Graphite tailing matrix soil and preparation method thereof

Abstract

The invention discloses graphite tailing matrix soil and a preparation method thereof, and belongs to the technical field of tailing remediation, and the preparation method comprises the step of uniformly mixing 93.26-95.94% of graphite tailings, 3-5% of animal waste, 0.16-0.24% of a modifier A and 0.9-1.5% of diatomite. According to the graphite tailing matrix soil and the preparation method thereof, a new way is provided for consumption of graphite tailing resources, so that the problems of source of ecological restoration soil in a mining area and stacking of a large amount of graphite tailings are solved, and a win-win situation of social development and ecological environment protection is realized.

Description

Technical Field

[0001] The invention relates to the technical field of tailings restoration, in particular to a graphite tailings matrix soil and a preparation method thereof. Background Art

[0002] As a key raw material in the fields of chemical industry, aerospace, military industry, metallurgy, etc., the demand for graphite has been rising year by year, which has led to a surge in the mining volume of graphite mines, and the discharge of graphite tailings produced after flotation has also increased simultaneously. Over time, the accumulation of solid waste from graphite tailings has caused irreparable damage to the environment. According to the latest statistics, more than 2,000 hectares of land have been used for tailings discharge storage. This accumulation has seriously inhibited the survival of active enzymes in the soil, causing damage to the surrounding environment and destroying the physical and chemical structure of the soil, thereby restricting plant growth. At the same time, the large accumulation of graphite tailings also increases the risk of tailings pond collapse accidents. At present, the utilization rate of graphite tailings is low, and the problem of tailings accumulation needs to be solved urgently.

[0003] In a short period of time, it is difficult for the damaged ecological environment of mines to achieve self-repair by natural conditions alone. Human intervention is needed to speed up the process of mine ecological restoration. In addition, the loss of water and soil resources in the damaged mining area is serious. Therefore, the primary issue to be solved at present is the source of soil in the process of ecological restoration. The basic means of ecological restoration in mining areas depends on vegetation restoration. Soil and water are necessary conditions for plant growth. The key is to study the movement of water in the soil and whether the soil can retain water, which is mainly reflected in the water holding capacity of the soil. Summary of the invention

[0004] The purpose of the present invention is to provide a graphite tailings matrix soil and a preparation method thereof, so as to provide a new approach for the disposal of graphite tailings resources, solve the problem of soil source for ecological restoration in mining areas and the problem of large-scale storage of graphite tailings, and achieve a win-win situation for social development and ecological environmental protection.

[0005] To achieve the above object, the present invention provides a graphite tailings matrix soil, which comprises 93.26-95.94% of graphite tailings, 3-5% of animal feces, 0.16-0.24% of modifier A and 0.9-1.5% of diatomaceous earth, calculated by mass fraction of 100%.

[0006] Preferably, the animal manure is one or more of chicken manure, duck manure, goose manure, pig manure, cow manure, sheep manure, and horse manure.

[0007] Preferably, the modifier A is a natural polymer flocculant, which is one or more of lignin or polyacrylamide.

[0008] The present invention provides a method for preparing graphite tailings matrix soil, comprising the following steps:

[0009] S1. Using graphite tailings sampled from the graphite tailings pond as the main raw material, pre-treating the graphite tailings;

[0010] S2, pre-treating the animal feces to obtain animal feces powder;

[0011] S3, adding modifier A, diatomaceous earth and animal feces powder obtained in S2 to the graphite tailings obtained in S1, and mixing them evenly to obtain graphite tailings matrix soil.

[0012] Preferably, the pretreatment in S1 comprises: air-drying the graphite tailings, removing impurities and stones with a particle size of >5 mm, and then drying at 100-105° C. for 6-8 hours.

[0013] Preferably, the pretreatment in S2 comprises: grinding the animal feces with a planetary ball mill, naturally air-drying the feces and then screening the feces with a 16-mesh sieve.

[0014] Preferably, the addition amount of graphite tailings in S3 is 93.26-95.94%, the addition amount of animal feces powder is 3-5%, the addition amount of modifier A is 0.16-0.24%, and the addition amount of diatomaceous earth is 0.9-1.5%.

[0015] Therefore, the present invention adopts the above-mentioned graphite tailings matrix soil and its preparation method, which has the following beneficial effects:

[0016] (1) The present invention uses graphite tailings as raw materials, provides a new way to consume graphite tailings resources, solves the problem of soil source for ecological restoration in mining areas and the problem of large-scale storage of graphite tailings, and achieves a win-win situation for social development and ecological environment protection;

[0017] (2) The present invention uses animal manure as raw material, which is agricultural, forestry and animal husbandry waste, and can quickly and effectively supplement the organic matter content, effectively increase the organic matter content in the tailings, and realize the comprehensive utilization of solid waste in terms of "reduction, resource utilization and harmlessness". It is a practical technology that conforms to the concept of circular economy and has practical application value;

[0018] (2) The graphite tailings matrix soil of the present invention is rich in organic matter, has a balanced soil pH, and has excellent water retention capacity. At the same time, it has good air permeability and can improve the growth of plants, which lays a foundation for the green reclamation of the mining area of ​​graphite tailings;

[0019] (3) The graphite tailings matrix soil material of the present invention is widely available, has a scientific and reasonable ratio, is easy to implement and pollution-free, and has a low production cost. It can also quickly and effectively supplement the organic matter content, effectively increase the organic matter content in the graphite tailings, and provide a suitable environment for plant growth. It has a wide range of applications, strong operability, and is easy to promote to other types of graphite tailings ponds, and has huge promotion and application value.

