A method for preventing oxidation and acidification of solid waste in a tailings pond

Abstract

The application discloses a method for preventing oxidation and acidification of solid waste in a tailing field, which comprises pretreatment of the tailing field, laying of biomass waste, interception of waste and through waste, punching and loading of the biomass waste, and ignition for anoxic combustion. The method adopts a laying structure of a solid waste layer, a biomass waste layer, an interception waste layer and a through waste layer, and performs in-situ anoxic combustion by punching and loading of the biomass waste, so that biochar generated by the anoxic combustion is wrapped around fine tailings to isolate sulfur from air contact and reduce generation of acidic waste liquid. The process also accelerates thermal weathering of the acidic tailings to make the tailings soilized, and the generated carbide can be used as a soil conditioner, so that the method achieves the purposes of preventing oxidation and acidification of solid waste in a tailing field and soilization of an acidic tailing waste field, and realizes the effect of environmental protection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tailings treatment, and particularly relates to a method for preventing solid waste oxidation and acidification in a tailings field. BACKGROUND

[0002] Mining activities cause a large amount of waste rock to be discharged and stacked, not only occupying a large amount of land resources, but also forming ore debris (i.e. tailings) through a series of mining activities, which is easy to produce acidic substances when in contact with air, and the extremely acidic environment is easy to accelerate the dissolution and toxicity of heavy metals. In addition, the composition and residual ore dressing reagents of the tailings seriously damage the ecological environment (especially the tailings containing heavy metals), and the sulfide ore will produce acidic waste liquid to further leach heavy metals, and the loss will cause harm to the entire ecological environment. The tailings field has great particularity, and its physicochemical properties are quite different from normal soil, usually showing great acidity (pH 2-3.5), lack of plant nutrient mechanism, serious water and soil loss, serious heavy metal pollution, etc. At the same time, the acidic wastewater produced by the tailings discharged into rivers will increase the mineralization and hardness of the water, reduce the water quality, and the water quality with too high hardness is not suitable for drinking. Once the wastewater containing heavy metals is absorbed by plants, it is easy to enter the human environment through the food chain, causing harm to human health. Therefore, the tailings field is a potential great danger, which is extremely harmful to human health and does not meet the theme of environmental protection in the world today.

[0003] Chinese patent CN104624620A discloses a method for non-soil covering vegetation restoration of strong acid tailings abandoned land, which comprises the steps of uniformly spreading slaked lime on the surface of the strong acid tailings abandoned land and performing surface loosening, applying soil improvement materials in the tailings which have been neutralized and released, and finally planting different plants on the soil surface. Although the invention can reduce acidic liquid to some extent, it still has some defects, such as a large amount of slaked lime still contained in the tailings field after the neutralization of the slaked lime and the acidic wastewater produced by the tailings, although the solubility of the slaked lime in water is very small, but its pH is about 12, which will make the soil strongly alkaline. Patent CN107347402A discloses an ecological restoration method for strong acid tailings abandoned land, which comprises the steps of covering neutralized slag from a metal mine environmental protection treatment system after site leveling and cleaning, adding compound fertilizer, organic fertilizer and artificial soil to the covering layer to increase the fertility of the covering layer, screening suitable plants and carrying out seedling raising, and planting in stages through the joint repair method of grass, shrub and tree, first sowing grass seeds, planting tree and shrub nutrient bags after the grass seeds germinate, and carrying out tending management. Although the invention can neutralize the acidic tailings to some extent, it can only play a short-term neutralizing role, and acidic wastewater will be produced after a long time.

[0004] In summary, the current domestic acid mine tailings waste land generally used in the surface of the waste land covered with different thickness of the guest soil matrix (or neutralization slag) method, but there are generally large, high cost, secondary pollution and other serious shortcomings, and most of the guest soil matrix in the improvement of the late planting plants, unable to promote the adaptive growth of plants, resulting in low survival rate, slow improvement problem. Therefore, it is very necessary to develop a kind of easy to achieve, fast, good and low cost method to prevent the oxidation and acidification of solid waste in tailings field. SUMMARY

[0005] The purpose of the present application is to provide a method for preventing the oxidation and acidification of solid waste in tailings field.

