阅读说明：本技术 一种组合式长期稳定运行的氯化铵法电解锌工艺流程 (Combined type zinc electrolysis process flow with long-term stable operation by ammonium chloride method ) 是由 彭勃 罗彦 于 2019-11-12 设计创作，主要内容包括：本发明提供一种组合式长期稳定运行的氯化铵法电解锌工艺流程,包括浸出、净化、电解主流程和超杂质原料循环粗洗涤、过量钙镁沉淀、氧化杂质过滤辅助流程,两个流程并行布置和连接,可独立工作,互不影响。本发明通过主辅流程的配合,以全流程、控温、紧凑并串布局、多工段、同步/异步和多种手段,控制电解液质量的稳定、解决复杂原料带来的多元素干扰,特别是氯化铵法电解锌长周期稳定高效运行的难题,对氨法处理高氟氯、高杂质含锌原料,和含锌钢铁、冶金烟尘等二次锌资源的环保、及资源再生利用具有积极的环保和经济意义。(The invention provides a combined type zinc electrolysis process flow by an ammonium chloride method with long-term stable operation, which comprises a main leaching process, a main electrolysis process and an auxiliary super-impurity raw material circulating coarse washing process, an excessive calcium and magnesium precipitation process and an impurity filtering auxiliary process, wherein the two processes are arranged and connected in parallel and can work independently without mutual influence. The invention controls the stability of the electrolyte quality by matching the main flow and the auxiliary flow and by means of full flow, temperature control, compact parallel-serial layout, multiple working sections, synchronization/asynchronism and multiple means, solves the problem of multi-element interference brought by complex raw materials, particularly the problem of long-period stable and efficient operation of zinc electrolysis by an ammonium chloride method, and has positive environmental protection and economic significance for treating high fluorine chlorine and high impurity zinc-containing raw materials and secondary zinc resources such as steel, zinc, metallurgical dust and the like by an ammonia method and recycling the resources.)

1. A combined zinc electrolysis process flow by an ammonium chloride method with long-term stable operation is characterized in that: according to the characteristics of the process for electrolyzing zinc by ammonium chloride, the process flow is divided into a main flow and an auxiliary flow, the two flows are arranged and connected in parallel, the process can be operated independently, impurities can be classified and removed in different process sections by different requirements and means according to the nature and the occurrence possibility of the impurities through interactive operation of each process section, the accumulation of the impurities is controlled, the types and the quantity of the impurities are controlled under normal electrolysis conditions for a long time, and the long-time, stable, low-cost and high-tolerance operation of the electrolysis process is ensured.

2. The combined zinc electrolysis process flow with long-term stable operation by the ammonium chloride method according to claim I, is characterized in that: the main process and the auxiliary process are arranged in parallel and connected compactly, the connection distance is shortened to the maximum extent, the temperature is reduced by less than 5-8 ℃ in the electrolyte transportation process, and all working sections are not interfered with each other during working and are independently controllable.

3. The combined zinc electrolysis process flow with long-term stable operation by the ammonium chloride method according to claim I, is characterized in that: the main process comprises the working sections of circulating washing and leaching, combined purification, mixed liquid/liquid-solid ammonia supplementing and re-purification, low-evaporation long-period electrodeposition and chilling stripping plate casting; the auxiliary process comprises the following steps: coarse washing of ultra-impurity raw materials, a high-efficiency chlorine salt evaporator, a calcium-magnesium precipitation tank, a post-electrolysis liquid filter working section, an organic oxide agglomeration filtering/filter press, a chilling flaking tank and a combination thereof.

4. The combined zinc electrolysis process flow with long-term stable operation by the ammonium chloride method according to claim 3, is characterized in that: the pre-coarse washing of the super-impurity raw material consists of a filter pressing circulating washing machine, the washing is not for the purpose of cleaning, only the raw material with the chlorine content of more than 6 percent is subjected to coarse washing, the chlorine content is controlled to be below 6 percent, and the washing liquid with the chlorine content of more than 20-30 percent and the chlorine salt solution after calcium and magnesium precipitation are sent to a desalting evaporator to remove chlorine salt, and the liquid returns to leaching.

