CN1231304C

CN1231304C - Red mud tillage layer soil for re-cultivation in mine and its making process

Info

Publication number: CN1231304C
Application number: CN 03117950
Authority: CN
Inventors: 彭光菊; 谢丽蓉
Original assignee: Guilin Minerals & Geologic Academy
Current assignee: Guilin Minerals & Geologic Academy
Priority date: 2003-05-23
Filing date: 2003-05-23
Publication date: 2005-12-14
Anticipated expiration: 2023-05-23
Also published as: CN1548251A

Abstract

The present invention discloses a new purpose of red mud, which is used for manufacturing topsoil for the reclamation of a mine, and a method for manufacturing the topsoil for the reclamation of a mine by using the red mud. In the method, the red mud is used as a substrate, 15% to 50% of compounding material, such as straws, waste slag liquid in a sugar industry, is added to 50% to 85% of red mud; the total water content in the mixed material is kept in the range of 30 % to 60% with the temperature controlled to be lower than 100 DEG C; after the mixed material is closed, fermented and decayed, the reclamation topsoil which comprises rich minerals and organic substances and has a loose structure and the pH of 5.5 to 8.5 is obtained. The method has the advantages of wide sources of raw material, simple manufacture technology and low cost, solves the problem of pollution caused by the red mud, provides the source of high-quality reclamation topsoil for the mine, and achieves the purposes of utilizing waste, treating waste by waste, and converting waste into valuable articles.

Description

Method for preparing plough layer soil for mine reclamation from red mud

The technical field is as follows:

the invention relates to comprehensive utilization and technology of industrial waste, in particular to technology for preparing mine reclamation plough layer soil by utilizing red mud which is industrial waste residue of an alumina plant.

(II) background technology:

red mud (red mud) is industrial waste residue discharged after aluminum hydroxide is smelted from bauxite, and is named because the appearance of the red mud is similar to that of red soil. Every time 1t of alumina is smelted, 0.6-2 t of red mud is discharged, and about 200 more than ten thousand of red mud discharged every year by the existing large-scale aluminum plant in China is investigated. A large amount of red mud not only occupies fertile farmlands and lands, but also attached alkali pollutes the environment. The red mud problem is not only the problem faced by the aluminum industry in China, but also the problem to be solved by the aluminum industry in the world.

In addition, various researches on the treatment and utilization of red mud are carried out at home and abroad, for example, the red mud is used for extracting iron, producing cement, being used as building and road building materials, preparing farmland calcium silicon fertilizer, extracting saline water caustic soda and the like, and some patents are also filed, but the application is not promoted because ofhigh practicability or production cost. On the other hand, since the release of the regulation for land reclamation from the country, the task of land reclamation of mines is becoming more and more important. At present, bauxite mine reclamation land mainly adopts stripping soil for mining, ore mud for washing ore and foreign soil on peripheral cultivated land, but because bauxite is buried shallowly, the mining operation level is promoted quickly, the land occupation speed is high, the cultivated land around the mine is few, and the reclamation soil source is very short. The reclamation difficulty is high, the reclamation and return period is long, and even in the reclaimed land, the return period is long due to the fact that chemical nutrient content of plough layer soil is low, organic matters are seriously lacked, soil texture is sticky and heavy, and hardening is caused. On the other hand, the red mud, which is waste residue of an alumina plant, is piled up like a mountain, and the red mud contains a large amount of mineral substances and has good dispersibility and viscosity, namely a large particle size distribution range. However, the caustic alkali attached to the red mud is large, generally accounts for 2-4%, and individually accounts for 10%, and the alkali content is several times of the limit of the plants. So that it cannot be directly used as reclamation topsoil.

(III) the invention content:

the invention aims to solve the problems and provides a new application of red mud, namely preparing plough layer soil for mine reclamation from red mud and a preparation method thereof, which can quickly eliminate the pollution problem of red mud, provide a high-quality source of the plough layer soil for mine reclamation, and have the advantages of wide material source, low cost and simple production process.

The manufacturing method of the plough layer soil for the reclamation of mines by using the red mud comprises the following steps:

1. the red mud is taken as a substrate, ingredients containing rich organic matters are added into the red mud, and the dosage range (weight ratio) of the red mud and the ingredients is as follows: 50-85% of red mud and 15-50% of ingredients. The raw material types in the ingredients comprise cut (crushed) straws and waste residues and liquid in sugar industry, wherein the straws comprise sugarcane tips (leaves), sorghum stalks and corn stalks; the waste residue and liquid in the sugar industry comprise bagasse, filter mud and molasses waste mash produced in the sugar manufacturing process, and the ingredients adopted by the invention are prepared by mixing one or more of the raw materials;

2. the red mud and the ingredients are mixed and stirred uniformly. Keeping the total moisture content in the mixture at 30-60%: the mixing temperature is controlled to be lower than 100 ℃:

3. putting the uniformly mixed red mud mixture into a prepared fermentation tank, sealing, fermenting and decomposing, wherein the fermentation and decomposition time is different according to the environment temperature and the variety of ingredients, and is 0.5-9 months, the pH value of the fermented and decomposed red mud soil is 5.5-8.5, the content of humus is more than 2%, the soil is loose, and when the volume weight is reduced, the red mud mixture can be used as plough layer soil for the re-cultivation of a mine re-cultivation area.

