CN108341424B - Production method of copper sulfate - Google Patents

Abstract

The invention discloses a production method of copper sulfate, which comprises the following steps: adding an oxidant into the acidic etching waste liquid to oxidize cuprous ions and ferrous ions in the acidic etching waste liquid, then adjusting the pH value to 1.7-1.9, stirring for reaction, adding activated carbon, settling and layering, taking supernatant, and filtering to obtain the impurity-removed acidic etching waste liquid; adding soluble magnesium salt into the alkaline etching waste liquid, stirring for reaction, settling and layering, and filtering the supernatant to obtain the alkaline etching waste liquid after impurity removal; mixing and reacting the acid etching waste liquid and the alkaline etching waste liquid after impurity removal to obtain basic copper chloride; converting the basic copper chloride ammonia into copper hydroxide, then filtering, washing water for purification, and pulping; and adding sulfuric acid to acidify until the pH value is 0.5-1.0, and then carrying out hot filtration, cooling crystallization, solid-liquid separation and drying treatment to obtain copper sulfate. The copper sulfate produced by the method can reach the standard of electroplating grade, and the recovery rate of copper in the etching waste liquid is high.

Description

Production method of copper sulfate

technical field

The invention relates to a production method of copper sulfate, and belongs to the technical field of copper sulfate production technology.

Background technique

Etching waste liquid is produced in the process of dissolving copper by chemical corrosion method in the printed circuit board (PCB) etching process. According to its acidity and alkalinity, it can be further divided into acid etching waste liquid and alkaline etching waste liquid. The content of copper in the acid etching waste liquid is about 30g/L~160g/L, and the content of copper in the alkaline etching waste liquid is about 40g/L~170g/L.

With the rapid development of the electronics industry, my country produces tens of thousands of tons of etching waste liquid every year. If these etching waste liquids are not properly treated and utilized, they will cause serious environmental pollution and great economic waste. The usual domestic treatment methods are: extracting copper from acid and alkali etching waste liquids to produce basic copper chloride, copper sulfate and copper oxide and other products.

At present, almost all electroplating grade copper sulfate as an electroplating additive is produced from the copper-containing etching waste liquid of circuit boards. However, the quality of the copper sulfate crude product obtained by the traditional copper sulfate production process is not up to the standard, and contains many impurities and metals. ionic, does not meet the plating grade standard for copper sulfate.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a method for producing copper sulfate, and the copper sulfate produced by the production can reach the standard of electroplating.

A production method of copper sulfate, comprising the steps:

Add an oxidant to the acid etching waste liquid to oxidize cuprous ions and ferrous ions in the acid etching waste liquid, then adjust the pH value to 1.7-1.9 and stir the reaction, then add activated carbon, and take the supernatant after sedimentation and stratification The liquid is filtered to obtain the acid etching waste liquid after impurity removal;

Adding soluble magnesium salt to the alkaline etching waste liquid and stirring the reaction, taking the supernatant after sedimentation and stratification, and filtering the supernatant to obtain the alkaline etching waste liquid after impurity removal;

The acid etching waste liquid after the impurity removal and the alkaline etching waste liquid after the impurity removal are mixed and reacted to obtain basic cupric chloride;

The basic cupric chloride is reacted with ammonia water to form a precipitate, filtered to obtain a filter residue, purified by washing water, and added with water to make a slurry to obtain a copper hydroxide slurry;

adding sulfuric acid to the copper hydroxide slurry, adjusting the pH value of the copper hydroxide slurry to 0.5-1.0, and then performing hot filtration treatment to obtain a copper sulfate-containing mixed solution; mixing the copper sulfate-containing The liquid is cooled and crystallized, and the solid-liquid separation is performed to obtain copper sulfate crystals, which can be dried.

In one of the embodiments, the reagent used to adjust the pH value to 1.7-1.9 is ammonia water. Adjusting the pH value to 1.7-1.9 with ammonia water can generate copper slime (Cu(OH) ₂ ·CuCl ₂ ), which is easy to adsorb precipitates such as ferric arsenate and cause co-sedimentation, and on the other hand, can avoid bringing in other impurities.

In one embodiment, the mass-volume ratio of the amount of the activated carbon to the acid etching waste liquid is (0.2-0.3) g:1L. The amount of activated carbon is mainly determined according to the volume of the acid etching waste liquid and the amount of organic impurities in it. According to the standard of adding 0.2-0.3g of activated carbon to 1L of the acid etching waste liquid, the organic impurities in the acid etching waste liquid can be effectively removed.

In one embodiment, the Baumé degree of the acid etching waste liquid after impurity removal is 24Be°˜30Be°, and the pH value is 1.0˜1.5.

