CN108950254B

CN108950254B - Method for extracting rhenium by combining high-rhenium arsenic filter cake and copper-containing waste liquid

Info

Publication number: CN108950254B
Application number: CN201810763350.1A
Authority: CN
Inventors: 文燕; 郑国渠; 黄辉荣; 王文斌; 杨利群; 袁雪生; 邹贤
Original assignee: Jinlong Copper Co ltd; Zhejiang University of Technology ZJUT
Current assignee: Jinlong Copper Co ltd; Zhejiang University of Technology ZJUT
Priority date: 2018-07-12
Filing date: 2018-07-12
Publication date: 2021-01-15
Anticipated expiration: 2038-07-12
Also published as: CN108950254A

Abstract

The invention relates to a method for jointly treating a high-rhenium arsenic filter cake and a copper-containing waste liquid and extracting rhenium from the high-rhenium arsenic filter cake, which specifically comprises the following steps: a) enriching rhenium in the arsenic filter cake; b) mixing and leaching the high-rhenium arsenic filter cake and the copper-containing waste liquid; c) ion exchange and desorption; d) and concentrating and crystallizing to obtain ammonium rhenate finished product. The content fluctuation range of rhenium in the high-rhenium arsenic filter cake is reduced by setting the cleaning period of the filtering layer of the smelting flue gas in the purification process of the purification system, the control of the subsequent extraction process time of rhenium is facilitated, and the monitoring of the rhenium yield is also facilitated; the high rhenium and arsenic filter cake and the copper-containing waste liquid are jointly treated, so that the cost investment in the aspects of raw materials, equipment, energy consumption and the like for independently treating the high rhenium and arsenic filter cake and the copper-containing waste liquid is saved; the treatment process adopts normal pressure leaching, so that the process cost is further reduced; the ammonia water solution is used as the desorption agent, so that the step of purifying the rhenium product is omitted, and the process flow is simplified.

Description

Method for extracting rhenium by combining high-rhenium arsenic filter cake and copper-containing waste liquid

Technical Field

The invention belongs to the technical field of nonferrous metals, and particularly relates to a method for jointly treating a high-rhenium arsenic filter cake and a copper-containing waste liquid and extracting rhenium from the high-rhenium arsenic filter cake.

Background

As the arsenic filter cake is used as a byproduct in the process of purifying non-ferrous metal smelting flue gas, most enterprises entrust qualification units to process because the arsenic filter cake belongs to dangerous solid waste containing high arsenic, and a small amount of high-value metal rhenium in the arsenic filter cake is lost along with the arsenic filter cake. Currently, there are three main ways to extract rhenium from arsenic filter cakes: firstly, adopting pressure oxygen-adding leaching-sulfur dioxide reduction arsenic precipitation-extraction rhenium extraction; second, one-stage alkaline leaching, two-stage oxidation leaching-dearsenization-extraction rhenium extraction. Thirdly, copper powder replacement-oxidation, reduction and arsenic precipitation by sulfur dioxide-ion exchange and rhenium extraction. Among the three modes, the first two processes are complex, the adopted amine extractant is volatile, has high toxicity and difficult back extraction, and simultaneously has the problem of environmental pollution caused by extraction waste liquid; the third mode has long process flow, consumes copper powder and oxygen and has high operation cost.

In most of rare and precious metal extraction processes, firstly, sulfuric acid leaching is carried out on raw materials for copper removal, and a byproduct copper-containing waste liquid is generated after acid leaching, wherein copper recovery generally adopts an independent recovery system such as electrodeposition or reduction displacement, and the like, so that the energy consumption and recovery cost are high, and the yield is low.

Disclosure of Invention

The invention aims to provide a method for synchronously realizing the treatment of a high-rhenium arsenic filter cake and a copper-containing waste liquid and extracting rhenium from the high-rhenium arsenic filter cake.