5. The combined zinc electrolysis process flow with long-term stable operation by the ammonium chloride method according to claim 3, is characterized in that: the circulating washing and leaching device can be integrated or continuous and comprises a clarifying section, a leaching section and a washing section, the temperature of the leaching device is kept within 20-80 ℃, and the capacity of the leaching device is 3-8 times of the capacity of the electrolytic cell.

6. The combined zinc electrolysis process flow with long-term stable operation by the ammonium chloride method according to claim 3, is characterized in that: the combined purification is formed by combining 2 or more self-grinding type replacement reactors and a depth purification tank in a multifunctional cascade manner, lead slag and copper-cadmium slag are replaced by zinc powder and zinc scum, and a displacer is subjected to iterative multiplexing, so that the consumption of the zinc powder is saved to the maximum extent, and the cost is reduced. The purification is rapid and efficient, the coarse purification time is less than 5 minutes, and the deep purification time is less than 60 minutes.

7. The combined zinc electrolysis process flow with long-term stable operation by the ammonium chloride method according to claim 3, is characterized in that: the liquid/solid ammonia supplementing mixed liquid tank integrates functions of liquid mixing, ammonia supplementing and re-purification, can supplement ammonia to leachate by ammonia water or solid ammonia, uses ammonium bicarbonate and ammonium carbonate for the solid ammonia supplementation, and is particularly suitable for controlling the temperature of ammonia supplementation to be not lower than 20-80 ℃ under the condition that liquid ammonia is inconvenient or unsafe to use.

8. The combined long-cycle zinc chloride electrolysis process according to claim 3, wherein: the electrolytic solution shunt purification design and combination comprise

1) The qualified electrolyte directly enters a mixed solution and leaching section;

2) the liquid continuously running for more than 15 days enters a particle impurity filter in a shunt way, and is mixed after being filtered;

3) after the operation is carried out for a period of time and the bath voltage rises by 10 percent compared with the normal state, the shunted part of liquid is treated by calcium and magnesium deposition, and the calcium and magnesium content of the treated liquid is controlled to be lower than 15 percent.

9. The combined zinc electrolysis process flow with long-term stable operation by the ammonium chloride method according to claim 3, is characterized in that: after the fluorine-chlorine content of the circulating crude washing liquid exceeds 25%, the high fluorine-chlorine electrolyte after calcium and magnesium precipitation is sent to an evaporation desalter for desalting, and desalted water is returned to leaching.

10. The combined type zinc electrolysis process flow with ammonium chloride method operating stably for a long time as claimed in claim 3, wherein the cathode plate is taken out after the electrodeposition is completed, and is sent to a chilling stripping section, the temperature of the cathode plate is controlled to be 0-100 ℃, the rapid cooling is carried out for 2-120 seconds, the different expansion rates of the electrode plate and the zinc sheet are utilized to carry out automatic stripping/stripping, and the zinc sheet is sent to be cast after being stripped.

Technical Field

The invention relates to a combined ammonia process zinc electrolysis process flow with long-term stable operation, in particular to a process equipment combination and a process flow with long-term stable operation of ammonium chloride process zinc electrolysis, solves the problems that the current ammonium chloride process zinc electrolysis process is difficult to operate for a long time, and the electrolysis efficiency is reduced and failed along with the time, and belongs to the field of hydrometallurgy.

Background

The ammonium chloride method zinc electrolysis technology is an effective chlorine-containing ammonia method zinc electrolysis technology, and is particularly suitable for treating zinc-containing steel smoke dust containing fluorine and chlorine and high iron-containing impurities, electroplating small ash, zinc hypoxide generated by enriching blast furnace and nonferrous metallurgical furnace smoke dust, and high-iron high-calcium-magnesium zinc oxide. The ammonium chloride electrolytic zinc process has been valued for its unique selective leaching and high-tolerance (fluorine-chlorine) electrolytic system since the technologies and documents of EZINEX, Lianggae Deng, etc. published by Engiten Impitant, Italy, in the 90 s of the last century and the realization of industrialized demonstration production. However, in practical application practice, due to different process flows, layouts, equipment and control conditions, the problems of poor quality of zinc sheets, low direct-casting fusion rate and high production cost generally exist, and particularly, along with the prolonging of production time, the accumulated impurities of the electrolyte rise and the reaction imbalance, the production efficiency, the product quality and the production benefit are further reduced, the normal production is difficult to maintain, and the popularization of the advanced technology is influenced.

