阅读说明：本技术 一种含铅废物化学处理方法 (Chemical treatment method for lead-containing waste ) 是由 刘洪强 于 2020-06-19 设计创作，主要内容包括：本发明涉及铅回收领域,公开了一种含铅废物化学处理方法,包括以下步骤：步骤1：溶媒配制,将不会与铅离子生成沉淀物的铵盐加入水中配制溶媒,并加入酸将溶媒的PH调整至3～6.5；步骤2：氧化,将含铅粉尘置入溶媒中,在含铅粉尘不再继续减少时,分离出上清液；步骤3：碳酸化处理,在上清液中加入碳酸盐,并将上清液的PH调整至7～9,继续反应1～3h后进行过滤,得到铅白。本发明的化学处理方法可以避免大量含铅废物扩散,从而提高铅的回收率。(The invention relates to the field of lead recovery, and discloses a chemical treatment method for lead-containing waste, which comprises the following steps: step 1: preparing a solvent, namely adding ammonium salt which does not generate precipitates with lead ions into water to prepare the solvent, and adding acid to adjust the pH value of the solvent to 3-6.5; step 2: oxidizing, namely placing the lead-containing dust into a solvent, and separating out supernatant when the lead-containing dust is not reduced any more; and step 3: and (3) carbonating, adding carbonate into the supernatant, adjusting the pH of the supernatant to 7-9, continuing to react for 1-3 h, and filtering to obtain the lead white. The chemical treatment method can avoid the diffusion of a large amount of lead-containing wastes, thereby improving the recovery rate of lead.)

1. A chemical treatment method for lead-containing waste is characterized by comprising the following steps: the method comprises the following steps:

step 1: preparing a solvent, namely adding ammonium salt which does not generate precipitates with lead ions into water to prepare the solvent, and adding acid to adjust the pH value of the solvent to 3-6.5;

step 2: oxidizing, namely placing the lead-containing dust into a solvent, and separating out supernatant when the lead-containing dust is not reduced any more;

and step 3: and (3) carbonating, adding carbonate into the supernatant, adjusting the pH of the supernatant to 7-9, continuing to react for 1-3 h, and filtering to obtain the lead white.

2. The method for chemically treating lead-containing waste as claimed in claim 1, wherein the method comprises the steps of: and 3, filtering in the step 3 to obtain primary filtrate, using the primary filtrate to prepare a solvent, and placing the specific ammonium salt into the primary filtrate when preparing the solvent.

3. The method for chemically treating lead-containing waste as claimed in claim 2, wherein: and (3) recycling the primary filtrate obtained in the step (3) in the step (1) for less than or equal to 6 times.

4. The method for chemically treating lead-containing waste as claimed in claim 3, wherein the method comprises the steps of: further comprising the step 4: and (3) crystallizing, namely heating the primary filtrate reaching the cycle number to boil, then cooling the primary filtrate until crystals are separated out, and then filtering the primary filtrate to obtain secondary filtrate.

5. The method for chemically treating lead-containing waste as claimed in claim 4, wherein the method comprises the steps of: and (4) preparing a solvent by using the secondary filtrate obtained in the step (4).

6. The method for chemically treating lead-containing waste as claimed in claim 4, wherein the method comprises the steps of: and in the step 4, cooling is carried out when crystals are separated out from the primary boiling filtrate.

7. The method for chemically treating lead-containing waste as claimed in claim 4, wherein the method comprises the steps of: and step 4, simultaneously condensing steam generated by boiling of the primary filtrate, and using the steam for preparing the solvent in the step 1.

8. The method for chemically treating lead-containing waste as claimed in claim 1, wherein the method comprises the steps of: in the step 1 or the step 2, H is added into the prepared solvent₂O₂。

9. The method for chemically treating lead-containing waste as claimed in claim 8, wherein: h is added in the step 1 or the step 2₂O₂When the solution color does not change, the continuous addition of H is stopped₂O₂。

10. The method for chemically treating lead-containing waste as claimed in claim 1, wherein the method comprises the steps of: and (3) after the lead-containing dust is added in the step (2), adjusting the pH value of the solvent to 3-6.5.

Technical Field

The invention relates to the field of lead recovery, in particular to a chemical treatment method for lead-containing waste.