In one embodiment, the Baumé degree of the alkaline etching waste liquid after impurity removal is 12Be°˜20Be°, and the pH value is 8.0˜9.0.

In one embodiment, in the step of reacting the basic cupric chloride with ammonia water to generate precipitation, the concentration of the ammonia water used is 20wt%, and the volume weight ratio of the consumption of the ammonia water to the basic cupric chloride is: (1.2～1.3)L: 1Kg. Ammonia conversion is carried out by reacting ammonia water with a mass concentration of 20% with basic cupric chloride, and reacting with 1.2L-1.3L ammonia water per 1Kg basic cupric chloride, which can be completely converted into copper hydroxide.

In one of the embodiments, the concentration of the sulfuric acid is greater than or equal to 98 wt %. A large amount of heat is generated during the acidification reaction of copper hydroxide slurry with concentrated sulfuric acid. With the progress of acidification, the temperature of the reaction system is getting higher and higher, and the solubility of copper sulfate in it is increasing. In this way, until the acidification is complete That is, when the pH value of the reaction system is 0.5 to 1.0, the temperature of the reaction system reaches about 100° C., which can provide heat for the subsequent crystallization reaction of copper sulfate.

In one of the embodiments, the step of obtaining the basic copper chloride by mixing and reacting the acidic etching waste liquid after the impurity removal and the alkaline etching waste liquid after the impurity removal specifically includes the following steps:

First, the acid etching waste liquid after impurity removal and the alkaline etching waste liquid after impurity removal are preheated to 43°C to 55°C, respectively, and then mixed in the presence of basic copper chloride seeds, and The reaction is carried out under the conditions of 68°C to 72°C and a stirring speed of 65r/min to 85r/min to obtain basic cupric chloride. In this way, by strictly controlling the reaction conditions, the basic cupric chloride crystallizes faster, and the production efficiency is improved. At the same time, the obtained basic cupric chloride crystal particles are uniform, have good fluidity, are easy to filter by pressure, and are doped with less impurities.

In one embodiment, during the reaction process of the acid etching waste liquid after impurity removal and the alkaline etching waste liquid after impurity removal, the acid etching waste liquid after impurity removal and preheating is continuously added and impurity removal and preheating The pH value of the last alkaline etching waste liquid when the acid etching waste liquid and the alkaline etching waste liquid are reacted is 4.30-5.00. In this way, by controlling the pH value of the reaction system to be between 4.30 and 5.00, the recovery rate of copper in the etching waste liquid can be improved, and the impurity content in the basic copper chloride can be reduced at the same time.

In one embodiment, the continuous addition of the preheated acid etching waste liquid and the preheated alkaline etching waste liquid is controlled at a flow rate of 2 cubic meters per hour to 6 cubic meters per hour. In this way, by controlling the flow rate of the acidic etching waste liquid and the alkaline etching waste liquid into the reactor within the range of 2 cubic meters per hour to 6 cubic meters per hour, the pH of the reaction system can be better adjusted to 4.30 to 5.00, and there is no need to add Other pH adjusters simplify the procedure and avoid the introduction of other ionic impurities due to the use of other pH adjusters. And the copper ion and chloride ion in the acidic etching waste liquid and the copper ammonia chloride complex and ammonia water in the alkaline etching waste liquid can be reacted to obtain basic copper chloride crystals with better crystal form.

The above method of the present invention removes impurities such as iron, aluminum and other metal ions and arsenic, as well as organic impurities and other water-insoluble substances in the etching waste liquid by performing impurity removal treatment on the acid etching waste liquid and the alkaline etching waste liquid respectively, and in the production process The reaction conditions are strictly controlled, and chloride ions, ammonia salts and sulfate ions are removed by washing and purifying the intermediate products, so that the copper sulfate produced can reach the electroplating-grade standard.

Further, in the neutralization reaction step of the acid etching waste liquid and the alkaline etching waste liquid, the acid etching waste liquid and the alkaline etching waste liquid are preheated to 43 ℃ ~ 55 ℃ respectively, so as to reduce the gap between the raw material and the crystallization reaction. The temperature difference can avoid unstable reaction, and add basic cupric chloride seed crystal to promote the formation of crystallization, and control the appropriate reaction temperature, pH and stirring speed, not only basic cupric chloride crystallizes quickly, but also the basic cupric chloride obtained by producing High purity, good particle flow, easy to filter, and high recovery rate of copper in etching waste liquid.

Then the high-purity basic copper chloride is reacted with ammonia water to form a copper hydroxide precipitate that is conducive to filtration, washing water purification, and beating. After washing water purification, dechloride ions and ammonium salts are removed to obtain high-purity copper hydroxide slurry. Thus, it is ensured that the purity of copper sulfate produced by subsequent acidification and crystallization can meet the requirements of electroplating grade.

