CN102399111A - Greening matrix and phytoremediation technology method of pulverized coal gangue - Google Patents

Abstract

The present invention relates to the phytoremediation technology of the environment polluted by solid waste, and specifically discloses an ecological restoration technology for the greening matrix of crushed coal gangue and the greening of coal gangue hills by plants, mainly using the mixture of crushed coal gangue and soil as the Greening substrate, in which the volume ratio of coal gangue to southern nutrient soil and flower soil is: 1:2~2:1 (that is, the volume of coal gangue accounts for 1/3~1/2); plant heavy metal non-accumulating plant tobacco and Cd accumulating plant dragon Sunflower, so as to achieve the purpose of greening and ecological restoration of coal gangue hills. The use of this phytoremediation technology using coal gangue solid waste matrix can effectively improve the air quality and ecological environment in coal mining areas.

Description

Greening matrix and phytoremediation technology method of pulverized coal gangue

Technical field:

The invention relates to a coal gangue hill ecological restoration matrix and plant restoration technology in a coal mining area, in particular to the vegetation greening technology of the coal gangue hill.

Background technique:

Coal is one of the important energy sources in my country. In 2007, the national raw coal output reached 2.55 billion tons. Coal gangue is solid waste in the process of coal mining and processing, and its output accounts for 10% to 30% of raw coal. Due to the impact of resource properties, economic conditions, technical equipment and market changes, the utilization rate of coal gangue in my country is less than 30%. Although some coal gangue can be reused as building materials and fuels, the comprehensive industrial utilization rate is still less than 5%. Therefore, most of the coal gangue are disposed of in the way of fixed-point stacking on the ground. With the increase of society's demand for energy, the amount of mining and processing of coal resources has also increased, and the continuous discharge and accumulation of coal gangue has formed thousands of gangue hills of different sizes, becoming the largest source of industrial solid waste.

Coal gangue mainly includes coal gangue discharged from well digging, coal gangue discharged from coal preparation and stripped coal gangue produced by open-pit coal mining. The mineral composition is relatively complex, usually quartz, mica, clay (illite and kaolinite), sulfur Iron ore (FeS2) and carbonates of calcium, magnesium and iron, the main chemical elements are oxides of silicon, aluminum, iron, calcium, titanium, sulfur, potassium, magnesium and sodium, as well as Cr, Cd, Co, Heavy metals such as Cu, Mn, Pb and Zn. The open-air stacking of coal gangue is very prone to spontaneous combustion, and the spontaneous combustion is mainly coal powder and combustible sulfur, and the sulfur mainly exists in the form of pyrite. Pyrite is a crystal structure formed under the condition of anoxic reduction. It occurs in coal seams and coal-measure strata. After mining, it is exposed to the air. The weathering rain effect and the catalysis of microorganisms take the lead in oxidation reaction under suitable water and air conditions, and release heat. The heat accumulation gradually increases the temperature inside the gangue hill, triggering spontaneous combustion, which in turn leads to explosions and landslide debris flows, etc. Disaster, causing heavy casualties and property damage! Spontaneous combustion of gangue dumps releases a large amount of irritating gases, such as CO, SO ₂ , H ₂ S and NO ₂ , causing an increase in human respiratory and cancer diseases in coal mining areas. At the same time, sulfide gas leads to acid rain, and the soluble sulfate formed seriously acidifies the water quality and soil in the surrounding environment. Especially during the oxidation process of pyrite, the Fe ²⁺ in it is oxidized to Fe ³⁺ , which is hydrolyzed in water to form Fe(OH) ₃ , which releases more H ⁺ into the water and lowers the pH of coal gangue weathered environment value, accelerated the oxidation process of sulfur and iron by Thiobacillus, and SO ₄ ^2- accumulated and leached to form acidic wastewater. In addition, in addition to pyrite, coal gangue also contains some sulfide minerals, such as marcasite, pyrrhotite, galena, sphalerite, chalcopyrite, molybdenite and goethite, etc., which are also acidic. An important source of wastewater, the corresponding heavy metals such as Mn, Pb, Cu, Zn and Mo are leached out. Precipitation causes acid waste water and leached heavy metals to migrate to the downhill and surrounding soil and rivers, resulting in severe acidification and accumulation of active heavy metals in the gangue dump and surrounding soil, turning the gangue dump into a bare black mountain! The soil vegetation is destroyed, and the ecological environment of the mining area deteriorates. Therefore, the greening treatment of gangue hills is the key to the improvement of the ecological environment in coal mining areas.