[0006] The purpose of the present application is achieved by the following steps:

[0007] S1, taking the surface solid waste of tailings field and moving out of the tailings field, then sieving, getting the retained waste on the sieve surface and the through waste passing through the sieve;

[0008] S2, uniformly spreading biomass waste on the surface of the tailings field, the spreading thickness is 6-10cm; then spreading the retained waste on the biomass waste, the spreading thickness is 2-5cm; then spreading the through waste on the retained waste, the spreading thickness is 2-5cm;

[0009] S3, vertically downwardly punching a plurality of holes in the through waste layer, the holes pass through the through waste layer, the retained waste layer, the biomass waste layer to the solid waste layer below the biomass waste layer in turn, then filling the holes with biomass waste, and then igniting the biomass waste in the holes, and after the biomass waste is burned out, filling the holes with the filler.

[0010] Compared with the prior art, the present application has the following technical effects:

[0011] 1. The present application adopts the arrangement structure of solid waste layer, biomass waste layer, retained waste layer and through waste layer, and carries out in-situ anoxic combustion by punching holes and filling biomass waste, the produced biochar is wrapped around the fine tailings to isolate sulfur from air contact, reduces the production of acid waste liquid, this process also accelerates the thermal weathering of acid mine tailings to make the soil, and the produced carbon compounds can be used as soil conditioner, so as to achieve the purpose of preventing the oxidation and acidification of solid waste in tailings and waste soil and rock pile, and realize the effect of protecting the environment.

[0012] 2. The present application selects biomass waste such as straw, which can realize the resource utilization of solid waste, effectively reduces the treatment cost of agricultural waste, reduces environmental pollution, and achieves the purpose of "waste treatment".

[0013] 3. The method of the present invention is simple to operate, low in cost, and has little secondary pollution. The low-temperature pyrolysis of biomass waste can effectively remove the residual mineral processing reagents in acidic tailings, thereby reducing the difficulty of tailings treatment and reducing pollution. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention;

[0015] In the diagram: 1-Solid waste layer, 2-Biomass waste layer, 3-Retained waste layer, 4-Passing waste layer, 5-Pore. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings, but this is not intended to limit the present invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0017] As attached Figure 1 The present invention includes the following steps:

[0018] S1. Take the surface solid waste from the tailings and remove it from the tailings. Then, screen it to obtain the retained waste on the screen surface and the through waste that passes through the screen surface.

[0019] S2. Spread biomass waste evenly on the surface of the tailings field to a thickness of 6-10cm; then spread the intercepted waste on the biomass waste to a thickness of 2-5cm; then spread the through waste on the intercepted waste to a thickness of 2-5cm.

[0020] S3. Make several vertical holes 5 on the waste layer 4. The holes 5 pass through the waste layer 4, the intercepted waste layer 3, the biomass waste layer 2 and the solid waste layer 1 below the biomass waste layer 2 in sequence. Then, fill the holes with biomass waste and ignite the biomass waste in the holes. After the biomass waste is burned out, fill the holes with filler.

[0021] Preferably, the solid waste is acidic tailings or acidic tailings mixed with waste soil and rocks.

[0022] Preferably, the solid waste has a pH < 3.5, a net acid production of 15~80 kg / t, and an electrical conductivity of 400~2000 μS / cm.

[0023] Preferably, the sieving is performed through a 2-8 mesh sieve.

[0024] Preferably, the biomass waste is one or more of the following: straw, coconut shell, sawdust, rice husk, dead branches, weeds, rice bran, shrub branches, and wood chips.

[0025] Preferably, the moisture content of the biomass waste is <15%.

[0026] Preferably, the holes penetrate to the bottom of the solid waste layer below the biomass waste layer.