The inventors have found that the main causes of these problems are: 1. more metal impurity ions, negative ions and organic functional groups are introduced into the zinc ammonium chloride system than into the zinc sulfate system, so that the quality of electrolyte and products can be influenced in different stages and time of the process, and the smooth proceeding and the efficiency of electrolysis are further influenced; 2. the process flow and layout of the prior ammonium chloride electrolytic zinc method mainly come from the knowledge and experience of the traditional zinc sulfate method, the design and layout are not carried out aiming at the characteristics of the zinc chloride ammonium method, and the requirements of the system are not met in the aspects of temperature control, impurity removal and quality control; 3, the process equipment lacks a targeted design, does not fully reflect the characteristics of the zinc ammonium chloride system in the aspects of selective leaching, rapid purification and high-temperature electrolysis, and is not properly matched with the requirements of the system. In a word, the current processes and equipment lack targeted design, and have the problems of incomplete system, unreasonable layout and inadaptation of equipment, so that the advantages of the new technology are difficult to exert, the energy consumption is high, the zinc powder consumption is large, and the product quality is low.

Disclosure of Invention

The invention aims to provide a combined ammonium chloride zinc electrolysis process flow and layout, which can realize long-term stable operation of zinc electrolysis in an ammonium zinc chloride system.

In order to solve the problems and achieve the aim, the combined type zinc chloride process electrolytic zinc process flow with long-term stable operation provided by the invention is realized by dividing the process flow into a main flow and an auxiliary flow according to the process characteristics and equipment characteristics of a zinc chloride ammonia system, wherein the main flow is responsible for continuous production, the auxiliary flow is responsible for independently regulating and controlling the quality of a solution, the two flows are arranged in parallel and connected in series and compactly, so that the main flow can be kept to operate independently and continuously, the quality of the solution of each process section can be controlled through the auxiliary flow, impurities are classified and removed in different process sections according to different process quality requirements and means according to the nature and the occurrence possibility of the impurities, the accumulation of the impurities is controlled, the types and the quantity of the impurities are controlled under normal electrolysis conditions for a long time, the stability and the low cost of the main flow electrolytic process, The operation with high tolerance solves the problem that the ammonium chloride zinc electrolysis process is difficult to operate stably for a long time.

The main process comprises the following steps: a circulating washing leaching, combined purification, low-evaporation long-period electrodeposition, mixed liquid/liquid solid ammonia supplement repurification, low-evaporation long-period electrodeposition and chilling stripping plate fusion casting section; the auxiliary process comprises the following steps: coarse washing of ultra-impurity raw materials, a high-efficiency chlorine salt evaporator, a calcium-magnesium precipitation tank, a post-electrolysis liquid filter working section, an organic oxide agglomeration filtering/filter press, a chilling flaking tank and a combination thereof.

Further, the pre-coarse washing of the super-impurity raw material consists of a filter pressing circulating washing machine, the washing is not performed with the aim of cleaning, only the raw material with the chlorine content of more than 6% is subjected to coarse washing, the chlorine content is controlled to be below 6%, the washing liquid with the chlorine content of more than 20-30% and the chlorine salt solution after calcium and magnesium precipitation are sent to a desalting evaporator to remove chlorine salt, and the liquid returns to leaching.

Further, the circulating washing leaching device can be integrated or continuous and comprises a clarifying section, a leaching section and a washing section, the temperature of the leaching device is kept in a range of 20-80 ℃, and the capacity of the leaching device is 3-8 times of that of the electrolytic cell.

Furthermore, the combined purification is formed by combining 2 or more self-grinding type replacement reactors and a depth purification tank in a multifunctional cascade manner, lead slag and copper-cadmium slag are replaced by zinc powder and zinc scum, and a displacer is subjected to iterative multiplexing, so that the consumption of the zinc powder is saved to the maximum extent, and the cost is reduced. The purification is rapid and efficient, the coarse purification time is less than 5 minutes, and the deep purification time is less than 60 minutes.

