Method for cooperatively weathering gas and phosphate tailings into soil

Abstract

The invention discloses a method for synergistically weathering gas and phosphate tailings into soil. The method comprises the following steps: firstly, preparing phosphate tailings into granular filler, loading methane-oxidizing bacteria on the granular filler, and constructing a biological filter bed which takes phosphate tailings particles as a biofilm carrier and takes the methane-oxidizing bacteria as dominant microorganisms; gas is introduced into the biological filter bed, the concentration of methane in the gas is 0.1%-30% by volume, methane in the gas is biologically oxidized by methane-oxidizing bacteria, mineral decomposition and reconstruction of phosphate tailing particles are accelerated by methane metabolites, available phosphorus components are released, and weathered products are obtained. According to the method, organic acid produced by biochemical degradation of methane through methane-oxidizing bacteria is utilized, decomposition reconstruction and weathering stabilization of various minerals in the phosphate tailings are accelerated, activation and release of phosphate fertilizer in the phosphate tailings are promoted, organic matter conversion of methane in weathered products is achieved, finally, biological carbon sequestration of methane and the phosphate tailings are rapidly weathered into soil, and the phosphorus tailings are rapidly decomposed into soil. Co-processing and recycling of the gas and the phosphate tailings are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of waste resource utilization, and specifically relates to a method for cooperative weathering of gas and phosphate tailings into soil. Background Art

[0002] A large amount of gas is emitted during coal mining, and the gas contains a large amount of methane. The greenhouse effect caused by methane is 20 to 30 times that of the same mass of carbon dioxide. Large amounts of direct gas discharge cause serious carbon emissions and waste of resources. Phosphorus tailings are solid wastes generated after phosphate ore is beneficiated. At present, they are mainly treated by stacking and landfilling, which occupies a large amount of land resources and damages the ecological environment; because the tailings contain a large amount of phosphorus-containing minerals, it causes a waste of resources. The existing technology disposes and recycles phosphorus tailings, because the physical separation method needs to rely on principles such as gravity, magnetism or flotation, and may require complex equipment and operations, resulting in high processing costs; because the chemical treatment method involves extraction-stripping, carbonization or calcination-leaching methods to change the chemical properties of the tailings, harmful substances may be introduced or difficult-to-treat wastewater may be produced, resulting in a high risk of environmental pollution. At present, there is no method for the coordinated disposal and resource utilization of gas and phosphorus tailings in the existing technology.

[0003] Therefore, it is very necessary to develop a method for the coordinated weathering of gas and phosphate tailings into soil that can solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for the coordinated weathering of gas and phosphate tailings into soil, utilizing organic acids produced by the biochemical degradation of methane by methanotrophic bacteria to accelerate the decomposition, reconstruction and weathering stabilization of various minerals in the phosphate tailings, promote the activation and release of phosphate fertilizers in the phosphate tailings, realize the organic matter conversion of methane in weathering products, and finally achieve the rapid weathering of biological carbon fixation of methane and phosphate tailings into soil, thereby realizing the coordinated disposal and resource utilization of gas and phosphate tailings.

[0005] The object of the present invention is achieved by comprising the following steps: S1. The phosphate tailings are made into particle fillers, and methane oxidizing bacteria are loaded on the particle fillers to construct a biofilter bed with the phosphate tailings particles as biofilm carriers and methane oxidizing bacteria as dominant microorganisms; S2. Gas is introduced into the biological filter bed. The methane concentration in the gas is between 0.1% and 30% by volume. The methane in the gas is oxidized by methanotrophic bacteria. The methane metabolites (organic acids, extracellular polymers, soluble microbial products, etc.) accelerate the mineral decomposition and reconstruction of the phosphate tailings particles, releasing effective phosphorus components to obtain weathering products. This process also realizes the proliferation of methanotrophic bacteria.

[0006] Methane oxidizing bacteria ( methane-oxidizing bacteria,MOB) is a microorganism that can metabolize with methane as the only carbon source and energy source. It is widely present in the environment and can biocatalytically oxidize methane. The biological oxidation process of methane can not only metabolize a large amount of organic acids, but organic acids, as the main driving force of biological weathering, can accelerate the weathering decomposition and reconstruction of silicate minerals, carbonate minerals, etc. The growth and proliferation of methane oxidizing bacteria can also produce a large amount of organic matter such as extracellular polymers (EPS) and soluble microbial products (SMP), which can not only effectively increase the organic carbon content of weathering products, but also improve the air permeability, moisture retention and fertilizer storage performance of phosphate tailings weathering products.