[0027] Preferably, the distance between two adjacent holes is 3-5 m, and the diameter of the hole is 4-6 cm.

[0028] Preferably, the amount of biomass waste filled into the hole in step S3 is 2 / 3 of the capacity of the hole.

[0029] Preferably, the filler is straw.

[0030] The application will be further described below in connection with Examples 1-13.

[0031] Example 1

[0032] The method for preventing oxidation and acidification of solid waste in a tailing pond comprises the following steps:

[0033] S1. Taking the surface solid waste of the tailing pond and removing it from the tailing pond, then sieving to obtain the retained waste on the sieve surface and the passed waste through the sieve;

[0034] S2. Uniformly spreading the biomass waste on the surface of the tailing pond with a spreading thickness of 6 cm; then spreading the retained waste on the biomass waste with a spreading thickness of 2 cm; and then spreading the passed waste on the retained waste with a spreading thickness of 2 cm;

[0035] S3. Vertically downwardly punching a plurality of holes through the passed waste layer, the retained waste layer, the biomass waste layer, and the solid waste layer below the biomass waste layer, then filling the holes with biomass waste, igniting the biomass waste in the holes, and filling the holes with a filler after the biomass waste is burned out.

[0036] Example 2

[0037] The method for preventing oxidation and acidification of solid waste in a tailing pond comprises the following steps:

[0038] S1. Taking the surface solid waste of the tailing pond and removing it from the tailing pond, then sieving to obtain the retained waste on the sieve surface and the passed waste through the sieve;

[0039] S2. Uniformly spreading the biomass waste on the surface of the tailing pond with a spreading thickness of 10 cm; then spreading the retained waste on the biomass waste with a spreading thickness of 5 cm; and then spreading the passed waste on the retained waste with a spreading thickness of 5 cm;

[0040] S3, vertically downwardly punch several holes on the passing waste layer, the holes pass through the passing waste layer, the trapped waste layer, the biomass waste layer to the solid waste layer below the biomass waste layer in turn, then load biomass waste into the holes, ignite the biomass waste in the holes, and load filler into the holes after the biomass waste is burned out.

[0041] Example 3

[0042] The method for preventing oxidation and acidification of solid waste in a tailings pond includes the following steps:

[0043] S1, take the surface solid waste of the tailings pond and move out of the tailings pond, then sieve, get the trapped waste left on the sieve surface and the passing waste through the sieve;

[0044] S2, evenly spread biomass waste on the surface of the tailings pond, the spreading thickness is 8 cm; then spread the trapped waste on the biomass waste, the spreading thickness is 3.5 cm; then spread the passing waste on the trapped waste, the spreading thickness is 3.5 cm;

[0045] S3, vertically downwardly punch several holes on the passing waste layer, the holes pass through the passing waste layer, the trapped waste layer, the biomass waste layer to the solid waste layer below the biomass waste layer in turn, then load biomass waste into the holes, ignite the biomass waste in the holes, and load filler into the holes after the biomass waste is burned out.

[0046] Example 4

[0047] The method for preventing oxidation and acidification of solid waste in a tailings pond includes the following steps:

[0048] S1, take the surface solid waste of the tailings pond and move out of the tailings pond, then sieve through a 2-mesh sieve, get the trapped waste left on the sieve surface and the passing waste through the sieve;

[0049] S2, evenly spread biomass waste on the surface of the tailings pond, the spreading thickness is 6 cm; then spread the trapped waste on the biomass waste, the spreading thickness is 2 cm; then spread the passing waste on the trapped waste, the spreading thickness is 2 cm;

[0050] S3, vertically downwardly punch several holes on the passing waste layer, the holes pass through the passing waste layer, the trapped waste layer, the biomass waste layer to the solid waste layer below the biomass waste layer in turn, then load biomass waste into the holes, ignite the biomass waste in the holes, and load filler into the holes after the biomass waste is burned out.

