obtaining zinc ingots.

[0105] Comparative Example 1

[0106] The only difference from Example 1 is that the solid-liquid ratio of zinc roasted sand to slurrying agent in step S1 is different:

[0107] S1. Ball milling:

[0108] The zinc roasted sand enters the ball milling process, and after being ball milled with clean water, a slurrying agent is added. The slurrying agent is the electrolytic tail liquid obtained by evaporating and concentrating the electrolyte obtained in S5, and the solid-liquid ratio is 1:2 to obtain a slurry.

[0109] Comparative Example 2

[0110] The only difference compared with Example 1 is that the concentration of the ammonium chloride solution in step S2 is different:

[0111] S2, continuous leaching: the slurry enters the continuous leaching process, the leaching agent is ammonium chloride solution (concentration is 235g / L), the solid-liquid ratio of slurry to leaching agent is 1:10, and the leachate is controlled to contain 40-45g / L Zn, 1-1.5g / L Pb, 0.2-0.5g / L Fe, 0.1-0.2g / L Cd, and NH4 + 75~80g / L, adjust the pH value to 5.0, enter the filter press section, use plate and frame filter press to separate solid and liquid, and obtain leachate and leach residue;

[0112] The above-mentioned continuous leaching process includes primary leaching and secondary leaching, wherein the primary leaching temperature is 60°C and the time is 2.5 hours; the secondary leaching temperature is 60°C and the time is 2 hours. The filter residue obtained after the secondary leaching is returned to the rotary kiln as a raw material for producing zinc roasted sand.

[0113] Comparative Example 3

[0114] The only difference from Example 1 is that the solid-liquid ratio of the slurry to the leaching agent in step S2 is different:

[0115] S2, continuous leaching: the slurry enters the continuous leaching process, the leaching agent is ammonium chloride solution (concentration is 250g / L), the solid-liquid ratio of slurry to leaching agent is 1:7, and the leachate is controlled to contain Zn40~45g / L, Pb1~1.5g / L, Fe 0.2~0.5g / L, Cd0.1~0.2g / L, NH4 + 75~80g / L, adjust the pH value to 5.0, enter the filter press section, use plate and frame filter press to separate solid and liquid, and obtain leachate and leach residue;

[0116] The above continuous leaching process includes primary leaching and secondary leaching, wherein the primary leaching temperature is 60°C and the time is 2.5 hours; the secondary leaching temperature is 60°C and the time is 2 hours, and the filter residue obtained after the secondary leaching is returned to the rotary kiln as a raw material for producing zinc roasted sand;

[0117] The difference between Comparative Example 4 and Example 1 is that the temperature and time of the first leaching and the second leaching in step S2 are different:

[0118] S2, continuous leaching: the slurry enters the continuous leaching process, the leaching agent is ammonium chloride solution (concentration is 250g / L), the solid-liquid ratio of slurry to leaching agent is 1:10, and the leachate is controlled to contain 40-45g / L Zn, 1-1.5g / L Pb, 0.2-0.5g / L Fe, 0.1-0.2g / L Cd, and NH4 + 75~80g / L, adjust the pH value to 5.0, enter the filter press section, use plate and frame filter press to separate solid and liquid, and obtain leachate and leach residue;

[0119] The above-mentioned continuous leaching process includes primary leaching and secondary leaching, wherein the primary leaching temperature is 45°C and the time is 2 hours; the secondary leaching temperature is 50°C and the time is 1.5 hours. The filter residue obtained after the secondary leaching is returned to the rotary kiln as a raw material for producing zinc roasted sand.

[0120] Comparative Example 5

[0121] The only difference from Example 1 is that the amount of lime added in step S3 is different:

[0122] S3, oxidation removal: ozone is introduced into the leachate, react for 10 minutes, lime is added, the amount of lime added is 0.75% of the weight of the leachate, the pH value is adjusted to 5.0, the reaction is carried out for 40 minutes, and the leachate enters the filter press section for solid-liquid separation to obtain filtrate and filter residue I. The filtrate enters the purification process, and the filter residue I is returned to the roasting workshop as a raw material for producing zinc roasted sand.

[0123] Comparative Example 6

[0124] The only difference from Example 1 is that the current density, temperature and time of electrolysis in step S5 are different:

[0125] S5. Electrolysis: The pure zinc filtrate enters the electrolysis process, using a graphite plate as an anode and an aluminum plate as a cathode, with a current density of 180A, a temperature of 35°C, and an electrolysis time of 30h to obtain zinc flakes and electrolyte; the electrolyte enters the evaporation and concentration process, and is centrifuged to obtain calcium chloride, ammonium chloride and electrolysis tail liquid.

[0126] Comparative Example 7

[0127] The only difference from Example 1 is that the melting and casting temperature in step S6 is different:

[0128] S6. Melting and casting: Melting and casting the zinc sheets at a temperature of 600° C., cooling, and obtaining zinc ingots.

