A method for detoxification of chromium-containing waste residue and recovery of chromium

A chromium waste slag and chromium recovery technology, applied in the direction of improving process efficiency, etc., can solve problems such as inability to efficiently recover chromium resources, chromium slag environmental hazards, consumption of acid and alkali, etc., to achieve full slag utilization, high social benefits and Economic benefit and low cost effect

Active Publication Date: 2019-04-09
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

For example, CN102191390A adopts sulfuric acid or hydrochloric acid to leach water-soluble and acid-soluble hexavalent chromium at normal temperature, and then collects the chromium resources leached through reduction and precipitation, but this method needs to adjust the pH 3 times, consuming a large amount of acid and alkali
CN104726705A uses potassium hydroxide aqueous solution, potassium carbonate aqueous solution, potassium metaaluminate aqueous solution mixed slurry and oxidizing gas to carry out leaching oxidation reaction on chromite, the process is relatively complicated
Chinese patent "a method for recovering hexavalent chromium resources from chromium slag" (CN102191390A) uses sulfuric acid or hydrochloric acid to leach water-soluble and acid-soluble hexavalent chromium at room temperature, which relatively improves the leaching of hexavalent chromium, but from chromium slag Only 60% to 80% of hexavalent chromium resources can be recovered in China, which can neither efficiently recover chromium resources nor completely detoxify chromium slag, and the treated chromium slag still has serious environmental hazards
From the above examples, it can be seen that the current heavy metal recovery methods still have problems such as high cost, complicated operation, and secondary pollution, and there is still a lot of room for improvement.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] (1) Take 0.5 tons of chromium-containing electroplating sludge (the main phases are calcium hydroxide and calcium carbonate), carry out aerobic roasting at 400° C. in ambient air, and grind after natural cooling.

[0024] (2) Ultrasonic the chromium-containing electroplating sludge treated in step (1) for 30 min at a frequency of 10 kHz.

[0025] (3) Put the chromium-containing electroplating sludge treated in step (2) into a hydrothermal kettle, then add water to make the solid-to-liquid ratio (w / w) 1:0.5, fully stir, add hydrochloric acid, sodium bicarbonate, Sodium carbonate, so that the concentration of hydrochloric acid in the system is 2mol / L, the concentration of sodium bicarbonate is 1mol / L, and the concentration of sodium carbonate is 1mol / L, fully stir, close the hydrothermal kettle, set the temperature to 60°C, and keep warm for reaction After 8 hours, cool naturally and slowly to room temperature, let stand for 12 hours, pour out the supernatant containing h...

Embodiment 2

[0029] (1) Take 1 ton of chromium-containing waste residue (main phases are hydrotalcite, hydrocalumite, calcium hydroxide, and magnesium oxide), perform aerobic roasting at 500° C. in ambient air, and grind after natural cooling.

[0030] (2) Ultrasonic the chromium-containing electroplating sludge treated in step (1) for 10 min at a frequency of 12 kHz.

[0031] (3) Put the chromium-containing electroplating sludge treated in step (2) into a hydrothermal kettle, then add water to make the solid-to-liquid ratio (w / w) 1:3, fully stir, add hydrochloric acid, sodium bicarbonate, Sodium carbonate, make the concentration of hydrochloric acid in the system be 2mol / L, the concentration of sodium bicarbonate is 1.5mol / L, the concentration of sodium carbonate is 0.3mol / L, fully stir, close hydrothermal kettle, setting temperature is 100 ℃, After heat preservation reaction for 4 hours, naturally and slowly cool to room temperature, let stand for 0.5 hours, pour out the supernatant cont...

Embodiment 3

[0034] (1) Take 2 tons of chromium-containing waste slag (the main phases are calcium hydroxide, magnesium hydroxide, ettringite, magnesium oxide, silicon dioxide), and carry out aerobic roasting at 800 ° C in ambient air, and carry out after natural cooling grind.

[0035] (2) Ultrasonic the chromium-containing electroplating sludge treated in step (1) for 50 min at a frequency of 15 kHz.

[0036] (3) Put the chromium-containing electroplating sludge treated in step (2) into a hydrothermal kettle, then add water to make the solid-to-liquid ratio (w / w) 1:5, stir well, add hydrochloric acid, sodium bicarbonate, Sodium carbonate, so that the concentration of hydrochloric acid in the system is 0.5mol / L, the concentration of sodium bicarbonate is 1mol / L, the concentration of sodium carbonate is 0.5mol / L, fully stir, close the hydrothermal kettle, set the temperature to 40 ℃, After heat preservation reaction for 12 hours, cool naturally and slowly to room temperature, let it stand...

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PUM

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Abstract

The invention belongs to the technical field of solid waste treatment and discloses a toxin removing and chromium recovering method for chromium-containing waste residues. The method comprises steps as follows: the chromium-containing waste residues are subjected to aerobic roasting, naturally cooled, then ground and subjected to ultrasonic treatment, the treated chromium-containing waste residuesare added to a hydrothermal reactor with surface and interface regulating agents and water, after uniform stirring and mixing, a mixture is subjected to a reaction for 0.5-24 h at 30-250 DEG C, an obtained product is cooled and left to stand after the reaction, solid residues and a chromium-containing supernatant are separated, the solid residues are washed and dried, detoxified waste residues are obtained, and the chromium-containing supernatant is subjected to chromium recovering treatment; the surface and interface regulating agents are hydrochloric acid, sodium hydrogen carbonate and sodium carbonate. According to the method, the problems that the leaching treatment of the chromium-containing waste residues is difficult, the cost is high, chromium recovery is difficult, detoxificationis incomplete and the like are solved, and the method has higher social benefit and economic benefit.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment, and in particular relates to a method for detoxifying chromium-containing waste residue and recovering chromium. Background technique [0002] The methods and technologies currently used for the separation and recovery of heavy metals containing chromium solid waste are mainly hydrometallurgy (including acid leaching, alkali leaching, and salt leaching), thermochemical methods (including smelting, roasting and leaching) and biometallurgy. For example, CN102191390A uses sulfuric acid or hydrochloric acid at normal temperature to leach water-soluble and acid-soluble hexavalent chromium, and then collects the leached chromium resources through reduction and precipitation, but this method needs to adjust the pH three times, consuming a large amount of acid and alkali. CN104726705A uses potassium hydroxide aqueous solution, potassium carbonate aqueous solution, potassium metaaluminate aq...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22B7/00C22B1/02C22B34/32
CPCC22B1/02C22B7/001C22B7/006C22B34/32Y02P10/20
Inventor 林璋宋瑶刘炜珍刘学明邓洪
Owner SOUTH CHINA UNIV OF TECH
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