Method for recovering scattered metal through cooperation of zinc sulfate solution salting-out purification and application

Abstract

The invention discloses a zinc sulfate solution salting-out deep purification cooperated scattered metal recovery method and application. Belongs to the technical field of zinc hydrometallurgy solution purification. A cooling tower of a zinc electrolysis part is specially used for deep cooling of zinc sulfate purified liquid, a salting-out agent is added to induce calcium and magnesium to be crystallized and separated out, and macromolecular net-shaped coprecipitate is formed. Meanwhile, the coprecipitate'absorbs' part of positive ions and'leaked 'purified particle residues, solid-liquid separation is easy, and the zinc sulfate solution is deeply purified. According to the invention, energy is fully utilized, conventional impurities in the zinc sulfate purified liquid are effectively reduced, and'leaked 'and'muddy' purified residues are removed. And the scattered metal thallium and indium are recovered while the zinc electrolysis power consumption is reduced. The method disclosed by the invention is simple in process technology, easy to realize industrial application and good in economic benefit.

Description

Technical Field

[0001] The invention relates to the technical field of purification of hydrometallurgical zinc solution, and in particular to a method for salting out and purifying a zinc sulfate solution and coordinating the recovery of scattered metals and its application. Background Art

[0002] The global annual output of electrolytic zinc is 10 million tons, of which the wet process produces about 80%. The main steps are: zinc sulfide ore → roasting and desulfurization → zinc roasted ore sulfuric acid leaching → zinc sulfate liquid purification → zinc electrolysis and electrowinning → zinc flake precipitation and casting.

[0003] The core process of wet zinc smelting is: sulfuric acid leaching of zinc roasted ore and purification of zinc sulfate solution. The main method of zinc sulfate solution purification is two-stage purification: 1) zinc powder replacement to remove copper and cadmium; 2) antimony salt or xanthate purification to remove cobalt and nickel. The effect of the two-stage purification is to remove impurities such as Ge, Sb, Cd, Co, Ni in the zinc sulfate solution to trace components (in wet zinc smelting, the quality standard of zinc electrolytic zinc sulfate solution: Ge: ≤0.00001g / L; As / Sb≤0.0001g / L; Co≤0.001g / L; Ni≤0.001g / L; Cd≤0.001g / L). This method has a good purification and impurity removal effect and is the current mainstream purification and impurity removal process, especially the purification process with antimony salt as an additive, which is widely used.

[0004] Although the zinc powder purification process can effectively remove copper, cadmium, cobalt, nickel and other impurities from zinc sulfate solution, it has the disadvantages of lengthy process, low purification efficiency, unstable quality, and overly dispersed purification slag. In addition, since most purification processes use open continuous reaction tanks, and the zinc powder used is fine in particle size and the purification temperature is high, particulate matter, displacement gas and steam are widely and unorganizedly discharged at the operation site, which seriously affects the physical and mental health of operators and causes great safety hazards in enterprises.

[0005] In order to ensure the continuous and stable production of electrolysis, in the actual production process, the purification process using zinc powder replacement is adopted. Due to the effect of the micro-battery equilibrium constant K of the replacement agent, Cd, Ni, Co and other impurities harmful to the zinc electrolysis process are difficult to remove to the milligram level, which limits the depth of purification impurity removal. In addition, due to the limitations of the liquid-solid separation facilities after purification (most of the facilities use plate-frame filter presses), there are often phenomena of liquid running between filter plates, slag running between plates (commonly known as "running muddy") and "leakage" of purification slag in the gaps between fiber cloths in production, and the purification slag is actually the "reaction mixture of the purification replacement agent"; during production, visible suspended matter appears in the purified liquid, which affects the clarity, transparency and quality of the purified liquid. In general, the impurity content of the purified granular slag, such as yellow medicine purification slag: Co: 1%, Cd: 1.5%, Ni: 0.5%. It is very easy to completely dissolve in acidic liquids. In general, it is partially dissolved when pH <4.5. During zinc electrolysis, the acidity of the electrolyte is generally 140-180g / L. In production, the purified granular slag often "runs into muddiness" or "leakages" into the electrolyte along with the purified zinc sulfate solution, and the purified granular slag "re-dissolves" into the electrolyte, causing a sudden increase in the concentration of local impurities in the electrolyte, and causing the concentration of local impurities Co, Ni, and Cd to increase by 100-1000 times, resulting in abnormal precipitation of electrolytic "burning plate" and a sharp increase in electrolytic power consumption. Sometimes it is as high as 3500-3600Kwh / t·Zn, and even electrolytic production cannot be carried out.

[0006] From the perspective of zinc electrolysis development trend, the solution purification depth of existing purification technology will be difficult to meet the future "long cycle, large plate production" production technology and equipment development requirements. From the perspective of resource utilization, the purification and recovery effect of existing purification technology for valuable metals such as Ge, Sb, Cd, and Co is poor and needs to be improved. From the perspective of safe production, existing purification technology is difficult to meet the safety and environmental protection requirements of green smelting.

[0007] How to further improve the quality of zinc sulfate solution, that is, to further reduce the content of impurities such as Ge, Sb, Cd, Co, and Ni, improve the clarity of the solution, and reduce the content of suspended particles ("turbid" and "leaky" purified slag), is a problem that is continuously sought to be improved and solved in the production of hydrometallurgical zinc.