Description of drawings

Fig. 1 is the production process flow diagram of copper sulfate in one embodiment of the present invention.

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the related drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the present disclosure is provided.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

As shown in Figure 1, the production method of the copper sulfate of an embodiment of the present invention comprises the following steps:

S1, add an oxidant to the acid etching waste liquid to oxidize cuprous ions and ferrous ions in the acid etching waste liquid, then adjust the pH value to 1.7～1.9 and stir the reaction, then add activated carbon, and take the The supernatant liquid is filtered to obtain the acid etching waste liquid after impurity removal.

Specifically, adding an oxidant to the acid etching waste liquid until the solution is green and transparent is the oxidation end point, the cuprous ions in the acid etching waste liquid are oxidized to divalent cupric ions, the ferrous ions are oxidized to ferric ions, and at the same time , arsenite is oxidized to arsenate. Arsenate reacts with iron ions, aluminum ions, etc. in the acid etching waste liquid to form stable iron arsenate and aluminum arsenate precipitates. If the color of the acid etching waste liquid is black and opaque, it is necessary to continue adding oxidant until the solution is green and transparent. It can be understood that, it can also be determined whether the oxidation end point is reached by a method such as sampling and detecting the cuprous and ferrous iron therein.

Further, by adjusting the pH value of the acid etching waste liquid, the pH value will be strictly controlled between 1.7 and 1.9, and the reaction is stirred for 0.5 to 3 hours. A small amount of divalent copper ions in the acid etching waste liquid is converted into copper mud, and co-precipitation occurs by adsorbing iron arsenate and aluminum arsenate. Then, an appropriate amount of activated carbon was added to adsorb organic impurities in the acid etching waste liquid, and after standing for about 10 hours, the water-insoluble substances such as iron arsenate, aluminum arsenate, copper mud and organic impurities were removed by sedimentation, stratification, and filtration to obtain electroplating-grade sulfuric acid. Acid etching waste liquid required for copper production. It can be understood that in order to meet the requirements of etching quality and performance in the PCB etching process, organic compounds are usually added to the etching solution to further improve the etching quality and rate, resulting in organic compounds in the etching waste solution, and these organic additives are often It is difficult to separate. Therefore, in order to ensure the purity of copper sulfate, an appropriate amount of activated carbon with strong adsorption capacity is added for adsorption and impurity removal to remove organic impurities in the etching waste liquid.

In one of the embodiments, the oxidizing agent is selected from at least one of sodium chlorate, hydrogen peroxide and potassium chlorate.

In one embodiment, the oxidizing agent is sodium chlorate. Further, a sodium chlorate solution with a concentration of 0.2g/L to 0.3g/L is used as the oxidant. In this way, the cuprous acid in the acid etching waste liquid is converted into divalent copper: 6Cu ⁺ +ClO ₃ -+6H ⁺ →6Cu ²⁺ +3H ₂ O+Cl-; ferrous iron is converted into ferric iron: 6Fe ²⁺ +ClO ₃ -+6H ⁺ →6Fe ³⁺ +3H ₂ O+Cl-; arsenite is converted to arsenate: AsO ₃ ^3- +ClO ₃ -+4H ⁺ →AsO ₄ ^3- +Cl-+2H ₂ O.

In one embodiment, the pH is adjusted to 1.7-1.9 with ammonia water, and the reaction is stirred for about 2 hours, so that the iron arsenate precipitation in the acidic etching waste liquid is co-sedimented together with the copper mud.

The iron ions in the acid etching waste liquid react with arsenate to form iron arsenate: Fe ³⁺ +AsO ₄ ^3- →FeAsO ₄ ↓, and the aluminum ions in the acid etching waste liquid react with arsenate to form aluminum arsenate: Al ³⁺ +AsO ₄ ^3- →AlAsO ₄ ↓. By adjusting the pH of the acid etching waste liquid to 1.7-1.9 with ammonia water, a small amount of chloride ions, copper ions and ammonia water in the acid etching waste liquid are reacted to form copper mud: 2CuCl ₂ +2NH ₃ ·H ₂ O→Cu(OH) ₂ ·CuCl ₂ ↓+2NH ₄ Cl, copper slime adsorbs iron arsenate and aluminum arsenate, and co-precipitates together to remove impurities such as arsenic, iron and aluminum. At the same time, adjusting the pH with ammonia water will not introduce new impurities, and the basic cupric chloride mother liquor produced in the subsequent step of generating basic cupric chloride is convenient for recycling, and can further reduce the pressure of sewage treatment.

