CN1803660A

CN1803660A - High-efficiency environment-friendly acid-mixed plating removal liquor

Info

Publication number: CN1803660A
Application number: CN 200610037957
Authority: CN
Inventors: 王水平; 丁四宜
Original assignee: YUHE METAL MATERIAL CO Ltd CHANGZHOU CITY
Current assignee: YUHE METAL MATERIAL CO Ltd CHANGZHOU CITY
Priority date: 2006-01-24
Filing date: 2006-01-24
Publication date: 2006-07-19
Anticipated expiration: 2026-01-24
Also published as: CN100441520C

Abstract

The invention relates to a high-efficiency environmental-friendly utilization method for acid-mixed removal plating liquid, which comprises: putting the liquid into reaction kettle, adding Na2CO3 or NaOH to neutralize free HNO3 and H2SO4, separating the micro impurity of iron, chrome and aluminum as hydroxide precipitate, and controlling the pH value; filtering, adding Na2CO3 saturated solution for neutralization, and adding a little CaCO3 to deposit copper as CuSO4 and excessive SO4- as CaSO4; filtering, preparing CuSO4 with slag and H2SO4, separating CuS and ZnS with added H2S gas; filtering again, adding Na2CO3 or NaHCO3 to deposit the nickel as basic nickel carbonate or nickel carbonate; filtering, preparing nickel sulfate with slag and sulfuric acid, and preparing NaNO3 product as normal technique. This invention makes full use of the sewage.

Description

Efficient and environment-friendly utilization method of mixed acid deplating liquid

Technical Field

The invention relates to an efficient and environment-friendly utilization method of a high-acidity deplating liquid, in particular to an efficient and environment-friendly utilization method of a nitric acid and sulfuric acid mixed acid deplating liquid.

Background

The main components of the mixed acid are more than 80% of nitric acid and less than 20% of sulfuric acid, and in the electroplating industry, because the plating layer sometimes treated is not ideal, the plating layer needs to be removed by the mixed acid and then electroplated again, and waste liquid, namely mixed acid deplating liquid, is generated in the process. The mixed acid deplating liquid mainly contains copper, nickel, sulfuric acid and a large amount of free nitric acid, wherein the free nitric acid accounts for more than 50 percent (G/V), and the mixed acid deplating liquid also contains trace iron, chromium, aluminum, zinc and other components. The existing method for treating and utilizing the waste liquid is mainly to evaporate nitric acid by a direct heating method, and then supplement a small amount of sulfuric acid to generate copper sulfate and a nickel sulfate crude product or prepare a mixed oxide, but in the existing treatment method, although the mixed acid deplating liquid can be treated, the valuable components of the mixed acid deplating liquid cannot be completely utilized, the sulfuric acid, the copper and the nickel in the mixed acid deplating liquid can only be treated into valuable products, and the rest components are all discharged as wastes, so that the production cost is increased, on the other hand, a large amount of resource waste and environmental pollution are caused, the treatment cost is increased to a great extent if the produced large amount of waste water and waste gas are subjected to independent harmless treatment, and secondary pollution is caused if the waste water and waste gas are not treated, so that the environmental protection cannot be achieved. People are always researching and improving a method for completely utilizing valuable components of mixed acid deplating solution, avoiding the waste of resources, changing waste into valuable, eliminating pollution and really realizing recycling economic utilization, but the problem is always difficult to solve.

Disclosure of Invention

The invention aims to provide a high-efficiency environment-friendly utilization method of mixed acid deplating solution, which can save resources, reduce cost, protect environment and fully utilize valuable components, aiming at the defects of the prior art.

The technical scheme for realizing the purpose is as follows: a high-efficiency environment-friendly utilization method of mixed acid deplating solution comprises the following steps: putting the mixed acid deplating solution into a reaction kettle, firstly adding sodium carbonate or sodium hydroxide to neutralize free nitric acid and sulfuric acid, hydrolyzing impurities such as trace iron, chromium, aluminum and the like to precipitate and separate out by hydroxide, and controlling the pH value in the whole reaction; filtering, adding sodium carbonate saturated solution into the filtrate for neutralization, adding a small amount of calcium carbonate to precipitate copper in the form of basic copper sulfate, and precipitating excessive sulfate radicals in the form of calcium sulfate; filtering, neutralizingthe filter residue with sulfuric acid to obtain copper sulfate, reacting the filtrate with hydrogen sulfide gas to separate out trace copper and zinc sulfide; then filtering, adding sodium carbonate or sodium bicarbonate into the filtrate to precipitate nickel in the form of basic nickel carbonate or nickel carbonate; and filtering, reacting the filter residue with sulfuric acid to prepare nickel sulfate, and preparing the sodium nitrate product from the filtrate by a conventional method.