[0008] At present, the main ways to improve purification technology are:

[0009] (1-1) The "As salt + zinc powder" is used to replace the Sb salt purification or xanthate purification technology to remove Co. The cobalt removal effect can be removed to below the milligram level, but highly toxic AsH3 gas will be produced during the replacement process.

[0010] (1-2) Wang Zhenhong, Zhou Yulin and others published a paper titled "Application Research on Arsenic Salt Purification of Cobalt-Nickel Slag Treatment Process", which studied the arsenic salt purification process. The arsenic salt purification process has significant advantages such as high impurity purification depth, high degree of automation, low zinc powder consumption, large purification capacity and low cost. However, the cobalt-nickel slag produced by purification contains a high level of arsenic, which makes it difficult to recover valuable metals, limiting the development of the process.

[0011] (2-1) In order to reduce the redissolution of the replacement slag, a spray air cooling tower is set up after the zinc powder replacement to appropriately reduce the temperature of the purified liquid to prevent the increase of the impurity content Cd and Ge caused by the redissolution of the purified slag. However, it is still unable to better solve the problem of removing the purified particle slag caused by "turbidity" and "leakage" between the plates of the filter machine during the filtration process.

[0012] (2-2) Patent No. CN201010620987.9 discloses a method and device for purifying and removing cadmium by using arsenic salts to prevent cadmium from re-dissolving in a wet zinc smelting process. The method adopts a two-stage cyclone and sedimentation method, which can effectively prevent the re-dissolution of cadmium caused by the circulation of fine particles in the cadmium removal system, thereby ensuring the quality of the liquid after cadmium removal.

[0013] (3-1) It has been reported that physical methods such as activated carbon adsorption, straw medium filtration, ultrasonic oscillation, or setting up large storage tanks to store the purified liquid, and natural cooling and clarification are used to improve the clarity of the purified liquid, which has a certain effect on removing purification residues.

[0014] (3-2) Patent No. CN201310709812.9 provides a novel wet zinc smelting solution purification process, in which a novel impurity remover activated carbon is added to the purified liquid after conventional solution purification and filtration. Compared with the traditional solution purification process, the organic matter content in the purified liquid is reduced by more than 60%, and the content of turbid fine particles, calcium and magnesium crystals is reduced by more than 80%, thereby achieving the purpose of improving the solution quality.

[0015] (4-1) Add a Ca and Mg removal process to the purified liquid, that is, add a cooling tower to the purified liquid to reduce the temperature of the purified liquid to 55-50°C, so that MgSO4 and CaSO4 can be crystallized and precipitated to achieve the effect of removing Mg and Ca. Due to the lack of introduced crystal seeds and the low temperature drop depth, only calcium and magnesium can be removed to a certain extent, and the adsorption removal effect on other conventional impurities (Ge, Ni, Cd, Co) and purified slag is not obvious.

[0016] (4-2) Patent No. CN202111655537.8 provides a method for treating calcium and magnesium in a wet zinc smelting process. The method is to cool the purified liquid containing calcium and magnesium obtained in the wet zinc smelting process to obtain a cooling liquid containing calcium and magnesium crystals, and then concentrate the cooling liquid containing calcium and magnesium crystals to obtain a supernatant and a calcium and magnesium underflow. This method is simple in process and can effectively solve the problem of high calcium and magnesium concentrations in the wet zinc smelting system.

[0017] (4-3) Journal of Central South University, Vol. 54, No. 2, Wang Yunyan, "Morphology Analysis and Deep Treatment Technology of Thallium-Containing Lead-Zinc Wastewater", prepared MnO2 and Fe3O4@PB adsorbents, and achieved a 95% removal rate of thallium in wastewater.

[0018] Therefore, providing a method and application of salting out and purifying zinc sulfate solution to synergistically recover rare metals is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0019] In view of this, the present invention provides a method for deep purification of zinc sulfate solution by salting out and coordinated recovery of scattered metals, which can not only effectively remove conventional impurities and "muddy" and "leaky" purification slag in the zinc sulfate solution, but also realize the recovery of scattered metals thallium and indium, thereby achieving both environmental and economic benefits.

[0020] To achieve the above object, the present invention adopts the following technical solution:

[0021] A method for salting out and purifying a zinc sulfate solution and recovering scattered metals in a coordinated manner comprises the following steps:

[0022] (1) During zinc electrolysis, part of the air cooling tower used for zinc electrolysis is used exclusively for deep cooling of the purified zinc sulfate liquid, and the purified zinc sulfate liquid is cooled by the air cooling tower;

[0023] (2) When the temperature drops, a salting-out agent is added, and the salting-out agent produces salting-out crystal seeds, which induce the calcium and magnesium ions in the zinc sulfate purified liquid to be at saturated concentrations as the temperature drops, and continuously produce salting-out precipitates; the salting-out agent is connected to the inlet of the cooling tower liquid lifting and delivery pump through the outlet of the dispensing tank, and is mixed with the zinc sulfate liquid in the pump cavity, producing a cavitation oxidation effect;

[0024] (3) The organic functional groups in the salting-out crystal seeds and the molecules of the salting-out precipitate produced produce a stable network macromolecular coprecipitate through coordination, chain bridge and chelation; the network macromolecular coprecipitate absorbs other metal cations in the zinc sulfate purified liquid into the precipitate, and then purifies and removes Ge in the purified liquid. 4+ 、Ni + 、Co 3+ / + 、Cd 2+The precipitate is graded by inclined plate cone (diameter 9-15m) and box filter press (liquid pressure 3-5kg / cm 2 ) to separate the reticular macromolecular coprecipitate and the zinc sulfate purified liquid.