During the experiment, the inventor found that when the pH value of the acid etching waste liquid was adjusted to 2.5 or above by adding ammonia water, the amount of co-precipitation was significantly increased, indicating that a large amount of copper ions reacted with ammonia water to form copper mud, which would lead to etching waste. The recovery rate of copper in the liquid is greatly reduced.

In one embodiment, the weight-to-volume ratio of the amount of activated carbon to the acid etching waste liquid to be treated is (0.2-0.3) g:1L. It can be understood that adding 0.2g to 0.3g of activated carbon per 1 liter of acid etching waste liquid can effectively adsorb organic impurities in the etching waste liquid and achieve the effect of removing organic impurities.

In one of the embodiments, the Baume degree of the acid etching waste solution after impurity removal is 24Be°˜30Be°, and the pH value is 1.0˜1.5.

In one embodiment, the mesh number of the filter screen for filtering the supernatant is 2500 meshes. In this way, the sediment and other fine impurities in the solution can be removed more effectively, and the effect of filtration and purification can be improved.

In one of the embodiments, the sedimentation mud of the acid etching waste liquid is dissolved with ammonia water to form a cupro ammonia solution after sedimentation and stratification, which can be used for reproduction and achieve the effect of recycling. Specifically, when the sedimentation mud and ammonia water are mixed, the ammonia water is added first, then the sedimentation mud is added, and the materials are cross-feeding, and the pH of the cupro-ammonia solution after the reaction is completed is about 8.8.

S2, adding soluble magnesium salt to the alkaline etching waste liquid and stirring the reaction, after sedimentation and stratification, the supernatant liquid is taken for filtration treatment, and the alkaline etching waste liquid after impurity removal is obtained. It can be understood that the soluble magnesium salt is selected from at least one of magnesium chloride, magnesium sulfate, and magnesium nitrate.

Preferably, magnesium chloride is used. Specifically, adding magnesium chloride hexahydrate solution to the alkaline etching waste liquid, stirring and reacting for 0.5 to 2 hours, in this way, magnesium ions react with arsenate ions or arsenite ions to form a precipitate: 3Mg ²⁺ +2AsO ₄ ^3- =Mg ₃ (AsO ₄ ) ₂ ↓, 3Mg ²⁺ +2AsO ₃ ^3- =Mg ₃ (AsO ₃ ) ₂ ↓. Then, the layers are separated by standing and sedimentation, and the supernatant liquid is taken for filtration treatment to obtain an alkaline etching waste liquid from which impurities such as arsenic and water-insoluble matter are removed.

Further, the added weight of magnesium chloride hexahydrate and the volume ratio of the alkaline etching waste liquid are 2g/L～2.5g/L. Specifically, first add 400Kg of magnesium chloride hexahydrate into 4m3 of water, stir well, and prepare a solution of magnesium chloride hexahydrate, then take 0.5m3 to 0.6m3 of magnesium chloride hexahydrate solution and add it to 25m3 of alkaline etching waste liquid, and stir for 0.5 ~2 hours.

In one of the embodiments, the Baume degree of the alkaline etching waste solution after impurity removal is 12Be°˜20Be°, and the pH value is 8.0˜9.0.

It can be understood that the steps S1 and S2 do not have a clear sequence, and the two can be performed simultaneously. If the acid etching waste liquid or alkaline etching waste liquid contains solid impurities such as sand and gravel, the etching waste liquid needs to be filtered and impurity removal treatment to filter out the solid particle impurities such as sand and gravel in the etching waste liquid and improve the subsequent purification. effect and efficiency, otherwise the filtering step can be omitted.

S3, mixing and reacting the acid etching waste liquid after impurity removal and the alkaline etching waste liquid after impurity removal to obtain basic cupric chloride.

Specifically, the acid etching waste liquid after impurity removal in step S1 and the alkaline etching waste liquid after impurity removal in step S2 are respectively preheated to 43° C. to 55° C. Mix under the conditions of 68 ℃～72 ℃, and the stirring speed is 65r/min～85r/min, and then carry out pressure filtration to collect the solid to obtain basic cupric chloride.

Further, the addition amount of the basic copper chloride seed crystal is 70Kg/15m ³ to 100Kg/15m ³ . It can be understood that the ratio of the weight of the added basic copper chloride seed crystal to the volume of the acid etching waste liquid and the alkaline etching waste liquid is 70Kg/15m ³ to 100Kg/15m ³ .

By preheating the acid etching waste liquid and the alkaline etching waste liquid to a suitable temperature of 43 ° C ~ 55 ° C respectively before the reaction, in order to reduce the temperature gap between the raw material and the crystallization reaction, avoid the unstable reaction, and add seeds to promote Crystal formation, control the appropriate reaction temperature and stirring speed, improve the generation efficiency of basic cupric chloride and the recovery rate of copper in the etching waste liquid. In the production process, it was found that when the stirring speed was adjusted to 90 r/min, the particle size of the generated basic cupric chloride was less than 30 μm, which adhered together and was difficult to wash and filter, and the moisture content of the filter cake was high, which was not conducive to industrial production.