[0020] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a graphite tailings matrix soil according to an embodiment of a graphite tailings matrix soil and a preparation method thereof of the present invention;

[0022] Figure 2 A particle gradation curve of graphite tailings in an embodiment of a graphite tailings matrix soil and a preparation method thereof of the present invention;

[0023] Figure 3 It is an XRD spectrum of graphite tailings of a graphite tailings matrix soil and a preparation method thereof according to an embodiment of the present invention;

[0024] Figure 4 This is a graph showing the evaporation test data results of a graphite tailings matrix soil and a preparation method thereof according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0026] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0027] Embodiment 1

[0028] like Figure 1 As shown, the present invention provides a graphite tailings matrix soil, including graphite tailings, animal feces, modifier A and diatomaceous earth. Modifier A can improve the soil flocculation ability of graphite tailings and maintain its fertility; diatomaceous earth improves the soil particle size of graphite tailings, slows down the rate of water loss in graphite tailings, and enhances water retention performance; animal feces powder belongs to agricultural, forestry and animal husbandry waste, which can quickly and effectively supplement the organic matter content and effectively increase the organic matter content in the tailings.

[0029] Graphite tailings are collected from a mining area in Luobei County, Hegang City, Heilongjiang Province, China. The particle size distribution curve is as follows: Figure 2 The results show that the particle size of graphite tailings is less than 2mm, and the content of particles with a particle size greater than 0.075mm accounts for 64.16%, which is classified as ultra-fine sand. The mineral phase composition of graphite tailings was measured by X-ray diffractometer, and the results are shown in Figure 3 As shown in Figure 2, the main chemical component of graphite tailings is SiO2, which has a content of 53.173%. The contents of Al2O3, CaO, and Fe2O3 are also high. In addition, it also contains a small amount of chemical components such as SO3, K2O, and TiO2.

[0030] The diatomaceous earth required for the present invention is a conventional experimental material purchased from a commercial channel. The experimental methods not mentioned are conventional experimental methods and will not be described in detail here.

[0031] The present invention provides a method for preparing the above-mentioned graphite tailings matrix soil, comprising the following steps:

[0032] S1. Graphite tailings sampled from the graphite tailings pond are used as the main raw material, and the graphite tailings are pretreated, including air-drying the graphite tailings, removing impurities and stones with a particle size of >5mm, and then drying them at 105℃ for 8h.

[0033] S2. Pre-treating the animal feces, including grinding the animal feces with a planetary ball mill, naturally air-drying the animal feces, and screening the animal feces with a 16-mesh sieve to obtain animal feces powder.

[0034] S3, adding modifier A, diatomaceous earth and animal feces powder obtained in S2 to the graphite tailings obtained in S1, and mixing them evenly to obtain graphite tailings matrix soil. The doping ratio of graphite tailings, animal feces powder, modifier A and diatomaceous earth was studied:

[0035] An orthogonal experiment was designed to mix animal manure powder, modifier A and diatomaceous earth into graphite tailings at the concentrations shown in Table 1.

[0036] Table 1 Orthogonal experimental design scheme

[0037]

[0038]

[0039] The relationship between mass moisture content and evaporation time was obtained by using the ring knife method, and the test data was visualized to draw a relationship curve, such as Figure 4 As shown. Figure 4 It can be seen that during the soil evaporation process, the curve presents three stages with obvious dividing points, namely the constant rate stage, the speed reduction stage and the residual stage.

[0040] During the evaporation of water in the graphite tailings matrix soil, the specific time point of transition from the constant rate stage to the rate reduction stage is the critical drop time, which is expressed as t l Indicates the volumetric moisture content of the graphite tailings matrix soil corresponding to the falling time point, expressed as θ rl In the process of evaporation of water in the graphite tailings matrix soil, the dividing point from the deceleration stage to the residual stage is the critical residual time, expressed as t c After the critical residual time point, the water release rate in the graphite tailings matrix soil slows down further and approaches a very low residual rate, which is usually related to the residual moisture content in the graphite tailings matrix soil.

[0041] The saturated volume moisture content, capillary volume moisture content, field volume moisture content and residual volume moisture content were measured by the ring knife method. The specific data results are shown in Table 2.

