A kind of environmental rock-based mineral material and its preparation method and application

Abstract

The present invention belongs to the technical field of soil improvement and restoration, and specifically relates to an environmental rock-based mineral material and a preparation method and application thereof. The present invention provides a preparation method for an environmental rock-based mineral material, comprising the following steps: the rock mineral is initially crushed and placed in a closed container, saturated water vapor is then introduced into the closed container for reaction, and secondary crushing is performed after the reaction is completed to obtain the environmental rock-based mineral material; wherein, during the reaction, the pressure of the closed container is 1-3MPa and the temperature is 200-350°C. The present invention prepares the material by heating the aqueous solution to a critical temperature, and the prepared powder has the advantages of complete grain development, small particle size, uniform distribution, good dispersibility, etc., and avoids the formation of hard agglomerates. Fine rock-based minerals have the characteristics of small particle size and large specific surface area, which are conducive to the adsorption and fixation of heavy metal Cd.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil improvement and restoration, and in particular relates to an environmental rock-based mineral material and a preparation method and application thereof. Background Art

[0002] Rock-base minerals are a kind of natural minerals, which are widely found in the strata. Soil minerals include primary minerals and secondary minerals, which are the main material sources of soil mineral nutrients. Primary minerals in soil are mainly inherited and evolved from soil-forming parent rocks, mainly feldspar, mica, quartz, etc., which exist in the sand and silt components of soil; primary minerals such as feldspar and mica in soil gradually form secondary minerals such as hydrated mica, chlorite, kaolinite, montmorillonite, vermiculite, diaspore, etc. through physical, chemical and biological effects. The particles are relatively small and mainly exist in the clay component of soil, also called clay minerals.

[0003] Environmental rock-based mineral materials are usually prepared from natural minerals or rocks through purification, processing, modification and other processes. They are a type of mineral materials that have good coordination with the ecological environment or directly have the function of preventing pollution and repairing the environment. Rock-based mineral materials are considered to be green, efficient and environmentally friendly heavy metal passivation materials because of their wide sources, abundant reserves, low prices, unique surface adsorption, ion exchange, spontaneous polarization and other characteristics. At present, the preparation of rock-based mineral materials mainly includes mechanical force method, physical method and chemical method. The mechanical force method is to use ultrafine grinding and other strong mechanical forces to purposefully activate the mineral surface, to a certain extent change the crystal structure, solubility, reaction activity, etc. of the mineral surface, mainly including ball milling ultrafine grinding and mechanical extrusion. Physical heating is divided into conventional drying method and microwave heating method according to the heat conduction method. High temperature can make the mineral lose crystal water and structural water, thereby changing the specific surface area and pore volume of the mineral. The commonly used chemical method is to add inorganic acid, which can increase the specific surface area of ​​the mineral and obtain solid materials with multiple pores and active sites. At present, the bottleneck in the research and application of rock-based mineral materials at home and abroad is still how to prepare them on a large scale, at low cost and in a controllable manner.