In order to achieve the purpose, the invention adopts the following technical scheme: a method for extracting rhenium by combining a high-rhenium arsenic filter cake and a copper-containing waste liquid comprises the following steps:

a) enrichment of rhenium in arsenic filter cake: purifying the smelting flue gas containing arsenic and rhenium in a flue gas purification system, setting a cleaning period of a filter layer in the purification system, and obtaining a product obtained by cleaning the filter layer, namely a rhenium-rich high-rhenium arsenic filter cake;

b) and mixing and leaching the high-rhenium arsenic filter cake and the copper-containing waste liquid: mixing and leaching the high rhenium arsenic filter cake obtained in the step a) and the copper-containing waste liquid at the normal pressure and the temperature of 60-100 ℃, and performing solid-liquid separation on the obtained mixed leaching liquid to obtain leaching liquid B1 and leaching residue B2;

c) ion exchange and desorption: absorbing rhenium by using leaching solution B1 through ion exchange resin to obtain solution C1 after ion exchange, and carrying out backwashing desorption on the ion exchange resin by using an ammonia water solution when the ion exchange resin is nearly saturated to obtain desorption solution C2 containing rhenium;

d) concentrating and crystallizing to produce ammonium rhenate finished products: evaporating and concentrating the desorption solution C2, reducing the temperature of the concentrated solution to separate out crystals, and carrying out solid-liquid separation to obtain the finished product of the rhenium amino acid.

Compared with the prior art, the invention has the following beneficial effects: the content fluctuation range of rhenium in the high-rhenium arsenic filter cake is reduced by setting the cleaning period of the filtering layer of the smelting flue gas in the purification process of the purification system, the control of the subsequent extraction process time of rhenium is facilitated, and the monitoring of the rhenium yield is also facilitated; the high rhenium and arsenic filter cake and the copper-containing waste liquid are jointly treated, so that the cost investment in the aspects of raw materials, equipment, energy consumption and the like for independently treating the high rhenium and arsenic filter cake and the copper-containing waste liquid is saved; the treatment process adopts normal pressure leaching, so that the process cost is further reduced; the ammonia water solution is used as the desorption agent, so that the step of purifying the rhenium product is omitted, and the process flow is simplified.

Preferably, introducing hydrogen sulfide gas or adding an arsenic precipitation agent into the ion-exchanged solution C1 in the step C), controlling the oxidation-reduction potential to be-50 mv, and performing solid-liquid separation after full precipitation to obtain a filtrate E1 and a filter residue E2: the filtrate E1 is directly returned to the leaching step for recycling, and the filter residue E2 is recycled or returned to a copper smelting system.

The redox potential is used to reflect the macroscopic oxidation-reduction exhibited by all species in aqueous solution. The higher the redox potential, the stronger the oxidation, and the lower the potential, the weaker the oxidation. A positive potential indicates that the solution exhibits some degree of oxidation, while a negative potential indicates that the solution exhibits reduction. In the invention, the arsenic precipitation is controlled so that the oxidation-reduction potential is in the range of-50 mv. It can be seen that the whole solution in the process is not subjected to oxidation-reduction reaction basically, that is, the valence state of the metal ions in the solution is not changed after the metal ions generate precipitates, so that the generated metal sulfide precipitates are easy to treat no matter the metal sulfide precipitates are recovered or returned to a copper smelting system. And the generated filter residue, filtrate and the like can be recycled: the filtrate E1 is dilute sulfuric acid and directly returns to the leaching step for recycling, and the filter residue E2 is sulfide precipitate of heavy metal ions such as arsenic and copper and the like and is recycled or returned to a copper smelting system. Compared with the prior art that arsenic filter cakes or copper-containing waste liquid are separately treated, waste residues and waste liquid generated in the treatment process pollute the environment to a certain extent, other raw materials are not introduced, waste generated in the treatment process can be recycled, and the advantages of the technical scheme are fully proved.

Preferably, in the step a), the cleaning period of the filter layer in the flue gas purification system is set to be 10-15 days.

Smelting flue gas containing arsenic and rhenium continuously passes through the flue gas purification system, tiny suspended powder in the flue gas continuously adheres to the surface of a filter layer in the purification system to form an adhesion layer, the adhesion layer also has a certain mechanical filtering effect on the continuously passing flue gas, the speed of the flue gas passing through the filter layer is influenced along with the continuous thickening of the adhesion layer, in order to ensure the flue gas purification efficiency, the filter layer needs to be cleaned, and the obtained waste residue after cleaning is a rhenium-rich high-rhenium arsenic filter cake, which can also be called rhenium-rich slag. The above flue gas purification process can be considered as a process for enriching rhenium in arsenic filter cake: in the smelting flue gas purification process, the filter layer in the purification system needs to be cleaned periodically, the time interval of cleaning the filter layer every two times is a cleaning period, and a certain amount of rhenium-rich high-rhenium arsenic filter cake can be obtained in each cleaning period.