[0042] Table 2 Water content index data results

[0043]

[0044] As shown in Table 2, the saturated volume moisture content, capillary volume moisture content and field volume moisture content are the largest in group E3, which are 52.07%, 47.47% and 35.45% respectively, while the residual volume moisture content is the largest in group E2, which is 3.39%. The results show that the amount of diatomite and modifier A has a greater impact on the moisture content index. This is because diatomite has a certain water absorption capacity, and modifier A has a certain water retention capacity. The two are mixed with the internal particles of the graphite tailings matrix soil, which changes its internal structure and retains as much water as possible in the graphite tailings matrix soil, thereby improving the water holding capacity of the graphite tailings matrix soil.

[0045] The orthogonal test results were analyzed by range analysis. Through the test results, the range of the mean of the residual volume moisture content of each group of graphite tailings matrix soil samples at each factor level was calculated. The larger the range result, the greater the influence of the material on the test results. At the same time, the optimal level of different influencing factors can be obtained according to the range analysis. The range analysis results of the influence of different materials on the residual volume moisture content of graphite tailings matrix soil are shown in Table 3.

[0046] Table 3 Range analysis of the influence of different materials on residual volume moisture content

[0047]

[0048]

[0049] As can be seen from Table 3, the residual volume moisture content of group E2 is the largest, which is 3.39%, and the residual volume moisture content of group E1 is the smallest, which is 0.98%. It can be seen that the amount of diatomite in the graphite tailings matrix soil is proportional to the residual volume moisture content. In addition, the significance of the orthogonal test on the influence of multiple factors is mainly reflected by the range. From the range R value, it can be seen that the range of diatomite influence > the range of modifier A influence > the range of animal feces powder influence, so the order of significance of the three materials on matrix suction is: diatomite > modifier A > animal feces powder. By comparing the mean k, the local optimal combination of the test is: B2C2D3, that is, the local optimal ratio of the test is: animal feces powder content is 4%, modifier A content is 0.16%, and diatomite content is 1.5%.

[0050] To further analyze the significance of the effects of the three materials on matrix suction, the above experimental data were analyzed by variance analysis using SPSS software, and the results are shown in Table 4. It can be seen from the table that the p values ​​of animal feces powder, modifier A and diatomaceous earth are all less than 0.05, among which the p values ​​of modifier A and diatomaceous earth are both less than 0.01, indicating that animal feces powder has a significant effect on matrix suction, and modifier A and diatomaceous earth have extremely significant effects on matrix suction. The size of the p value can also be used to judge that the significance order of the three materials is: diatomaceous earth>modifier A>animal feces powder, which is consistent with the conclusion of the above range analysis.

[0051] In summary, the optimal ratio of graphite tailings matrix soil is: 94.34% graphite tailings, 4% animal feces powder, 0.16% modifier A and 1.5% diatomaceous earth.

[0052] Table 4 Analysis of variance of the significance of the effects of three materials on matrix suction

[0053]

[0054] Therefore, the present invention adopts the above-mentioned graphite tailings matrix soil and its preparation method to provide a new way for the disposal of graphite tailings resources, so as to solve the problem of soil source for ecological restoration in mining areas and the problem of large-scale storage of graphite tailings, and achieve a win-win situation for social development and ecological environmental protection.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A graphite tailings matrix soil, characterized in that: Calculated by mass fraction of 100%, it includes 93.26-95.94% of graphite tailings, 3-5% of animal excrement, 0.16-0.24% of modifier A and 0.9-1.5% of diatomaceous earth.

2. A graphite tailings matrix soil according to claim 1, characterized in that: The animal manure is one or more of chicken manure, duck manure, goose manure, pig manure, cow manure, sheep manure, and horse manure.

3. A graphite tailings matrix soil according to claim 1, characterized in that: The modifier A is a natural polymer flocculant, which is one or more of lignin and polyacrylamide.

4. A method for preparing a graphite tailings matrix soil as described in any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Using graphite tailings sampled from the graphite tailings pond as the main raw material, pre-treating the graphite tailings; S2, pre-treating the animal feces to obtain animal feces powder; S3, adding modifier A, diatomaceous earth and animal feces powder obtained in S2 to the graphite tailings obtained in S1, and mixing them evenly to obtain graphite tailings matrix soil.

5. The method for preparing a graphite tailings matrix soil according to claim 4, wherein: The pretreatment in S1 includes: air-drying the graphite tailings, removing impurities and stones with a particle size greater than 5 mm, and then drying at 100 to 105° C. for 6 to 8 hours.

6. The method for preparing a graphite tailings matrix soil according to claim 4, wherein: The pretreatment in S2 includes: grinding the animal feces with a planetary ball mill, and then naturally air-drying and screening through a 16-mesh sieve.

7. The method for preparing a graphite tailings matrix soil according to claim 4, wherein: The added amount of graphite tailings in the S3 is 93.26-95.94%, the added amount of animal feces powder is 3-5%, the added amount of modifier A is 0.16-0.24%, and the added amount of diatomaceous earth is 0.9-1.5%.

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