[0025] After cooling, the zinc sulfate liquid is concentrated into the "integrated liquid-solid sedimentation classifier" equipped with inclined plate sedimentation and cone classification. The supernatant of the classifier is the zinc sulfate solution after deep purification by salting out, and then directly enters the zinc electrolysis process. After the bottom flow liquid is filtered by the plate and frame filter press, the residue is used for the comprehensive recovery of scattered metal thallium and indium.

[0026] The present invention does not require additional cooling tower equipment and process energy consumption; the cooling tower is configured by migrating 30% of the cooling towers in the zinc electrolysis process, independently configured, and dedicated to cooling the purified liquid, thereby achieving deep cooling of the purified liquid and still meeting the normal control of the electrolyte temperature of 38-40°C in the zinc electrolysis process.

[0027] Furthermore, the temperature is lowered from 75-82° C. to 30-35° C. This can ensure that the electrolyte temperature of zinc electrolysis is controlled at 38-40° C.

[0028] Furthermore, when the temperature drops, as Ca 2+ / Mg 2+ The ions are precipitated, the pH value of the solution decreases, and the solution becomes slightly acidic; to prevent the precipitate from dissolving back, lime water is added to control the pH value of the solution after the cooling end point zinc sulfate purification to 4.8-5.0; the mass concentration of the lime water is 20-30%.

[0029] Further, when used for wet electrolytic zinc production, in order to strengthen the agglomeration effect of the network macromolecules, ferrous sulfate is added, and under the action of a strong oxidant (potassium permanganate), a trivalent iron precipitate is produced, whose structure is similar to the network molecular structure. In order to increase the efficiency of the van der Waals force of mutual attraction between molecules, aluminum acetate is introduced to produce macromolecular precipitates of PbSO4 and Tl(COOH)3 to strengthen the agglomeration, precipitation and separation effect of the precipitate. Therefore, the salting-out agent is composed of the following mass percentages as raw materials: potassium permanganate or manganese dioxide 5-20%, ferrous sulfate 15-45%, lead acetate 40-70%; it is harmless to the zinc electrolysis process.

[0030] Furthermore, when zinc salts (such as zinc sulfate monohydrate, zinc sulfate heptahydrate, commercial-grade zinc oxide, etc.) are produced, the influence of the metal Mn element on the quality of the zinc salt product is considered, and the oxidant used is hydrogen peroxide; the salting-out agent is composed of the following raw materials in percentage by mass: 20-30% hydrogen peroxide, 15-35% ferrous sulfate, and 45-75% lead acetate.

[0031] Furthermore, the preparation method of the salting-out agent is: weighing each raw material according to its composition percentage, then taking lead acetate as the base material, adding the remaining raw materials while stirring, and mixing evenly to obtain the salting-out agent.

[0032] The method of using the salting-out agent is: connect the outlet pipe of the container containing the salting-out agent to the inlet of the input pump, so that the salting-out agent and the purified zinc sulfate liquid are mixed in the pump cavity of the input pump, thereby obtaining a stronger oxidation effect.

[0033] The present invention adopts the method of salting out crystal seeds by constructing, and using zinc sulfate to purify the Mg in the liquid. 2+ , Ca 2+ At a relatively saturated concentration, as the temperature decreases, the KSP of MgSO4 and CaSO4 decreases, and the salting out of seeds further induces the precipitation of MgSO4 and CaSO4.

[0034] The salting-out crystal seeds have the characteristics of macromolecular elements and organic functional groups (methyl, hydroxyl) groups. Organic functional groups can be realized in sulfated elements. Through coordination, linkage and chelation, salting-out crystal seeds are produced and macromolecular network co-precipitates are formed with calcium and magnesium precipitation. The dissolved components of the introduced salting-out agent must be harmless to the zinc electrolysis production process.

[0035] The resulting macromolecular network precipitate has the ability to purify "partial cations" (Ge 4+ 、Cd 2+ 、Co + / Co 3+ 、Ni + ) and the effect of "purifying slag"; while taking into account the scattered metal TL + / TL 3+ 、In 3+ Recovery; to achieve the effect of removing impurities from the purified zinc sulfate liquid and removing the purified particle slag.