[0004] At present, with the rapid economic development and highly intensive agricultural production, soil is constantly polluted by various "harmful" substances. Heavy metals that pollute farmland soil mainly include elements with significant biological toxicity such as mercury, cadmium, lead, chromium and metalloid arsenic, as well as elements with certain toxicity such as zinc, copper, nickel, etc., which mainly come from mining waste, pesticides, wastewater, sludge and atmospheric deposition. Excessive heavy metals can cause plant physiological dysfunction and nutritional imbalance. The enrichment coefficient in crop seeds is high. After heavy metals enter the human body through the food chain, they threaten human health. In-situ passivation remediation can meet the treatment needs of large areas of medium and light heavy metal-contaminated farmland in my country due to its low cost, convenient operation, short remediation time, and significant relief of plant toxicity of heavy metals in soil. Therefore, in-situ passivation remediation technology has been widely praised in the remediation of heavy metal-contaminated farmland soil in my country. At present, there are many studies on in-situ passivation (stabilization) materials for heavy metals, including different phosphorus-containing materials, biochar, clay minerals, oxides, agricultural by-products (compost, organic fertilizer, etc.). In the past 20 years, my country has conducted a lot of research on the remediation of farmland soil contaminated by heavy metals using in-situ passivation technology. This research field is currently in the world's leading position. However, looking at the existing research results and existing patented technologies, it still faces certain technical limitations, such as: the performance of single technologies for contaminated soil remediation is poor, there are few combination modes of integrated technologies, and poor synergy; the effects of existing farmland remediation inhibitors and passivators (materials) are unstable, and there is a lack of cost-effective and long-lasting stabilization materials; the passivator materials contain other harmful elements, and there is a problem of waste expansion; the cost of passivation materials is high. Based on this, the development of cost-effective, long-lasting, and environmentally friendly stabilization materials is still one of the important development directions of farmland heavy metal stabilization remediation technology in the future. Summary of the invention

[0005] The present invention provides an environmental rock-based mineral material and a preparation method and application thereof, the purpose of which is to solve the problem in the prior art that the raw material cost of soil passivators is high and secondary pollution to the soil environment may be caused.

[0006] In view of the above-mentioned technical defects, one of the objects of the present invention is to provide a method for preparing environmental rock-based mineral materials, a second object of the present invention is to provide environmental rock-based mineral materials obtained by the preparation method, and a third object of the present invention is to provide applications of the environmental rock-based mineral materials.

[0007] In a first aspect, the present invention provides a method for preparing an environmental rock-based mineral material, comprising the following steps:

[0008] The rock mineral is initially crushed and placed in a sealed container, saturated water vapor is introduced into the sealed container for reaction, and then crushed again after the reaction is completed to obtain the environmental rock-based mineral material;

[0009] During the reaction, the pressure of the sealed container is 1-3 MPa (for example, 2 MPa), and the temperature is 200-350°C (for example, 210°C, 220°C, 230°C, 240°C, 310°C, 330°C).

[0010] The preparation process of the present invention can ensure that the particle size of the obtained rock-based mineral material reaches the micron level, the specific surface area is large, and the cation exchange capacity is large, thereby increasing the adsorption performance of heavy metals.

[0011] In the above preparation method, as a preferred embodiment, during the reaction process, the pressure and temperature are maintained for 60-180 min (for example: 80 min, 100 min, 120 min, 140 min, 160 min).

[0012] In the above preparation method, as a preferred embodiment, the pressure of the closed container is 1.2-2.4 MPa (for example: 1.6 MPa, 1.8 MPa, 2.0 MPa, 2.2 MPa), and the temperature is 250-300°C (for example: 260°C, 270°C, 280°C, 290°C).

[0013] In the above preparation method, as a preferred embodiment, the particle size of the rock mineral after the preliminary crushing is ≥30 mm, more preferably 30-60 mm (for example: 40 mm, 50 mm).

[0014] The method of the present invention can process large-sized rock minerals with low energy consumption to obtain nano-scale rock-based mineral material powders. That is, the present invention uses critical state water to process large-sized rock minerals, and then only needs simple grinding to obtain micron-scale rock-based mineral material powders, without consuming a large amount of energy like directly using mechanical force to crush rock minerals.

[0015] In the above preparation method, as a preferred embodiment, the secondary crushing time is 10s-1min (for example: 20s, 40s, 50s);

[0016] The secondary pulverization method is dry grinding. Preferably, the stable power of the pulverizer is 1.1 kW.

[0017] The equipment for secondary pulverization in the present invention can be a dry mill, a crusher or a pulverizer.

[0018] In the above preparation method, as a preferred embodiment, the rock minerals include one or more of albite, potassium feldspar, andesine, labradorite, hornblende, pyroxene, and calcium feldspar.

