Harmless treatment method for mineralizing cyanidation tailings through cooperation of steel slag and microorganisms and application

Abstract

The invention relates to the field of harmless treatment of dangerous solid wastes, in particular to a harmless treatment method for mineralizing cyanidation tailings through steel slag and microorganisms, which comprises the following steps: preparing a bacterial liquid, inoculating with sporosarcina pasteurii, and culturing to prepare a microbial bacterial liquid; steel slag-cyanidation tailing slurry is prepared, specifically, steel slag and cyanidation tailings are sequentially weighed according to the proportion and mixed to be uniform, then a microbial bacterium solution, a cementing solution and water are added, the mixture is stirred to be uniform, and microbial cementing filling slurry is obtained; and underground backfilling. The prepared underground backfill slurry removes cyanide in tailings, solidifies heavy metal, is good in cementing property, can be used as an underground backfill material for backfill, provides a new solution for resource utilization of cyanidation tailings, also promotes high additional utilization of solid waste steel slag, reduces environmental influence, provides potential value, and has a wide application prospect. And sustainable development is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of harmless treatment of hazardous solid wastes, and in particular to a harmless treatment method and application of steel slag synergistically processed with microbial mineralization and cyanidation tailings. Background Art

[0002] With the development of the gold industry, the amount of dangerous industrial wastes such as cyanide tailings generated by the gold smelting industry has continued to increase. A large amount of cyanide tailings has been sent to tailings piles for storage, which has brought about a series of environmental pollution and safety problems. The comprehensive utilization of cyanide tailings resources should be taken seriously. According to incomplete statistics, my country currently produces about 24.5 million tons of cyanide tailings each year. Cyanide tailings have small particle size, light weight, large surface area, serious mud phenomenon, and complex tailings composition.

[0003] Cyanide tailings are hazardous wastes generated by gold production enterprises in the process of refining gold using the cyanide gold extraction method. They are loose in nature and contain cyanide and heavy metals. Long-term storage of cyanide tailings not only occupies a large amount of land resources, but also the heavy metals and cyanide contained in them will migrate and diffuse under the action of rainwater leaching and surface runoff, causing unimaginable losses to the surrounding environment.

[0004] Microbial mineralization is a new technology for solidification and stabilization, with advantages such as simple operation and environmental friendliness. However, the use of microbial induced calcium carbonate precipitation (MICP) alone to solidify tailings has disadvantages such as low compressive strength of samples and poor stabilization of heavy metals. Steel slag has good cementing properties. Based on the original properties of cyanide tailings, steel slag and MICP technology are used to cement cyanide tailings. The addition of steel slag improves the compressive strength of the cementing body and the stability of heavy metals and cyanide, reducing the environmental risks in the storage process of cyanide tailings. At the same time, it also provides new ideas for the resource utilization of industrial solid waste steel slag and the improvement of underground mine backfill materials.

[0005] Reference Publication (Announcement) No.: CN116371890A Chinese invention patent discloses a method for resource recovery and harmless treatment of gold cyanide tailings, which treats cyanide tailings through a series of processes such as raw material treatment, preheating roasting, oxidation roasting and electric furnace smelting to achieve the purpose of removing cyanide in the tailings. However, the method of high-temperature roasting has the problems of high energy consumption, complex process conditions, and inconvenient operation. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a harmless treatment method and application of steel slag coordinated microbial mineralization cyanidation tailings, which provides a new solution for the resource utilization of cyanidation tailings, and will also promote the high added value utilization of solid waste steel slag, reduce environmental impact, provide potential value, and achieve sustainable development.

[0007] The specific technical scheme is as follows: This application provides a method for harmless treatment of steel slag synergistic with microbial mineralization cyanidation tailings, comprising the following steps:

[0008] S1. Preparation of bacterial solution: select laboratory preserved strains, inoculate the strains into liquid culture medium, place in a shaker for culture, and prepare microbial bacterial solution;

[0009] S2. Preparation of steel slag-cyanide tailings slurry: weigh steel slag and cyanide tailings in proportion, mix them evenly, add microbial liquid, cementing liquid and water and stir evenly to obtain microbial cementing filling slurry;

[0010] S3. Backfilling underground: The microbial cementing filling slurry is pumped through a grouting machine along the pipeline to the underground backfill space for backfilling.