[0036] To ensure Mg 2+ , Ca 2+ The precipitation reaction continues, and the salting agent is added while achieving a deep temperature drop of ΔT = 30-40°C and a final temperature T < 30°C. The pH value is controlled at 4.8-5.0 during the process. The salting agent produces salting precipitation seeds Fe(OH)3 and PbSO4, which further induces Mg 2+ , Ca 2+ MgSO4 and CaSO4 precipitates are generated. At the same time, under the action of organic functional groups (hydroxyl groups), the molecules of the precipitates form a network coprecipitate of macromolecular elements through coordination, bridging and chelation. The reaction formula is:

[0037] (1) Calcium and magnesium precipitation reaction:

[0038] Mg 2+ +SO4 2-=MgSO4↓

[0039] Ca 2+ +SO4 2- =CaSO4↓

[0040] (2) Oxidation reaction of iron and thallium (indium):

[0041] (2-1) Oxidation reaction of potassium permanganate or manganese dioxide:

[0042] 2Fe 2+ +MnO 4- +4H + =2Fe 3+ +MnO2+2H2O

[0043] 2Fe 2+ +MnO2+4H + =2Fe 3+ +Mn 2+ +2H2O

[0044] 3TL + (In + )+2MnO 4- +8H + =3TL 3+ (In 3+ )+2MnO2↓+4H2O

[0045] TL + (In + )+MnO2+4H + =TL 3+ (In 3+ )+Mn 2+ +2H2O

[0046] (2-2) Oxidation reaction of hydrogen peroxide:

[0047] 2Fe 2+ +H2O2+2H + =2Fe 3+ +2H2O

[0048] TL + (In + )+H2O2+2H + =TL 3+ (In 3+ )+2H2O

[0049] (2-3) Air oxidation reaction:

[0050] 2Fe 2+ +O2+4H + =2Fe 3+ +2H2O

[0051] 2TL + (In + )+O2+4H + =2TL 3+ (In 3+ )+2H2O

[0052] (3) Precipitation reaction:

[0053] Fe 3+ +3OH - =Fe(OH)3↓

[0054] TL 3+ (In 3+ )+3OH - =TL(OH)3↓(In(OH)3↓)

[0055] 3Pb(COOH)2+Tl2(SO4)3=3PbSO4↓+2Tl(COOH)3↓

[0056] 3Pb(COOH)2+In2(SO4)3=3PbSO4↓+2In(COOH)3↓

[0057] The coprecipitates are macromolecular element network coprecipitates of Fe(OH)3, PbSO4, MgSO4 / CaSO4, Tl(COOH)3 / In(COOH)3, and Tl(OH)3 / In(OH)3. Fe(OH)3 is a colloidal particle with a network structure, and PbSO4 and Tl(COOH)3 are both crystal nuclei with large molecular weight. Macromolecular element network coprecipitates are formed between the molecules of the coprecipitates. Under the action of the van der Waals force field, some metal cations (Ge 4+ 、Cd 2+ 、Ni + 、Co + / Co 3+ ) and "leaking" and "turbid" purification slag particles are "retained" and purified and removed.

[0058] Among them, "occlusion" means that when the crystal grows very fast, the impurities adsorbed on the surface of the crystal do not have time to leave the crystal surface and are included in the crystal, which is called "occlusion". Unlike mechanical inclusions, the impurities "occluded" cannot be removed by washing.

[0059] Setting and condition control of salting-out purification reactor:

[0060] The principles for selecting salting-out reactors are as follows:

[0061] (1) Cooling equipment that evaporates water and takes away the latent heat of vaporization to reduce Mg 2+ / Ca 2+ The final temperature is determined by the fact that under acidic conditions, the solubility of calcium sulfate is lowest at 29°C, so the deep cooling to 28-30°C is determined.

[0062] (2) Satisfy the requirements of blast oxidation Fe 2+ →Fe 3+ , producing Fe(OH)3 precipitate.

[0063] (3) After evaporation of water, Mg is relatively increased 2+ , Ca 2+ Saturated concentration promotes the precipitation of MgSO4 and CaSO4.

[0064] (4) The salting-out agent is added by sucking it into the pump cavity, which produces cavitation oxidation and forms a reaction effect of cavitation activation of the salting-out agent.

[0065] An industrial spray air cooling tower is selected as the salting-out reactor.

[0066] Configuration of spray air cooling tower:

[0067] Determination of the number of cooling tower sets:

[0068] The zinc electrolysis process of hydrometallurgy is an exothermic reaction, and its reaction formula is:

[0069] Zinc electrolytic electrowinning reaction formula:

[0070] Cathode: Zn 2+ +2e=Zn↓

[0071] 2H + +2e=H2↑(when impurities exist)

[0072] Anode: 2OH - -2e=H2O+0.5O2↑

[0073] Overall reaction formula:

[0074]

[0075] Where Q1=240*10 3 KJ / h·t·Zn

[0076] Zinc electrolysis process condition control requirements: electrolyte temperature is controlled at 38-40℃.

[0077] During the design, the heat balance calculation for the zinc electrolysis process refers to the following heat balance calculation.

[0078] Calculation of heat balance: converted per ton of zinc,

[0079] Income item: Total calories per ton of zinc is (340-360)*10 3 KJ / h; of which:

[0080] (1) Heat generated during electrolysis: Q1 = 240*10 3 KJ / h, accounting for 70%;

[0081] (2) Heat brought in by the purified zinc sulfate solution: Q2 = 100*10 3 KJ / h, accounting for 30%.

