阅读说明：本技术 一种不锈钢酸洗污泥处理方法 (Stainless steel pickling sludge treatment method ) 是由 王攀 杨贤有 罗启贵 邓俊 罗培强 宋忠仪 杨波 黄敏 于 2020-05-22 设计创作，主要内容包括：本发明公开了一种不锈钢酸洗污泥处理方法,包括如下步骤：S1粉碎；S2氨浸：S3萃取和反萃取；S4电积；S5蒸氨；S6强磁选；S7超重力分选。本发明采用氨水选择性浸出铬铜锌镍钴,氨浸渣强磁选磁性铁渣,超重力分选出合金态重金属,分步实现重金属资源完全回收利用,工艺原理简单,技术成熟,可适用于不锈钢企业酸洗污泥的处理。(The invention discloses a stainless steel pickling sludge treatment method, which comprises the following steps: s1 grinding; s2 ammonia leaching: s3 extraction and back extraction; s4 electrodeposition; s5 ammonia distillation; s6, strong magnetic separation; s7 high gravity sorting. According to the invention, ammonia water is adopted to selectively leach chromium, copper, zinc, nickel and cobalt, the ammonia leaching residue is used to strongly separate magnetic iron slag, alloy-state heavy metals are separated by virtue of supergravity, and complete recycling of heavy metal resources is realized step by step.)

1. A stainless steel pickling sludge treatment method is characterized in that: the method comprises the following steps:

s1 crushing: drying, dehydrating and crushing the sludge subjected to acid washing to be below 80 meshes as a sample for later use;

s2 ammonia leaching: and (4) putting the sample obtained in the step (S1) into an ammonia leaching tank, adding ammonia water for soaking, and performing solid-liquid separation to obtain ammonia leaching residue and ammonia leaching solution:

s3 extraction and back extraction: carrying out circulating ammonia leaching on the ammonia leaching solution obtained in the step S2 for multiple times in the step S2 to enable metal ions to reach certain concentration, then sending the metal ions to an extraction column, and separating an organic phase and ammonia water after circulating mixing; the ammonia water returns to the ammonia leaching section of the step S2 for recycling, and the organic phase is sent to a back extraction column to be separated out the extractant and the extractant respectively containing Cr after being circularly mixed³⁺、Cu²⁺、Zn²⁺、Ni²⁺、Co²⁺The extracting agent returns to the extraction section for recycling;

s4 electrodeposition: respectively containing Cr obtained in the step S3³⁺、Cu²⁺、Zn²⁺、Ni²⁺、Co²⁺The electrolyte is sequentially sent to an electrolytic cell for electrodeposition, and corresponding metal product deposits are respectively obtained on a negative plate;

s5 ammonia distillation: blowing ammonia from the ammonia leaching residue obtained in the step S2 through a hot air blower to obtain ammonia water and deamination residue; the evaporated ammonia water is condensed and returned to the ammonia leaching section of S2 for cyclic utilization;

s6 strong magnetic separation: performing strong magnetic separation on the deamination slag obtained in the step S5 to obtain magnetic iron slag and non-magnetic slag; the magnetic iron slag obtained by enrichment is sent to a stainless steel smelting plant for recycling;

s7 hypergravity sorting: carrying out supergravity separation on the nonmagnetic slag obtained in the step S6 to obtain stainless steel alloy and tailings; the stainless steel alloy is sent to a stainless steel smelting plant for recycling; the tailings are sent to a cement plant to be used as an additive for recycling, and the water is returned to the supergravity separation section for recycling.

2. The stainless steel pickling sludge treatment method according to claim 1, characterized in that: and (S2) soaking ammonia water in ammonia leaching at normal temperature in a sealed manner, wherein the mass percentage concentration of the ammonia water in the ammonia leaching is 20%, and the liquid-solid ratio is 0.5: 1-1: 1.