In one embodiment, the basic cupric chloride seed crystals are added in the form of being dispersed in a saturated aqueous basic cupric chloride solution or a dispersion of the filtrate obtained by filtration of a mixed solution containing basic cupric chloride.

Specifically, adding water or basic cupric chloride mother liquor into the reactor, stirring and heating to 68°C-72°C, then adding basic cupric chloride seed crystals. Wherein, the basic cupric chloride mother liquor is the filtrate produced by filtration of the mixed solution containing basic cupric chloride in step S3.

In one embodiment, during the reaction process of the acid etching waste liquid after impurity removal and the alkaline etching waste liquid after impurity removal, the acid etching waste liquid after impurity removal and preheating is continuously added and impurity removal and preheating The pH value of the last alkaline etching waste liquid when the acid etching waste liquid and the alkaline etching waste liquid are reacted is 4.30-5.00.

Further, the flow rate of the acidic etching waste liquid after impurity removal and the alkaline etching waste liquid after impurity removal is controlled to be 2 cubic meters per hour to 6 cubic meters per hour . By strictly controlling the flow rate of the acid etching waste liquid and the alkaline etching waste liquid after removing impurities in the reaction process, it is convenient to adjust the pH of the reaction system to maintain between 4.30 and 5.00, so as to make the reaction more sufficient, improve the production efficiency, and at the same time promote the etching waste The recovery of copper in the liquid has high purity in the obtained basic copper chloride.

S4, the basic cupric chloride obtained in step S3 is reacted with ammonia water to form a precipitate, filtered to obtain a filter residue, purified by washing water, and added with water for beating to obtain a copper hydroxide slurry.

Specifically, ammonia water with a concentration of 20wt% is fully reacted with the basic copper chloride prepared in step S3 to generate copper hydroxide: Cu ₂ (OH) ₃ Cl+4NH ₃ ·H ₂ O→Cu(OH) ₂ ↓ +[Cu(NH ₃ ) ₄ ] ²⁺ +Cl-, then pressure filtration, the obtained filter cake is purified by washing water, and tap water is added for beating to obtain copper hydroxide slurry.

Further, according to the ratio of 1Kg basic cupric chloride to 1.2L-1.3L of 20wt% ammonia water, the ammonia water and basic cupric chloride are mixed and reacted. By controlling the ratio of ammonia water and basic cupric chloride, basic cupric chloride is fully converted into cupric hydroxide, and the filter cake after pressure filtration is purified by washing water to effectively remove residual chloride ions and ammonia salts in the filter cake .

S5, adding sulfuric acid to the copper hydroxide slurry obtained in step S4 and adjusting the pH value of the copper hydroxide slurry to 0.5-1.0, and then performing thermal filtration to obtain a mixed solution containing copper sulfate; The liquid is cooled and crystallized, and the solid-liquid separation is carried out to obtain filter residue and filtrate, and the filter residue is dried to obtain copper sulfate.

Specifically, 98% by mass of concentrated sulfuric acid is added to the copper hydroxide slurry for acidification to generate copper sulfate: Cu(OH) ₂ +H ₂ SO ₄ =CuSO ₄ +2H ₂ 0 . With the addition of concentrated sulfuric acid, the pH value of the mixed system gradually decreases, and the acidification is completed when the pH value drops to 0.5 to 1.0. Due to the mixed reaction of concentrated sulfuric acid with copper hydroxide and water, a large amount of heat is generated, and even the solution is partially boiled. When the acidification is completed, the temperature of the reaction system reaches about 100 °C; then the reaction system is subjected to hot pressure filtration to obtain copper sulfate-containing Mixed solution; cool the mixed solution containing copper sulfate to below 45°C, copper sulfate crystals are precipitated, copper sulfate crystals and filtrate are obtained after solid-liquid separation, and copper sulfate crystals are dried to obtain copper sulfate products (CuSO ₄ ·5H ₂ 0), the impurity content of the obtained copper sulfate production is low and reaches the electroplating grade standard.

In one embodiment, the filtrate obtained after cooling, crystallization and filtration of the mixed solution containing copper sulfate is circulated to step S5 to replace part of the concentrated sulfuric acid to acidify the copper hydroxide slurry. In this way, the consumption and cost of concentrated sulfuric acid can be effectively saved, and at the same time, the pressure and cost of waste liquid treatment can be reduced.