[0011] Preferably: the strain in step S1 is Sporosarcina pasteurii, which has been registered and preserved in the China General Microbiological Culture Collection Center (CGMCC) on July 6, 2023, with the strain collection number CGMCC NO.27818, and is a bacterium with high urease activity.

[0012] Preferably, the components of the liquid culture medium in step S1 are: 10.0 g / L peptone, 5.0 g / L yeast extract and 10.0 g / L sodium chloride, and the pH value is adjusted to 7.3.

[0013] Preferably, the culture conditions of the shaking incubator in step S1 are 37° C., 180 r / min, and the culture time is 24 h.

[0014] Preferably, the pH value of the cyanidation tailings in step S2 is 8.04, which is alkaline, and the water content is 10.3%; the particle size of the steel slag is 46-400 mesh.

[0015] Preferably, the ratio of the microbial cementing filling slurry in step S2 is: 0-18 parts of steel slag, 182-200 parts of cyanide tailings, 30 parts of bacterial liquid, 10 parts of cementing liquid and 25 parts of water.

[0016] Preferably, the ingredients of the binder in step S2 are: 0.8 mol / L anhydrous calcium chloride and 0.8 mol / L urea.

[0017] Technical effects and advantages of the present invention:

[0018] The underground backfill slurry prepared by the present invention removes cyanide from the tailings, solidifies heavy metals, and has good bonding properties. The 7d compressive strength can reach 1.97MPa, meeting the relevant requirements for the utilization of cyanide tailings in "HJ943-2018 Technical Specifications for Cyanide Slag Pollution Control in Gold Industry", and can be used as an underground backfill material for backfilling, providing a new solution for the resource utilization of cyanide tailings, and will also promote the high added value utilization of solid waste steel slag, reduce environmental impact, provide potential value, and achieve sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the unconfined compressive strength of the steel slag-cyanide tailings cemented sample provided in the embodiment of the present invention;

[0020] Figure 2 This is a SEM comparison diagram of the sample before and after MICP bonding strengthened by steel slag provided in the examples of the present application;

[0021] Figure 3 The toxicity leaching of the samples before and after the steel slag enhanced MICP cemented cyanidation tailings provided in the embodiments of the present application;

[0022] Figure 4 is the cyanide leaching content of the steel slag-cyanide tailings cementation sample provided in the examples of the present application;

[0023] Figure 5 It is a graph showing the changes in the forms of copper, lead, zinc and cadmium in the samples of the embodiments of the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

[0025] The harmless treatment technology of cyanide tailings based on steel slag collaborative microbial mineralization and underground backfill application in this embodiment selects laboratory preserved microbial mineralization strains for cultivation, prepares bacterial solution, and then uses steel slag as an auxiliary agent to prepare steel slag-cyanide tailings cementation sample, promotes the formation of heavy metal binding phase with low biological toxicity, and degrades cyanide in cyanide tailings, thereby achieving the purpose of harmless treatment, and has good cementation performance, and the 7d compressive strength can reach 1.97MPa, which meets the relevant requirements for the utilization of cyanide tailings in "HJ943-2018 Technical Specifications for Cyanide Slag Pollution Control in Gold Industry", and provides a new idea for the improvement of underground mine filling materials.