[0082] (0057) Expenditure item: The heat expenditure per ton of zinc is as follows:

[0083] Electrolyte discharged and taken away: (75-80)*10 3 KJ / h, accounting for 23-25%;

[0084] Thermal evaporation from the electrolyte surface: (70-76)*10 3 KJ / h, accounting for 21-23%;

[0085] Other heat loss: (10-12)*10 3 KJ / h, accounting for 3-4%;

[0086] Residual heat: (172-174)*10 3 KJ / h, accounting for 50%.

[0087] The zinc electrolyte and the purified liquid (new electrolyte) are first converging and then cooled. The converging and cooling of the new liquid is: the purified liquid is directly added to the electrolyte to replenish the consumed zinc. The acidity of the electrolyte is generally 140-170g / L; the temperature is controlled at 38-40℃. The temperature control of the electrolyte mostly adopts a spray air cooling tower, which circulates and cools the electrolyte outside the electrolytic cell to remove excess heat.

[0088] Among the cooling towers configured in the zinc electrolysis process, 70% are used for process temperature control Q1 of the electrolysis process, and 30% are used for cooling the purified liquid Q2.

[0089] Furthermore, the volume ratio of the purified zinc sulfate solution to the salting-out agent is 1:0.003-0.005.

[0090] Furthermore, in step (3), the diameter of the inclined plate cone is 9-15m, and the liquid feed pressure of the box filter press is 3-5kg / cm 2

[0091] In the production of hydrometallurgical zinc, the mainstream process is: zinc sulfide ore → roasting desulfurization → high-acid leaching of zinc roasted sand → purification of zinc sulfate liquid → zinc electrolytic electrowinning → zinc sheet casting. During the process, the process temperature rises from leaching to purification, and the leaching temperature is 60-65℃; the final temperature of antimony salt purification is 80-85℃, the acidity of sulfuric acid gradually decreases, the pH of the leaching process is 2.5-5.0, and the pH value of the purified liquid is generally 5.0-5.2.

[0092] During the high-temperature and high-acid leaching process, there are a lot of gangue components in the zinc ore. During the leaching and purification process, as the temperature and acidity change, the Ca / Mg in the zinc sulfate solution will produce MgSO4 / CaSO4 dissolution and precipitation, making Mg 2+ , Ca 2+ In a relatively saturated concentration state.

[0093] On the other hand, the purified granular slag completely dissolves at a pH value < 4.5, releasing impurities in the purified slag, resulting in an increase in the impurity content of the solution.

[0094] In general, the impurity content in the purification slag (particulate matter) is, for example, 1% for xanthate purification slag Co, 5% for cadmium purification slag, and 0.5% for Ni. The re-dissolution or re-dissolution of the purification slag has a great influence on the quality of the purified zinc sulfate liquid, especially the purification slag in the turbidity (liquid) between the plates of the filter press and the fine particles of purification slag "leaked" in the gaps between the plate and frame fiber cloth in the purified liquid. If they are mixed into the purified liquid and cannot be effectively removed, they will directly enter the electrolysis process, which will seriously affect the normal production of the electrolysis process. In actual production, due to the limitations of solid-liquid separation equipment, "turbid" and "leaky" purification granular slag are often found in the purified liquid. When the purification slag enters the electrolysis production in excess or excessive accumulation, the electrolysis "burns the plate", causing the cathode to precipitate zinc flakes abnormally and "re-dissolve", or even fall off, resulting in the power consumption of electrolytic zinc as high as 3500Kwh / t·Zn, or even higher. (During normal production, power consumption: 3000KWh / t·Zn.)

[0095] The present invention also provides the application of the above-mentioned method for salting out and purifying zinc sulfate solution and coordinating the recovery of scattered metals in the recovery of metallic thallium and metallic indium.

[0096] The present invention also provides a method for the above-mentioned zinc sulfate solution salting out purification and coordinated recovery of scattered metals to induce the removal of Mg in the zinc sulfate solution. 2+ and Ca 2+ Application in.

[0097] The beneficial effects of the present invention include at least:

[0098] The method of the invention makes the electrolyte cleaner. Under the condition of deep cooling, the solution temperature is less than 30°C, and the zinc sulfate purified solution has been deeply purified and processed before entering the electrolysis.

[0099] (1) The present invention deeply removes Mg 2+ , Ca 2+ , reducing the density and viscosity of the electrolyte, reducing the electrolyte resistance, reducing the electrolytic cell voltage and power consumption. It is beneficial to the control of the electrolytic cell voltage.

[0100] (2) The salting-out agent (a mixture of FeSO4, Pb(COOH)2 and KMnO4 or MnO2) prepared in the present invention produces a "retention effect" of the macromolecular element network coprecipitate produced by salting-out, which deeply purifies the conventional impurities (Ge 4 + 、Cd 2+ 、Ni + 、Co + / Co 3+ ) content is significantly reduced, and the purified granular slag caused by "leakage" and "turbidity" is effectively removed.

[0101] (3) The present invention realizes the comprehensive recovery of scattered elements (Tl, In).

[0102] (4) The macromolecular element network coprecipitate produced in the present invention has stable crystal form and is easy to separate into solid and liquid.

[0103] (5) The optimally configured salting-out reactor of the present invention does not increase investment and process energy consumption. The method of the present invention can reduce the power consumption of industrial zinc electrolysis by 50-100 KWh / t·Zn, and has good industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0104] Figure 1 It is a schematic diagram of the process flow of the present invention.