[0007] Preferably, the methanotrophic bacteria include Methylobacterium ( Methylobacter ), Methylococcus ( Methylococcus ), Methylomonas (Methylomonas )、Methylmicrobium( Methylomicrobium ), Methylsarcinia Methylosarcina ), Methylcampal bacteria ( Methylosinus ), Methylocystis ( Methylocystis )、Ⅰb subtype bacteria ( Methylococcus and Methylocaldum )

[0008] Preferably, the phosphate tailings are the tailings remaining after extracting concentrate from ore dressing.

[0009] Preferably, before preparing the granular filler in step S1, a binder is added to the phosphate tailings and mixed evenly, and the binder includes one or more of bentonite, sodium silicate, and aluminum dihydrogen phosphate.

[0010] Preferably, the granular filler prepared in step S1 is firstly pressed by a granulator or a molding machine on the phosphate tailings, and then sintered, and the particle size of the granular filler is 5-200 mm.

[0011] Preferably, the biofilter bed is operated in an intermittent infiltration mode of methane oxidizing bacteria solution or a continuous circulation leaching mode of methane oxidizing bacteria solution; intermittent infiltration is intermittent soaking to dissolve and strip off the weathering products on the surface of the phosphate tailings particles.

[0012] The technical principle of the present invention is that methane in gas is oxidized and metabolized by methanotrophic bacteria to organic acids, dissolved organic carbon, etc., so as to achieve rapid removal of gas and biological carbon fixation. Organic acids, the metabolites of methanotrophic bacteria, accelerate the decomposition and reconstruction of minerals in phosphate tailings, and dissolved organic carbon in the metabolites helps release phosphorus from apatite, improves the organic fertilizer effect of weathering products of phosphate tailings, and forms high-quality soil.

[0013] Compared with the prior art, the present invention has the following technical effects: 1. The present invention utilizes methanotrophic bacteria to biologically oxidize methane in gas, and the metabolites are organic acids, extracellular polymers, soluble microbial products, etc., which dissolve and ion-exchange silicate minerals, carbonate minerals, phosphorus-containing minerals, etc. in phosphate tailings, thereby promoting their biological weathering. This weathering not only accelerates the decomposition, reconstruction and stabilization process of phosphate tailings, but also promotes the release of effective phosphorus, significantly increasing the proportion of effective phosphorus in weathering products.

[0014] 2. The present invention utilizes the adsorption and adhesion of the metabolites of methane oxidized by methanotrophic bacteria, so that the organic fertilizer effect and agglomeration of the weathered products of phosphate tailings are effectively improved. In this process, the organic carbon conversion and biological carbon fixation of methane are achieved, and the air permeability, moisture retention and fertilizer storage performance of the weathered products are significantly improved, so that they can be used as ecological matrix soil, realizing the resource utilization transformation of phosphate tailings from bulk industrial solid waste to ecological matrix soil.

[0015] 3. The present invention realizes the proliferation of methane oxidizing bacteria in the process of methane biological oxidation, and the phosphate tailings also act as a carrier. Under the adsorption and adhesion of methane oxidizing bacteria on the surface of phosphate tailings, the agglomeration of weathering products is greatly improved. This process further accelerates the weathering of phosphate tailings and the proliferation of methane oxidizing bacteria, forming a synergistic effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the embodiments and drawings, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0018] Example 1 As attached Figure 1 As shown, the method for cooperative weathering of gas and phosphate tailings into soil in this embodiment includes the following steps: S1. Bentonite is added to the phosphate tailings and mixed evenly. The phosphate tailings are pressed and sintered to form a granular filler with a particle size of 10 mm. Phosphate tailings are the tailings left after the concentrate is extracted by ore dressing. Methane oxidizing bacteria are loaded on the granular filler to construct a biofilter bed with phosphate tailing particles as biofilm carriers and methane oxidizing bacteria as dominant microorganisms; the methane oxidizing bacteria are Methylocystis ( Methylocystis )、Ⅰb subtype bacteria ( Methylococcus and Methylocaldum ) of mixed flora; S2. Gas is introduced into the biological filter bed, and the methane concentration in the gas is 8% by volume. The methane in the gas is biologically oxidized by methane oxidizing bacteria. The methane metabolites accelerate the mineral decomposition and reconstruction of the phosphate tailing particles, releasing effective phosphorus components to obtain weathering products. The weathering products are sent out as ecological matrix soil; in which, the methane oxidizing bacteria liquid is intermittently infiltrated.

[0019] Example 2 In this embodiment, the method for weathering gas and phosphate tailings into soil in cooperation with each other is to remove the methane oxidizing bacteria, which is Methylobacterium ( Methylobacter ), Methylococcus ( Methylococcus ), Methylomonas ( Methylomonas ), the particle size of the granular filler is 20 mm, the bentonite is replaced by sodium silicate, the methane concentration in the gas is 10% by volume, and the rest is the same as in Example 1.