[0019] In a second aspect, the present invention also provides an environmental rock-based mineral material obtained by the above-mentioned preparation method.

[0020] In the above-mentioned environmental rock-based mineral material, as a preferred embodiment, the particle size of the environmental rock-based mineral material is less than 1 mm. Preferably, the particle size of the environmental rock-based mineral material is 10-40 μm, such as 14.59-28.43 μm.

[0021] In the above-mentioned environmental rock-based mineral materials, as a preferred embodiment, the specific surface area of ​​the environmental rock-based mineral materials is 35m 2 / g or more, preferably 35-80m 2 / g, such as 42.36-58.70m 2 / g.

[0022] In the above-mentioned environmental rock-based mineral materials, as a preferred embodiment, the soil cation exchange capacity is above 80 cmol / kg, preferably 80-140 cmol / kg, such as 96.43-126.4 cmol / kg.

[0023] In a third aspect, the present invention also provides an application of an environmental rock-based mineral material in the treatment of heavy metal pollution in soil.

[0024] In the above application, as a preferred embodiment, the application is to mix the above environmental rock-based mineral material with heavy metal contaminated soil; more preferably, the mass ratio of the environmental rock-based mineral material to the heavy metal contaminated soil is (1-3):100; the Cd content in the heavy metal contaminated soil is 0.8-2.2 mg / kg.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention provides a method for preparing an environmental rock-based mineral material, comprising the following steps: the rock mineral is initially crushed and placed in a closed container, saturated water vapor is introduced into the closed container for reaction, and secondary crushing is performed after the reaction is completed to obtain the environmental rock-based mineral material; wherein, during the reaction, the pressure of the closed container is 1-3MPa and the temperature is 200-350°C. The material raw material cost of the present invention is low, the preparation method is simple and easy to operate, the equipment requirements are low, the energy consumption is low, the reaction time is short, and it is suitable for industrial production. The rock minerals of the present invention are all naturally formed, non-chemically synthesized, and will not cause secondary pollution to the environment. They are suitable for large-scale heavy metal contaminated soil remediation. The present invention prepares the material by heating the aqueous solution to the critical temperature. The prepared powder has the advantages of complete grain development, small particle size, uniform distribution, good dispersibility, etc., and avoids the formation of hard agglomerates. Fine rock-based minerals have the characteristics of small particle size and large specific surface area, which are conducive to the adsorption and retention of heavy metal Cd.

[0027] 2. The environmental rock-based mineral material provided by the present invention has the characteristics of large specific surface area and strong adsorption, and can react with heavy metal ions by complexation, precipitation, etc., thereby reducing the biological effectiveness of heavy metals in the soil. Specifically, the specific surface area of ​​the environmental rock-based mineral material can be 42.36-58.70m 2 / g. The environmental rock-based mineral material of the present invention is a simple, economical and efficient passivating agent for heavy metal-contaminated soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 XRD pattern of the environmental rock-based mineral material prepared in Example 1 of the present invention;

[0029] Figure 2 The average particle size of the environmental rock-based mineral material prepared in Example 6 of the present invention is measured by a laser particle size analyzer;

[0030] Figure 3 These are the results of measuring the specific surface area of ​​the environmental rock-based mineral material prepared in Example 6 of the present invention. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below so that those skilled in the art can practice and reproduce them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art are within the scope of protection of the present invention.

[0032] Example 1

[0033] This embodiment provides a method for preparing an environmental rock-based mineral material, comprising the following steps:

[0034] (1) crushing potassium feldspar in a crusher to obtain a mineral with an average particle size of 50 mm;

[0035] (2) placing the crushed potassium feldspar in a high-pressure reactor, introducing saturated water vapor into the reactor for reaction, controlling the temperature in the reactor to be 250° C., controlling the pressure in the reactor to be 1.2 MPa, and maintaining the temperature and pressure for 120 min;

[0036] (3) After the reaction is completed, the mixture is cooled, the reactor is opened, and the mixture in the reactor is collected and crushed by a pulverizer for 30 seconds. The stable power of the pulverizer is 1.1 kW. After crushing, the environmental rock matrix mineral material is obtained. Figure 1 The analysis results show that the main components of the mineral are SiO2, KAlSi3O8, Na(Si2Al)O6·H2O, (K 0.94 Na 0.06 )(AlSi3O8), NaAlSi3O8, etc.

