阅读说明：本技术 一种赤泥中重金属的钝化方法及应用 (Passivation method and application of heavy metals in red mud ) 是由 王冬芳 叶静宏 蔡冬清 许贺 吴庆川 于 2021-08-18 设计创作，主要内容包括：一种赤泥中重金属的钝化方法及应用,涉及土壤重金属污染的修复的技术领域。包括如下步骤：将赤泥风干粉碎后与钙镁磷肥搅拌均匀得到A；将麦饭石、沸石、鸡蛋壳以混合均匀得到B；将玉米秸秆粉碎后和新鲜牛粪混合均匀,得到混合物C；利用0.1 mol/L的HCl将C调节pH值至3-5,随后向混合物中分别加入FeSO-(4)·7H-(2)O和H-(2)O-(2),得到富有腐植酸和黄腐酸的有机肥D；将制得的A、B、D混合均匀后得到低毒性且富含腐植酸、黄腐酸、钙镁磷的赤泥E。具有良好的吸附性、溶出性、矿化性和生物活性等,可有效吸附固定重金属。钝化后的赤泥不仅可以利用其有利成分为作物提供养分,还可以作为有机肥修复酸性土壤,促进甘蔗生长。(A passivation method and application of heavy metals in red mud, relating to the technical field of remediation of soil polluted by heavy metals. The method comprises the following steps: air drying and crushing the red mud, and uniformly stirring the crushed red mud and a calcium magnesium phosphate fertilizer to obtain A; mixing Maifanitum, zeolite, and ovum gallus Domesticus crusta uniformly to obtain B; crushing corn straws, and uniformly mixing the crushed corn straws with fresh cow dung to obtain a mixture C; adjusting the pH of C to 3-5 with 0.1 mol/L HCl, and then adding FeSO to the mixture 4 ·7H 2 O and H 2 O 2 Obtaining an organic fertilizer D rich in humic acid and fulvic acid; the prepared A, B, D is mixed evenly to obtain the red mud E which has low toxicity and is rich in humic acid, fulvic acid, calcium, magnesium and phosphorus. Has good adsorptivity, dissolubility, mineralization property, biological activity and the like, and can effectively adsorb and fix heavy metals. The passivated red mud not only can provide nutrients for crops by utilizing the beneficial components of the red mud, but also can be used as an organic fertilizer to repair acid soil and promote the growth of sugarcane.)

1. A passivation method of heavy metals in red mud is characterized by comprising the following steps:

step (1): air-drying and crushing the red mud to 100-mesh and 200-mesh powder, and uniformly stirring the powder and a calcium-magnesium phosphate fertilizer to obtain A;

step (2): mixing Maifanitum, zeolite, and ovum gallus Domesticus crusta uniformly to obtain B;

and (3): crushing corn straws into 1-10 cm long, and then uniformly mixing the corn straws with fresh cow dung to obtain a mixture C;

and (4): adjusting the pH value of the C obtained in the step (3) to 3-5 by using 0.1 mol/L HCl, and then adding 1-2 g of FeSO into the mixture₄·7H₂O and 1-2 mL H₂O₂Stirring for 30-50 min to obtain an organic fertilizer D rich in humic acid and fulvic acid;

and (5): the prepared A, B, D is mixed evenly to obtain the red mud E which has low toxicity and is rich in humic acid, fulvic acid, calcium, magnesium and phosphorus.

2. The method for passivating the heavy metals in the red mud according to claim 1, wherein the ratio of red mud wind and calcium magnesium phosphate fertilizer in the step (1) is (3-5): the mass ratio of (1-2) is stirred uniformly.

3. The method for passivating the heavy metals in the red mud according to claim 1, wherein the proportion of maifanite, zeolite and eggshell in the step (2) is (1-3): (1-3): and (1-3) stirring uniformly.

4. The method for passivating heavy metals in red mud according to claim 3, wherein the Maifanitum is 60-80 mesh.

5. The method for passivating the heavy metals in the red mud according to claim 3, characterized in that the zeolite is 80-100 mesh.

