阅读说明：本技术 一种铬污染物中提取铬的工艺 (The technique of chromium is extracted in a kind of chromium pollutant ) 是由 李顺灵 潘志恒 黄立志 齐水莲 景倩慧 赵豆豆 于 2019-09-16 设计创作，主要内容包括：本发明属于铬污染物技术领域,具体涉及一种铬污染物中提取铬的工艺,包括以下步骤：(1)第一次酸化：将预处理后的铬渣加水调节至液固比为2-3:1,加入H<Sub>2</Sub>SO<Sub>4</Sub>调节pH值至5.5-6.0,酸化2-3h,再通过动力型旋液分离器,渣浆中一部分铬渣随上旋液进入絮凝沉淀罐,经沉淀得沉泥和上清液,渣浆中另一部分铬渣排出并和沉泥进行铬渣湿法解毒；(2)第二次酸化：向上清液中加入H<Sub>2</Sub>SO<Sub>4</Sub>调节pH值至3.5-4.5,再加入还原剂,搅拌10-20min后,再加入氢氧化钠溶液,调节PH值8.5-9.5,搅拌10-20min后,沉淀,使用板框压滤机将其压滤脱水处理,滤饼即为氢氧化铬沉淀；本发明成本低、提取率高。(The invention belongs to chromium pollutant technical fields, and in particular to the technique of chromium is extracted in a kind of chromium pollutant, comprising the following steps: (1) be acidified for the first time: adding water to be adjusted to liquid-solid ratio pretreated chromium slag and be 2-3:1, H is added 2 SO 4 It adjusts pH value and is acidified 2-3h to 5.5-6.0, then pass through power type cyclone hydraulic separators, a part of chromium slag enters flocculation sedimentation tank with upper spinning liquid in slurry, is precipitated to obtain heavy mud and supernatant, and the discharge of another part chromium slag is simultaneously in slurry and heavy mud carries out chromic slag wet method detoxifcation；(2) it is acidified for second: H being added into supernatant 2 SO 4 PH value is adjusted to 3.5-4.5, reducing agent is added, after stirring 10-20min, adds sodium hydroxide solution, adjust pH value 8.5-9.5, after stirring 10-20min, precipitating is handled its filter-press dehydration using plate and frame filter press, filter cake is chromium hydroxide precipitation；The present invention is at low cost, recovery rate is high.)

1. extracting the technique of chromium in a kind of chromium pollutant, which comprises the following steps:

It is acidified for the first time: adding water to be adjusted to liquid-solid ratio pretreated chromium slag and be 2-3:1, H is added₂SO₄PH value is adjusted to 5.5- 6.0, it is acidified 2-3h, then pass through power type cyclone hydraulic separators, a part of chromium slag enters flocculation sedimentation tank with upper spinning liquid in slurry, passes through Heavy mud and supernatant are precipitated to obtain, the discharge of another part chromium slag and and heavy mud progress chromic slag wet method detoxifcation in slurry；

Second of acidification: H is added into supernatant₂SO₄PH value is adjusted to 3.5-4.5, reducing agent is added, stirs 10-20min Afterwards, add sodium hydroxide solution, adjust pH value 8.5-9.5, after stirring 10-20min, precipitating, using plate and frame filter press by its Filter-press dehydration processing, filter cake is chromium hydroxide precipitation.

2. extracting the technique of chromium in chromium pollutant according to claim 1, which is characterized in that the reductant concentration is 0.026-0.185kg/L。

3. extracting the technique of chromium in chromium pollutant according to claim 1, which is characterized in that the H₂SO₄Quality it is dense Degree is 90-98%.

4. extracting the technique of chromium in chromium pollutant according to claim 1, which is characterized in that the reducing agent is Jiao Ya At least one of sodium sulphate, sodium thiosulfate, sodium sulfite.

5. extracting the technique of chromium in chromium pollutant according to claim 1, which is characterized in that chromium in the step (1) Slag pretreatment is after sieving chromium slag of the partial size greater than 30mm and to be crushed to 30mm hereinafter, being then less than the chromium slag of 30mm with partial size 200-300 mesh is ground into wet ball mill.

6. extracting the technique of chromium in chromium pollutant according to claim 1, which is characterized in that the filter-press dehydration processing Filtrate afterwards enters wet ball mill and reuses.

7. extracting the technique cyclone hydraulic separators of chromium in a kind of chromium pollutant described in claim 1, which is characterized in that described Cyclone hydraulic separators, including motor, motor output shaft connect feed liquor cylinder, and feed liquor cylinder top is equipped with the first liquid outlet, feed liquor cylinder housing If the big opening of funnel-form shell, shell is fixedly connected with motor base, the small opening of shell is slag notch, and the side wall of shell is also Equipped with the second liquid outlet and inlet, the second liquid outlet is higher than inlet, and baffles are equipped in shell, and baffles are located at first and go out Below liquid mouth and the second liquid outlet, baffles are located in the liquid inlet top, and baffles are sheathed on the outside of feed liquor cylinder, the outer lower part of feed liquor cylinder It is arranged impeller, impeller is located in the liquid inlet lower section.

8. extracting the technique cyclone hydraulic separators of chromium in chromium pollutant according to claim 7, which is characterized in that described Baffles are annular shape, and the outer ledge of baffles is fixedly connected with the inner sidewall of shell.