[0037] Example 2

[0038] This embodiment provides a method for preparing environmental rock-based mineral materials, comprising the following steps:

[0039] Steps (1) and (3) of this embodiment are the same as those of Embodiment 1, and step (2) is as follows:

[0040] The crushed potassium feldspar is placed in a high-pressure reactor, and saturated water vapor is introduced into the reactor for reaction. During the reaction, the temperature in the reactor is controlled to be 250°C, the pressure in the reactor is controlled to be 2.4 MPa, and the duration of heat and pressure maintenance is 120 minutes.

[0041] Example 3

[0042] This embodiment provides a method for preparing environmental rock-based mineral materials, comprising the following steps:

[0043] Steps (1) and (3) of this embodiment are the same as those of Embodiment 1, and step (2) is as follows:

[0044] The crushed potassium feldspar is placed in a high-pressure reactor, and saturated water vapor is introduced into the reactor for reaction. During the reaction, the temperature in the reactor is controlled to be 300°C, the pressure in the reactor is controlled to be 1.2 MPa, and the duration of heat and pressure maintenance is 120 minutes.

[0045] Example 4

[0046] This embodiment provides a method for preparing environmental rock-based mineral materials, comprising the following steps:

[0047] Steps (1) and (3) of this embodiment are the same as those of Embodiment 1, and step (2) is as follows:

[0048] The crushed potassium feldspar is placed in a high-pressure reactor, and saturated water vapor is introduced into the reactor for reaction. During the reaction, the temperature in the reactor is controlled at 300°C, the pressure in the reactor is controlled at 2.4 MPa, and the duration of heat and pressure maintenance is 120 minutes.

[0049] Example 5

[0050] This embodiment provides a method for preparing an environmental rock-based mineral material, comprising the following steps:

[0051] (1) crushing hornblende in a crusher to obtain a mineral with an average particle size of 50 mm;

[0052] (2) placing the crushed amphibole in a high-pressure reactor, introducing saturated water vapor into the reactor for reaction, controlling the temperature in the reactor to be 250° C., controlling the pressure in the reactor to be 1.2 MPa, and maintaining the temperature and pressure for 120 min;

[0053] (3) After the reaction is completed, the reaction vessel is opened and the mixture in the reaction vessel is collected and crushed by a pulverizer for 30 seconds. The stable power of the pulverizer is 1.1 kW. After crushing, the environmental rock matrix mineral material is obtained.

[0054] Example 6

[0055] This embodiment provides a method for preparing environmental rock-based mineral materials, comprising the following steps:

[0056] Steps (1) and (3) of this embodiment are the same as those of Embodiment 5, and step (2) is as follows:

[0057] The crushed amphibole was placed in a high-pressure reactor, and saturated water vapor was introduced into the reactor for reaction. During the reaction, the temperature in the reactor was controlled at 250°C, the pressure in the reactor was controlled at 2.4 MPa, and the duration of heat and pressure maintenance was 120 minutes.

[0058] Example 7

[0059] This embodiment provides a method for preparing environmental rock-based mineral materials, comprising the following steps:

[0060] Steps (1) and (3) of this embodiment are the same as those of Embodiment 5, and step (2) is as follows:

[0061] The crushed amphibole was placed in a high-pressure reactor, and saturated water vapor was introduced into the reactor for reaction. During the reaction, the temperature in the reactor was controlled at 300°C, the pressure in the reactor was controlled at 1.2 MPa, and the duration of heat and pressure maintenance was 120 minutes.