The following are specific examples

Example 1

1. Acid etching waste liquid removal:

Add 5m3 of tap water to the sodium chlorate dispensing tank, then add 2 tons of solid sodium chlorate, and stir to prepare a sodium chlorate solution.

Start the acid etching waste liquid lift pump, start pressure filtration, the generated filtrate overflows to the acid etching waste hydraulic filter tank, and the filtrate is lifted to the acid etching waste liquid purification tank by the pressure filter tank lift pump for purification treatment.

Turn on the mixer, add sodium chlorate solution to the acid etching waste liquid purification tank to oxidize Cu ⁺ and Fe ²⁺ in the acid etching waste liquid to Cu ²⁺ and Fe ³⁺ , and judge the oxidation end point according to the color of the acid etching waste liquid. When the acid etching waste liquid is green and transparent, it is the oxidation end point, and there is no need to continue adding sodium chlorate solution; otherwise, continue adding sodium chlorate solution until it is green and transparent. Add ammonia water to the purification tank, adjust the pH value of the acid etching waste liquid to 1.8, react for about 2 hours, and then stop stirring.

Based on the ratio of the weight of activated carbon to the volume of acid etching waste liquid, add activated carbon to the acid etching waste liquid purification tank at a rate of 5Kg/20m ³ to 6Kg/20m ³ to adsorb organic impurities such as petroleum. Then, it was left to settle for about 10 hours, and the precipitation was layered with the supernatant. The supernatant was filtered through a precision filter and lifted to the acid etching waste liquid working tank for use.

The acid etching waste liquid before and after removal of impurities is detected, and the results are shown in Table 1 below, and the degree of Baume after removal of impurities is 29Be °.

Table 1 Indexes of acid etching waste liquid before and after removal of impurities

index pH Cu²⁺(g/L) Fe(ppm) Al(ppm) As(ppm) Organic impurities Before impurity removal -1 110 35 7 2 a small amount After cleaning 1.5 100 20 5 0.3 none

2. Removal of impurities from alkaline etching waste liquid

Add 0.6m ³ of magnesium chloride hexahydrate solution with a concentration of 0.1Kg/L into the 25m ³ alkaline etching waste liquid, stir for about 45 minutes, to remove the arsenic in the alkaline etching waste liquid, and let stand for about 10 hours to carry out sedimentation and stratification, The supernatant is filtered through a precision filter, and the filtrate is lifted to the alkaline etching waste liquid working tank for use.

The alkaline etching waste liquid before and after removal of impurities is detected, and the results are shown in Table 2 below, and the degree of Baume after removal of impurities is 27Be °.

Table 2 Indexes of alkaline etching waste liquid before and after removal of impurities

index pH Cu(g/L) As(ppm) Organic impurities Before impurity removal 8 100 9 a small amount After cleaning 8.5 90 0.1 none

3. Neutralization reaction to produce basic copper chloride

1) Seed preparation

Add tap water to the crystallizing tank until the designated position, that is, just immersing the steam pipe in the crystallizing tank. During the process of pumping tap water into the crystallization reaction tank, start the mixer of the crystallization tank, the stirring speed is 75r/min, and open the self-circulation of the crystallization tank.

Open the steam heating valve, raise the temperature of the material in the crystallization tank to 70 ± 2 °C, and close the steam heating valve when the temperature is reached. Add 80Kg of basic copper chloride seed crystals to the crystallizing tank.

2) Raw material preheating

Start the acid etching waste liquid infusion automatic control device, feed into the acid etching waste liquid preheating tank, turn on the steam, and raise the temperature to 45°C.

Start the automatic control device for alkaline etching waste liquid infusion, feed into the alkaline etching waste liquid preheating tank, turn on the steam, and raise the temperature to 45°C.

3), production start

When the temperature of the material in the crystallizing tank reaches 70±2°C and the temperature of the material in the preheating tank reaches 45°C, the acid etching waste liquid and alkaline etching waste liquid feed pumps are respectively started to feed into the crystallizing tank.

In the process of production and start-up, ensure that the temperature of the reaction crystallization in the crystallization tank is 68 ℃ ~ 72 ℃, and the rotation speed of the crystallization stirring is 75r/min. The feeding amount is gradually increased from small to 6000L/h, and the pH value of the material in the crystallization tank is reduced from 7 to pH 4.30-5.0, and the pH is slowly adjusted until the production of basic copper chloride is normal.

4), after the production of basic cupric chloride is normal, and the liquid level in the crystallizing tank reaches 30cm～50cm from the top of the tank, the basic cupric chloride slurry in the crystallizing tank is pumped into the filter press to carry out pressure filtration and dehydration, The filtrate, the basic cupric chloride mother liquor, flows into the clarification barrel, and overflows into the crystallization mother liquor pool from the clarification barrel; the filter cake is basic cupric chloride.