Furthermore, the liquid/solid ammonia supplementing mixed liquid tank integrates functions of liquid mixing, ammonia supplementing and repurification, can supplement ammonia to the leachate by ammonia water or solid ammonia, uses ammonium bicarbonate and ammonium carbonate for the solid ammonia supplementation, and is particularly suitable for controlling the temperature of ammonia supplementation to be not lower than 20-80 ℃ under the condition that liquid ammonia is inconvenient or unsafe to use.

Further, the design and combination of the post-electrolysis liquid shunt purification comprise

1) The qualified electrolyte directly enters a mixed solution and leaching section;

2) the liquid continuously running for more than 15 days enters a particle impurity filter in a shunt way, and is mixed after being filtered;

3) after the operation is carried out for a period of time and the bath voltage rises by 10 percent compared with the normal state, the shunted part of liquid is treated by calcium and magnesium deposition, and the calcium and magnesium content of the treated liquid is controlled to be lower than 15 percent.

Further, after the fluorine-chlorine content of the circulating crude washing liquid exceeds 25%, the high fluorine-chlorine electrolyte after calcium and magnesium precipitation is sent to an evaporation desalter for desalting, and desalted water returns to leaching;

further, the method is characterized in that the cathode plate is taken after electrodeposition is finished, the cathode plate is sent to a chilling stripping section, the temperature of the cathode plate is controlled to be 0-100 ℃, rapid cooling is carried out for 2-120 seconds, automatic stripping/stripping is carried out by utilizing different expansion rates of the electrode plate and the zinc sheet, and the zinc sheet is sent to casting after stripping.

The working process of the invention is 1, controlling impurity raw material pretreatment system (comprising ultra-impurity raw material coarse washing and high-efficiency chlorine salt evaporator), according to the chlorine content of the raw material, carrying out shunt treatment on the raw material, directly carrying out leaching procedure on the raw material with the chlorine content lower than 6%, sending the raw material with the chlorine content higher than 6% to an ultra-impurity coarse washing section for circular washing, and carrying out filter pressing/filtering on the impurity coarse washing to control the chlorine content below 6% for leaching. The coarse washing is a simple and efficient water washing impurity removal process with low requirement, when the concentration of fluorine and chlorine in the circulating washing liquid exceeds 20%, the liquid after residue precipitation is sent to a chlorine salt evaporation system for desalination treatment after opening a circuit, the salt is recycled, the desalted liquid is recycled for washing, and the residues and the leached residues are converged for treatment; 2. the circular washing type leaching system is an integral leaching tank with the capacity 2-8 times that of the electrolytic tank, and is divided into clarification, leaching and washing sections. The integral leaching has the characteristics of large capacity and thermal capacity and small solution temperature change, is favorable for the characteristics of high ammonium chloride leaching temperature, high leaching speed, easy filtration and large influence of leaching temperature and time on leaching rate, is matched with proper pH value, leaching concentration and stirring position and speed control, a washing filter press is arranged on a leaching tank, the leaching slag is circularly washed and filter-pressed on the tank until the zinc content of the slag is lower than 3-15%, the slag is discharged in an open circuit manner, the leaching solution is continuously discharged from a clarification section, the leaching slag after filter pressing is returned to the washing section for further leaching, and the leaching solution is removed from a purification section; 3. the combined continuous purification system is continuously and multistage-carried out, the patent technology of self-grinding roller replacement reactor and anti-reverse-dissolution multi-energy cascade purification process is used, zinc scum, waste zinc sheets/particles and zinc powder are used as a displacer to obtain copper-cadmium slag and high-lead slag, the purified liquid is sent to a mixed liquid/ammonia supplementation/repurification tank, and the mixed liquid ammonia supplementation tank provides a flexible interface, can adapt to ammonia water or solid ammonia supplementation and further controls impurities to obtain mixed purified liquid; 4. the electrolysis is carried out at proper temperature, flow, pH value and current density, and the temperature is controlled, so that the requirements of zinc-ammonium complex electrolysis are met, and energy is provided for the heat balance of the system; 5. and (3) after electrodeposition, taking the cathode plate, sending the cathode plate to a chilling stripping plate, wherein the chilling stripping plate technology comprises a series of technical know-how and a chilling tank, and can realize automatic stripping or stripping, after zinc sheets are stripped, sending the zinc sheets to fusion casting, returning zinc scum generated by fusion casting to a combined purifier for use, and packaging and warehousing zinc ingots. 6. The electrolyzed solution enters a distribution tank, shunt treatment is carried out according to the impurity content/continuous production time of the electrolyte, firstly, the electrolyzed solution enters a pressure filtration impurity removal section to remove various impurities and agglomerated organic matters, and the solution is clarified; secondly, the calcium and magnesium are precipitated in a calcium and magnesium precipitation section, so that the content of calcium and magnesium in liquid is reduced, and the conductivity of the system is improved; and thirdly, directly returning the mixture to the mixing tank and the leaching tank for use. The raw material treatment before leaching and the post-liquid treatment after electrolysis are carried out in a shunting way or in parallel, and the production progress and the efficiency of the main flow are not influenced.