[0062] Example 8

[0063] This embodiment provides a method for preparing environmental rock-based mineral materials, comprising the following steps:

[0064] Steps (1) and (3) of this embodiment are the same as those of Embodiment 5, and step (2) is as follows:

[0065] The crushed amphibole was placed in a high-pressure reactor, and saturated water vapor was introduced into the reactor for reaction. During the reaction, the temperature in the reactor was controlled at 300°C, the pressure in the reactor was controlled at 2.4 MPa, and the duration of heat and pressure maintenance was 120 minutes.

[0066] Example 9

[0067] (1) crushing potassium feldspar in a crusher to obtain a mineral with an average particle size of 80 mm;

[0068] (2) placing the crushed potassium feldspar in a high-pressure reactor, introducing saturated water vapor into the reactor for reaction, controlling the temperature in the reactor to be 250° C., controlling the pressure in the reactor to be 1.2 MPa, and maintaining the temperature and pressure for 120 min;

[0069] (3) After the reaction is completed, the reaction vessel is opened and the mixture in the reaction vessel is collected and crushed by a pulverizer for 30 seconds. The stable power of the pulverizer is 1.1 kW. After crushing, the environmental rock matrix mineral material is obtained.

[0070] Test Example 1

[0071] The mineral materials obtained from the environmental rock-based mineral materials obtained in Examples 1-9 were subjected to performance tests, and the test indicators included pH, specific surface area, average particle size, soil cation exchange capacity, available potassium content, bulk density, and Cd content.

[0072] The pH test method refers to the soil testing series standards: NY / T 1121.1-2006;

[0073] The specific surface area was tested by low temperature nitrogen adsorption method using a specific surface area analyzer (BET-N2:

[0074] The measurement was performed by Quantachrome Instruments, US;

[0075] The test method for soil cation exchange capacity refers to the soil testing series standards: NY / T 1121.5-2006;

[0076] The test method for available potassium content refers to soil available potassium and slow-release potassium: NY / T 889-2004;

[0077] The test method of bulk density refers to the soil testing series standards: NY / T 1121.4-2006;

[0078] The test method for Cd content refers to the determination of lead and cadmium in soil quality by graphite furnace atomic absorption spectrophotometry: GB / T17141-1997.

[0079] The specific test results are shown in Table 1.

[0080] Table 1

[0081]

[0082]

[0083] Test Example 2

[0084] In this test example, the method of simulating field experiments was adopted. The soils used in the experiments were taken from two different types of surface soils of 0 - 20 cm in Hunan Province (the main rice - producing area) and Henan Province (the main wheat - producing area). The average cadmium content in both soils exceeded three times the soil pollution risk screening value specified in the "National Soil Environmental Quality Standard GB 15618 - 2018" (0.4 mg·kg for paddy fields -1 , 5.5 < pH ≤ 6.5 and 0.3 mg·kg for others -1 , 6.5 < pH ≤ 7.5). The basic physical and chemical properties of the two soils are shown in Table 2.

[0085] Table 2

[0086]

[0087] The rice variety was indica rice XS09, and the wheat variety was Liaochun No. 18.

[0088] The experiment was arranged in the greenhouse of the Chinese Academy of Agricultural Sciences. The greenhouse environment was treated with rain - proof by using a transparent film on the top. The two soils were respectively filled into PVC cultivation containers (0.8 * 1.2 * 0.4 m), filled with soil to 0.25 m, and then urea (0.429 g·kg -1 soil), KH2PO4 (0.263 g·kg -1 soil), and KCl (0.420 g·kg -1 soil) were added as base fertilizers, and each treatment was repeated three times; the treatments included in the experiment were the treatment without adding rock - based mineral materials (CK), and the rock - based mineral materials of Examples 1 - 9 with an added concentration of 2% (which means adding 2 g of rock - based mineral materials to 100 g of soil); then irrigation was carried out until 70% of the maximum water - holding capacity of the soil, and it was balanced for two weeks.