[0051] Example 5

[0052] The method for preventing oxidation and acidification of solid waste in a tailings pond includes the following steps:

[0053] S1, take the surface solid waste of tailings field and move out of the tailings field, then pass through 8 mesh sieve, get the retained waste retained on the sieve surface and the through waste passing through the sieve surface;

[0054] S2, evenly spread the biomass waste on the surface of the tailings field, the spreading thickness is 10 cm; then spread the retained waste on the biomass waste, the spreading thickness is 5 cm; then spread the through waste on the retained waste, the spreading thickness is 5 cm;

[0055] S3, vertically downwardly punch a plurality of holes on the through waste layer, the holes pass through the through waste layer, the retained waste layer and the biomass waste layer to the solid waste layer below the biomass waste layer in turn, then fill the holes with biomass waste, ignite the biomass waste in the holes, and fill the holes with fillers after the biomass waste is burned out.

[0056] Example 6

[0057] The method for preventing the oxidation and acidification of the solid waste of the tailings field comprises the following steps:

[0058] S1, take the surface solid waste of tailings field and move out of the tailings field, then pass through 5 mesh sieve, get the retained waste retained on the sieve surface and the through waste passing through the sieve surface;

[0059] S2, evenly spread the biomass waste on the surface of the tailings field, the spreading thickness is 8 cm; then spread the retained waste on the biomass waste, the spreading thickness is 3.5 cm; then spread the through waste on the retained waste, the spreading thickness is 3.5 cm;

[0060] S3, vertically downwardly punch a plurality of holes on the through waste layer, the holes pass through the through waste layer, the retained waste layer and the biomass waste layer to the solid waste layer below the biomass waste layer in turn, then fill the holes with biomass waste, ignite the biomass waste in the holes, and fill the holes with fillers after the biomass waste is burned out.

[0061] Example 7

[0062] The method for preventing the oxidation and acidification of the solid waste of the tailings field comprises the following steps:

[0063] S1, take the surface solid waste of tailings field and move out of the tailings field, then pass through 2 mesh sieve, get the retained waste retained on the sieve surface and the through waste passing through the sieve surface;

[0064] S2, evenly spread the biomass waste on the surface of the tailings field, the spreading thickness is 6 cm; then spread the retained waste on the biomass waste, the spreading thickness is 2 cm; then spread the through waste on the retained waste, the spreading thickness is 2 cm;

[0065] S3, drilling several holes vertically downward through the pass-through waste layer, the interval between two adjacent holes is 3m, the diameter of the hole is 4cm, the hole passes through the pass-through waste layer, the trapped waste layer, the biomass waste layer and the bottom of the solid waste layer below the biomass waste layer in sequence, then biomass waste is filled into the hole, the biomass waste in the hole is ignited, after the biomass waste is burned out, filler is filled into the hole, the amount of biomass waste filled in the hole is 2 / 3 of the capacity of the hole.

[0066] Example 8

[0067] The method for preventing oxidation and acidification of solid waste in a tailings pond comprises the following steps:

[0068] S1, taking the surface solid waste of the tailings pond and moving out of the tailings pond, then passing through an 8-mesh sieve to obtain trapped waste remaining on the sieve surface and pass-through waste passing through the sieve;

[0069] S2, uniformly spreading biomass waste on the surface of the tailings pond, the spreading thickness is 10cm; then spreading the trapped waste on the biomass waste, the spreading thickness is 5cm; then spreading the pass-through waste on the trapped waste, the spreading thickness is 5cm;

[0070] S3, drilling several holes vertically downward through the pass-through waste layer, the interval between two adjacent holes is 5m, the diameter of the hole is 6cm, the hole passes through the pass-through waste layer, the trapped waste layer, the biomass waste layer and the bottom of the solid waste layer below the biomass waste layer in sequence, then biomass waste is filled into the hole, the biomass waste in the hole is ignited, after the biomass waste is burned out, filler is filled into the hole, the amount of biomass waste filled in the hole is 2 / 3 of the capacity of the hole.