Land reclamation in mining areas and greening of gangue hills are research fields that have attracted much attention internationally, and vegetation reconstruction of waste rock hills is the best strategy for ecological restoration in mining areas. In order to control the oxidation of gangue pyrite from the source, prevent the generation of acid wastewater, the leaching of heavy metals, the dusting of surface weathered particles, and improve the soil fertility of surface weathered materials, various treatment technologies have been tried at home and abroad for many years. Such as no-covering soil afforestation technology; loess, sludge or compost covering technology to prevent the penetration of oxygen and water to active sulfide; adding Thiobacillus ferrooxidans fungicide to inhibit pyrite biooxidation; coal gangue surface coating passivation treatment technology Inhibit the oxidation of pyrite; add fly ash and alkaline substances (such as NaOH, limestone, quicklime, NaCO3) to increase the pH of the leachate, promote the precipitation of heavy metals, and inhibit the oxidation of pyrite and the leaching of heavy metals. Due to the risk of secondary pollution from sludge, fly ash and limestone, etc., the effect of fungicides is low and the duration is short. At present, gangue hills are still covered with loess after being rolled by plastic machinery, and then planted with grass and trees. , artificially build a plant ecosystem, and improve the ecological environment of the gangue dump and its surrounding areas. At present, the land reclamation rate in my country is only about 10%. One of the reasons is the lack of effective solid waste treatment technology and ecological restoration technology. Using coal gangue as a greening substrate and planting heavy metal-resistant plants with large biomass can not only turn waste into treasure, but also expand the greening area of the mining area, so that the vegetation ecological environment of the mining area can be gradually restored. The application of this technology is very important for the ecological environment of the mining area. The improvement and sustainable development are of great significance.

The greening matrix of crushed coal gangue and the technical method of plant reclamation have determined the optimum mixing ratio range of crushed coal gangue and soil matrix suitable for vegetation growth in the reclamation environment, providing a basis for reducing the amount of soil covering and reclamation costs for mine reclamation effective method. This method explores the greening technology of crushed coal gangue matrix suitable for the growth of heavy metal non-accumulating plant tobacco (Nicotiana tabacu) and Cd accumulating plant Solanum nigrum, which provides a scientific basis for reclamation and greening of coal gangue hills and technical support.

Invention content:

The object of the present invention is to provide a kind of coal gangue pulverized material greening substrate and plant reclamation technology method. The application of the coal gangue greening matrix can not only provide some nutrients for plants, but also prevent soil compaction and increase the biomass of tobacco and black nightshade plants; the growth and greening technology of the two plants in the coal gangue greening matrix are coal The reclamation and greening of gangue dumps provides a new way.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A kind of greening matrix of crushed coal gangue mainly uses the crushed coal gangue as a substrate, and the soil is selected from the southern nutrient soil produced by Changchun Flower Soil Factory (physical and chemical indicators: particle size 3.0-6.5mm, pH 4.5-5.5, organic matter 50%, Nitrogen 300-600mg/kg, phosphorus 150-300mg/kg, potassium 300-500mg/kg, water content 45-55%), used for green plants, flowers, potted plants, seeds, plants and gardening supplies, etc. In the coal gangue pulverized material matrix prepared by coal gangue and soil, coal gangue:soil=1:2～2:1, that is, the volume ratio of coal gangue to coal gangue pulverized material matrix is 1/3～1/2, and soil accounts for 1/3～1/2. The volume ratio of the crushed coal gangue matrix is 1/3-1/2.

The technical method of plant reclamation is mainly to plant the heavy metal non-accumulating plant tobacco and the heavy metal Cd accumulating plant Solanum nigrum in the matrix.