3. The stainless steel pickling sludge treatment method according to claim 1, characterized in that: the field strength of the strong magnetic separation in the step S6 is 5000-10000 GS.

4. The stainless steel pickling sludge treatment method according to claim 1, characterized in that: the supergravity sorting in step S7 has density 4 as a sorting limit.

5. The stainless steel pickling sludge treatment method according to claim 1, characterized in that: the supergravity sorting of step S7 uses water as a medium.

6. The stainless steel pickling sludge treatment method according to claim 1, characterized in that: the specific operation of step S1 is: the sludge after acid washing is dried to constant weight (4 hours) at 105 ℃, and then is crushed to below 80 meshes by a disc grinder to be used as a sample for standby.

7. The stainless steel pickling sludge treatment method according to claim 1, characterized in that: in step S3, ammonia leaching is circulated for 5-10 times.

8. The stainless steel pickling sludge treatment method according to claim 1, characterized in that: the current for strong magnetic separation in step S6 is 1-3A.

Technical Field

The invention relates to the field of treatment of industrial waste residues and sludge in the steel and metallurgy industries, in particular to a stainless steel pickling sludge treatment method.

Background

The stainless steel sheet product is used for decoration and living appliances, and in the processing process of the sheet material, a plurality of fine stainless steel oxide metal powder and uneven wrapping points are attached to the surface of the sheet material and need to be removed by sections such as grinding, pickling and polishing, so that the stainless steel pickling sludge is formed. In the pickling process, metal oxides are dissolved in acid to form heavy metal sulfate, in order to reach the wastewater discharge standard, enterprises adopt limestone and lime to remove acid and settle heavy metals, and the amount of stainless steel pickling sludge generated after treatment is large, a large amount of heavy metals are contained, the stainless steel pickling sludge needs to be managed according to industrial hazardous wastes, and the disposal cost is high.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a method for treating stainless steel pickling sludge, which can recover various heavy metals in the stainless steel pickling sludge, can recycle ammonia water, an extracting agent and water in a system and does not discharge waste water and waste liquid.

The invention firstly provides a stainless steel pickling sludge treatment method, which comprises the following steps:

s1 crushing: drying the sludge subjected to acid washing at 105 ℃ to constant weight (4 hours), and then drying, dehydrating and crushing the sludge by using a disc mill until the size of the sludge is below 80 meshes for later use as a sample;

s2 ammonia leaching: and (4) putting the sample obtained in the step (S1) into an ammonia leaching tank, adding ammonia water for soaking, and performing solid-liquid separation to obtain ammonia leaching residue and ammonia leaching solution:

the metal ions in the ammonia leaching solution are: cr (chromium) component³⁺、Cu²⁺、Zn²⁺、Ni²⁺、Co²⁺；

S3 extraction and back extraction: carrying out circulating ammonia leaching on the ammonia leaching solution obtained in the step S2 for multiple times in the step S2 to enable metal ions to reach certain concentration, then sending the metal ions to an extraction column, and separating an organic phase and ammonia water after circulating mixing; the ammonia water returns to the ammonia leaching section of the step S2 for recycling, and the organic phase is sent to a back extraction column to be separated out the extractant and the extractant respectively containing Cr after being circularly mixed³⁺、Cu²⁺、Zn²⁺、Ni²⁺、Co²⁺The extracting agent returns to the extraction section for recycling;

the ammonia leaching of the multiple circulation is 5 to 10 times, and the metal ions in the organic phase are Cr³⁺、Cu²⁺、Zn²⁺、Ni²⁺、Co²⁺；