[0089] Rice and wheat seeds were soaked in 5% H2O2 for 20 min, rinsed clean with deionized water, placed on a petri dish covered with wet filter paper, and cultured at 28℃ in a plant climate incubator until germination. Finally, the rice was transferred into the PVC cultivation container filled with S1 soil, and the wheat was transferred into the PVC cultivation container filled with S2 soil. After the seedlings grew, thinning was carried out to keep the spacing between seedlings at 5 cm.

[0090] Table 3

[0091]

[0092]

[0093] In Table 3, the letters a, b, c, d, e, f, g, and h are used to indicate the significance of the differences between different treatment conditions in the same soil. Different letters mean that the properties or contents of the two treatments are significantly different (P<0.01). If one letter is the same, it means that the difference is not significant.

[0094] Table 3 shows the effects of the rock-based mineral materials prepared by the treatment methods of Examples 1-9 on the physical and chemical properties and effective Cd content of the two soils. The detection of the relevant data of the two soils in Table 3 was sampled and completed 40 days after the rock-based mineral materials were mixed in the corresponding soils. Specifically, after the application of the rock-based mineral materials, the pH, CEC, and available K content of the soil were improved. Compared with the control group (no rock-based mineral materials were added), the rock-based mineral materials of Examples 1-9 can significantly reduce the effective Cd content in the soil. Specifically, for S1, the Cd reduction rate was 37.2-50.7%; for S2, the Cd reduction rate was 34.5-47.9%. For different treatment methods, the overall performance of the effective Cd content in the two soils was Example 6≈Example 3<Example 2<Example 7<Example 5<Example 8≈Example 4<Example 1<Example 9<Control Group.

[0095] Table 4

[0096]

[0097]

[0098] In Table 4, letters a, b, c, d, e, f, and g are used to indicate the significant difference in Cd content between different treatment conditions in the same soil or in the same part of rice or wheat plants. Different letters after the content mean that there is a significant difference in Cd content between the two treatments (P<0.01). If one letter is the same, it means that the difference is not significant.

[0099] Table 4 shows the Cd content (mg / kg) of each part of rice (S1) and wheat (S2) plants in two soils respectively prepared by the rock-based mineral materials according to the treatment methods of Examples 1-9. It can be seen from Table 4 that the accumulation of Cd in different parts of rice and wheat plants according to different treatment methods is root>stem and leaf>grain. For the two soils, the overall performance of Cd accumulation in different treatment methods is Example 6 < Example 3 < Example 8 < Example 4 < Example 2≈ Example 7 < Example 5 < Example 1 < Example 9 < Control Group.

[0100] As shown in Table 4, compared with the control group (no addition of rock-based mineral materials), the soil heavy metal remediation method of Example 1 reduced the Cd content of rice grains by 36.4%, and the Cd content of wheat grains by 29.1%; the soil heavy metal remediation method of Example 2 reduced the Cd content of rice grains by 45.5%, and the Cd content of wheat grains by 41.8%; the soil heavy metal remediation method of Example 3 reduced the Cd content of rice grains by 59.1%, and the Cd content of wheat grains by 49.1%; the soil heavy metal remediation method of Example 4 reduced the Cd content of rice grains by 63.6%, and the Cd content of wheat grains by 63.6%. The Cd content of rice grains was reduced by 47.3%; the soil heavy metal remediation method of Example 5 was used to reduce the Cd content of rice grains by 27.3%, and the Cd content of wheat grains by 36.4%; the soil heavy metal remediation method of Example 6 was used to reduce the Cd content of rice grains by 65.9%, and the Cd content of wheat grains by 54.5%; the soil heavy metal remediation method of Example 7 was used to reduce the Cd content of rice grains by 40.9%, and the Cd content of wheat grains by 43.6%; the soil heavy metal remediation method of Example 8 was used to reduce the Cd content of rice grains by 56.8%, and the Cd content of wheat grains by 50.9%. The soil heavy metal remediation method of Example 9 was used to reduce the Cd content of rice grains by 20.5%, and the Cd content of wheat grains by 23.6%.