Background

Lead is a common non-ferrous metal, and because of its excellent performance, lead compounds and alloys thereof are widely used in the industries of storage batteries, cable sheathing, machine manufacturing, ship manufacturing, light industry, lead oxide, and the like. However, lead is toxic and greatly affects the health of human bodies after being taken in, so that the used lead-containing waste cannot be discarded at will, and the lead-containing waste is generally required to be recycled in order to improve the utilization rate of lead.

The secondary lead enterprises recovering lead in the lead-containing waste generally adopt a physical method for recovery, namely the waste is firstly crushed into lead-containing dust, then the lead-containing dust is repeatedly smelted as a raw material of a smelting furnace, combustible substances in the lead-containing dust are combusted, and finally lead oxide and lead sulfate are obtained to complete the recovery of lead.

However, in the actual operation of the method, because the particle size of the lead-containing dust is small, the lead-containing dust is easy to discharge from the smelting furnace along with the waste gas, on one hand, the lead recovered is reduced because the lead-containing dust is discharged, and the lead recovery rate is low; on the other hand, because the waste gas volume is big, the difficulty of carrying out pollution abatement to the waste gas that the smelting furnace discharged is great, and the cost is higher, and the leaded dust in the waste gas also can not be retrieved completely, and the leaded dust that discharges is extremely easily dispersed in the air, causes the lead pollution.

Disclosure of Invention

The invention aims to provide a chemical treatment method for lead-containing waste to avoid the diffusion of a large amount of lead-containing waste so as to improve the recovery rate of lead.

In order to achieve the purpose, the invention adopts the following technical scheme: a method for chemically treating lead-containing waste comprises the following steps:

step 1: preparing a solvent, namely adding ammonium salt which does not generate precipitates with lead ions into water to prepare the solvent, and adding acid to adjust the pH value of the solvent to 3-6.5;

step 2: oxidizing, namely placing the lead-containing dust into a solvent, and separating out supernatant when the lead-containing dust is not reduced any more;

and step 3: and (3) carbonating, adding carbonate into the supernatant, adjusting the pH of the supernatant to 7-9, continuing to react for 1-3 h, and filtering to obtain the lead white.

The beneficial effect of this scheme does:

the lead in the lead-containing dust exists mainly in the form of lead oxide and lead sulfate, and after the lead-containing dust in the scheme is put into the solvent, lead oxide, lead sulfate and a small amount of lead sulfide are dissolved in the solvent, so that the amount of the lead-containing dust in the solvent is reduced, and other compounds containing elements such as antimony, tin, silicon, calcium, carbon and the like are precipitated, and can be separated from the lead. In the whole separation process, a large amount of waste gas is not generated as in the traditional method, so that the lead-containing dust is not discharged along with the waste gas, the lead-containing dust in the waste gas is not required to be recycled, the recycling cost is saved, and the lead pollution to the environment is avoided; and the lead loss caused by incomplete recovery of lead-containing dust in the traditional method is avoided, so that the lead recovery rate is improved.

Further, filtering in the step 3 to obtain a primary filtrate, using the primary filtrate to prepare a solvent, and placing the specific ammonium salt into the primary filtrate when preparing the solvent.

The beneficial effect of this scheme does: and 3, when the carbonation treatment is carried out, the concentration of the lead ions in the supernatant is gradually reduced along with the reaction, and finally, a small amount of lead ions can not react with carbonate and still remain in the primary filtrate under the condition of low concentration. In addition, the discharge of waste water can be reduced, and the waste water treatment cost is reduced.

Further, the recycling times of the primary filtrate obtained in the step 3 in the step 1 are less than or equal to 6 times.

The beneficial effect of this scheme does: because lead sulfate exists in the lead-containing dust, when the lead sulfate is dissolved in the solvent, sulfuric acid ions are mixed in the solvent, so when the treatment of the step 2 and the step 3 is carried out, sulfate appears in the supernatant, the concentration of salt in the solvent is close to saturation, and the dissolution of lead oxide and lead sulfate in the lead-containing dust is not facilitated, so that the recovery of lead is not facilitated. The scheme limits the cycle times, so that the problem that the dissolution of lead oxide and lead sulfate is reduced due to excessive cycle times, and the recovery efficiency of lead is reduced can be avoided.

Further, the method also comprises the step 4: and (3) crystallizing, namely heating the primary filtrate reaching the cycle number to boil, then cooling the primary filtrate until crystals are separated out, and then filtering the primary filtrate to obtain secondary filtrate.