[0026] The following is the process of microorganisms inducing calcium carbonate precipitation to capture heavy metals and fix heavy metals by carbonate co-precipitation:

[0027] (NH2)2CO+H2O→2NH3+CO2

[0028]

[0029]

[0030]

[0031] The following is the cyanide degradation process:

[0032]

[0033]

[0034]

[0035]

[0036] Embodiment 1:

[0037] (1) Preparation of bacterial solution

[0038] The bacterial strain preserved in the laboratory was selected, and the pasteurian spore Sarcina strain was inoculated into a liquid culture medium, wherein the liquid culture medium components were: peptone 10.0 g / L, yeast extract 5.0 g / L and sodium chloride 10.0 g / L, the pH value was adjusted to 7.3, and the culture was placed in a shaking incubator at 37°C and 180 r / min for 24 hours to obtain a microbial culture liquid;

[0039] (2) Preparation of steel slag-cyanide tailings slurry

[0040] Weigh 10 parts of 80-mesh steel slag and 190 parts of cyanide tailings, mix them evenly, then add 30 parts of bacterial solution, 10 parts of binder and 25 parts of water and stir evenly to obtain steel slag-cyanide tailings slurry.

[0041] (3) Backfilling

[0042] The microbial cementing slurry is pumped along the pipeline through a grouting machine to the underground backfill space for backfilling.

[0043] Embodiment 2:

[0044] (1) Preparation of bacterial solution

[0045] The bacterial strain preserved in the laboratory was selected, and the pasteurian spore Sarcina strain was inoculated into a liquid culture medium, wherein the liquid culture medium components were: peptone 10.0 g / L, yeast extract 5.0 g / L and sodium chloride 10.0 g / L, the pH value was adjusted to 7.3, and the culture was placed in a shaking incubator at 37°C and 180 r / min for 24 hours to obtain a microbial culture liquid;

[0046] (2) Preparation of steel slag-cyanide tailings slurry

[0047] Weigh 10 parts of 150-mesh steel slag and 190 parts of cyanide tailings, mix them evenly, then add 30 parts of bacterial solution, 10 parts of binder and 25 parts of water and stir evenly to obtain steel slag-cyanide tailings slurry.

[0048] (3) Backfilling

[0049] The microbial cementing slurry is pumped along the pipeline through a grouting machine to the underground backfill space for backfilling.

[0050] Embodiment 3:

[0051] (1) Preparation of bacterial solution

[0052] The bacterial strain preserved in the laboratory was selected, and the pasteurian spore Sarcina strain was inoculated into a liquid culture medium, wherein the liquid culture medium components were: peptone 10.0 g / L, yeast extract 5.0 g / L and sodium chloride 10.0 g / L, the pH value was adjusted to 7.3, and the culture was placed in a shaking incubator at 37°C and 180 r / min for 24 hours to obtain a microbial culture liquid;

[0053] (2) Preparation of steel slag-cyanide tailings slurry

[0054] Weigh 10 parts of 200-400 mesh steel slag and 190 parts of cyanide tailings, mix them evenly, then add 30 parts of bacterial solution, 10 parts of binder and 25 parts of water and stir evenly to obtain steel slag-cyanide tailings slurry.

[0055] (3) Backfilling

[0056] The microbial cementing slurry is pumped along the pipeline through a grouting machine to the underground backfill space for backfilling.

[0057] As a preferred embodiment, in the above embodiments 1-3, in step S2, the cyanidation tailings are from a gold mine tailings pile in Baotou, with a pH value of 8.04, alkaline, and a moisture content of 10.3%. The steel slag is produced from a steel plant in Zhengzhou, Henan, with a particle size of 46-400 mesh.

[0058] refer to Figure 1-Figure 5As shown in the figure, the results show that when the steel slag mesh size is 150 and the steel slag content is between 1% and 5%, the unconfined compressive strength of the cemented sample increases from 0.69MPa to 1.97MPa. As the cementation process proceeds, the solidified block becomes uniformly dense, calcium carbonate is deposited in the gaps, the porosity decreases, and the solidified sample can be used for underground backfill after solidification. After adding steel slag, the leaching concentrations of Cu, Pb, Zn and Cd ions in the sample were reduced to 1.053 mg / L, 12.830 mg / L, 0.965 mg / L and 0.148 mg / L, respectively, and the stabilization efficiencies were 78.68%, 48.59%, 63.47% and 49.66%, respectively. At the same time, the concentration of easily releasable cyanide in the sample was reduced to 0.022 mg / L, and the leaching amount was reduced by 72.02%, meeting the relevant requirements for the utilization of cyanide tailings in "HJ943-2018 Technical Specifications for Cyanide Slag Pollution Control in Gold Industry".

