阅读说明：本技术 一种使用微生物激发钢渣活性的方法 (Method for exciting steel slag activity by using microorganisms ) 是由 钱春香 张霄 伊海赫 于 2020-07-07 设计创作，主要内容包括：本发明涉及一种使用微生物激发钢渣活性的方法,包括以下步骤：1)将微生物接种至相应的培养基中培养,制备菌体浓度为10<Sup>8</Sup>~10<Sup>9</Sup>cells/ml的浓缩菌液；2)将钢渣粉倒入搅拌锅中,并加入所述的浓缩菌液与水搅拌均匀,再加入砂搅拌至均匀后倒入模具中振捣成型或压制成型；3)成型后,将试件置于相对湿度为60%±3%,温度为20℃±2℃的环境中养护1天后脱模,之后在相对湿度95%以上,温度为20℃±2℃的环境中养护2d后,再将试样放入养护装置中,在相对湿度为70%±3%,CO<Sub>2</Sub>压力下养护4-6小时。该方法可以显著提高钢渣的反应活性,促进钢渣碳化过程中矿物相离子溶出和稳定的碳酸盐矿物生成,提高钢渣胶凝材料制品强度和稳定性,具有高效、工艺简单、经济环保等特点。(The invention relates to a method for exciting steel slag activity by using microorganisms, which comprises the following steps: 1) inoculating microorganism into corresponding culture medium, culturing to obtain thallus concentration of 10 8 ~10 9 cell/ml concentrated bacterial liquid; 2) pouring the steel slag powder into a stirring pot, adding the concentrated bacterial liquid and water, uniformly stirring, adding sand, uniformly stirring, and pouring into a mould for vibration molding or compression molding; 3) after molding, placing the test piece in an environment with relative humidity of 60% +/-3% and temperature of 20 ℃ +/-2 ℃ for curing for 1 day, then demolding, then curing for 2 days in an environment with relative humidity of more than 95% and temperature of 20 ℃ +/-2 ℃, then placing the test piece in a curing device, and curing for 70% +/-3% and CO 2 Curing under pressure for 4-6 hours. The method can obviously improve the reaction activity of the steel slag and promote minerals in the carbonization process of the steel slagThe phase ions are dissolved out, the carbonate minerals are stably generated, the strength and the stability of the steel slag cementing material product are improved, and the steel slag cementing material has the characteristics of high efficiency, simple process, economy, environmental protection and the like.)

1. A method for stimulating the activity of steel slag by using microorganisms is characterized by comprising the following steps:

1) inoculating microorganism into corresponding culture medium, culturing to obtain thallus concentration of 10⁸~10⁹cell/mL concentrated bacterial liquid;

2) Pouring the steel slag powder into a stirring pot, adding the concentrated bacterial liquid and water, uniformly stirring, adding sand, uniformly stirring, and pouring into a mould for vibration molding or compression molding;

3) after molding, placing the test piece in an environment with the relative humidity of 60% +/-3% and the temperature of 20 ℃ +/-2 ℃ for curing for 1 day, then demolding, then curing for 2 days in an environment with the relative humidity of more than 95% and the temperature of 20 ℃ +/-2 ℃, then placing the test piece in a curing device, and placing the test piece in a CO (carbon monoxide) device with the relative humidity of 70% +/-3% and the pressure of 0.1-0.5MPa₂Curing under pressure for 4-6 hours.

2. The method for activating the steel slag by using the microorganisms as claimed in claim 1, wherein the steel slag powder, the bacterial liquid, the water and the sand are mixed according to a mass ratio of 1: 0.05-0.25: 0.1-0.4: 1 to 3.

3. The method for activating the activity of steel slag by using microorganisms as claimed in claim 1, wherein in the step 2), the slurry is formed by stirring uniformly, and the vibration forming or the press forming is selected according to the product requirement, and the corresponding water addition is adjusted, wherein the press forming pressure is 2-15 MPa.

4. The method as claimed in claim 3, wherein the concentrated bacterial liquid is prepared by culturing at least one of bacillus, yeast, acid-producing bacteria, etc.

Technical Field

The invention belongs to the cross scientific technology in the fields of microbiology and material science, and relates to a method for stimulating the activity of steel slag by using microorganisms.