Description of drawings:

Figure 1: Growth of tobacco in different gangue matrices (0, 1/3, 1/2, 2/3 and 1 in the legend represent the volume ratios of gangue to gangue pulverized matrices respectively);

Figure 2: Tobacco biomass and plant height in different gangue matrices

Figure 3: Growth of Solanum nigrum in different gangue substrates (0, 2/3 and 1 in the legend represent the volume ratio of gangue to the crushed gangue substrate respectively);

Figure 4: Biomass and plant height in different gangue matrices;

Detailed ways

Example 1 Tobacco Pot Experiment

The coal gangue samples were collected from gangue hills in Huainan, Anhui, and the soil was selected from southern nutrient soil. The greening matrix of pulverized coal gangue mainly uses gangue as the matrix. After the crushed coal gangue passes through a 2mm sieve, the mixed gangue sample and soil are the greening matrix of pulverized coal gangue. The pulverized coal gangue and soil are mixed according to different ratios of 0:1, 1:2, 1:1, 2:1 and 1:0, so that the volume ratio of coal gangue to the greening matrix reaches: 0, 1/3, 1 /2, 2/3 and 1, put into 15cm×13cm plastic pots, and sow after watering. Tobacco NC89 was sown on May 27, 2009, seedlings were planted within 30 days, and 2 healthy seedlings were left in each pot; when the tobacco grew for 3 months, two tobacco plants were taken out of the pot, and the plant height of tobacco in different proportions of coal gangue matrix was measured and biomass. The experiment site was set in the greenhouse of China University of Mining and Technology (Beijing), and watering was performed irregularly during the tobacco growth period according to the water shortage in the basin.

The experimental results are as follows:

Tobacco is a model plant for plant research, easy for tissue culture and gene transformation, and not resistant to heavy metals. From sowing on May 27, 2009 to harvesting on August 26, 2009, it grew for about 90 days (Fig. 1). At 23 days after sowing, the tobacco seedlings in the whole gangue matrix were smaller, while the tobacco seedlings in the greening matrix of other crushed coal gangue were more consistent, indicating that tobacco could use part of the nutrients in the gangue matrix. At 62 days, from left to right, with the continuous increase of coal gangue content, the change of tobacco plant height showed a trend of first increasing and then decreasing. Among them, 1/2-2/3 of the gangue substrate grows best, and the plant height is higher than that of the whole soil. The leaves of the seedlings in the whole gangue substrate are yellow and weak. It indicated that 1/3～2/3 of the gangue greening substrate can improve the soil structure and promote the growth of tobacco seedlings in the early stage, while the whole gangue substrate is poor in nutrients and cannot meet the needs of tobacco growth. When the tobacco was grown for 90 days (Figure 2), the biomass and plant height of the tobacco in the whole gangue substrate were very small, significantly lower than 1/3-2/3 of the gangue greening substrate and the whole soil; 1/3-2/3 The biomass and plant height of tobacco in the gangue greening matrix reached 75% and 50% of the tobacco biomass and plant height in the whole soil respectively, but the lower leaves turned yellow and dried, which may be due to the need for a large amount of tobacco in the later stage of growth Nutrients, but due to the lack of nutrients in the gangue matrix. Therefore, if the growth of the entire growth period of tobacco is to be completed, certain fertilizers must be applied in the late growth period. It shows that 1/3～2/3 of coal gangue greening substrate can promote the early growth of tobacco seedlings, and tobacco can be used for greening treatment of coal gangue hills.

Example 2 Solanum nigrum pot experiment

Coal gangue samples were collected from gangue hills in Anhui, and the soil was selected from southern nutrient soil. The greening matrix of pulverized coal gangue mainly uses coal gangue as the matrix, and the coal gangue sample is passed through a 2mm sieve and mixed with soil to form the greening matrix of pulverized coal gangue. The pulverized coal gangue and the soil are mixed according to different ratios of 0:1, 2:1 and 1:0, so that the volume ratio of coal gangue to the greening matrix reaches: 0, 2/3 and 1 respectively; Sow nightshade on June 3, 2009, sow 10 seeds per pot, and cover with a thin layer of soil. During its growth period, according to the lack of water in the pot, water it irregularly. When growing for 3 months, the plant height and biomass of Solanum nigrum in different proportions of coal gangue matrix were measured.