[0020] Example 3 In this embodiment, the method for weathering gas and phosphate tailings into soil in cooperation with each other is to remove the methane oxidizing bacteria, which is Methylobacterium ( Methylobacter ), the methane concentration in the gas is 0.1% by volume, the methane oxidizing bacteria liquid is continuously circulated and leached, and the rest is the same as in Example 1.

[0021] Example 4 In this embodiment, the method for weathering soil with gas and phosphate tailings is to remove the methane oxidizing bacteria, which is Methylococcus ( Methylococcus ), the methane concentration in the gas is 30% by volume, the methane oxidizing bacteria liquid is continuously circulated and leached, and the rest is the same as in Example 1.

[0022] Example 5 In this embodiment, the method for synergistic weathering of gas and phosphate tailings into soil is performed by removing the methane oxidizing bacteria, which is Methylomonas (Methylomonas ), the methane concentration in the gas is 15% by volume, the methane oxidizing bacteria liquid is continuously circulated and leached, and the rest is the same as in Example 1.

[0023] Example 6 In this embodiment, the method for weathering gas and phosphate tailings into soil in cooperation with each other removes the methane oxidizing bacteria as Methylmicrobacterium ( Methylomicrobium ), and the rest is the same as in Example 1.

[0024] Example 7 In this embodiment, the method for weathering gas and phosphate tailings into soil in combination with methane oxidizing bacteria is Methylsarcinia ( Methylosarcina ), and the rest is the same as in Example 1.

[0025] Example 8 In this embodiment, the method for weathering gas and phosphate tailings into soil in combination with methane oxidizing bacteria is methylcamphor ( Methylosinus ), and the rest is the same as in Example 1.

[0026] Example 9 In this embodiment, the method for weathering soil with gas and phosphate tailings is to remove the methane oxidizing bacteria Methylocystis ( Methylocystis ), and the rest is the same as in Example 1.

[0027] Example 10 In this embodiment, the method for weathering soil with gas and phosphate tailings is used to remove the methane oxidizing bacteria, which are subtype Ib bacteria ( Methylococcus and Methylocaldum ), and the rest is the same as in Example 1.

[0028] Embodiment 11 In this embodiment, the method for weathering gas and phosphate tailings into soil in cooperation with each other is to remove the methane oxidizing bacteria, which is Methylobacterium ( Methylobacter ), Methylococcus ( Methylococcus ), Methylomonas (Methylomonas )、Methylmicrobium( Methylomicrobium ), Methylsarcinia Methylosarcina ), Methylcampal bacteria ( Methylosinus ), Methylocystis ( Methylocystis )、Ⅰb subtype bacteria ( Methylococcus and Methylocaldum ) and the rest is the same as in Example 1.

Claims

1. A method for cooperative weathering of gas and phosphate tailings into soil, characterized in that The following steps are involved: S1. The phosphate tailings are made into particle fillers, and methane oxidizing bacteria are loaded on the particle fillers to construct a biofilter bed with the phosphate tailings particles as biofilm carriers and methane oxidizing bacteria as dominant microorganisms; S2. Gas is introduced into the biological filter bed. The methane concentration in the gas is 0.1%~30% by volume. The methane in the gas is oxidized by methane-oxidizing bacteria. The methane metabolites accelerate the mineral decomposition and reconstruction of the phosphate tailings particles, releasing effective phosphorus components to obtain weathering products.

2. The method for cooperative weathering of gas and phosphate tailings into soil according to claim 1, characterized in that The methanotrophic bacteria include one or more of methylobacterium, methylcoccus, methylomonas, methylmicrobacterium, methylsarcinia, methylcampobacter, methylsporangium, and subtype Ib bacteria.

3. The method for cooperative weathering of gas and phosphate tailings into soil according to claim 1, characterized in that The phosphate tailings are the tailings left after the concentrate is extracted through mineral processing.

4. The method for cooperative weathering of gas and phosphate tailings into soil according to claim 1, characterized in that In step S1, before preparing the granular filler, a binder is added to the phosphate tailings and mixed evenly, wherein the binder includes one or more of bentonite, sodium silicate, and aluminum dihydrogen phosphate.

5. The method for cooperative weathering of gas and phosphate tailings into soil according to claim 1, characterized in that In step S1, the granular filler is prepared by first pressing the phosphate tailings through a granulator or a molding machine, and then sintering the granular filler. The particle size of the granular filler is 5 to 200 mm.

6. The method for cooperative weathering of gas and phosphate tailings into soil according to claim 1, characterized in that The operation mode of the biological filter bed is intermittent infiltration of the methane oxidizing bacteria liquid or continuous circulation leaching of the methane oxidizing bacteria liquid.

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