[0129] The hydrometallurgical zinc smelting processes provided in Examples 1 to 8 and Comparative Examples 1 to 7 were tested to detect the zinc leaching effect and the yield and purity of zinc ingots. The test results are shown in Table 1:

[0130] Table 1

[0131]

[0132] It can be seen from Table 1 that, compared with the hydrometallurgical zinc smelting process provided in Comparative Examples 1-7, the leaching rate, direct recovery rate and purity of zinc obtained in the hydrometallurgical zinc smelting process provided in Examples 1-8 are all higher. It can be seen that the hydrometallurgical zinc smelting process provided in the present invention has excellent zinc leaching rate and high direct recovery rate, and the hydrometallurgical zinc smelting process is simple in process flow, low in cost, and suitable for industrial production.

[0133] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. It should be understood that in various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution, some or all of the steps can be executed in parallel or in sequence, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0134] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0135] Unless otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present application can be combined with each other to form a new technical solution.

[0136] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydrometallurgical zinc smelting process, characterized in that: The following steps are involved: S1. Ball milling: After ball milling, the zinc roasted sand is added with a slurrying agent and stirred evenly to obtain a slurry; S2, continuous leaching: the slurry enters the continuous leaching process, the pH value is adjusted to 5.0-6.0, the solid-liquid separation is carried out, and the leaching liquid and the leaching residue are obtained; S3, oxidative removal: ozone is introduced into the leaching solution, reacted for 10 to 20 minutes, lime is added, the pH value is adjusted to 5.0 to 6.0, reacted for 40 to 50 minutes, solid-liquid separation is performed, and filtrate and residue I are obtained; S4, purification: the filtrate is reacted in a purifier for 35-40 minutes to obtain a purified liquid. When the lead, cadmium and copper in the purified liquid are less than 0.005 g / L, 0.002 g / L and 0.002 g / L, the solid-liquid separation is performed to obtain a pure zinc filtrate and a filter residue II; S5, electrolysis: the pure zinc filtrate enters the electrolysis process to obtain zinc flakes and electrolyte, and the electrolyte enters the evaporation concentration process, centrifugally separates, and obtains calcium chloride, ammonium chloride and electrolysis tail liquid; S6. Melting and casting.

2. A hydrometallurgical zinc smelting process according to claim 1, characterized in that: The preparation steps of zinc roasted sand in S1 are as follows: The secondary zinc oxide and zinc-containing waste slag are put into a rotary kiln for calcination, and then pass through a preheating zone and a reaction zone in sequence, and then are cooled and ball-milled to obtain zinc roasted sand.

3. A hydrometallurgical zinc smelting process according to claim 2, characterized in that: The zinc content of the secondary zinc oxide is 45% to 65%, and the zinc content of the zinc-containing waste slag is 30% to 45%; The temperature of the preheating zone is 300-800°C, and the length of the preheating zone is 10-15m; the temperature of the reaction zone is 800-1500°C, and the length of the reaction zone is 15-20m.

4. A hydrometallurgical zinc smelting process according to claim 1, characterized in that: The slurrying agent in S1 is the electrolytic tail liquid obtained by evaporating and concentrating the electrolyte obtained in S5, and the solid-liquid ratio is 1-1.5:5.5-6.

5. A hydrometallurgical zinc smelting process according to claim 1, characterized in that: The continuous leaching process in S2 includes primary leaching and secondary leaching, wherein the primary leaching temperature is 60-65°C and the time is 2.5-3h; the secondary leaching temperature is 60-65°C and the time is 2-2.5h.

6. A hydrometallurgical zinc smelting process according to claim 1, characterized in that: The leaching agent in the continuous leaching process in S2 is an ammonium chloride solution, the concentration of the ammonium chloride solution is 250-260 g / L, and the solid-liquid ratio of the slurry to the leaching agent is 1-1.5:10-15.

7. A hydrometallurgical zinc smelting process according to claim 1, characterized in that: The leaching solution obtained from S2 contains Zn 40-45g / L, Pb 1-1.5g / L, Fe 0.2-0.5g / L, Cd 0.1-0.2g / L, NH4 + 75~80g / L.

8. A hydrometallurgical zinc smelting process according to claim 1, characterized in that: The amount of lime added to S3 is 1% to 1.5% of the weight of the leachate.

9. A hydrometallurgical zinc smelting process according to claim 1, characterized in that: In the electrolysis process of S5, a graphite plate is used as an anode, an aluminum plate is used as a cathode, the current density is 200-450A, the temperature is 40-45°C, and the electrolysis time is 34-36h.

10. A hydrometallurgical zinc smelting process according to claim 1, characterized in that: The melting and casting temperature in S6 is 450-550°C.

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