4. Basic copper chloride to chlorine

The filtered basic cupric chloride is transferred to the ammonia transfer tank, and 1 ton of basic cupric chloride is mixed with 1.2 cubic meters of 20 wt% ammonia water, and the ammonia water is pumped for reaction, and copper hydroxide is generated after the reaction for about 0.5 hours.

5. Copper hydroxide washing water beating

The copper hydroxide in the ammonia transfer tank is pumped into the copper hydroxide filter press for pressure filtration. After the filter cake is washed with water, the copper hydroxide is discharged into the copper hydroxide beating tank, and tap water is added for beating to obtain hydroxide. copper paste.

6. Sulfuric acid acidification

Pump the slurry in the copper hydroxide beating tank into the acidification tank. After pumping, start adding 98% concentrated sulfuric acid. The pH of the acidification end point is 0.8 and the temperature is about 100 °C. After the acidification is completed, the acidified hot material is pressed. Filter by filter, the filtrate enters the crystallizing tank, the cooling water of the crystallizing tank is opened for cooling, and the slurry is centrifuged, washed, centrifuged, dried and packaged after cooling to below 45°C to obtain copper sulfate product.

7. Detection

The copper sulfate product obtained from the production is detected, and the detection results are shown in Table 3 below.

The detection index of table 3 copper sulfate products

Example 2

Example 2 is basically the same as Example 1, except that the basic cupric chloride mother liquor produced in Example 1 is used to replace the tap water in Example 1.

Example 3

Embodiment 3 is basically the same as embodiment 2, and the difference lies in the following aspects:

1), in the acid etching waste liquid impurity removal step, the pH value of the adjustment of the acid etching waste liquid is different by adding ammonia water to the purification tank, the pH value of embodiment 2 is 1.8, and the pH value of embodiment 3 is 1.9.

2) The raw materials are different, specifically:

The Baume degree of the acid etching waste liquid before the impurity removal is 27Be°, the pH value is -0.5, and the Baume degree after the impurity removal is 26Be°, and the pH value is 1.5;

The Baume degree of the alkaline etching waste liquid before impurity removal is 16Be° and the pH value is 10.5, and the Baume degree after impurity removal is 15Be° and the pH value is 9.0.

3) The preheating temperature is different, specifically: the preheating temperature of Example 2 is 45°C, and the preheating temperature of Example 3 is 48°C.

Example 4

Embodiment 4 is basically the same as embodiment 2, and the difference lies in the following aspects:

1), in the acid etching waste liquid removing impurity step, add ammonia water to the purification tank to adjust the pH value of the acid etching waste liquid is different, the pH value of embodiment 2 is 1.8, and the pH value of embodiment 4 is 1.7.

2) The raw materials are different, specifically:

The Baume degree of the acid etching waste liquid before the impurity removal is 25Be°, the pH value is -0.8, and the Baume degree after the impurity removal is 24Be°, and the pH value is 1.2;

The Baumé degree of the alkaline etching waste liquid before impurity removal is 13Be° and the pH value is 9, and the Baumé degree after impurity removal is 12Be° and the pH value is 8.5.

3) The preheating temperature is different, specifically: the preheating temperature of Example 2 is 45°C, and the preheating temperature of Example 4 is 55°C.

The copper sulfate products obtained in Examples 2 to 4 were sampled and detected. According to the statistical analysis of the detection results, the quality of the copper sulfate products obtained in Examples 2 to 4 met the standards in Table 4 below, and all met the requirements of electroplating-grade copper sulfate.

Table 4 Detection indicators of copper sulfate products

Comparative Example 1

Comparative Example 1 is basically the same as Example 1, the difference is that adding ammonia water to the purification tank will adjust the pH value of the acid etching waste liquid and adjust the pH value of the copper hydroxide slurry. The pH value of the acid etching waste liquid was adjusted to 1.8, and the pH value of the acid etching waste liquid was adjusted to 1.2 in Comparative Example 1. The pH value of the copper hydroxide slurry was adjusted to 0.8 in Example 1, and the pH value of the copper hydroxide slurry was adjusted to 1.5 in Comparative Example 1.

The copper sulfate product obtained from the production is detected, and the results are shown in Table 5 below.

Table 5 comparative example 1 copper sulfate product detection index

As can be seen from the above table 5, the copper sulfate product produced in Comparative Example 1 does not meet the electroplating grade standard.

Comparative Example 2

Comparative example 2 is basically the same as embodiment 2, and the difference lies in the following aspects:

1) In step 4, the reagent added in the reaction with basic cupric chloride is different. What is added in Example 2 is 20wt% ammonia water, and what is added in Comparative Example 2 is a 20wt% sodium hydroxide solution. Correspondingly, the reaction is generated after about 0.5 hours. The precipitates are also different, Example 2 is a blue flocculent copper hydroxide precipitate, and Comparative Example 2 is a brown-black flake-like copper oxide precipitate.