The rhenium content in the arsenic filter cake is high or low, the fluctuation is large, the subsequent treatment process flow is difficult to control, and the rhenium yield is unstable. And setting a cleaning period of a filtering layer in the flue gas purification system, if the period is 10-15 days, not only ensuring the purification efficiency of smelting flue gas, but also realizing the enrichment of rhenium in the arsenic filter cake, and reducing the fluctuation range of rhenium content to be more beneficial to the monitoring of the rhenium yield.

Preferably, in the step b), the copper-containing waste liquid is copper anode slime pickle liquor containing 1.0-5.0% of copper. Copper anode slime is a slime that adheres to the surface of the anode matrix or settles on the bottom of the electrolytic cell or is suspended in the electrolyte during the electrolytic refining process in copper smelting, wherein most or most of the precious metals and some of the rare elements in the ore, concentrate or flux are enriched. The copper anode slime sulfuric acid immersion liquid is formed by immersing copper anode slime in a sulfuric acid solution with a certain concentration, and since a large amount of sulfur dioxide is contained in copper smelting flue gas and is a raw material for preparing sulfuric acid, most of metal elements in the copper anode slime exist in the sulfuric acid solution in a metal ion form by using sulfuric acid as an immersion solvent, so that subsequent adsorption or precipitation treatment is facilitated. The invention adopts the normal pressure acid leaching method, the leaching solvent can be obtained from local materials, the investment cost is greatly reduced, the waste acid liquid after the treatment can be recycled, and the invention is energy-saving and environment-friendly.

Further, in the step b), the rhenium and arsenic-rich filter cake and the copper anode mud pickle liquor containing 1.0-5.0% of copper are added into a leaching tank in a liquid-solid ratio of 3-5: 1 for mixed leaching.

The invention adopts atmospheric pressure leaching, and compared with the high requirement of pressure leaching on leaching equipment, the atmospheric pressure leaching does not need the equipment to have the function of sealing and pressurizing, so the cost on process equipment is lower, and the operation is simpler and more convenient. The leaching temperature is selected to be 60-100 ℃, and the ion diffusion speed is reduced and the leaching effect is poor due to the excessively low temperature; the temperature increase increases, on the one hand, the diffusion coefficient and, on the other hand, the solubility of the solid in the solvent, and thus the dissolution rate, while the chemical action is accelerated by increasing the temperature. However, the temperature is too high, so that ore pulp splashing is easily caused, and for the leaching agent with corrosiveness, the ore pulp splashing has certain danger to workers or peripheral working equipment, so that the proper leaching temperature needs to be selected.

In the leaching process, proper leaching conditions and liquid-solid ratio need to be selected, the method is used for acid leaching under the normal pressure at the temperature of 60-100 ℃, under the conditions, the liquid-solid ratio is too high, the concentration of metal ions in the obtained leaching solution is low, and the volume of the leaching solution is increased; and if the liquid-solid ratio is too low, the leaching speed and leaching rate of metal elements in the solid particles can be reduced, and under the condition that the liquid-solid ratio is 3-5: 1, the leaching rate in the leaching process can be ensured, and excessive pressure on leaching equipment due to overlarge volume of the leaching solution can be avoided. In addition, the leaching time depends on the concentration of the leaching solvent, the activity of the metal to be leached, the contact area between the metal and the solvent, and other factors. The leaching time is too short, and the metal elements cannot fully react with the solvent, so that the aim of leaching cannot be fulfilled; and the leaching time is too long, so that the time used in the whole process flow is prolonged, and the leaching time needs to be determined according to actual conditions. In addition, the leaching residue B2 still contains a small amount of heavy metals which are not dissolved out by the leaching solvent, and the heavy metals can be returned to the copper smelting system for recycling, thereby further avoiding the loss of the heavy metals and the pollution of the waste residue to the environment.

Preferably, in the step D), the separated liquid D1 is mixed with the desorption liquid C2 to be treated, and the ammonium rhenate finished product is produced through the treatment of the step D). The process of producing the finished product of the rhenium amino acid in the desorption solution C2 can be divided into two parts, namely evaporation concentration of the desorption solution and crystallization of the rhenium amino acid. The desorption solution evaporation concentration is to evaporate and remove most of water in the solution, so that the volume of the desorption solution is reduced; the principle of the ammonium rhenate crystallization production is that the rhenium acid is slightly soluble in cold water and easily soluble in hot water, so after the temperature is reduced, as the solubility of the rhenium acid is rapidly reduced, the solution is gradually saturated and supersaturated from an unsaturated state, and a large amount of rhenium acid crystals are separated out.

