Phosphate tailings and biomass composite soil conditioner and method of making same

Abstract

The application discloses a phosphorus tailing and biomass composite soil conditioner and a preparation method thereof. In the preparation process, the phosphorus tailing is air-dried and sieved to obtain phosphorus tailing material, agricultural waste is dried, crushed and sieved to obtain agricultural waste material, and biomass is pyrolyzed in an anaerobic manner and sieved to obtain biochar material. Then, the phosphorus tailing material, the biochar material and the agricultural waste material are mixed at a proper proportion and subjected to microwave irradiation modification to obtain the composite soil conditioner. The application utilizes the phosphorus tailing to compound agricultural waste such as straw, and adopts irradiation technology to modify the phosphorus tailing and the agricultural waste, thereby developing the composite conditioner. The composite conditioner can effectively reduce the toxicity of heavy metals in soil, solves the problems of deterioration of physicochemical properties of soil in a metal mining area, poor soil structure and low soil biodiversity, and improves the survival rate of plants.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of soil improvement, and more particularly to a phosphorus tailings and biomass composite soil conditioner and a preparation method thereof. BACKGROUND

[0002] Phosphorus tailings have become one of the industrial wastes with a large output. According to statistics, the utilization rate of phosphorus tailings is only about 10%, the comprehensive utilization amount of tailings in 2020 is about 441 million tons, and the annual comprehensive utilization rate is about 34%, which is much lower than that of other bulk solid wastes. Therefore, it is urgent to explore the comprehensive utilization way of phosphorus tailings. The comprehensive utilization of phosphorus tailings can not only solve the problems of resource waste, tailings accumulation, and ecological environment pollution, but also generate certain economic benefits. The resource utilization of tailings as a green industry is an important breakthrough for turning waste into treasure and benefiting the people.

[0003] Phosphorus tailings contain essential elements for crop growth, such as phosphorus, magnesium, calcium, and iron. Therefore, applying phosphorus tailings to the agricultural field is an effective way of resource utilization of phosphorus tailings. At present, the application of phosphorus tailings in the agricultural field in China mainly includes phosphorus tailings reclamation, fertilizer production, soil conditioner preparation, and soil water retaining agent preparation. Although the technology of preparing fertilizer or soil conditioner from phosphorus tailings has been studied in recent years, it is still in the laboratory stage and has high cost in practical application. Therefore, it is urgent to develop an efficient, low-cost, and widely applicable method. SUMMARY

[0004] Therefore, the present application provides a phosphorus tailings and biomass composite soil conditioner and a preparation method thereof. Agricultural wastes such as phosphorus tailings and corn straw are used as matrix materials, and are modified by irradiation and other means. Through the cross-fusion of mineralogy, ecological environment science, and material science, the environmental problems in the mining area are solved, the ecological restoration cost is reduced, the ecological restoration of the mine is promoted, and the resource utilization way of phosphorus tailings and agricultural wastes is opened up.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] A preparation method of a phosphorus tailings and biomass composite soil conditioner, comprising the following steps:

[0007] (1) air-drying and sieving the phosphorus tailings to obtain phosphorus tailings materials;

[0008] (2) drying, crushing, and sieving the agricultural wastes to obtain agricultural waste materials;

[0009] (3) sieving the biomass after anaerobic pyrolysis at 500-600 DEG C for 4-6 hours to obtain biochar materials;

[0010] (4) mixing phosphorus tailings material, biochar material, agricultural waste material according to weight ratio (1-5):(1-5):(1-5) to obtain mixed material;

[0011] (5) modifying the mixed material by microwave irradiation to obtain a composite soil conditioner.

[0012] Preferably, the phosphorus tailings in step (1) are sieved through an 80-mesh sieve.

[0013] Preferably, the agricultural waste in step (2) is one or more of corn stalks and peanut shells.

[0014] Preferably, the agricultural waste in step (2) is sieved through a 20-mesh sieve.

[0015] Preferably, the biomass in step (3) is one or more of corn stalks and peanut shells.

[0016] Preferably, the biomass in step (3) is sieved through an 80-mesh sieve.

[0017] Preferably, the microwave power in step (5) is 950 W, and the irradiation time is 10-30 min.

[0018] In addition, the present application also provides a phosphorus tailings and biomass composite soil conditioner prepared by the method described in the above technical solution.

[0019] As can be seen from the above technical solution, compared with the prior art, the present application provides a phosphorus tailings and biomass composite soil conditioner and a preparation method thereof, which has the following beneficial effects:

[0020] The present application utilizes phosphorus tailings to compound agricultural waste such as straw, and modifies the same by irradiation technology to develop a composite conditioner, which can effectively reduce the toxicity of heavy metals in soil, solve the problems of deterioration of soil physical and chemical properties, poor soil structure, low soil biodiversity, etc. in metal mining areas, and improve the survival rate of plants. The materials selected by the present method are convenient to obtain, low in cost, and can effectively prevent secondary pollution and soil compaction, etc., and have strong applicability and operability. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] In the following examples,

[0023] Phosphorus tailings treatment method: dry the phosphorus tailings and sieve them through an 80-mesh sieve to obtain phosphorus tailings material;

[0024] Agricultural waste material: corn stalks, peanut shells were dried, crushed and passed through a 20 mesh screen to obtain the agricultural waste material;

[0025] Biochar material: corn stalks, peanut shells were pyrolyzed in a high-temperature electric furnace at 500-600°C for 4-6h without oxygen, then sieved to obtain biochar material, passed through an 80 mesh screen.