[0101] Table 5

[0102]

[0103]

[0104] In Table 5, letters a, b, c, d, e, f, g, h, and v are used to indicate the significant differences in the yields of rice and wheat under different treatment conditions in the same soil. Different letters after the yields mean that there is a significant difference in yield between the two treatments (P<0.01). If one letter is the same, it means that the difference is not significant.

[0105] Table 5 shows the rice and wheat yields (expressed in thousand-grain weight (g)) of the rock-based mineral materials prepared by the treatment methods of Examples 1-9 for the two soils. It can be seen from Table 5 that for different treatment methods, the overall performance of rice and wheat yields is Example 6> Example 3≈ Example 8> Example 7> Example 4≈ Example 5> Example 2> Example 1> Example 9> Control Group. Specifically, compared with the control group (no addition of rock-based mineral materials), the rice yield increased by 8.95-31.3% using different soil heavy metal passivation remediation methods; the wheat grain yield increased by 13.4-42.2%.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A method for preparing environmental rock-based mineral materials, characterized in that: The following steps are included: The rock mineral is initially crushed and placed in a sealed container, saturated water vapor is introduced into the sealed container for reaction, and then secondary crushing is performed after the reaction is completed to obtain the environmental rock-based mineral material; Wherein, during the reaction process, the pressure of the closed container is 1-3MPa and the temperature is 200-350°C; The rock minerals include one or more of albite, potassium feldspar, andesine, labradorite, hornblende, pyroxene, and calcium feldspar; The particle size of the environmental rock-based mineral material is 10-40 μm; The specific surface area of ​​the environmental rock-based mineral material is 35-80m 2 / g.

2. The method for preparing environmental rock-based mineral materials according to claim 1, characterized in that: During the reaction, the pressure and temperature are maintained for 60-180 min.

3. The method for preparing environmental rock-based mineral materials according to claim 1, characterized in that: The pressure of the sealed container is 1.2-2.4 MPa, and the temperature is 250-300°C.

4. The method for preparing environmental rock-based mineral materials according to claim 1, characterized in that: The particle size of the rock mineral after the preliminary crushing is ≥30 mm.

5. The method for preparing environmental rock-based mineral materials according to claim 4, characterized in that: The rock mineral has a particle size of 30-60 mm after the preliminary crushing.

6. The method for preparing environmental rock-based mineral materials according to claim 1, characterized in that: The secondary crushing time is 10s-1min; The secondary crushing method is dry grinding, and the stable power of the crusher is 1.1 kW.

7. An environmental rock-based mineral material obtained by the preparation method according to any one of claims 1 to 6.

8. The environmental rock-based mineral material according to claim 7, characterized in that: The soil cation exchange capacity of the environmental rock-based mineral material is above 80 cmol / kg.

9. The environmental rock-based mineral material according to claim 7, characterized in that: The soil cation exchange capacity of the environmental rock-based mineral material is 80-140 cmol / kg.

10. Use of an environmental rock-based mineral material obtained by the preparation method according to any one of claims 1 to 6 or an environmental rock-based mineral material according to any one of claims 7 to 9 in treating heavy metal pollution in soil.

11. The use according to claim 10, characterized in that: The application is to mix the environmental rock-based mineral material obtained by the preparation method of any one of claims 1 to 6 or the environmental rock-based mineral material according to any one of claims 7 to 9 with heavy metal contaminated soil; the mass ratio of the environmental rock-based mineral material to the heavy metal contaminated soil is (1-3): 100; the Cd content in the heavy metal contaminated soil is 0.8-2.2 mg / kg.

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