[0105] Figure 2 The equipment structure connection diagram of the method of the present invention is composed in the order of pump cavity cavitation mixing - air cooling tower - inclined plate cone classification - underflow filter press to form an integrated salting out reactor;

[0106] Figure 3 Connection diagram of main process equipment for conventional industrial production of zinc electrolysis;

[0107] In the attached Figure 3 Among them, 1-homogenizing tank; 2-transporting pump (cavitation mixing pump); 3-air cooling tower; 4-inclined plate cone classifier; 5-sludge pump; 6-filter press.

[0108] Figure 4 This is an experimental diagram for zinc electrolysis application;

[0109] In the attached Figure 4In the figure, 1-high-level tank; 2-small zinc electrolytic cell; 3-anode; 4-cathode; 5-liquid collecting tank; 6-liquid supply pump; 7-conductive bar; 8-insulating board; 9-multi-function meter. DETAILED DESCRIPTION

[0110] The following will combine the drawings in the embodiments of the present invention to simulate the experiment, clearly and completely describe the technical solution in the embodiments of the present invention, and conduct relevant practical application experiments to verify. Figure 4 (Zinc electrolysis application experiment). Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0111] Example 1

[0112] (1) Take 50 ml of the purified liquid and determine its composition: Mg: 15 g / L, Ge: 0.0005 g / L, Ni: 0.001 g / L, Co: 0.001 g / L, Tl: 0.0005 g / L, In: 0.10 g / L, Cd: 0.001 g / L, Sb: 0.0005 g / L. Put it in a 100 ml beaker and measure its temperature to be 81°C.

[0113] (2) Blow air into the beaker and add Ca(OH)2 dropwise while stirring in the beaker, control the pH value to 5.0, and cool to 40°C. After standing for 1 hour, vacuum filter and collect the obtained filtrate and filter residue. The composition of the obtained filtrate is: Ge: 0.0001g / L, Ni: 0.001g / L, Co: 0.0008g / L, Tl: 0.0003g / L, In: 0.08g / L, Cd: 0.0009g / L, Sb: 0.0002g / L, Mg: 10.5g / L.

[0114] Calculated Mg removal rate: 30%, conventional impurity removal rate: 10-12%.

[0115] Further zinc electrolysis application experiments were carried out, and the device and condition control are shown in Figure 4.

[0116] Table 1: Application effect verification of zinc electrolysis

[0117]

[0118] Example 2

[0119] (1) Take 50 ml of the purified liquid and determine its composition: Mg: 15 g / L, Ge: 0.0005 g / L, Ni: 0.001 g / L, Co: 0.001 g / L, Tl: 0.0005 g / L, In: 0.10 g / L, Cd: 0.0018 g / L, Sb: 0.0005 g / L. Put it in a 100 ml beaker and measure its temperature to be 81°C.

[0120] (2) Blow air into the beaker and drop Ca(OH)2 and Pb(COOH)2 into the beaker, control the pH end point to 5.0, and cool down to 40°C. After standing for 1 hour, extract the supernatant without filtering, and detect and analyze the components of the supernatant: Ge: 0.0004g / L, Ni: 0.0005g / L, Co: 0.0006g / L, Tl: 0.0003g / L, In: 0.045g / L, Cd: 0.0013g / L, Sb: 0.0003g / L, Mg: 7.5g / L.

[0121] Calculated Mg removal rate: 50%, conventional impurity removal rate is affected by the clarity of the solution and fluctuates, removal rate: 20-55%.

[0122] Example 3

[0123] (1) Take 50 ml of the purified liquid and determine its composition: Mg: 15 g / L, Ge: 0.0005 g / L, Ni: 0.001 g / L, Co: 0.001 g / L, Tl: 0.0005 g / L, In: 0.10 g / L, Cd: 0.001 g / L, Sb: 0.0005 g / L. Put it in a 100 ml beaker and measure its temperature to be 82 °C.

[0124] (2) Blow air into the beaker and add Ca(OH)2 and FeSO4 dropwise while stirring. The pH endpoint is controlled at 5.0 and the mixture is cooled to 40°C. After standing for 1 hour, vacuum filter and collect the obtained filtrate and residue. The components of the obtained filtrate are as follows: Ge: 0.0003 g / L, Ni: 0.0006 g / L, Co: 0.0005 g / L, Tl: 0.00006 g / L, In: 0.03 g / L, Cd: 0.0006 g / L, Sb: 0.00029 g / L, Mg: 5.25 g / L.

[0125] The technical Mg removal rate is 65%, and the conventional impurity removal rate fluctuates, with a removal rate of 30-70%.

[0126] Example 4

[0127] (1) Take 50 ml of the purified liquid and determine its composition: Mg: 15 g / L, Ge: 0.0005 g / L, Ni: 0.001 g / L, Co: 0.001 g / L, Tl: 0.0005 g / L, In: 0.10 g / L, Cd: 0.001 g / L, Sb: 0.0005 g / L. Put it in a 100 ml beaker and measure its temperature to be 81°C.