[0026] Example 1

[0027] The phosphorus tailings material, corn stalk material and biochar material were mixed in a ratio of 3:1:1 by weight to obtain a mixed material;

[0028] The mixed material was irradiated under the condition of microwave power 950W for 15min to obtain the activated modified composite soil conditioner product.

[0029] Example 2

[0030] The phosphorus tailings material, peanut shell material and biochar material were mixed in a ratio of 3:1:1 by weight to obtain a mixed material;

[0031] The mixed material was irradiated under the condition of microwave power 950W for 20min to obtain the activated modified composite soil conditioner product.

[0032] Example 3

[0033] The phosphorus tailings material, corn stalk and peanut shell mixture material and biochar material were mixed in a ratio of 3:1:1 by weight to obtain a mixed material;

[0034] The mixed material was irradiated under the condition of microwave power 950W for 30min to obtain the activated modified composite soil conditioner product.

[0035] Comparative Example 1

[0036] The phosphorus tailings material, corn stalk material and biochar material were mixed in a ratio of 3:1:1 by weight to obtain a mixed material;

[0037] No irradiation modification treatment was performed.

[0038] Example 4

[0039] The phosphorus tailings material, corn stalk and peanut shell mixture material and biochar material were mixed in a ratio of 5:3:1 by weight to obtain a mixed material;

[0040] The mixed material was irradiated under the condition of microwave power 950W for 30min to obtain the activated modified composite soil conditioner product.

[0041] Example 5

[0042] The phosphorus tailings material, corn straw and peanut shell mixture material and the biochar material were mixed in a ratio of 5:4:2 by weight to obtain a mixed material;

[0043] The mixed material was irradiated under the condition of microwave power of 950 W for 30 min to obtain an activated modified composite soil conditioner product.

[0044] Test Example

[0045] This example is a pot experiment.

[0046] The mine soil after passing through a 20-mesh sieve was weighed in a plastic flowerpot, and the composite soil conditioner products produced by Comparative Example 1 and Example 4 were applied to the soil, with an addition amount of 1.5% of the soil mass.

[0047] A blank test was arranged at the same time, i.e. without using any soil conditioner product.

[0048] After thorough mixing, the experimental group and the control group were watered to maintain 65% of the maximum water holding capacity of the soil.

[0049] The above soil was seeded with 40 rye grass seeds that had been subjected to germination treatment, and water was sprayed to maintain the soil moisture content at about 65%, and cultured for 60 days, and the germination rate, root length, seedling length, fresh weight, dry weight, and soil pH, organic matter content, and heavy metal available state were measured.

[0050] The measurement results show that the soil pH of the control group (blank group) was 5.05, the pH after applying the conditioner product of Comparative Example 1 (experimental group) was 7.52, and the pH after applying the conditioner product of Example 4 (experimental group) was 7.59, all of which significantly improved the soil acidity; the germination rate after applying the conditioner of Comparative Example 1 was 14% higher than the control, the root length was 18% higher than the control, the seedling length was 16% higher than the control, the fresh weight increase was 17% higher than the control, the dry weight was 8% higher than the control, the organic matter content was 25% higher than the control, and the available state of lead content was reduced by 30%.

[0051] The germination rate after applying the conditioner of Example 4 was 15% higher than the control, the root length was 10% higher than the control, the seedling length was 20% higher than the control, the fresh weight increase was 17% higher than the control, the dry weight was 11% higher than the control, the organic matter content was 30% higher than the control, and the available state of lead content was reduced by 39%.

[0052] The various embodiments described in this specification are implemented in a progressive manner, each embodiment focusing on the differences from other embodiments, and the same or similar parts between embodiments can be mutually referred to. For the apparatus disclosed by the embodiments, since it corresponds to the method disclosed by the embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method part.

[0053] The above description of disclosed embodiments enables one of ordinary skill in the art to make or use the application. Various modifications to these embodiments will be readily apparent to those of ordinary skill in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method of preparing a phosphorous tailings and biomass composite soil conditioner, characterized by, The method comprises the following steps: (1) drying and sieving phosphorous tailings through an 80-mesh sieve to obtain a phosphorous tailings material; (2) drying and sieving agricultural waste through a 20-mesh sieve to obtain an agricultural waste material; (3) pyrolyzing biomass at 500-600 DEG C for 4-6 hours in an anaerobic environment and then sieving the biomass through an 80-mesh sieve to obtain a biochar material; (4) mixing the phosphorous tailings material, the biochar material and the agricultural waste material according to a weight ratio of (3-5):(1-3):(1-2) to obtain a mixed material; (5) modifying the mixed material by microwave irradiation, wherein the microwave power is 950 W and the irradiation time is 10-30 minutes, to obtain a composite soil conditioner.

2. A method of preparing a phosphorous tailings and biomass composite soil conditioner according to claim 1, characterised in that, The agricultural waste in step (2) is one or more of corn stalks and peanut shells.

3. A method of preparing a phosphorous tailings and biomass composite soil conditioner according to claim 1, characterised in that, The biomass in step (3) is one or more of corn stalks and peanut shells.

4. A phosphorous tailings and biomass composite soil conditioner prepared by the method of any one of claims 1-3.