2) The operation of step 5 copper oxide washing water beating is the same as that of embodiment 2, the difference is that the operation object of embodiment 2 is copper hydroxide, the operation object of comparative example 2 is copper oxide, and what is obtained is copper oxide slurry .

3) The operation of sulfuric acid acidification in step 6 is the same as that of Example 2, except that the acidification object of sulfuric acid in Example 2 is copper hydroxide, and the acidification object of Comparative Example 2 is copper oxide.

The copper sulfate product obtained from the production is detected, and the results are shown in Table 6 below.

Table 6 comparative example 2 copper sulfate product detection index

During operation, it was found that since the copper oxide in Comparative Example 2 was precipitated as flakes, it was difficult to separate by filtration and purify with washing water.

As can be seen from the above table 6, the copper sulfate production of Comparative Example 2 does not meet the electroplating grade standard, especially the content of chloride greatly exceeds the electroplating grade standard.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. a production method of copper sulfate, is characterized in that, comprises the steps: Add an oxidant to the acid etching waste liquid to oxidize cuprous ions and ferrous ions in the acid etching waste liquid, then adjust the pH value to 1.7-1.9 and stir the reaction, then add activated carbon, and take the supernatant after sedimentation and stratification The liquid is filtered to obtain the acid etching waste liquid after impurity removal; The soluble magnesium salt is added to the alkaline etching waste liquid for reaction, and the supernatant liquid is filtered after sedimentation and stratification to obtain the alkaline etching waste liquid after impurity removal; The acidic etching waste liquid after the impurity removal and the alkaline etching waste liquid after the impurity removal are preheated to 43° C. to 55° C. respectively, and then mixed and reacted in the presence of basic copper chloride seeds to obtain The basic copper chloride; The basic cupric chloride is reacted with ammonia water to form a precipitate, filtered to obtain a filter residue, purified by washing water, and added with water to make a slurry to obtain a copper hydroxide slurry; adding sulfuric acid to the copper hydroxide slurry and adjusting the pH value of the copper hydroxide slurry to 0.5-1.0, and then performing hot filtration treatment to obtain a copper sulfate-containing mixed solution; mixing the copper sulfate-containing The liquid is cooled and crystallized, and the solid-liquid separation is performed to obtain copper sulfate crystals, which can be dried. 2 . The production method of copper sulfate according to claim 1 , wherein the reagent used for adjusting the pH value to 1.7 to 1.9 is ammonia water. 3 . 3 . The method for producing copper sulfate according to claim 1 , wherein the mass volume ratio of the activated carbon to the acid etching waste liquid is (0.2～0.3) g:1L. 4 . 4. the production method of copper sulfate according to claim 1, is characterized in that, the Baume degree of the acid etching waste liquid after described impurity removal is 24Be °～30Be °, and pH value is 1.0～1.5. 5 . The production method of copper sulfate according to claim 1 , wherein the Baumé degree of the alkaline etching waste liquid after the described impurity removal is 12Be°～20Be°, and the pH value is 8.0～9.0. 6 . 6. the production method of copper sulfate according to any one of claim 1～5, is characterized in that, in the step that described basic cupric chloride and ammoniacal liquor are reacted to generate precipitation, the concentration of ammoniacal liquor used is 20wt%, so The volume-to-weight ratio of the ammonia water to the basic copper chloride is (1.2-1.3) L:1Kg. 7 . The method for producing copper sulfate according to claim 1 , wherein the concentration of the sulfuric acid is greater than or equal to 98 wt %. 8 . 8. the production method of copper sulfate according to any one of claim 1～5, is characterized in that, the acid etching waste liquid after described impurity removal and the alkaline etching waste liquid after described impurity removal are in basic chlorine The mixing reaction in the presence of the copper ion seed crystal is a reaction at 68° C. to 72° C. and a stirring speed of 65 r/min to 85 r/min. 9. the production method of copper sulfate according to claim 8, is characterized in that, in the acid etching waste liquid after the impurity removal and the alkaline etching waste liquid after the impurity removal in the reaction process, continue to add impurity removal and preheating The pH value of the acid etching waste liquid and the alkaline etching waste liquid after removing impurities and preheating is 4.30-5.00 when the acid etching waste liquid and the alkaline etching waste liquid are reacted. 10. the production method of copper sulfate according to claim 9, is characterized in that, the flow rate of described continuous adding the acid etching waste liquid after preheating and the alkaline etching waste liquid after preheating is controlled at 2 cubic/hour～ 6 cubic meters per hour.

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