[0128] (2) Blow air into the beaker and add Ca(OH)2 and salting-out agent (FeSO4 / Pb(COOH)2 / KMnO4) dropwise while stirring. The amount of salting-out agent added is 0.3‰ (volume ratio). The pH end point is controlled to be 5.0 and the temperature is cooled to 40°C. After standing for 1 hour, vacuum filter and collect the obtained filtrate and residue. The obtained filtrate contains: Ge: 0.00001g / L, Ni: 0.0004g / L, Co: 0.0001g / L, Tl: 0.00001g / L, In: 0.003g / L, Cd: 0.0001g / L, Sb: 0.0001g / L, Mg: 2.89g / L.

[0129] The calculated purification efficiency exceeds 90%, and the removal and enrichment effects of scattered elements (Tl, In) are good, which is conducive to the comprehensive recovery in the next step.

[0130] Table 2 Comparison of salting-out purification efficiency of different component additives in Examples 1-4

[0131]

[0132] It can be seen from Table 1 that the effects of adding FeSO4 and Pb(COOH)2 simultaneously are better than the effects of adding FeSO4 or Pb(COOH)2 alone, and the purification efficiency is significantly improved by adding the salting-out agent of the present invention, and the solution is clear.

[0133] Example 5

[0134] (1) Take 50 ml of the purified liquid and determine its composition: Mg: 16 g / L, Ge: 0.0005 g / L, Ni: 0.002 g / L, Co: 0.002 g / L, Tl: 0.0018 g / L, In: 0.11 g / L, Cd: 0.002 g / L, Sb: 0.00038 g / L. Put it in a 100 ml beaker and measure its temperature to be 83 °C.

[0135] (2) Blow air into the beaker and add Ca(OH) dropwise while stirring. 2、Salting-out agent (FeSO4 / Pb(COOH)2 / KMnO4), amount of salting-out agent added: 0.3‰ (volume ratio), control the pH end point value to 4.8, and cool to 40°C. After standing for 1.5 hours, vacuum filter and collect the obtained filtrate and residue. The obtained filtrate contains: Ge: 0.00001g / L, Ni: 0.0002g / L, Co: 0.0002g / L, Tl: 0.00001g / L, In: 0.004g / L, Cd: 0.0005g / L, Sb: 0.00005g / L, Mg: 2.28g / L.

[0136] The calculated purification efficiency is over 90%, the removal and enrichment effects of scattered elements (Tl, In) are good, which is beneficial to the comprehensive recovery in the next step, and the solution is clear.

[0137] Example 6

[0138] (1) Take 50 ml of the purified liquid and determine its composition: Mg: 12 g / L, Ge: 0.0005 g / L, Ni: 0.002 g / L, Co: 0.002 g / L, Tl: 0.0017 g / L, In: 0.11 g / L, Cd: 0.002 g / L, Sb: 0.00035 g / L. Put it in a 100 ml beaker and measure its temperature to be 82°C.

[0139] (2) Blow air into the beaker and add Ca(OH)2 and salting-out agent (FeSO4 / Pb(COOH)2 / KMnO4) dropwise into the beaker while stirring. The amount of salting-out agent added is 0.5‰ (volume ratio). The pH end point is controlled to be 4.8 and the temperature is cooled to 35°C. After standing for 1.5 hours, vacuum filter and collect the obtained filtrate and residue. The obtained filtrate contains: Ge: 0.00001g / L, Ni: 0.00015g / L, Co: 0.0003g / L, Tl: 0.00001g / L, In: 0.003g / L, Cd: 0.00034g / L, Sb: 0.00004g / L, Mg: 2.08g / L.

[0140] The calculated purification efficiency exceeds 90%, and the removal and enrichment effects of scattered elements (Tl, In) are good, which is conducive to the comprehensive recovery in the next step.

[0141] Example 7

[0142] (1) Take 50 ml of the purified liquid and determine its composition: Mg: 14 g / L, Ge: 0.0005 g / L, Ni: 0.002 g / L, Co: 0.0024 g / L, Tl: 0.0021 g / L, In: 0.11 g / L, Cd: 0.0023 g / L, Sb: 0.00035 g / L; in a 100 ml beaker, measure its temperature to be 82 °C.

[0143] (2) Blow air into the beaker and add Ca(OH)2 and salting-out agent (FeSO4 / Pb(COOH)2 / KMnO4) dropwise into the beaker while stirring. The amount of salting-out agent added is 0.3‰ (volume ratio). The pH end point is controlled to be 5.0 and the temperature is cooled to 30°C. After standing for 1.5 hours, vacuum filter and collect the obtained filtrate and residue. The obtained filtrate contains: Ge: 0.00001g / L, Ni: 0.001g / L, Co: 0.0003g / L, Tl: 0.00001g / L, In: 0.003g / L, Cd: 0.0003g / L, Sb: 0.0003g / L, Mg: 2.30g / L.

[0144] The calculated purification efficiency is over 90%, the removal and enrichment effects of scattered elements (Tl, In) are good, which is beneficial to the comprehensive recovery in the next step, and the solution is clear.