The invention relates to a combined zinc electrolysis process flow by an ammonium chloride method with long-term stable operation, which is characterized in that: 1. and (3) controlling the quality of the whole process: through the combination of the process and the equipment, the raw materials and the electrolyte are subjected to multi-stage purification before leaching, during leaching and after electrolysis, so that the long-term stability of the quality of the electrolyte is ensured; 2. the main and auxiliary processes are compactly and flexibly arranged: the main process comprises the following steps: a continuous washing type leaching, combined continuous purification, low evaporation long-period electrodeposition and chilling stripping plate fusion casting section; the auxiliary process comprises the following steps: coarse washing of super-impurity raw materials, a high-efficiency chloride salt evaporator, a calcium-magnesium precipitation tank and a post-electrolysis liquid filter. The main electrolysis process and the auxiliary purification process are arranged in parallel and connected compactly, so that the connection distance and temperature control are shortened to the maximum extent, the temperature is reduced by less than 5-8 ℃ in the transportation process of the electrolyte, and the working sections are not interfered with each other and are independently controllable; 3. impurity control before leaching: the ultra-impurity raw material is washed by simple amount control, the chlorine content of the raw material is controlled to be below 6 percent, the basic quality of liquid can be ensured, impurities are controlled at the front end, the process consumption is reduced, and the system efficiency is improved; 4. combined purification of leachate: the combined purification is at least 2.5 sections, including 1 section of coarse purification, 1 section of deep purification and half section of repurification, almost all metal impurity particles are purified in each section of the combination according to requirements, the purification is rapid and continuous, the substitution agent of zinc cadmium-lead-zinc cadmium is used iteratively, the zinc powder is saved, the half section of repurification is the integration of liquid mixing/ammonia supplementation/purification, and metal and non-metal impurities are controlled; 5. purifying the electrolyzed solution: carrying out two treatments on impurities generated by decomposition and oxidation in the electrolyzed solution according to accumulation conditions, wherein 1 is filtering to eliminate particle impurities and organic matter agglomeration; 2, performing precipitation treatment on excessive calcium and magnesium, and converging the treated liquid into a desalter for desalting and opening a circuit, and performing final quality control on the quality assurance of the system liquid; 6. the whole process and equipment are combined, the main part and the auxiliary part are respectively arranged, the connection is flexible, the space is not occupied, no additional work is added, and the purpose of the invention is completely realized in the daily and normal operation process.

Drawings

FIG. 1 is a schematic flow diagram of the present invention.

Detailed Description

The invention is further described below with reference to the drawings and examples, but the scope of protection of the invention is not limited to the examples described.