Background

The steel slag is a solid slag body consisting of slag-making materials, smelting reactants, furnace bodies and fettling materials which are eroded and dropped off and impurities brought by metal furnace burden in the steel production process, and is a byproduct in the steel production process. In production, 15% -20% of steel slag is generated every 1 t of steel is produced. China, as a world major country for steel production, has large steel slag discharge but low utilization rate. The total amount of steel slag piled in steel mills all over 3 hundred million tons, occupies more than 1 ten thousand mu, and still increases by more than 3000 ten thousand tons every year. The steel slag can not be well utilized at present, occupies more and more land, pollutes the environment and causes resource waste. Therefore, the problems of waste slag treatment and resource utilization of iron and steel enterprises are more and more emphasized. In the past, building materials are one of the most extensive and effective ways for recycling solid wastes.

The main active mineral component of the steel slag is C₂S、C₃S、C₄AF and RO phases (solid solution formed by oxides of Mg, Fe, Mn and the like) and the like are similar to cement components, but have the problems of slow hydration rate, poor stability and the like. In the dissolving stage of the steel slag in the initial reaction stage, the rate of dissolved ions determines the rate of the mineralization reaction. After the steel slag is dissolved by adding water, an alkaline solution can be formed. In alkaline systems, the steel slag phase dissolves relatively slowly and the solubility decreases as the dissolution and reaction proceeds. The microbial excitation can promote the dissolution of steel slag phase ions, reduce the alkalinity of a liquid phase, facilitate the dissolution of silicate phases and free oxides in the steel slag, provide more hydration reactants than a high-alkalinity system and increase the early hydration of the steel slag.

In general, the carbonation reaction degree of the steel slag is low, the conditions are harsh, and the process is slow. In order to accelerate the process, special microorganisms are extracted from the nature, sufficiently suitable living, breeding and activating reaction conditions are provided, the ion dissolution rate of the steel slag phase carbonation reaction process is improved through the enzymolysis and substrate decomposition of the microorganisms, and the combination with carbonate ions is promoted to form more stable carbonate and active substances. A microorganism technology for exciting the activity of steel slag is an advanced technology for utilizing wastes and saving resources and energy, is an effective method for preparing a cementing material by exciting the activity of the steel slag, can solve the problem of consumption of a large amount of steel slag generated by steel smelting, and can relieve the greenhouse effect to a certain extent. The method has the advantages of short treatment time, simple process, low investment, no secondary pollution and high economic and social benefits.

Disclosure of Invention

The technical problem is as follows: the method for exciting the activity of the steel slag by using the microorganisms has the advantages of low cost, obvious effect, environmental friendliness and no secondary pollution.

The technical scheme is as follows: the invention is based on a method for stimulating the activity of steel slag by using microorganisms, which comprises the following steps:

1) Inoculating microorganism into corresponding culture medium, culturing to obtain thallus concentration of 10⁶~10⁷each/mL of concentrated bacterial liquid;

2) pouring the steel slag powder into a stirring pot, adding the concentrated bacterial liquid and water, uniformly stirring, adding sand, uniformly stirring, and pouring into a mould for vibration molding or compression molding;

3) after molding, placing the test piece in an environment with the relative humidity of 60% +/-3% and the temperature of 20 ℃ +/-2 ℃ for curing for 1 day, then demolding, then curing for 2 days in an environment with the relative humidity of more than 95% and the temperature of 20 ℃ +/-2 ℃, then placing the test piece in a curing device, and placing the test piece in a CO (carbon monoxide) device with the relative humidity of 70% +/-3% and the pressure of 0.1-0.5MPa₂Curing under pressure for 4-6 hours.

The steel slag cementing material product comprises steel slag powder, bacterial liquid, water and sand according to a mass ratio of 1: 0.05-0.25: 0.1-0.4: 1-3.

The concentrated bacterial liquid is prepared by culturing at least one of bacillus, saccharomycetes, acid-producing bacteria and the like.