[0145] Example 8

[0146] (1) Take 50 ml of the purified liquid and determine its composition: Mg: 2.7 g / L, Ge: 0.0005 g / L, Ni: 0.002 g / L, Co: 0.0024 g / L, Tl: 0.0021 g / L, In: 0.11 g / L, Cd: 0.0023 g / L, Sb: 0.00035 g / L. Put it in a 100 ml beaker and measure its temperature to be 82°C.

[0147] (2) Blow air into the beaker and add Ca(OH)2 and salting-out agent (FeSO4 / Pb(COOH)2 / KMnO4) dropwise into the beaker while stirring. The amount of salting-out agent added is 0.5‰ (volume ratio). The pH end point is controlled to be 4.8 and the temperature is cooled to 25°C. After standing for 1.5 hours, vacuum filter and collect the obtained filtrate and residue. The obtained filtrate contains: Ge: 0.00001g / L, Ni: 0.001g / L, Co: 0.0003g / L, Tl: 0.00001g / L, In: 0.003g / L, Cd: 0.0003g / L, Sb: 0.00032g / L, Mg: 2.7g / L.

[0148] The calculated purification efficiency is over 90%, the removal and enrichment effects of scattered elements (Tl, In) are good, which is beneficial to the comprehensive recovery in the next step, and the solution is clear.

[0149] The obtained solution was further subjected to zinc electrolysis verification test, and the device and condition control are shown in Figure 4.

[0150] Zinc electrolysis industrial application effect verification parameters:

[0151] Cell voltage: 3.21-3.22V, power efficiency: 89.1%, power consumption: 2945KWh / t·Zn

[0152] The summary of the effect parameters verified by simulation experiments and application experiments is shown in Table 3.

[0153] Table 3: Effect parameters of simulation experiment and application verification test

[0154]

[0155]

[0156] Combining the data in the table, we can see that: 1. The drop in cell voltage is Mg 2+ 2. Ge which has a great influence on the electrolytic efficiency of zinc 4+ 、Co + / Co 3+ The deep removal of metal elements such as Ni improves the electrical efficiency. Therefore, the decrease in cell voltage and the improvement in electrical efficiency significantly reduce the power consumption of zinc electrolysis.

[0157] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for salting out and purifying zinc sulfate solution and recovering scattered metals, characterized in that: The following steps are involved: (1) During the zinc electrolysis process, part of the air cooling tower used for zinc electrolysis is used exclusively for cooling the purified zinc sulfate liquid, and the purified zinc sulfate liquid is cooled by the air cooling tower; (2) When the temperature drops, a salting-out agent is added, and the salting-out agent produces salting-out seeds, which induce the calcium and magnesium ions in the zinc sulfate purified liquid to be at saturated concentrations, and the salting-out precipitate is continuously produced as the temperature drops; (3) The organic functional groups in the salting-out crystal seeds and the molecules of the generated salting-out precipitates produce stable network macromolecular co-precipitates through coordination, chain bridges and chelation; the network macromolecular co-precipitates absorb other metal cations in the zinc sulfate purified liquid into the precipitate, and then purify and remove the metal cations in the purified liquid. The precipitate is separated from the network macromolecular co-precipitate and the zinc sulfate cooled liquid by using an inclined plate cone grading and a box filter press.

2. The method for salting out and purifying zinc sulfate solution and recovering scattered metals according to claim 1, characterized in that: The cooling in step (1) is from 75-82°C to 30-35°C.

3. The method for salting out and purifying zinc sulfate solution and recovering scattered metals according to claim 2, characterized in that: When cooling, lime water is added to control the pH of the zinc sulfate purified solution at the cooling end point to be 4.8-5.0; The mass concentration of the lime water is 20-30%.

4. The method for salting out and purifying zinc sulfate solution and recovering scattered metals according to claim 1, characterized in that: In wet electrolytic zinc production, the salting-out agent is composed of the following raw materials in percentage by mass: 5-20% potassium permanganate or manganese dioxide, 15-45% ferrous sulfate, and 40-70% lead acetate; When zinc salts are produced, the salting-out agent is composed of the following raw materials in percentage by mass: 20-30% hydrogen peroxide, 15-35% ferrous sulfate, and 45-75% lead acetate.

5. The method for salting out and purifying zinc sulfate solution and recovering scattered metals according to claim 4, characterized in that: The preparation method of the salting-out agent is as follows: weighing various raw materials according to their composition percentages, then taking lead acetate as a base material, adding the remaining raw materials while stirring, and mixing evenly to obtain the salting-out agent.

6. The method for salting out and purifying zinc sulfate solution and recovering rare metals according to claim 1 or 4, characterized in that: The volume ratio of the purified zinc sulfate solution to the salting-out agent is 1:0.003-0.

005.

7. The method for salting out and purifying zinc sulfate solution and recovering scattered metals according to claim 1, characterized in that: The diameter of the inclined plate cone in step (3) is 9-15m, and the liquid feed pressure of the box filter press is 3-5kg / cm 2 .

8. Use of the method for salting out and purifying zinc sulfate solution and recovering rare metals according to any one of claims 1 to 7 in recovering metallic thallium and metallic indium.

9. A method for salting out and purifying zinc sulfate solution and recovering rare metals according to any one of claims 1 to 7, wherein Mg in the zinc sulfate solution is induced to be removed. 2+ and Ca 2+ Application in.

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