[0071] Example 9

[0072] The method for preventing oxidation and acidification of solid waste in a tailings pond comprises the following steps:

[0073] S1, taking the surface solid waste of the tailings pond and moving out of the tailings pond, then passing through a 5-mesh sieve to obtain trapped waste remaining on the sieve surface and pass-through waste passing through the sieve;

[0074] S2, uniformly spreading biomass waste on the surface of the tailings pond, the spreading thickness is 8cm; then spreading the trapped waste on the biomass waste, the spreading thickness is 3.5cm; then spreading the pass-through waste on the trapped waste, the spreading thickness is 3.5cm;

[0075] S3, punch several holes vertically downward through the pass-through waste layer, the interval between two adjacent holes is 4m, the diameter of the hole is 5cm, the hole passes through the pass-through waste layer, the trapped waste layer, the biomass waste layer to the bottom of the solid waste layer below the biomass waste layer in turn, then fill the biomass waste into the hole, ignite the biomass waste in the hole, after the biomass waste is burned out, fill the filler into the hole.

[0076] Example 10

[0077] The method for preventing the oxidation and acidification of the solid waste in the tailing pond comprises the following steps:

[0078] S1, take the surface solid waste of the tailing pond and move out of the tailing pond, then pass through a 5mm sieve, get the trapped waste on the sieve surface and the pass-through waste through the sieve;

[0079] S2, uniformly spread the biomass waste on the surface of the tailing pond, the spreading thickness is 8cm; then spread the trapped waste on the biomass waste, the spreading thickness is 3.5cm; then spread the pass-through waste on the trapped waste, the spreading thickness is 3.5cm;

[0080] S3, punch several holes vertically downward through the pass-through waste layer, the interval between two adjacent holes is 4m, the diameter of the hole is 5cm, the hole passes through the pass-through waste layer, the trapped waste layer, the biomass waste layer to the bottom of the solid waste layer below the biomass waste layer in turn, then fill the biomass waste into the hole, ignite the biomass waste in the hole, after the biomass waste is burned out, fill the filler into the hole.

[0081] Example 11

[0082] The method for preventing the oxidation and acidification of the solid waste in the tailing pond comprises the following steps:

[0083] S1, take the surface solid waste of the tailing pond and move out of the tailing pond, then pass through a 2mm sieve, get the trapped waste on the sieve surface and the pass-through waste through the sieve;

[0084] S2, uniformly spread the biomass waste on the surface of the tailing pond, the spreading thickness is 6cm; then spread the trapped waste on the biomass waste, the spreading thickness is 2cm; then spread the pass-through waste on the trapped waste, the spreading thickness is 2cm;

[0085] S3, punch several holes vertically downward through the pass-through waste layer, the interval between two adjacent holes is 3m, the diameter of the hole is 4cm, the hole passes through the pass-through waste layer, the trapped waste layer, the biomass waste layer to the bottom of the solid waste layer below the biomass waste layer in turn, then fill the biomass waste into the hole, ignite the biomass waste in the hole, after the biomass waste is burned out, fill the filler into the hole.

[0086] The soil 10-15 cm below the surface of the tailing field after 1 month and 6 months of treatment was taken according to the method of Example 11, and the soil quality parameters are shown in the following table.

[0087] Table 1 Soil quality parameters of a test site of a certain copper mine

[0088] Indicator pH NAG-pH EC (ms / cm) / Detection value <3.0 2.92 2.32 / Metallic sulfide Cu (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 562 613 621 0.93

[0089] Table 2 Soil quality parameters of the test site after 1 month of the end of the test

[0090] Indicator pH NAG-pH EC (ms / cm) / Detection value 4.55 3.84 1.78 / Metallic sulfide Cu (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 555 611 618 0.93

[0091] Table 3 Soil quality parameters of the test site after 6 months of the end of the test

[0092] Indicator pH NAG-pH EC (ms / cm) / Detection value 4.97 3.83 1.80 / Metallic sulfide Cu (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 549 609 617 0.93

[0093] As can be seen from Tables 1-3, after the method of the present application is implemented, the pH value in the tailing waste site is increased from less than 3.0 before implementation to 4.97; the EC (electrical conductivity for measuring the concentration of soluble salt in soil, reflecting the degree of soil hardening, the larger the value, the more unfavorable for plant growth) is decreased from 2.32 to 1.78; the NAG-PH (net acid production Ph, an index for measuring the acidification potential of soil, the smaller the acid production capacity is stronger, otherwise weaker) is increased from 2.92 to 3.84.