The bacterial liquid is added into the steel slag, so that the hydration and mineralization rate of the system can be accelerated, the hydrated calcium carbonate aluminate is generated in the hydrated product, the calcium carbonate content is obviously improved, and the strength and durability of the carbonized steel slag cementing material building material product are obviously improved. The method utilizes microorganisms to accelerate the dissolution rate of phase ions in the steel slag and improve carbonization and mineralization reactions The speed reduces the alkalinity of a reaction system, fully exerts the activity excitation effect of the microorganisms, and further improves the speed of the mineralization reaction of the microorganisms. Thereby improving the dissolution of calcium ions in phases in the steel slag and leading free CaO and MgO phases with higher alkalinity in the steel slag to be leached in a shorter time. Under the condition of curing under certain carbon dioxide pressure, CO can be increased₂Conversion to CO₃ ^2-Efficiency of (2) with dissolved Ca in a microbial-steel slag cement system²⁺Formation of CaCO₃The strength is obviously improved.

The invention has the beneficial effects that: compared with the prior art, the invention has the following advantages:

1. the microbial addition obviously improves the dissolution of calcium ions in the steel slag, so that free CaO and MgO phases with higher alkalinity in the phases can be leached in a shorter time, and the leaching reaction of calcium magnesium silicate phases in the steel slag is improved. Under the condition of curing under certain carbon dioxide pressure, the microorganism can promote CO₂Conversion to carbonate with Ca leached from the system²⁺Formation of CaCO₃The strength of the steel slag cementing material building material product is obviously improved.

The microbial technology method adopted by the invention has the characteristics of high efficiency, simple maintenance method, economy, environmental protection and the like, the formed mineral phase is stable, the prepared steel slag cementing material product has strong durability, and carbon dioxide generated in the process can be effectively captured and utilized to slow down the greenhouse effect.

Drawings

FIG. 1 shows the effect of different amounts of microbes on the dissolution rate of calcium ions from steel slag.

FIG. 2 is a graph showing the effect of different amounts of microbes on the strength of steel slag cement.

FIG. 3 is a TG diagram of carbonized and cured steel slag and microbe-excited steel slag cementing material.

FIG. 4 SEM image of a sample of cementitious material (a) a sample of steel slag; (b) the microorganisms excite the steel slag sample.

FIG. 5 is an appearance diagram of a microorganism-excited steel slag brick product prepared by the method.

The specific implementation mode is as follows:

for the purpose of promoting an understanding of the invention, reference will now be made in detail to the embodiments of the invention illustrated in the accompanying drawings.

The bacillus adopted by the invention is derived from China center for industrial microorganism culture collection.

The invention relates to a microbiological technology for exciting steel slag activity, which comprises the following steps:

1) obtaining a bacillus concentrated bacterial liquid: inoculating bacillus into a sterilized culture medium solution, wherein each liter of the culture medium contains 3-7 g of peptone, 4-6 g of beef extract, 6-7 g of NaCl, 16-18 g of agar and MgSO (MgSO)₄0.3-0.7 g, controlling pH to 7-8, performing shake culture at 32-38 deg.C for 24h to obtain a bacillus-containing bacterial solution, centrifuging at 4 deg.C at 6000-8000 rpm for 10-15 min, removing nutrient substances from the upper layer of culture medium, adding deionized water, and concentrating to obtain a concentrated bacterial solution with a bacterial concentration of 10 ⁸~10⁹cells/mL。

2) Pouring the steel slag powder into a stirring pot, adding the concentrated bacterial liquid and water, uniformly stirring, adding sand, uniformly stirring, and pouring into a mould for vibration molding or compression molding;

3) after molding, the test piece is placed in an environment with relative humidity (60% +/-3%) and temperature of 20 ℃ +/-2 ℃ for curing for 1 day, then demoulding is carried out, then the test piece is cured for 2 days in an environment with relative humidity of more than 95% and temperature of 20 ℃ +/-2 ℃, then the test piece is placed in a curing device, and CO is added into the environment with humidity (70% +/-3%) and 0.1-0.5MPa₂And curing for 4-6 h under pressure.

4) The steel slag cementing material product comprises steel slag powder, bacterial liquid, water and sand according to a mass ratio of 1: 0.05-0.25: 0.1-0.4: 1-3.