S4 electrodeposition: respectively containing Cr obtained in the step S3³⁺、Cu²⁺、Zn²⁺、Ni²⁺、Co²⁺The electrolyte is sequentially sent to an electrolytic cell for electrodeposition, and corresponding metal products (chromium, copper, zinc, nickel and cobalt) are respectively deposited on a negative plate;

s5 ammonia distillation: blowing ammonia from the ammonia leaching residue obtained in the step S2 through a hot air blower to obtain ammonia water and deamination residue; the evaporated ammonia water is condensed and returned to the ammonia leaching section of S2 for cyclic utilization;

the deamination slag contains Fe as metal ions²⁺、Fe³⁺、Al³⁺、Mn⁴⁺、Mg²⁺、Ti⁴⁺；

S6 strong magnetic separation: performing strong magnetic separation on the deamination slag obtained in the step S5 to obtain magnetic iron slag and non-magnetic slag; enriching the resulting magnetic iron slag (Fe (OH)₃、Fe₂O₃、Fe₃O₄Simple substance iron and magnetic alloy) are sent to a stainless steel smelting plant for recycling;

the current intensity of the strong magnetic separation is 1-3A.

S7 hypergravity sorting: carrying out supergravity separation on the nonmagnetic slag obtained in the step S6 to obtain stainless steel alloy and tailings; stainless steel alloy (powder and granular) is sent to a stainless steel smelting plant for recycling; the tailings (Fe-Al-Ca-Mg-Si) are sent to a cement plant to be used as an additive for recycling, and the water is returned to the supergravity separation section for recycling.

The rotating speed of the super-gravity separator is 180r/min, and the liquid-solid ratio is (1: 3-1: 4).

The invention also provides the following optimization scheme:

preferably, the ammonia water in the ammonia leaching in the step S2 has a mass percentage concentration of 20% and a liquid-solid ratio of 0.5: 1-1: 1, and is soaked in a closed manner at normal temperature.

Preferably, the field strength of the strong magnetic separation in the step S6 is 5000-10000 GS.

Preferably, the supergravity sorting in step S7 has the density 4 as the sorting limit.

Preferably, the supergravity sorting of step S7 uses water as a medium.

Preferably, the specific operation of step S1 is: the sludge after acid washing is dried to constant weight (4 hours) at 105 ℃, and then is crushed to below 80 meshes by a disc grinder to be used as a sample for standby.

Preferably, the ammonia leaching is circulated 5 to 10 times in step S3.

Preferably, the current for strong magnetic separation in step S6 is 1-3A.

The invention has the beneficial effects that:

(1) the method adopts ammonia water to selectively leach chromium, copper, zinc, nickel and cobalt, strongly selects magnetic iron slag from the ammonia leaching slag, separates out alloy-state (powder and granular) heavy metals by virtue of supergravity, realizes complete recycling of heavy metal resources step by step, has a simple process principle and mature technology, and is suitable for treatment of pickling sludge of stainless steel enterprises.

(2) The ammonia water, the extracting agent and the water can be recycled, no waste water and waste liquid is discharged, no secondary pollution is caused, and the method is green, economic and environment-friendly.

(3) The whole process of the invention has no tailings to stack, realizes the full recycling of resources, and has good development of economic benefit and social benefit.

Drawings

FIG. 1 is a process flow diagram of the stainless steel pickling sludge treatment method of the present invention.

Detailed Description

In order that those skilled in the art will better understand the technical solutions of the present invention, the present invention will be further described in detail with reference to the following embodiments.

At present, most stainless steel manufacturers at home have similar sludge, namely thousands of tons of sludge and tens of thousands of tons of sludge, and a plurality of departments begin to renovate the sludge in the recent years under a strict environmental control system. The inventor analyzes the main reasons: no one in the previously published patent technologies is used for researching the existence forms of the heavy metal elements in the acid-washed sludge, and meanwhile, the economic cost of treatment, the secondary pollution source problem and the feasibility of application are not considered.