The experimental results are as follows:

Tobacco is a heavy metal-sensitive plant. From Example 1, it is known that 1/3-2/3 of the gangue substrate is suitable for the growth of tobacco seedlings in the early stage. Solanum nigrum is a heavy metal Cd accumulating plant and has great application potential for phytoremediation of Cd-contaminated soil. Coal gangue contains trace amounts of heavy metals. In order to study its ability to repair 2/3 gangue, the growth and biomass of nightshade in 0, 2/3 and 1 gangue substrates were analyzed. The growth of nightshade in different gangue substrates is significantly different (Figure 3). For example, after 40 days of growth, the leaves of nightshade in the whole gangue substrate are always yellow and weak, while the leaves of nightshade in the whole soil and 2/3 gangue substrate The leaves remained green, and the plant height and biomass of Solanum nigrum in 2/3 gangue substrate were the largest, which were significantly higher than those in the whole soil and gangue substrate. When growing for about 3 months, the nightshade in different substrates all bloomed and bear fruit (Fig. 3), and the plant height of Solanum nigrum in 2/3 gangue substrate was significantly higher than that in the whole soil and the whole gangue substrate (Fig. 4), but Its side branches and flowers and fruits are obviously less than those in the whole soil matrix; the nightshade in the whole soil matrix is luxuriant in branches and leaves, and the fruits are numerous; the plants in the whole gangue matrix are short, with few branches, flowers and fruits, but after all It can use the nutrients in coal gangue to complete its growth throughout the growth period, which shows that nightshade has a higher repairing ability to coal gangue than tobacco. Biomass (Fig. 4) analysis shows that the fresh weight of Solanum nigrum in 2/3 gangue matrix can reach 66% of the whole soil, indicating that 2/3 of gangue matrix can promote the early growth of Solanum nigrum. During the flowering and fruiting period, because the lack of coal gangue nutrients can not meet the growth needs, 2/3 of the gangue matrix has fewer branches of nightshade, which is consistent with the conclusion of the tobacco pot experiment. Therefore, in the process of 2/3 coal gangue vegetation restoration, timely addition of fertilizers can promote the long-term growth and flowering of reclaimed plants.

The novelty of the present invention lies in: 1. In this method, there are few types of reclamation substrates, which reduces the complexity of construction, and at the same time, avoids the risk of secondary pollution caused by other restoration substrates, such as sludge, fly ash and limestone; 2. .This method can save the amount of covering soil for reclamation, and reduce the construction cost and difficulty; 3. The optimum ratio of crushed coal gangue and soil matrix suitable for plant growth has been explored, which provides a greening and greening of soil vegetation in mining areas. Technical Support.

Claims (5)

1. coal gangue pulverizing article afforesting matrix, it is characterized in that: utilize coal gangue pulverizing article as matrix, wherein in the mixture of coal gangue and soil, the coal gangue volume accounts for 1/3～2/3, and the soil volume accounts for 1/3～2/3.

2. coal gangue phytoremediation technology method; It is characterized in that: like claims 1 described coal gangue pulverizing article afforesting matrix, plantation non-accumulation plant tobacco of heavy metal and Cd accumulation plant black nightshade water according to soil lack of water situation; Prolongation along with two plant growth phases; Living weight constantly increases, and green area coverage improves thereupon, quickens to reclaim the recovery of waste dump vegetation and the change of mining area ecological environment.

3. require described coal gangue pulverizing article afforesting matrix and right 2 to require the said method of utilizing tobacco and black nightshade to repair coal gangue according to right 1, the tobacco of plantation and black nightshade are that seed is directly sowed in the coal gangue pulverizing article afforesting matrix.

4. require the said method of utilizing tobacco and black nightshade to repair coal gangue according to right 2, it is characterized in that: the tobacco of plantation and black nightshade grew about 90 days, and tobacco is in vegetative growth phase always, and black nightshade then gets into fruiting period; Tobacco and black nightshade all can be used for the green plants of earthing waste dump.

5. require the application method of described coal gangue pulverizing article afforesting matrix according to right 1 and right 2; It is characterized in that: with coal gangue pulverizing article with cover on the waste dump after soil mixes according to a certain percentage; Carrying out earthing administers; Both economize on the soil amount, and can improve the structure of soil again, promoted the growth of plant.

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