6. The method for passivating the heavy metals in the red mud according to claim 3, wherein the eggshells are crushed to 50-100 meshes.

7. The method for passivating the heavy metals in the red mud according to claim 1, wherein the proportion of the corn stalks and the fresh cow dung in the step (3) is (1-3): and (1-3) stirring uniformly.

8. The method for passivating the heavy metals in the red mud according to claim 1, wherein A, B, D in the step (5) is expressed as (16-20): (2-4): the mass ratio of (1-2) is stirred uniformly.

9. The application of the red mud E obtained by the passivation method of heavy metals in red mud according to claim 1.

Technical Field

The invention relates to the technical field of remediation of soil polluted by heavy metals.

Background

The red mud is high-alkaline solid waste generated in the production process of alumina, and 1-1.5 tons of red mud is generated when 1 ton of alumina is produced. At present, China has become the biggest alumina producing country and red mud producing country in the world, the red mud production amount is about 7300 million tons in 2013, the comprehensive utilization rate is only 4 percent, the accumulated stockpiled red mud exceeds 3.5 million tons, and the global accumulated stockpiled red mud exceeds 30 million tons.

The red mud has the characteristics of strong saline-alkali property, small particle size and the like, dust is easy to generate and causes harm to soil, water and even human health around a storage yard, and the migration of Pb, As, Cd, V, Cr and Cu in the red mud is increased under the condition of rainwater leaching, so that the red mud has potential harm to the environment. At present, research on a method for repairing heavy metals in red mud is still blank, so that a technology for repairing heavy metals in red mud needs to be developed urgently.

At present, the remediation technologies for heavy metal pollution of soil mainly comprise physical technologies (soil-moving method, soil-changing method and the like), chemical technologies (soil washing, extraction, electric remediation, passivant addition and the like) and biological technologies (phytoremediation, microbial remediation and the like). The soil restoration method by adding the passivator has the advantages of low cost, convenient operation, obvious effect, suitability for large-area popularization and more attention in recent years.

Disclosure of Invention

The invention provides a technology for passivating heavy metals in red mud by combining a remediation method of heavy metals in soil, aiming at the problems of large red mud stacking amount and easy migration of heavy metals in red mud, and simultaneously, the technology can convert industrial waste red mud into agricultural organic fertilizer, so that heavy metals in red mud can be repaired, nutrients can be provided for crops to promote the growth of the crops by utilizing favorable components of the agricultural organic fertilizer, and the passivated red mud can also repair acid soil to promote the growth of sugarcane.

The technical scheme of the invention is as follows: a passivation method of heavy metals in red mud comprises the following steps:

step (1): air-drying and crushing the red mud to 100-mesh and 200-mesh powder, and uniformly stirring the powder and a calcium-magnesium phosphate fertilizer to obtain A;

step (2): mixing Maifanitum, zeolite, and ovum gallus Domesticus crusta uniformly to obtain B;

and (3): crushing corn straws into 1-10 cm long, and then uniformly mixing the corn straws with fresh cow dung to obtain a mixture C;

and (4): adjusting the pH value of the C obtained in the step (3) to 3-5 by using 0.1 mol/L HCl, and then adding 1-2 g of FeSO into the mixture₄·7H₂O and 1-2 mL H₂O₂Stirring for 30-50 min to obtain an organic fertilizer D rich in humic acid and fulvic acid;

and (5): the prepared A, B, D is mixed evenly to obtain the red mud E which has low toxicity and is rich in humic acid, fulvic acid, calcium, magnesium and phosphorus.

Preferably, the red mud wind and the calcium magnesium phosphate fertilizer are prepared from (3-5): the mass ratio of (1-2) is stirred uniformly.

Preferably, the medical stone, the zeolite and the eggshell of the invention are prepared from (1-3): (1-3): and (1-3) stirring uniformly.

Preferably, the medical stone is 60-80 meshes.

Preferably, the zeolite of the present invention is 80 to 100 mesh.

Preferably, the ground egg of the present invention is crushed to 50 to 100 mesh.