For the selection of the desorption agent, ammonium thiocyanate solution is commonly used as the desorption agent in the prior art, and the finished product of the rhenium acid obtained after crystallization contains a certain amount of impurities and needs to be purified by repeatedly dissolving and crystallizing with ammonia water solution. The invention directly selects the ammonia water solution as the desorption agent, which not only omits the purification step of the finished product of the rhenium amino acid, but also can keep the desorption liquid in a liquid state even under the temperature condition lower than the freezing point of water because the melting point of the ammonia water solution is very low, for example, the melting point of 25 percent ammonia water solution is-57.5 ℃, thereby being more beneficial to the crystallization and precipitation of the rhenium amino acid. And NH in the aqueous ammonia solution during the crystallization process₄ ⁺Can produce the homoionic effect with the ammonium rhenate to promote the degree of depth of crystallization to go on in the crystallization environment, thereby improve crystallization efficiency, improved the ammonium rhenate product output.

And separating liquid D1 is an ammonium rhenate saturated solution at the temperature of ammonium rhenate finished product crystal production, separating liquid D1 and desorption liquid C2 to be treated are mixed, and then the mixture is treated in step D), namely, evaporation concentration and cooling are carried out to separate out crystals, so that the yield of rhenium can be further improved. And (3) selecting the temperature in the step of cooling and crystallizing the concentrated solution: can be reduced to below 0 ℃, because the lower the temperature, the smaller the solubility of the rhenium acid, and the more ammonium rhenate crystals are separated out; it is also possible to set the temperature not lower than 0℃, at which the amount of ammonium rhenate crystallized slightly less than in the case of the former temperature, but in practice, this is only the amount of ammonium rhenate crystallized at the first time, and in the subsequent process, the separated liquid D1 obtained at the previous time is mixed with the desorption liquid C2 to be treated, and the amount of ammonium rhenate crystallized is substantially the same as in the case of the temperature lowered to 0℃ or lower. That is, the overall process does not affect the rhenium yield as long as the concentrated desorption solution is lowered to a temperature at which crystallization can occur.

Compared with the prior art, the method jointly disposes the high rhenium arsenic filter cake and the acidic copper-containing waste liquid, and saves the cost investment of raw materials, equipment, energy consumption and the like for the independent treatment of the high rhenium arsenic filter cake and the copper-containing waste liquid. The cleaning period of a filter layer in the flue gas purification system is set, so that the fluctuation range of the rhenium content in the high-rhenium arsenic filter cake is reduced, and the subsequent treatment process is easier to control; the equipment investment is further reduced by adopting normal pressure leaching; the ammonia water solution is used as a desorption agent, so that the step of purifying the rhenium product is omitted, and the crystallization output rate of the rhenium product is improved; the leaching raw materials all utilize the byproduct to be recovered and treated, and other raw materials are not introduced in the process, so that the treatment cost is greatly reduced; the whole process realizes the recycling of waste residues and waste liquid, no three wastes are discharged, the production process is clean and efficient, the environment is friendly, and the resource utilization rate is greatly improved.

Drawings

FIG. 1 is a process flow diagram of the combined extraction of rhenium from a high rhenium arsenic filter cake and a copper-containing waste liquid.

Detailed Description

The technical scheme disclosed by the invention is further explained by 9 embodiments as follows:

example 1:

a) purifying the smelting flue gas containing arsenic and rhenium in a flue gas purification system, setting the cleaning period of a filter layer in the purification system to be 10 days, and measuring the rhenium content in the obtained arsenic filter cake with dimethylglyoxime spectrophotometry to be 1.16 percent;

b) adding the arsenic filter cake containing 1.16% of rhenium and the copper anode mud sulfuric acid immersion liquid containing 1% of copper into a leaching tank according to the liquid-solid ratio of 3:1, mixing and leaching for 2 hours at the conditions of normal pressure and 60 ℃, and performing solid-liquid separation on the obtained mixed leaching liquid to obtain a leaching liquid B1 and a leaching residue B2;

c) the leaching solution B1 adsorbs rhenium through ion exchange resin to obtain solution C1 after ion exchange, and when the ion exchange resin is nearly saturated, ammonia water solution is used for backwashing and desorbing the ion exchange resin to obtain desorption solution C2 containing rhenium;

d) and evaporating and concentrating the desorption solution C2, reducing the temperature of the concentrated solution to-10 ℃, separating out crystals, and carrying out solid-liquid separation to obtain a separation solution D1 and a solid rhenium amino acid finished product.

e) Introducing hydrogen sulfide gas into the ion-exchanged liquid C1 or adding an arsenic precipitation agent, controlling the oxidation-reduction potential to be-50 mv, and carrying out solid-liquid separation after full precipitation to obtain a filtrate E1 and a filter residue E2: the filtrate E1 is dilute sulfuric acid and directly returns to the step of acid leaching of copper anode slime for recycling, and the filter residue E2 is sulfide precipitate of heavy metal ions such as arsenic, copper, lead and the like, and is recycled or returned to a copper smelting system.