The beneficial effect of this scheme does: when the primary filtrate is heated, the liquid in the primary filtrate is evaporated, and the concentration of the salt is further increased, so that after the primary filtrate is cooled, the salt in the primary filtrate can precipitate crystals due to supersaturation, thereby separating out excessive salt in the primary filtrate, and the salt can be recycled after being filtered.

Further, the secondary filtrate obtained in step 4 is used for solvent preparation.

The beneficial effect of this scheme does: the lead which is not recovered is still in the secondary filtrate, and the secondary filtrate is utilized to reconfigure the solvent, so that the lead can be prevented from being discharged, the loss is caused, and the recovery rate of the lead is further improved.

Further, in step 4, cooling is carried out when crystals are separated out from the primary filtrate after boiling.

The beneficial effect of this scheme does: the primary filtrate needs to evaporate more water to separate out crystals due to supersaturation of salt concentration in a boiling state, so that the salt concentration in the primary filtrate is higher, and more crystals can be separated out after temperature reduction.

Further, step 4 simultaneously condenses the steam generated by boiling the primary filtrate, and is used for preparing the solvent in step 1.

The beneficial effect of this scheme does: the steam can be condensed to be liquefied into water again, thereby recycling the water and reducing the consumption of the water.

Further, in step 1 or step 2, H is added to the formulated vehicle₂O₂。

The beneficial effect of this scheme does: h₂O₂The lead-containing dust has both oxidizability and reducibility, so that lead-containing compounds such as lead oxide, lead sulfide and the like in the lead-containing dust can be effectively dissolved in a solvent, the lead recovery efficiency is improved, and other ionic impurities are not increased.

Further, H is added in the step 1 or the step 2₂O₂When the solution color does not change, the continuous addition of H is stopped₂O₂。

The beneficial effect of this scheme does: the color of the solution changes with the continuous dissolution of the lead-containing compound, so that whether the lead-containing compound is completely dissolved can be judged according to the change of the color, thereby avoiding the addition of H₂O₂And the lead-containing compound is still undissolved and the lead in the lead-containing compound cannot be recovered due to the shortage, so the scheme can further improve the recovery rate of the lead.

Further, after the lead-containing dust is added in the step 2, the pH value of the solvent is adjusted to 3-6.5.

The beneficial effect of this scheme does: in the whole step 2, the solvent is kept acidic, namely the lead-containing dust is always in an acidic condition, so that the generation of basic lead carbonate is effectively avoided, and the dissolving speed is accelerated.

Detailed Description

The following is further detailed by way of specific embodiments:

a method for chemically treating lead-containing waste comprises the following steps:

step 1: preparing a solvent, namely adding one or more of ammonium chloride, ammonium nitrate, ammonium acetate and ammonium citrate into water to prepare the solvent until the concentration of the ammonium salt in the solvent is more than or equal to 50%, and then adding one or more of sulfuric acid, hydrochloric acid, nitric acid and acetic acid to adjust the pH of the solvent to 3-6.5;

step 2: oxidizing, putting the lead-containing dust into the solvent, stirring, and adding H into the solvent₂O₂During the process, the color of the solvent changes, and the continuous addition of H is stopped until the color of the solution does not change any more₂O₂(ii) a Simultaneously adding one or more of sulfuric acid, hydrochloric acid, nitric acid and acetic acid into the solvent again, and adding H₂O₂Adjusting the pH value of the post-solution to keep the pH value of the solvent at 3-6.5; separating out supernatant when the lead-containing dust is not reduced any more;

and step 3: carbonating, namely adding carbonate into the supernatant, adjusting the pH of the supernatant to 7-9, continuously reacting for 1-3 h, filtering to obtain lead white and primary filtrate, heating the lead white until the lead white is decomposed to obtain red lead, and completing the recovery of lead;

and 4, step 4: crystallizing, namely using the primary filtrate obtained in the step 3 to prepare the solvent in the step 1, and recycling the primary filtrate, wherein in the preparation process, specific ammonium salt is placed into the primary filtrate, the recycling frequency of the primary filtrate is less than or equal to 6, specifically, the primary filtrate in the embodiment of the scheme is recycled for 6 times; after the sixth circulation is completed, heating the primary filtrate obtained in the 6 th circulation to boiling, and simultaneously condensing steam generated in boiling to obtain condensed water; and (4) when crystals are separated out from the primary filtrate, cooling the primary filtrate until crystals are continuously separated out, filtering the primary filtrate again to obtain secondary filtrate, and repeating the step 4 to obtain the secondary filtrate and condensed water which are both used for solvent preparation.