[0059] The present invention utilizes steel slag to cooperate with microbial mineralization to prepare steel slag-cyanide tailings slurry, stabilizes heavy metals in cyanide tailings and adsorbs and degrades cyanide therein, the concentration of easily releasable cyanide in the sample is 0.022 mg / L, the degradation efficiency of total cyanide is 72.02%, and the material can be used for underground backfilling while being harmlessly treated. The backfill material has good cementing performance, and the 7d compressive strength can reach 1.97 MPa. After the sample undergoes 30 dry-wet and freeze-thaw cycles, the heavy metal ion fixation effect is still stable, which meets the relevant requirements for the utilization of cyanide tailings in "HJ943-2018 Technical Specifications for Pollution Control of Cyanide Slag in Gold Industry", provides a new solution for the resource utilization of cyanide tailings, and will also promote the high added value utilization of solid waste steel slag, reduce environmental impact, provide potential value, and achieve sustainable development.

[0060] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. The structures, devices and operating methods not specifically described and explained in the present invention are implemented according to the conventional means in the field unless otherwise specified and limited.

Claims

1. A method for harmless treatment of steel slag synergistic with microbial mineralization cyanidation tailings, characterized in that: The following steps are involved: S1. Preparation of bacterial solution: select laboratory preserved strains, inoculate the strains into liquid culture medium, place in a shaker for culture, and prepare microbial bacterial solution; S2. Preparation of steel slag-cyanide tailings slurry: weigh steel slag and cyanide tailings in proportion, mix them evenly, add microbial liquid, cementing liquid and water and stir evenly to obtain microbial cementing filling slurry; S3. Backfilling underground: The microbial cementing filling slurry is pumped through a grouting machine along the pipeline to the underground backfill space for backfilling.

2. The method for harmless treatment of steel slag synergistic with microbial mineralization cyanidation tailings according to claim 1, characterized in that: The strain in step S1 is Sporosarcina pasteurii, which was registered and preserved in the General Microbiological Center of China National Microbiological Culture Collection Administration on July 6, 2023, and the strain collection number is CGMCCNO.27818.

3. The method for harmless treatment of steel slag synergistic with microbial mineralization cyanidation tailings according to claim 1, characterized in that: The components of the liquid culture medium in step S1 are: 10.0 g / L peptone, 5.0 g / L yeast extract and 10.0 g / L sodium chloride, and the pH value is adjusted to 7.

3.

4. The method for harmless treatment of steel slag synergistic with microbial mineralization cyanidation tailings according to claim 1, characterized in that: The proportion of the microbial cementing filling slurry in step S2 is: 0-18 parts of steel slag, 182-200 parts of cyanide tailings, 30 parts of bacterial liquid, 10 parts of cementing liquid and 25 parts of water.

5. The method for harmless treatment of steel slag synergistic with microbial mineralization cyanidation tailings according to claim 1, characterized in that: The pH value of the cyanidation tailings in step S2 is 8.04, and the moisture content is 10.3%; the particle size of the steel slag is 46-400 mesh.

6. The method for harmless treatment of steel slag synergistic with microbial mineralization cyanidation tailings according to claim 1, characterized in that: The culture conditions of the shaking incubator in step S1 are 37° C., 180 r / min, and the culture time is 24 h.

7. The method for harmless treatment of steel slag synergistic with microbial mineralization cyanidation tailings according to claim 1, characterized in that: The ingredients of the binder in step S2 are: 0.8 mol / L anhydrous calcium chloride and 0.8 mol / L urea.

8. Use of the harmless treatment method of steel slag synergistic with microbial mineralization cyanidation tailings according to any one of claims 1 to 7 in underground backfilling.

9. The use according to claim 8, characterized in that: The microbial cementing filling slurry is pumped along the pipeline to the underground backfill space through a grouting machine for backfilling.

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