[0094] The heavy metal content in the test site has a slight change, indicating that the method of the present application can reduce the migration of heavy metals and better fix the heavy metals in the soil. And the test site parameter level after 1 month and 6 months of the end of the test is studied, and the values do not change significantly, indicating that the method has a long-term effect on preventing the oxidation and acidification of tailing and waste rock pile solid waste.

[0095] Example 12

[0096] The method for preventing the oxidation and acidification of tailing field solid waste comprises the following steps:

[0097] S1, taking the surface solid waste of the tailing field and moving out of the tailing field, then passing through a 5-mesh sieve to obtain the intercepted waste on the sieve surface and the through waste;

[0098] S2, uniformly spreading biomass waste on the surface of the tailing field, the spreading thickness is 8 cm; then spreading the intercepted waste on the biomass waste, the spreading thickness is 4 cm; then spreading the through waste on the intercepted waste, the spreading thickness is 4 cm;

[0099] S3, drilling a plurality of holes vertically downward through the waste layer, the interval between two adjacent holes is 4m, the diameter of the hole is 5cm, the hole passes through the waste layer, the trapped waste layer, the biomass waste layer and the solid waste layer below the biomass waste layer in turn, then the biomass waste is filled into the hole, and the biomass waste in the hole is ignited, after the biomass waste is burned out, the filler is filled into the hole.

[0100] After the treatment is completed, the soil 16-20 cm below the surface of the tailing field is taken at 1 month and 6 months, and the soil quality parameters are shown in the following table.

[0101] Table 4 Soil quality parameters of a test site of a copper mine

[0102] Indicator pH NAG-pH EC (ms / cm) Detection value <3.0 2.92 2.32 Metallic sulfide Cu (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 503 621 634 0.93

[0103] Table 5 Soil quality parameters of the test site after 1 month of the test

[0104] Indicator pH NAG-pH EC (ms / cm) Detection value 4.73 3.89 1.70 Metallic sulfide Cu (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 497 618 631 0.92

[0105] Table 6 Soil quality parameters of the test site after 6 months of the test

[0106] Indicator pH NAG-pH EC (ms / cm) Detection value 5.03 3.88 1.70 Metallic sulfide Cu (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 495 615 629 0.92

[0107] As shown in Tables 4-6, the method can not only improve the pH value of the soil, but also reduce the migration of heavy metals, thereby reducing the pollution to the environment.

[0108] Through field tests, the method can prevent the oxidation and acidification of the solid waste of the tailing and waste rock pile, effectively prevent the acidification of the tailing, reduce the generation of acidic liquid and enhance the soilization of the tailing to some extent.

[0109] Example 13

[0110] The method for preventing the oxidation and acidification of the solid waste of the tailing field comprises the following steps:

[0111] S1, taking the solid waste of the surface layer of the tailing field and moving out of the tailing field, then passing through an 8-mesh sieve to obtain trapped waste on the sieve surface and through waste passing through the sieve;

[0112] S2, uniformly spreading the biomass waste on the surface of the tailing field, the spreading thickness is 10cm; then spreading the trapped waste on the biomass waste, the spreading thickness is 5cm; then spreading the through waste on the trapped waste, the spreading thickness is 5cm;

[0113] S3, vertically downwards through the waste layer, the interval between two adjacent holes is 5m, the diameter of the hole is 6cm, the hole sequentially passes through the waste layer, the trapped waste layer, the biomass waste layer to the solid waste layer below the biomass waste layer, then the biomass waste is loaded into the hole, the biomass waste in the hole is ignited, after the biomass waste is burned out, the filler is loaded into the hole.