5) The analysis and detection of the performances of the steel slag gelled material product show that the addition of the microorganism can obviously improve the dissolution of calcium ions in the phase of the steel slag, and after the addition of the microorganism is improved, Ca is added²⁺The maximum leaching rate is also improved, so that the free CaO and MgO phases with higher alkalinity in the steel slag phase can be leached in a shorter time, and the leaching reaction of the calcium-magnesium silicate phase in the steel slag is promoted. Under the condition of curing under certain carbon dioxide pressure, the microorganism can promote CO₂Conversion to carbonate with Ca leached from the system ²⁺Formation of CaCO₃The strength of the steel slag cementing material building material product is obviously improved. In addition, the solid waste product prepared by the technology has higher strength, stable volume and no efflorescence phenomenon, and the microorganism excitation promotes the calcium ion conversion, so that the content of calcium carbonate after carbonization is increased, and the internal density of the cementing material product is improved.

6) The attached figures 1, 2, 3 and 4 in the specification respectively show the influence of the added microorganisms on the dissolution rate and strength of calcium ions in the steel slag cementing material, SEM images of steel slag and steel slag cementing material products excited by the microorganisms and a steel slag material brick product excited by the microorganisms prepared by the method. The test results show that the steel slag excited by microorganisms has increased ion dissolution rate, obviously improved phase transformation rate, obviously improved strength of the steel slag cementing material in a certain microorganism concentration range, obviously increased calcium carbonate content in the product, obviously improved internal compactness of the product, and obviously improved strength of the steel slag cementing material in a certain microorganism concentration range. The steel slag cementing material product prepared by the method has excellent performance and good application effect. The method has the advantages of low cost, obvious effect, environmental friendliness and no secondary pollution.

Example 1:

one of the mixture ratios is selected to prepare the steel slag mortar product, and the steps and the product effects are as follows:

(1) obtaining a bacillus concentrated bacterial liquid: inoculating Bacillus in sterilized culture medium solution containing peptone 7g, beef extract 6g, NaCl 7g, agar 18g, and MgSO 2 per liter₄0.7g, controlling the pH value to be 7-8, carrying out shake culture at 32 ℃ for 24h to obtain a bacillus-containing bacterial solution, carrying out high-speed centrifugation at 6000-8000 rpm at 4 ℃ for 15min, removing nutrient substances of an upper layer culture medium, adding deionized water, and concentrating the bacterial solution to obtain a bacterial solution with the thallus concentration of 10⁸~10⁹cells/mL。

(2) The steel slag cementing material product is prepared from steel slag powder, bacterial liquid, water and sand according to the mass ratio of 1: 0.10: 0.3: 3. Pouring 450g of steel slag powder into a stirring pot, adding 45g of concentrated bacterial liquid and 135g of water, uniformly stirring, adding 1350g of sand, uniformly stirring, and pouring into a mold for vibration molding or compression molding;

TABLE 1 microbial-activated steel slag cementing material ratio/g

Steel slag	Concentrated bacterial liquid	Water (W)	Sand
				450	45	135	1350

(3) After molding, the test piece is placed in an environment with relative humidity (60% +/-3%) and temperature of 20 ℃ +/-2 ℃ for curing for 1 day, then demoulding is carried out, then the test piece is cured for 2 days in an environment with relative humidity of more than 95% and temperature of 20 ℃ +/-2 ℃, then the test piece is placed in a curing device, and the test piece is cured in an environment with humidity (70% +/-3%), CO ₂Curing for 4 hours under the pressure of 0.3 MPa.

(4) The steel slag cementing material product prepared by the technology has the strength reaching 45.0MPa, is improved by 50 percent compared with the steel slag without microorganism, and has the advantages of obviously improved calcium ion dissolution rate, obviously higher calcium carbonate content and higher compaction degree in the cementing material product. The method has the advantages of low cost, obvious effect, environmental friendliness and no secondary pollution.

In addition, the microorganism-excited steel slag brick product prepared by the method has no efflorescence cracking phenomenon in the actual road paving engineering application as shown in figure 5, and all the performances meet the national regulations.

The technical means disclosed by the scheme of the invention are not limited to the technical means disclosed by the technical means, and also comprise the technical scheme formed by equivalent replacement of the technical features. The present invention is not limited to the details given herein, but is within the ordinary knowledge of those skilled in the art.