Acid leaching technology: the water-soluble ions and the hydrous hydrogen oxide form in the pickling sludge are easy to be leached by acid, but according to the research on the existing forms of various heavy metal elements, most of metal alloy forms exist in the pickling sludge, the reaction of the metal alloy with sulfuric acid and hydrochloric acid is extremely slow, heating and stirring are needed, leaching can be carried out only by adding aqua regia to prolong the leaching time, but higher requirements on equipment environment are required in large-scale industrial production and difficult to realize, part of iron oxides which do not need to be treated in the pickling process consume a large amount of acid, the acid consumption is increased, the subsequent separation and purification process is more complicated, the difficulty in treating waste acid and wastewater is higher, and the pickling technology has certain limitation.

High-temperature reduction roasting technology: the process can generate a large amount of smoke and dust pollution, and has the disadvantages of complicated recycling process, high equipment investment cost, high energy consumption and high pollution, thereby belonging to the current process strictly prohibited by China.

Based on the technical difficulties, as shown in fig. 1, the invention firstly provides a stainless steel pickling sludge treatment method, which comprises the following steps:

s1 crushing: drying, dehydrating and crushing the sludge subjected to acid washing to be below 80 meshes as a sample for later use;

s2 ammonia leaching: and (4) putting the sample obtained in the step (S1) into an ammonia leaching tank, adding ammonia water for soaking, and performing solid-liquid separation to obtain ammonia leaching residue and ammonia leaching solution:

in the step S2, ammonia water can completely leach out water-soluble ionic state and aqueous hydrogen oxidation state parts of chromium, copper, zinc, nickel and cobalt, wherein the mass percentage concentration of the ammonia water is 20%, and the liquid-solid ratio is 0.5: 1-1: 1;

s3 extraction and back extraction: carrying out circulating ammonia leaching on the ammonia leaching solution obtained in the step S2 for multiple times in the step S2 to enable metal ions to reach certain concentration, then sending the metal ions to an extraction column, and separating an organic phase and ammonia water after circulating mixing; the ammonia water returns to the ammonia leaching section of the step S2 for recycling, and the organic phase is sent to a back extraction column to be separated out the extractant and the extractant respectively containing Cr after being circularly mixed³⁺、Cu²⁺、Zn²⁺、Ni²⁺、Co²⁺The extracting agent returns to the extraction section for recycling;

s4 electrodeposition: respectively containing Cr obtained in the step S3³⁺、Cu²⁺、Zn²⁺、Ni²⁺、Co²⁺The electrolyte is sequentially sent to an electrolytic cell for electrodeposition, and corresponding metal products (chromium, copper, zinc, nickel and cobalt) are respectively deposited on a negative plate;

s5 ammonia distillation: blowing ammonia from the ammonia leaching residue obtained in the step S2 through a hot air blower to obtain ammonia water and deamination residue; the evaporated ammonia water is condensed and returned to the ammonia leaching section of S2 for cyclic utilization;

s6 strong magnetic separation: performing strong magnetic separation on the deamination slag obtained in the step S5 to obtain magnetic iron slag and non-magnetic slag; enriching the resulting magnetic iron slag (Fe (OH)₃、Fe₂O₃、Fe₃O₄Simple substance iron and magnetic alloy) are sent to a stainless steel smelting plant for recycling;

s7 hypergravity sorting: carrying out supergravity separation on the nonmagnetic slag obtained in the step S6 to obtain stainless steel alloy and tailings; stainless steel alloy (powder and granular) is sent to a stainless steel smelting plant for recycling; the tailings (Fe-Al-Ca-Mg-Si) are sent to a cement plant to be used as an additive for recycling, and the water is returned to the supergravity separation section for recycling.

In order to improve the ammonia leaching effect, the ammonia water in the ammonia leaching in the step S2 is soaked in a closed manner at normal temperature, wherein the mass percentage concentration of the ammonia water is 20%, and the liquid-solid ratio is 0.5: 1-1: 1.

The field strength of the strong magnetic separation in the step S6 is 5000-10000 GS.

The supergravity sorting in step S7 has density 4 as a sorting limit.

The supergravity sorting of step S7 uses water as a medium.

The foregoing is a detailed description of the invention and the following is an example of the invention.