9. extracting the technique cyclone hydraulic separators of chromium in chromium pollutant according to claim 7, which is characterized in that described Impeller includes chassis, and chassis is equipped with rotating vane, and reinforcing rib is equipped between chassis and feed liquor cylinder lateral wall.

Technical field

The invention belongs to chromium pollutant technical fields, and in particular to the technique of chromium is extracted in a kind of chromium pollutant.

Background technique

Chrome Salt Industry is important industry indispensable in national economy, is mainly used for plating, tanning, printing and dyeing, medicine, urges Agent, corrosion inhibition for metal etc..The main waste residue (i.e. chromium slag) discharged during chromium salt production is a kind of danger with severe toxicity Dangerous waste, wherein Cr⁶⁺It is the root of toxicity.It is according to the analysis to China part chromium slag Chemical Composition Characteristics as a result, total in chromium slag Chromium average content is about 3%~5%, and Cr VI average content is about 1%~5%(with Cr₂O₃Meter).There are six kinds of components to contain in chromium slag There is Cr⁶⁺, respectively Sodium Chromate Tetrahydrate 99, calcium chromate, chromium calcium aluminate and alkali formula ferric chromate, calcium silicates-calcium chromate solid solution and iron aluminium Sour calcium-calcium chromate solid solution.Wherein Sodium Chromate Tetrahydrate 99 and free calcium chromate are water-dissolving phase, are easily dissolved by surface water, rainwater；Its Though Yu Si kind component is insoluble in water, during long-term outdoor stockpiling, easily cause chromium slag to environment through weathering and aquation In, long-term pollution.

Chromium slag tradition detoxification is that trivalent chromium is solidificated in hexavalent chrome reduction in waste residue at trivalent chromium at present, so Security landfill afterwards, but the trivalent chromium in waste residue is relatively stable in waste residue, is difficult renewable resources utilization, therefore, the prior art It needs further to improve.

Summary of the invention

The purpose of the present invention is to provide the techniques that chromium is extracted in a kind of chromium pollutant at low cost, recovery rate is high.

Based on above-mentioned purpose, the present invention is adopted the following technical scheme that:

The technique of chromium is extracted in a kind of chromium pollutant, which comprises the following steps:

(1) it is acidified for the first time: adding water to be adjusted to liquid-solid ratio pretreated chromium slag and be 2-3:1, H is added₂SO₄Adjust pH value to 5.5-6.0 is acidified 2-3h, then passes through power type cyclone hydraulic separators, and chromium slag enters flocculation sedimentation tank with upper spinning liquid in slurry, through heavy Form sediment to obtain heavy mud and supernatant, and the mud that sinks carries out chromic slag wet method detoxifcation；

(2) it is acidified for second: H being added into supernatant₂SO₄PH value is adjusted to 3.5-4.5, reducing agent is added, stirs 10- After 20min, add sodium hydroxide solution, adjust pH value 8.5-9.5, after stirring 10-20min, using plate and frame filter press by its Filter-press dehydration processing, filter cake is chromium hydroxide precipitation.

Further, the reductant concentration is 0.026-0.185kg/L.

Further, the mass concentration of the H2SO4 is 90-98%.

Further, the reducing agent is at least one of sodium pyrosulfite, sodium thiosulfate, sodium sulfite.

Further, chromium slag pretreatment is after sieving chromium slag of the partial size greater than 30mm and to be crushed in the step (1) To 30mm hereinafter, the chromium slag for being then less than 30mm with partial size enters wet ball mill and is ground to 200-300 mesh.

Further, treated that filtrate enters wet ball mill reuses for the filter-press dehydration.

Further, the cyclone hydraulic separators, including motor, motor output shaft connect feed liquor cylinder, and feed liquor cylinder top is set There is the first liquid outlet, is arranged funnel-form shell outside feed liquor cylinder, the big opening of shell is fixedly connected with motor base, and the small of shell is opened Mouth is slag notch, and the side wall of shell is additionally provided with the second liquid outlet and inlet, and the second liquid outlet is higher than inlet, is equipped in shell Baffles, baffles are located at below the first liquid outlet and the second liquid outlet, and baffles are located in the liquid inlet top, and baffles are sheathed on On the outside of feed liquor cylinder, the outer lower part of feed liquor cylinder is arranged impeller, and impeller is located in the liquid inlet lower section.

Further, the baffles are annular shape, and the outer ledge of baffles is fixedly connected with the inner sidewall of shell.

Further, the impeller includes chassis, and chassis is equipped with rotating vane, between chassis and feed liquor cylinder lateral wall Equipped with reinforcing rib.

The present invention is to extract water soluble hexavalent chromium in chromium slag and part acid soluble hexavalent chromium before chromic slag wet method detoxifcation Chromium hydroxide and resource reclaim are prepared, the chromium slag after extracting Cr VI carries out wet method detoxifcation again, which can reduce chromium slag The cost of wet method detoxifcation, and can the biggish economic benefit of resource reclaim Cr VI generation.

Detailed description of the invention

Fig. 1 is process flow chart of the invention；

Fig. 2 is the structural schematic diagram of power type cyclone hydraulic separators；

Fig. 3 is the structural schematic diagram of feed liquor cylinder

Fig. 4 is the structural schematic diagram of impeller.

Specific embodiment