CN1096009A

CN1096009A - Compound for treatment of electroplating wastes

Info

Publication number: CN1096009A
Application number: CN 93111196
Authority: CN
Inventors: 孙玉芬
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-05-31
Filing date: 1993-05-31
Publication date: 1994-12-07

Abstract

A kind of compound for treatment of electroplating wastes is a kind of aqueous solution that contains hydrazine 8%～15%, sodium sulphite 1g/l～1.5g/l, flocculation agent PM5mg/l～7ml/l.Treatment agent of the present invention can be finished redox, one step of precipitin reaction, needn't regulate its pH value specially before and after handling, and bed drain purge is few, processing is simple to operation, do not need specific equipment.

Description

Compound for treatment of electroplating wastes

The present invention relates to the processing of a kind of processing of waste water, particularly waste electroplating liquor containing chromium.

The treatment process of chromate waste water is a lot of at present, as chemical method, ion exchange method, electroosmose process, electrolytic process etc., wherein chemical reduction method is again a method commonly used, it is to add reductive agent in containing the solution of hexavalent chromium, these reductive agents have ferrous sulfate, sodium bisulfite, sulfurous gas, iron powder etc., they become trivalent chromium to regulate pH value then hexavalent chrome reduction to make it become chromium hydroxide and remove. and these methods have many data introductions. disclose among the clear 60-227882 as opening that a kind of redox under the situation of adjusting PH contains organic chromate waste water with hydrogen peroxide and ferrous salt the Japanese Patent spy, and for example the Japanese Patent spy open disclose among the clear 60-166088 a kind of with sulfuric acid, sodium bisulfite reduction of hexavalent chromium ion is that trivalent chromic ion is regulated pH value and made its precipitation, adds the flocculation agent accelerate precipitation and also removes by filter. their weak point is that the big and waste residue of dosing causes secondary pollution too much.

In view of above-mentioned weak point of the prior art the object of the present invention is to provide the few electroplating wastewater chemical processing agent of a kind of waste residue.

Purpose of the present invention can realize by following measure: a kind of compound for treatment of electroplating wastes is characterized in that: it contains hydrazine, sodium sulphite and flocculation agent PM, and its each component concentration ratio is as follows:

Hydrazine 8%～15% sodium sulphite 1g/l～1.5g/l

The remaining amount of flocculation agent PM 5mg/l～7mg/l. water

The optimum content of this each component of treatment agent is as follows:

Hydrazine 10% sodium sulphite 1g/l

The remaining amount of flocculation agent 5mg/l water.

The present invention mainly adds sodium sulphite and flocculation agent PM with hydrazine simultaneously as main component and constitutes. its main action principle is: hydrazine be the strong reductant sexavalent chrome under acidic conditions with Cr ₂O 2- ₇Form exists, under alkaline condition with CrO 2- ₄Form exists and promptly has column balancing down

General chromium-electroplating waste water is acid, so be with Cr ₂O 2- ₇Form exists. after adding hydrazine, following reaction is arranged, promptly

[H in the solution of reaction back ⁺] reduce, pH value rises can make [Cr ³⁺] [OH ^-] ³＞KspCr(OH) ₃Kspcr(OH) ₃=6.3 * 10 ^-31Therefore can make Cr ³⁺With Cr(OH) ₃Form is precipitated out, and removes chromic purpose thereby reach. because the pH value rising also can be removed other metal sublayer of a part such as Ni in the solution ²⁺, Zn ²⁺, Cu ²⁺, pb ²⁺Wait its reaction formula as follows:

For thoroughly removing metal ion, in treatment agent, add sodium sulphite again, itself and these metal ion has following reaction:

In order to make the precipitation rapid subsidence, thus in treatment agent, add a certain amount of flocculation agent such as polyacrylamide, so that the separation of solid-liquid.The synergy of above-mentioned three kinds of components can make the various heavy metal ion in the electroplating wastewater settle down rapidly. and each about ionic content is in the electroplating wastewater under the usual conditions:

Cr ₂O 2- ₇Sexavalent chrome is 100～150mg/l

Zn ²⁺100mg/l Cu ²⁺50mg/l pb ²⁺10～15mg/l

Hg ²⁺3～10mg/l Ni ²⁺50mg/l

The hydrazine that therefore in this treatment agent, should include some amount, if altogether content be lower than 8% the actual the reaction time that uses to grow, easy oxidation by air when being higher than 15% o'clock long-term existence and reduce its reducing power, and add-on is wayward. can be with about 40% industrial hydrazine hydrate (the hydrate N of hydrazine during actual preparation ₂H ₄.H ₂O) thin up becomes 8～15% the aqueous solution, preferably 10% the aqueous solution.Contain sodium sulphite in order further to remove heavy metal ion treatment agent remaining in the waste water, its content can be allocated according to remaining heavy metal ion content in the waste water, usually with 1g/l～1.5g/l, preferably in treatment agent, also add a certain amount of flocculation agent such as polyacrylamide in addition with 1g/l., its content generally can make the precipitation rapid subsidence at 5mg/l～7mg/l, its optimum content is that 5mg/l. treatment agent of the present invention is when reality is used, should calculate the volume number that should add treatment agent according to the content and the reaction equation of hexavalent chromium in the chromate waste water, the treatment agent of this quantity at room temperature added in the electroplating wastewater promptly can make waste liquid become blackish green by xanthochromia through stirring, and then there is small amount of precipitate to precipitate rapidly, the various ionic content of its supernatant liquor all reach emission standard, can directly discharge.