As can be seen from the figure l, the zinc-containing raw material is divided into two paths according to the fluorine-containing chlorine content, wherein 1, the fluorine-containing chlorine with the concentration lower than 6 percent directly enters a washing type leaching section for leaching; 2, circulating and roughly washing the fluorine and chlorine content of more than 6 percent to be roughly washed, and reducing the fluorine and chlorine content to below 6 percent; the qualified raw materials are sent to a washing type leaching section for ammonium chloride leaching, and the difference of the leaching is that when the leaching is carried out, a washing type filter press circularly filters the leaching solution, and the leaching solution is discharged in a shunting way until the zinc content of filter pressing residues is lower than 3-15%; the qualified leachate is sent into a combined purification section, and is purified by one or more self-grinding roller replacers to be subjected to serial or parallel continuous coarse purification, zinc scum or broken zinc sheets can be used for purification, and the liquid after coarse purification is sent into a deep purification tank to be subjected to deep purification by using zinc powder, so that the rapidness, the high efficiency and the saving are realized; the purified liquid is sent to a mixed liquid/ammonia supplementing tank, and the mixed liquid is supplemented with ammonia and then purified, and is in linkage operation with the electrolytic tank; the low-evaporation long-period electrolysis is carried out under the conditions of temperature control, semi-closed state and no stirring or low stirring, the electrolysis time is longer than 36 hours, and the zinc sheet stripping is mainly carried out by chilling type automatic stripping; the electrolyzed solution is processed in three ways, 1, the qualified solution is sent to a mixing tank and a leaching tank for circulation; 2, removing the waste liquid from a filter pressing and filtering section to perform circulating filter pressing and impurity removing treatment, and returning the treated liquid to a mixed liquid tank; and 3, the fatigue electrolyte enters a calcium-magnesium precipitation tank for precipitation, and the precipitated liquid is sent to an evaporation desalter for further desalting to recover the activity of the liquid.

Example 1 direct leaching of raw materials

The raw materials are zinc hypoxide, zinc 41%, lead 4% and fluorine-containing chlorine 4%, the raw materials are fed into a leaching tank through a spiral blanking machine or size mixing at a speed of 4.5 tons/hour, countercurrent washing leaching is carried out, and the solid ratio of the leaching solution is 8-12: 1, the leachate contains 4.5 to 5.5mol/l of ammonium chloride, the temperature is 30 to 90 ℃, the stirring is carried out, the leaching time is 2 hours, the zinc content of the leachate is more than 37g/l, the lead content is 3.6g/l, other copper is 0.05g/l, cadmium is 0.3g/l, and iron is trace;

example 2 leaching of ultra-impurity raw materials after coarse washing

Small ash: zinc 61%, iron 5% and fluorine-containing chlorine 15.5%, coarse circulation washing and filter pressing, leaching with zinc 62.2%, iron 5.4% and fluorine-chlorine less than 6%;

example 3 Combined purification of leach liquors

Leaching solution: 37g/l of zinc, 5g/l of lead, a trace amount of iron, 0.05 of other copper and 0.3 of cadmium, two-stage coarse purification of zinc dross, one-stage deep purification of zinc powder, ammonia supplementation and repurification of the first-stage mixed liquid, 38g/l of zinc, 0.008 of lead, 0.003 of copper, 0.006 of cadmium and a trace amount of other components.

Example 4 filtration of the electrolyzed solution

The electrolyzed solution (after 20 days of operation) contains 20g/l of zinc, trace of copper, cadmium and lead, yellow color and floating substances. After filtering/pressure filtering the electrolyzed solution, the filtrate is clean and transparent, a plurality of organic oxide filter residues are removed, and the filtrate is back mixed with the solution or is in a leaching section.

Example 5 precipitation of calcium and magnesium from the electrolyzed solution

After electrolysis (after 2 months of operation), the cell voltage slightly rises, the liquid viscosity increases, and the power consumption increases. Judging that the calcium, magnesium and fluorine and chlorine in the liquid body are increased. Opening the solution into a calcium-magnesium precipitation tank according to 1/2-1/10, adding ammonium bicarbonate to raise the pH value to above 10, stirring for reaction until calcium-magnesium precipitate is formed, filtering to remove, and leaching the liquid or further desalting.

The invention eliminates impurities in the electrolytic process by physical and chemical means according to the change of raw materials and liquid in different states and time through reasonable equipment and process combination before leaching, during leaching and after entering and exiting, thereby achieving the long-term, stable and effective operation of the ammonia process electrolytic zinc system.

The main process and the auxiliary processes are arranged and connected in parallel, and can work simultaneously without mutual interference. Moreover, the auxiliary process is flexibly intervened when necessary, and unnecessary consumption can be reduced to the maximum extent.

While embodiments of the present invention have been described, and not by way of limitation, other variations of the disclosed embodiments, as would be readily apparent to one of skill in the art, are intended to be included within the scope of the present invention, which is defined in the claims.