The invention has the advantages that:

(1) the straw, bagasse, filter mud and molasses waste mash added into the red mud are changed and changed by cellulose, hemicellulose → sugar → wine → vinegar in the fermentation process Neutralizing the attached alkali in the red mud to maintain the pH value of the alkaline earth between 5.5 and 8.5, so as to meet the requirement of the pH value of soil required by the growth of crops;

(2) through the fermentation, decomposition and decomposition of organic matters in the ingredients, the humic substances of more than 2 percent are added to the red mud. The red mud plough layer soil not only overcomes the defects of heavy clay, easy caking and hardening, easy drought and no water retention of the original red mud, but also combines humus with iron, phosphorus, calcium and the like in the red mud to provide nutrition for plants, forms a chromium compound with active aluminum ions in the red mud, reduces the concentration of the active aluminum ions in the soil, reduces the harm of the aluminum ions to crops, and finally enables the red mud to become plough layer soil which contains rich mineral substances and organic matters and has a loose structure. Not only solves the pollution problem of the red mud, but also provides high-quality plough layer soil for mine reclamation;

(3) the re-tillage time of the mine re-tillage land can be shortened to less than one year, so that the period of the mine mining land is shortened;

(4) waste residues and liquid in the sugar industry are used as ingredients, waste is treated by waste, so that worries of alumina plants are solved, a more convenient way is found for waste treatment in the sugar industry, and the development of the sugar industry can be promoted;

(5) the raw materials are wide in source, the production process is simple, and the production cost is low;

(6) the production process is the neutralization process of acidic substances and alkaline substances, and no secondary pollution and potential safety hazard are generated.

(IV) specific embodiment:

1. preparing a fermentation tank and ingredients: a groove with the width of 1.5 meters and the height of about 1 meter is dug out from a dense land block which is leeward and exposed to the sun, has high terrain and good drainage as a fermentation tank; the mixture of 60-90% of sugarcane tips or bagasse and 40-10% of molasses waste mash is adopted as the ingredients;

2. mixing materials: mixing 75% of main materials (red mud) and 25% of auxiliary materials, wherein the water content of the auxiliary materials is 30-50%, the mixing temperature is controlled at 15-60 ℃, and the main materials and the auxiliary materials are fully and uniformly mixed;

3. fermenting and decomposing: and (3) putting the uniformly mixed red mud mixture into a fermentation tank, sealing the opening of the tank by using clay or a plastic film, fermenting and decomposing. The process takes 1-6 months, wherein the time consumption is long when the environmental temperature and the mixing temperature are low and the fermentation and decomposition of the straws are long;

4. opening the kiln for application: after the fermentation temperature is stable and falls back, opening the kiln and spreading on reclaimed bottom plate soil. The pH value of the fermented and decomposed red mud soil is 6-8.5, the decomposed plant matter content is more than 2%, the soil is loose, the volume weight is reduced, and the red mud soil can be used as plough layer soil to be spread on reclaimed bottom plate soil for the reclamation of a mine reclamation area.

The topsoil prepared in the above embodiment is used for pot experiments of crops, and the crops grow well under the condition that other fertilizers are not applied.

Claims

1. The method for preparing plough layer soil for mine reclamation by using red mud is characterized by comprising the following steps:

(1) the red mud is taken as a substrate, ingredients containing rich organic matters are added into the red mud, and the dosage weight ratio of the red mud to the ingredients is as follows: 50-85% of red mud and 15-50% of ingredients;

(2) uniformly mixing and stirring the red mud and the ingredients, and keeping the total moisture content in the mixture at 30-60%; controlling the mixing temperature to be lower than 100 ℃;

(3) placing the uniformly mixed red mud mixture into a prepared fermentation tank, sealing, fermenting and decomposing, wherein the fermentation and decomposition time is 0.5-9 months according to the temperature and the variety of ingredients, the pH value of the fermented and decomposed red mud soil is 5.5-8.5, the content of humus is about 2%, the soil is loose, and the volume weight is reduced, so that the red mud mixture can be used as plough layer soil for reclamation in a mine reclamation area.

2. The method according to claim 1, wherein the ingredients are prepared by mixing one or more of the following raw materials, wherein the raw materials in the ingredients comprise straw and waste residues and liquid in sugar industry; the straw comprises chopped or crushed sugarcane tips or sugarcane leaves, sorghum stalks and corn stalks; the waste residue and liquid in sugar industry include bagasse, filter mud, and waste molasses mash produced in sugar production process.