The present invention has following advantage compared to existing technology:

1. this treatment agent can be finished redox, one step of precipitin reaction.

2. bed drain purge is few.

3. needn't regulate pH value specially before and after handling.

4. handle simple, convenient, do not need specific equipment.

Embodiment 1

Get that to contain sexavalent chrome be 150mg/l, Cu ²⁺Be 60mg/l, Ni ²⁺Be 52mg/l, electroplating wastewater 1 liter of PH=4 directly adds treatment agent of the present invention (N wherein in it ₂H ₄Be 10%, Na ₂S is 1g/l, and PM is 5mg/l) 0.5ml, stir after one minute, solution becomes blackish green by yellow and generates small amount of precipitate, at the bottom of throw out sinks to glass very soon, gets supernatant liquor and analyzes it and form, and the content of its metal ion is respectively: Cr ⁶⁺＜0.02mg/l, Cr ³⁺＜0.02mg/l, Cu ²⁺＜0.05mg/l, Ni ⁺＜0.05mg/l, PH=8.2, each relevant ion all reaches emission standard, can directly discharge, the heavy 0.6g(of remaining throw out does).

Embodiment 2

Get that to contain sexavalent chrome be 95mg/l, Zn ²⁺Be Zincing passivation rinse water 1 liter of 75mg/l, PH=3.8, in it, add 0.4ml treatment agent of the present invention (N wherein ₂H ₄Content be 8%, 1g/l, PM=5mg/l). solid-liquid separation after normal temperature stirs, the content of each metal ion species is respectively in the supernatant liquor: Cr ⁶⁺＜0.02mg/l, Cr ³⁺＜0.02mg/l, Zn ²⁺＜0.5mg/l, PH 7.9 reach emission standard and can directly discharge, and remaining throw out is that 0.3g(does).

Example 3

Get that to contain sexavalent chrome be 120mg/l, Zn ²⁺Be 70mg/l, Cu ²⁺Be 40mg/l, Ni ²⁺Be gravure plating plating roller waste water 1 liter of 26mg/l PH=4, in it, add 0.4ml treatment agent of the present invention (N wherein ₂H ₄Content is 10%, Na ₂S is 1.5g/l, and PM is 6mg/l) stirred at normal temperatures 1 minute, promptly there are precipitation generation and rapid precipitation to get off, the content of each metal ion species is respectively in the supernatant liquor: Cr ⁶⁺＜0.02mg/l, Cr ³⁺＜0.02mg/l, Zn ²⁺＜0.5mg/l, Ni ²⁺＜0.05mg/l, Cu ²⁺＜0.02mg/l, reaching emission standard can directly discharge, remaining throw out is that 0.5g(does).

Example 4

1 liter of certain low chromium chromatic passivation waste liquid contains Cr ⁶⁺Be 2.6 grams per liters, Zn ²⁺Be 0.5 grams per liter, H ₂SO ₄Be 0.5mg/l and other impurity. because this passivating solution can't continue to use.Make it nuisancelessization with treatment agent of the present invention. add this treatment agent (N wherein ₂H ₄Be 15%, Na ₂S is 1.5g/l, and PM is 7mg/l) 5.5ml, at room temperature stir 2 minutes after, solution becomes blackish green and generates throw out; The throw out rapid subsidence.Oven dry behind its sedimentation and filtration is weighed as 7.1g, measures its component in the supernatant liquor that filters out, the concentration of its each metal ion is: Cr ⁶⁺＜0.02mg/l, Cr ³⁺＜0.02mg/l, Zn ²⁺＜0.5mg/l, PH=8.3 can directly discharge.

Example 5

Waste liquid 1 liter after certain low chromic acid chromium plating electroplate liquid uses, containing sexavalent chrome is 26g/l, and sulfur acid 0.3g/l, trivalent chromium are 2g/l and other impurity. for making it innoxious, handled with treatment agent of the present invention. at room temperature, (wherein contain N to wherein adding treatment agent ₂H ₄Be 15%, Na ₂S is 1g/l, and PM is 5mg/l 55ml, stirs after 2 minutes, places, and the content that filters, analyzes each component in its supernatant liquor is: Cr ⁶⁺＜0.02mg/l, Cr ³⁺＜0.02mg/l, PH=7.2 can directly discharge, its precipitation is heavily done for 56g().

Annotate: ratio used among the present invention all is weight percentage except that special indicating.

Claims

1, a kind of compound for treatment of electroplating wastes is characterized in that: it contains hydrazine, sodium sulphite and flocculation agent PM, and its each component concentration ratio is as follows:

Hydrazine 8%～15%

Sodium sulphite 1g/l～1.5g/l

Flocculation agent PM 5mg/l～7mg/l

The remaining amount of water

2, compound for treatment of electroplating wastes according to claim 1 is characterized in that:

Hydrazine 10%

Sodium sulphite 1g/l

Flocculation agent PM 5mg/l

The remaining amount of water.