A method for in-situ immobilization of vanadium ore-contaminated soil by modified biochar

A technology of polluted soil and biochar, applied in the restoration of polluted soil, etc., can solve the problems of high cost, high repair cost, serious environmental pollution, etc., and achieve no secondary pollution, obvious fixation effect, and rich void structure Effect

Active Publication Date: 2017-04-19
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main raw material for vanadium extraction in my country is stone coal, which is a low-grade polymetallic symbiotic ore. The traditional stone coal vanadium extraction process has a low metal recovery rate. Every ton of V produced 2 o 5 About 200 tons of waste residues are produced, which seriously pollutes the environment and produces a large amount of vanadium-containing waste residues, waste water and waste gas
Vanadium and associated heavy metals such as chromium, manganese, copper, zinc, and manganese gradually migrate to the soil environment during the long-term accumulation process, causing serious soil heavy metal pollution. At present, there are few soil in-situ remediation technologies for vanadium-contaminated soil in my country
Traditional treatment methods include heat treatment, physical and chemical methods, and biological methods, all of which have high repair costs and risks such as secondary pollution. In-situ repair technology shows advantages, but traditional curing agent materials are expensive and have limited effects on compound pollution
Moreover, the current domestic soil remediation technology for vanadium mine pollution is rarely involved.

Method used

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  • A method for in-situ immobilization of vanadium ore-contaminated soil by modified biochar

Examples

Experimental program
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Effect test

Embodiment 1

[0024] After removing impurities, washing, killing, crushing and sterilizing the collected vegetation, it is cracked at a high temperature of 450°C under the protection of nitrogen gas, and maintained for 30 minutes, and then cooled to room temperature by nitrogen gas to obtain solid particles, which are then cleaned and removed. , dried at 60°C for later use; the granules were added to the mixed system of calcium hydrogen phosphate dissolved in 5% dilute nitric acid at a molar ratio of 1:1 according to the ratio of 1g:40ml, ultrasonicated for 20min, filtered, washed, and placed in Dry at 55°C, grind and pass through a 1mm sieve to obtain modified biochar, apply the modified biochar evenly to the surface of the polluted site at a mass ratio of 1%, plow the soil at a depth of 0-15cm, mix it evenly, and spray it Tap water keeps the field water holding capacity of the soil at 60%, and maintains for 30 days. Soil leaching experiments showed that the leaching toxicity of heavy meta...

Embodiment 2

[0026] After removing impurities, killing greens, crushing, and sterilizing the collected vegetation, it was cracked at a high temperature of 500°C under the protection of nitrogen, maintained for 30 minutes, and continued to pass through nitrogen to cool to room temperature to obtain solid particles, which were washed with ethanol and ultrapure water to remove After mixing, dry it at 50°C for later use. Add the granule to the mixed system of calcium hydrogen phosphate dissolved in 5% dilute nitric acid at a molar ratio of 2:1 according to the ratio of 1g:50ml, sonicate for 20min, and filter , cleaned, dried at 55°C, and passed through a 2mm sieve after grinding to obtain modified biochar. The modified biochar was evenly applied to the surface of the polluted site at a mass ratio of 2%, and the soil at a depth of 0-15cm was plowed. Mix evenly, keep the field water holding capacity of the soil at 60% by spraying tap water, and maintain for 30 days.

[0027] Soil leaching experi...

Embodiment 3

[0029] After removing impurities, killing greens, crushing, and sterilizing the collected vegetation, it was cracked at a high temperature of 550°C under the protection of nitrogen, maintained for 30 minutes, and continued to pass through nitrogen to cool to room temperature to obtain solid particles, which were washed with ethanol and ultrapure water to remove After mixing, dry it at 50°C for later use. Add the granules to the mixed system of calcium hydrogen phosphate dissolved in 5% dilute nitric acid in a molar ratio of 3:1 according to the ratio of 1g:60ml, sonicate for 20min, and filter , cleaned, dried at 55°C, ground and sieved through a 3mm sieve to get the modified biochar, the modified biochar was evenly applied to the surface of the polluted site at a mass ratio of 3%, and the soil at a depth of 0-15cm was taken for plowing , mix evenly, keep the field water holding capacity of the soil at 60% by spraying tap water, and maintain for 30 days.

[0030] Soil leaching ...

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Abstract

The invention discloses a method for in situ fixation of vanadium ore polluted soil by modified charcoal and belongs to the technical field of soil in-situ remediation. The method comprises the following steps: 1, after harvested plants in vanadium ore polluted sites are pretreated, the pretreated plants are subjected to pyrolysis at 450-550 DEG C under the nitrogen protection, the pyrolysis time lasts for 30 min, then nitrogen is introduced continuously, the mixture I is cooled to room temperature to obtain solid particles, and the solid particles are cleaned and then dried at 60 DEG C to obtain charcoal particles for standby application; 2, calcium hydrophosphate is dissolved in dilute nitric acid with the mass concentration being 5%, calcium hydrophosphate and the dilute nitric acid are sufficiently mixed according to the the molar ratio of (1-3):1; 3, the charcoal particles are added in a calcium hydrophosphate-nitric acid mixing system according to the fact that 1 g of charcoal particles are added into 40-60 ml of calcium hydrophosphate-nitric acid mixing system, and ultrasonic treatment is performed for 20 min; 4, the mixture II is filtered, and the filtered substance is cleaned and dried at 55 DEG C to obtain modified charcoal; 5, the modified charcoal is sufficiently mixed with soil samples at the mass ratio of 1%-3%, the soil field capacity is kept to be 60%, and maintenance is carried out for 30 days. A soil leaching experiment result shows that compared with the leaching toxicities of heavy metals namely V, Cr and Pb of soil which is not fixed by modified charcoal, the leaching toxicities of heavy metals namely V, Cr and Pb of the soil fixed by modified charcoal are respectively reduced by 70%, 50% and 35%.

Description

technical field [0001] The invention belongs to the technical field of soil in-situ remediation, and in particular relates to a method for in-situ fixation of vanadium ore polluted soil by modified biochar. Background technique [0002] China has rich reserves of vanadium ore resources. Metal vanadium has high melting point, hard texture, and ductility. It is widely used in industrial fields, electronic technology, aviation, railways and other fields. As the application scope of vanadium continues to expand, the amount of vanadium mining continues to increase, and the environmental problems brought about by the vanadium smelting process are also becoming more and more prominent. The main raw material for vanadium extraction in my country is stone coal, which is a low-grade polymetallic symbiotic ore. The traditional stone coal vanadium extraction process has a low metal recovery rate. Every ton of V produced 2 o 5 About 200 tons of waste residues are produced, which seriou...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B09C1/10
Inventor 蒋建国刘诺张文杰丁旭彤
Owner TSINGHUA UNIV
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