The dilute sulfuric acid concentration recovered was measured to be 25.4% and the rhenium recovery was 99.1% as calculated by the amount of rhenium product crystallized.

2-9:

examples 2-9 were the same as example 1, with the process parameters shown in Table 1:

according to the data obtained in the 9 embodiments, the rhenium content in the high-rhenium arsenic filter cake obtained by the method for extracting rhenium by combining the high-rhenium arsenic filter cake and the copper-containing waste liquid is very small in fluctuation after the cleaning period of the filter layer is set when the smelting flue gas continuously passes through the flue gas purification system, and convenience is provided for determining the time required by the subsequent control of each part of the process flow. The concentration of the recovered dilute sulfuric acid is about 20-30%, and the dilute sulfuric acid is returned to the leaching step for cyclic utilization, so that the requirement of the leaching process on the concentration of a leaching solvent can be met; the comprehensive recovery rate of rhenium is calculated to be more than 98 percent and can reach 99.5 percent at most.

Compared with the prior art, the technical scheme of the invention synchronously realizes the high rhenium arsenic filter cake,

The method has the advantages of short process flow, low cost investment of process equipment, no discharge of three wastes in the whole process, realization of cyclic utilization of waste residues and waste liquid and great reduction of system operation cost, and is used for treating the copper-containing waste liquid and efficiently recovering rhenium.

Table 1: relevant test data and Process parameters in examples 2 to 9

Note: the data measured in the various examples of the invention, such as the rhenium content of the high rhenium arsenic filter cake, the concentration of the recovered dilute sulfuric acid, and the resulting rhenium yield, are average values of a number of tests performed under the process parameters of the example.

Claims

1. A method for extracting rhenium by combining a high-rhenium arsenic filter cake and a copper-containing waste liquid is characterized by comprising the following steps: the method comprises the following steps:

c) ion exchange and desorption: absorbing rhenium by using the leaching solution B1 through ion exchange resin to obtain solution C1 after ion exchange, and carrying out backwashing desorption on the ion exchange resin by using an ammonia water solution when the ion exchange resin is nearly saturated to obtain desorption solution C2 containing rhenium;

d) concentrating and crystallizing to produce ammonium rhenate finished products: evaporating and concentrating the desorption solution C2, reducing the temperature of the concentrated solution to separate out crystals, and carrying out solid-liquid separation to obtain a finished product of the rhenium amino acid;

in the step a), setting a cleaning period of a filter layer in a flue gas purification system to be 10-15 days;

introducing hydrogen sulfide gas into the ion-exchanged liquid C1 in the step C) or adding an arsenic precipitation agent, controlling the oxidation-reduction potential to be-50 mv, and carrying out solid-liquid separation after full precipitation to obtain a filtrate E1 and a filter residue E2: and directly returning the filtrate E1 to the leaching step for recycling, and recovering or returning the filter residue E2 to a copper smelting system.

2. The method for extracting rhenium from the high-rhenium arsenic filter cake and the copper-containing waste liquid in a combined manner according to claim 1, characterized in that: in the step b), the copper-containing waste liquid is copper anode slime pickle liquor containing 1.0-5.0% of copper.

3. The method for extracting rhenium from the high-rhenium arsenic filter cake and the copper-containing waste liquid in a combined manner according to claim 2, characterized in that: in the step b), the high-rhenium arsenic filter cake and the copper anode mud pickle liquor containing 1.0-5.0% of copper are added into a leaching tank in a liquid-solid ratio of 3-5: 1 for mixed leaching.

4. The method for extracting rhenium from the high-rhenium arsenic filter cake and the copper-containing waste liquid in a combined manner according to claim 1, characterized in that: in the step D), the separation liquid D1 is mixed with the desorption liquid C2 to be treated, and the ammonium rhenate finished product is produced after the treatment in the step D).