The main chemical reaction formula of the invention is as follows:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14) ↑

the efficient and environment-friendly utilization method of the mixed acid deplating solution has the advantages that: (1) the method can treat nickel, copper and nitric acid with extremely high utilization value in the mixed acid deplating solution, and can obtain high-quality valuable copper sulfate, nickel sulfate and sodium nitrate products. The copper sulfate can be used as agricultural pesticide and nonferrous metal flotation agent and used for manufacturing other chemical industry raw materials; the nickel sulfate is used for electroplating, a nickel battery mordant, a metal colorant, an organic synthesis catalyst, a color glaze in the ceramic industry, a nickel catalyst, the manufacture of other nickel salts and the like; sodium nitrate is used as a raw material for producing potassium nitrate, explosives, picric acid dyes and the like, as a glass defoaming agent, a flux and an oxidizing agent in the enamel industry, a tobacco combustion improver, a metal cleaning agent, a penicillin culture agent, an aluminum alloy heat treatment agent, a molten caustic soda decolorant and the like, and is also used as a fertilizer in agriculture. The utilization method of the invention can change waste into valuable and improve the economic added value. (2) The method can also recycle the nitrogen oxides and nitric acid steam which are pollution sources and are generated in the original treatment method, and convert the nitrogen oxides and nitric acid steam into valuable sodium nitrate which is available in market penetration, thereby realizing the complete conversion of valuable components. The invention originally creates the complete utilization of mixed acid deplating liquid for treating nickel, copper and nitric acid, realizes the real high-efficiency utilization and avoids the great waste of resources. The impurity components such as trace iron, chromium, aluminum, zinc and the like contained in the mixed acid deplating liquid can be processed into valuable components by the method, and a small amount of calcium sulfate and trace copper and zinc sulfides produced in the method are also valuable components. (3) And no nitrogen oxide is discharged in the whole treatment and utilization process, and nitrogen oxide generated in the technological process completely absorbs the waste gas by alkali liquor due to the adoption of the gas suction principle of a jet pump, so that the waste gas is not harmful to human health, the method is very environment-friendly, and the requirement of circular economy is met. (4) The method has the advantages of no three-waste discharge after treating the mixed acid stripping solution, low use cost, no secondary pollution and environmental protection. In a word, the utilization method saves resources, reduces the cost, protects the environment, realizes the cyclic utilization of the resources, and is a novel, efficient and environment-friendly method for utilizing the mixed acid deplating solution, which can fully utilize valuable components.

Drawings

FIG. 1 is a block diagram of a process flow of the present invention.

FIG. 2 is a flow diagram of the process equipment of the present invention.

Detailed Description

The invention is explained in more detail below with reference to the figures and examples.

As shown in fig. 1, an embodiment of a high-efficiency environment-friendly utilization method of mixed acid deplating solution comprises the following steps: putting the mixed acid deplating solution into a reaction kettle, firstly adding sodium carbonate or sodium hydroxide to neutralize free nitric acid and sulfuric acid, hydrolyzing impurities such as trace iron, chromium, aluminum and the like to precipitate and separate out by hydroxide, and controlling the pH value in the whole reaction; filtering, namely filtering iron hydroxide, chromium hydroxide and aluminum hydroxide filter residues, wherein the main components in the filtrate are sodium nitrate, sodium sulfate, copper ions, zinc ions and nickel ions, heating to 80-85 ℃ when the pH reaches 3.8-4, keeping the temperature and stirring for 1 hour, combining a small amount of washing liquor in the filtrate, sending the filtrate into a copper precipitation cylinder, heating to 80-85 ℃, slowly adding a sodium carbonate saturated solution into the filtrate to neutralize the filtrate to pH 5.5-6, adding a small amount of calcium carbonate according to the sulfate radical content in the filtrate until the final copper content and the sulfate radical content meet the requirements, keeping the temperature for 1 hour, precipitating copper in the form of basic copper sulfate, and precipitating excessive sulfate radicals in the form of calcium sulfate; filtering, wherein the filter residue part mainly comprises basic copper sulfate and calcium sulfate, the filter residue is subjected to neutralization reaction with sulfuric acid to prepare copper sulfate through filtering and washing, a small amount of white residue after the copper sulfate is washed can be used for preparing precipitated calcium sulfate, the filter filtrate part mainly comprises nickel nitrate, sodium nitrate, trace copper ions and zinc ions, and the filter filtrate reacts with added hydrogen sulfide gas to separate out trace copper and zinc sulfides so that copper and zinc meet the requirements; filtering, wherein filter residues are trace copper sulfide and zinc sulfide, the main components of the filtrate are nickel nitrate and sodium nitrate, heating the filtrate to 70-80 ℃, slowly adding a sodium carbonate or sodium bicarbonate saturated solution into the filtrate to neutralize the filtrate to the pH value of 7.5-8, and stirring for 1 hour under heat preservation to precipitate nickel in the form of basic nickel carbonate or nickel carbonate; and filtering to obtain basic nickel carbonate or nickel carbonate as filter residue, reacting the filter residue with sulfuric acid to prepare nickel sulfate and sodium nitrate as filtrate, and concentrating, crystallizing, dehydrating, drying and crushing the filtrate by a conventional method to prepare a sodium nitrate product.