Preferably, the corn stalks and fresh cow dung of the invention are mixed in the ratio of (1-3): and (1-3) stirring uniformly.

Preferably, A, B, D of the present invention is expressed as (16-20): (2-4): the mass ratio of (1-2) is stirred uniformly.

The application of the red mud E obtained by the method for passivating the heavy metals in the red mud is disclosed.

The invention provides a method for passivating heavy metals in red mud and application thereof. The calcium magnesium phosphate fertilizer not only provides 12 to 18 percent of low-concentration phosphorus, but also provides a large amount of nutrient substances needed by crops such as silicon, calcium, magnesium and the like; the medical stone and the zeolite are natural clay minerals, are rich in aluminosilicate substances, have good adsorbability, dissolution property, mineralization property, biological activity and the like, and can effectively adsorb and fix heavy metals; the main component of the egg shell is CaCO₃The purpose of passivating heavy metals in the red mud is achieved by increasing the pH value of the red mud(ii) a The cow dung is rich in organic humic acid, can play a role in chelating heavy metal in the red mud, and provides nutrients for soil.

Detailed Description

A passivation method of heavy metals in red mud comprises the following steps:

step (1): air-drying and crushing the red mud to 100-mesh and 200-mesh powder, and uniformly stirring the powder and a calcium-magnesium phosphate fertilizer to obtain A;

step (2): mixing Maifanitum, zeolite, and ovum gallus Domesticus crusta uniformly to obtain B;

and (3): crushing corn straws into 1-10 cm long, and then uniformly mixing the corn straws with fresh cow dung to obtain a mixture C;

and (4): adjusting the pH value of the C obtained in the step (3) to 3-5 by using 0.1 mol/L HCl, and then adding 1-2 g of FeSO into the mixture₄·7H₂O and 1-2 mL H₂O₂Stirring for 30-50 min to obtain an organic fertilizer D rich in humic acid and fulvic acid;

and (5): the prepared A, B, D is mixed evenly to obtain the red mud E which has low toxicity and is rich in humic acid, fulvic acid, calcium, magnesium and phosphorus.

The red mud wind and the calcium magnesium phosphate fertilizer are prepared from (3-5): the mass ratio of (1-2) is stirred uniformly.

The medical stone, zeolite and egg shell of the invention are prepared from (1-3): (1-3): and (1-3) stirring uniformly.

The medical stone is 60-80 meshes, the zeolite is 80-100 meshes, and the egg shell is crushed to 50-100 meshes.

The corn straw and the fresh cow dung are prepared from (1-3): and (1-3) stirring uniformly.

A, B, D of the present invention is expressed as (16-20): (2-4): the mass ratio of (1-2) is stirred uniformly.

The application of the red mud E obtained by the method for passivating the heavy metals in the red mud is disclosed.

Example 1:

step (1): drying and crushing the red mud into 100-mesh powder with 200 meshes, mixing the powder with a calcium-magnesium phosphate fertilizer in a proportion of 3: 1, uniformly stirring to obtain A;

step (2): pulverizing 60-mesh Maifanitum and 80-mesh zeolite into 50-mesh eggshell, mixing the raw materials in a proportion of 1: 1: 1 to obtain B;

and (3): corn stalks are crushed into 5 cm long, and then are mixed with fresh cow dung to obtain a mixture with the weight ratio of 1: 1 to obtain a mixture C;

and (4): the pH of 10 g C obtained in step (3) was adjusted to 3 with 0.1 mol/L HCl, and 1g of FeSO was added to the mixture₄·7H₂O and 1mL H₂O₂Stirring for 30 min to obtain an organic fertilizer D rich in humic acid and fulvic acid;

and (5): the prepared A, B, D was mixed at a ratio of 20: 3: 1 to obtain the red mud E which has low toxicity and is rich in humic acid, fulvic acid, calcium, magnesium and phosphorus, thereby realizing the agricultural use of industrial wastes.