[0114] The soil 20-24 cm below the surface of the tailing field is taken after 1 month and 6 months of treatment according to the method of Example 13, and the soil quality parameters are shown in the following table.

[0115] Table 7 Soil quality parameters of a certain pyrite test site

[0116] Indicator pH NAG-pH EC (ms / cm) Detection value <3.0 2.82 2.30 Metallic sulfide Fe (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 621 523 601 0.93

[0117] Table 8 Soil quality parameters of the test site after 1 month of the test

[0118] Indicator pH NAG-pH EC (ms / cm) Detection value 4.89 3.89 1.71 Metallic sulfide Fe (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 618 519 597 0.92

[0119] Table 9 Soil quality parameters of the test site after 6 months of the test

[0120] Indicator pH NAG-pH EC (ms / cm) Detection value 5.07 3.88 1.71 Metallic sulfide Fe (mg / kg) Zn (mg / kg) Pb (mg / kg) Cd (mg / kg) Detection value 617 515 593 0.92

[0121] From the test results of Example 11-Example 13, it can be seen that the present application can effectively prevent the oxidation and acidification of the solid waste of the tailings and waste rock pile, and the method of the present application is suitable for various acid tailings waste sites.

Claims

1. A method of preventing oxidation acidification of a tailings pond solid waste, characterized by The method comprises the following steps: S1, taking the surface solid waste of the tailing field and moving out the tailing field, and then sieving to obtain the retained waste on the sieve surface and the passing waste through the sieve; the solid waste is acid tailings or acid tailings mixed with waste rock piles; the pH of the solid waste is less than 3.5, the net acid production is 15-80 kg / t, and the conductivity is 400-2000 us / cm; S2, uniformly spreading the biomass waste on the surface of the tailing field, the spreading thickness is 6-10 cm; then spreading the retained waste on the biomass waste, the spreading thickness is 2-5 cm; and then spreading the passing waste on the retained waste, the spreading thickness is 2-5 cm; S3, vertically downwardly punching a plurality of holes in the passing waste layer, the holes pass through the passing waste layer, the retained waste layer, the biomass waste layer and the solid waste layer below the biomass waste layer in sequence, then filling the holes with biomass waste, igniting the biomass waste in the holes, and filling the holes with fillers after the biomass waste is burned out; The fillers are straws. The solid waste layer, the biomass waste layer, the retained waste layer and the passing waste layer are arranged, the holes are punched and filled with biomass waste for in-situ anoxic combustion, the produced biochar is wrapped around the fine tailings to isolate sulfur from air contact, and the generation of acid waste liquid is reduced.

2. The method of preventing oxidation and acidification of solid waste at a tailings site according to claim 1, wherein The sieving is sieving through a 2-8 mesh sieve.

3. The method of preventing oxidation and acidification of solid waste at a tailings site according to claim 1, wherein The biomass waste is one or more of straws, coconut shells, sawdust, rice husks, dry branches, weeds, bran, shrub branches and wood chips.

4. The method for preventing oxidation and acidification of solid waste in a tailings pond according to claim 1 or 3, characterized in that The moisture content of the biomass waste is less than 15%.

5. The method of preventing the oxidation and acidification of solid waste in a tailings pond of claim 1, wherein The holes penetrate to the bottom of the solid waste layer below the biomass waste layer.

6. The method of preventing the oxidation and acidification of solid waste in a tailings pond of claim 1, wherein The distance between two adjacent holes is 3-5 m, and the diameter of the hole is 4-6 cm.

7. The method of preventing the oxidation and acidification of solid waste at a tailings site according to claim 1, 5 or 6, wherein The amount of biomass waste filled in the hole in the step S3 is 2 / 3 of the capacity of the hole.

Images