As shown in figure 2, the efficient and environment-friendly utilization method of the mixed acid deplating solution can be realized by the following equipment in the process flow diagram, wherein the equipment comprises 1 a waste gas absorption cylinder, 2 an impurity removal neutralization cylinder, 3 a copper deposition cylinder, 4 a nickel purification cylinder, 5 a nickel deposition cylinder, 6 a copper sulfate formation cylinder, 7 a nickel sulfate synthesis cylinder, 8 a nickel sulfate concentration cylinder, 9 a nickel sulfate waste heat vacuum evaporation crystallization cylinder, 10 a copper sulfate water-cooling crystallization cylinder, 11 a sodium nitrate concentration cylinder, 12-19 a washing water guide washing cylinder, 20-25 a vacuum suction filtration basin, 26, a filter, 27-28, a spin dryer, 29, a nickel sulfate mother liquor pool (back concentration cylinder), 30, a copper sulfate mother liquor pool (mother liquor back copper sulfate synthesis cylinder), 31-36 and a storage suction filtration cylinder. The equipment can be made of acid-resistant stainless steel or reinforced polypropylene, and the impurity removal neutralization cylinder 2, the copper precipitation cylinder 3, the nickel purification cylinder 4, the nickel precipitation cylinder 5, the copper sulfate formation cylinder 6 and the nickel sulfate synthesis cylinder 7 are stirred by adopting cylinder belts, the stirring speed is preferably 120 revolutions per minute, and the stirring speed of the nickel sulfate waste heat vacuum evaporation crystallization cylinder 9 and the copper sulfate water-cooling crystallization cylinder 10 is preferably 20 revolutions per minute. And (3) feeding the material from the outlet of the sodium nitrate concentration cylinder 11 to a cooling tank, naturally cooling, crystallizing, dehydrating, drying and crushing to prepare a sodium nitrate product. In the process equipment flow chart shown in figure 2, the materials are conveyed by adopting a vacuum mode for suction, so that the phenomena of fluid leakage and equipment easy damage caused by pump conveying are avoided, and meanwhile, hydroxide harmful substances generated in the impurity removal neutralization cylinder 2 are directly conveyed into the waste gas absorption cylinder 1 and are completely absorbed by adopting an alkali liquor injection pump, so that the process equipment flow chart is very environment-friendly.

Claims

1. A high-efficiency environment-friendly utilization method of mixed acid deplating solution is characterized by comprising the following steps: the method comprises the following steps: putting the mixed acid deplating solution into a reaction kettle, firstly adding sodium carbonate or sodium hydroxide to neutralize free nitric acid and sulfuric acid, hydrolyzing impurities such as trace iron, chromium, aluminum and the like to precipitate and separate out by hydroxide, and controlling the pH value in the whole reaction; filtering, adding sodium carbonate saturated solution into the filtrate for neutralization, adding a small amount of calcium carbonate to precipitate copper in the form of basic copper sulfate, and precipitating excessive sulfate radicals in the form of calcium sulfate; filtering, neutralizing the filter residue with sulfuric acid to obtain copper sulfate, reacting the filtrate with hydrogen sulfide gas to separate out trace copper and zinc sulfide; then filtering, adding sodium carbonate or sodium bicarbonate into the filtrate to precipitate nickel in the form of basic nickel carbonate or nickel carbonate; and filtering, reacting the filter residue with sulfuric acid to prepare nickel sulfate, and preparing the sodium nitrate product from the filtrate by a conventional method.