And (3) uniformly spreading the E obtained in the step (5) on the surface layer of the acid soil according to the using amount of 50 kg/mu, and then carrying out rotary tillage, wherein after 60 days, the sugar brix of the sugarcane is improved by 3.17%, and the yield is improved by 17.86%.

Example 2:

step (1): drying and crushing the red mud into 20 meshes, mixing the crushed red mud with a calcium magnesium phosphate fertilizer in a proportion of 4: 1, uniformly stirring to obtain A;

step (2): pulverizing 60-mesh Maifanitum and 80-mesh zeolite into 80-mesh egg shell, mixing the raw materials in a ratio of 2: 1: 1 to obtain B;

and (3): the corn straws are crushed into 2 cm long, and then the crushed corn straws are mixed with fresh cow dung to obtain a mixture with the weight ratio of 2: 1 to obtain a mixture C;

and (4): the pH of 10 g C obtained in step (3) was adjusted to 3 with 0.1 mol/L HCl, and 1g of FeSO was added to the mixture₄·7H₂O and 2 mL H₂O₂Stirring for 50 min to obtain an organic fertilizer D rich in humic acid and fulvic acid;

and (5): the prepared A, B, D was mixed at 18: 3: 2 to obtain the red mud E which has low toxicity and is rich in humic acid, fulvic acid, calcium, magnesium and phosphorus, thereby realizing the agricultural use of industrial wastes.

And (3) uniformly spreading the E obtained in the step (5) on the surface layer of the acid soil according to the using amount of 75 kg/mu, and then carrying out rotary tillage, wherein after 60 days, the sugar brix of the sugarcane is improved by 3.51%, and the yield is improved by 34%.

The soluble heavy metal lead in the red mud obtained by the embodiment is 2.86 multiplied by 10 before passivation³mg/kg, which is less than 0.001 mg/kg after passivation; the amount of soluble heavy metal cadmium in the red mud obtained by the embodiment is 8.09mg/kg before passivation and 0.002 mg/kg after passivation; the amount of soluble heavy metal chromium in the red mud obtained by the embodiment is 66mg/kg before passivation and 3.136 mg/kg after passivation; the amount of soluble heavy metal copper in the red mud obtained by the embodiment is 338mg/kg before passivation and 0.339 mg/kg after passivation; the pH values before and after the acid soil is repaired by the method are respectively 5.6 and 6.995; the brix of the sugarcane processed by the prior art is 17.52, and the brix of the sugarcane processed by the embodiment is 18.565; the acre yield of the sugarcane processed by the prior art is 4 tons, and the acre yield of the sugarcane processed by the embodiment is 5.285 tons.

Example 3:

step (1): drying and crushing the red mud into 50 meshes, mixing the crushed red mud with a calcium magnesium phosphate fertilizer in a proportion of 5: 1, uniformly stirring to obtain A;

step (2): pulverizing 80-mesh Maifanitum, 100-mesh zeolite, and 100-mesh ovum gallus Domesticus crusta to powder, mixing at a ratio of 1: 1: 1 to obtain B;

and (3): the corn straws are crushed into 10 cm long, and then the crushed corn straws are mixed with fresh cow dung to obtain a mixture with the weight ratio of 3: 1 to obtain a mixture C;

and (4): the pH of 10 g C obtained in step (3) was adjusted to 5 with 0.1 mol/L HCl, and 1g of FeSO was added to the mixture₄·7H₂O and 1mL H₂O₂Stirring for 50 min to obtain an organic fertilizer D rich in humic acid and fulvic acid;

and (5): the prepared A, B, D was mixed at a ratio of 10: 2: 1 to obtain the red mud E which has low toxicity and is rich in humic acid, fulvic acid, calcium, magnesium and phosphorus, thereby realizing the agricultural use of industrial wastes.

And (3) uniformly spreading the E obtained in the step (5) on the surface layer of the acid soil according to the using amount of 100 kilograms per mu, and then carrying out rotary tillage, wherein after 60 days, the sugar brix of the sugarcane is improved by 1.36%, and the yield is improved by 28.2%.