阅读说明：本技术 一种利用钢铁厂固废的复合掺合料及其制备方法 (Composite admixture utilizing solid waste of iron and steel plant and preparation method thereof ) 是由 刘艳 王文涛 李仕彬 陈常明 黄从运 于 2021-11-11 设计创作，主要内容包括：本发明公开了一种利用钢铁厂固废的复合掺合料,组成按重量份数计如下：矿渣80～90份、钢渣5～10份、塔底灰3～9份、粉煤灰1～5份、化学活化剂1～3份；包括以下步骤：将所述矿渣、钢渣、粉煤灰、塔底灰分别进行化学成分分析；配料保证混合物的化学组成：SiO-(2)29％～34％、CaO 35％～40％、Al-(2)O-(3)10％～18％、Fe-(2)O-(3)1.5％～3％、SO-(3)2.5％～4％,烧失量≤2.5％；将所述矿渣、钢渣分别破碎,控制粒径＜5mm,然后与粉煤灰、塔底灰一起投入磨机；粉磨的同时,加入化学活化剂一起粉磨30～40min,通过选粉机控制比表面积≥450m～(2)/Kg,即得到复合掺合料。(The invention discloses a composite admixture utilizing solid wastes of an iron and steel plant, which comprises the following components in parts by weight: 80-90 parts of slag, 5-10 parts of steel slag, 3-9 parts of tower bottom ash, 1-5 parts of fly ash and 1-3 parts of chemical activating agent; the method comprises the following steps: respectively carrying out chemical component analysis on the slag, the steel slag, the fly ash and the tower bottom ash; the ingredients ensure the chemical composition of the mixture: SiO 2 2 29％～34％、CaO 35％～40％、Al 2 O 3 10％～18％、Fe 2 O 3 1.5％～3％、SO 3 2.5-4 percent of the total weight of the coal, and the ignition loss is less than or equal to 2.5 percent; crushing the slag and the steel slag respectively, controlling the particle size to be less than 5mm, and putting the crushed slag, the fly ash and tower bottom ash into a mill; adding a chemical activating agent to grind for 30-40 min while grinding, and controlling the specific surface area to be more than or equal to 45 through a powder selecting machine0m 2 and/Kg, obtaining the composite admixture.)

1. The composite admixture utilizing the solid wastes of the steel plant is characterized by comprising the following components in parts by weight:

80-90 parts of slag, 5-10 parts of steel slag, 3-9 parts of tower bottom ash, 1-5 parts of fly ash and 1-3 parts of chemical activating agent; the slag, the steel slag, the tower bottom ash and the fly ash are all from solid waste of a steel plant.

2. The composite admixture utilizing the solid wastes of the steelworks as claimed in claim 1 is characterized in that the mixture consisting of the slag, the steel slag, the tower bottom ash and the fly ash comprises the following components in percentage by weight:

SiO₂ 29％～34％、CaO 35％～40％、Al₂O₃ 10％～18％、Fe₂O₃ 1.5％～3％、SO₃2.5-4 percent and the ignition loss is less than or equal to 2.5 percent.

3. The admixture for compounding solid wastes of iron and steel works as claimed in claim 1, wherein said slag comprises the following components in weight percent: SiO 2₂ 30％～35％、CaO 35％～40％、Al₂O₃ 8％～20％、Fe₂O₃ 0.1％～2％、MgO 6％～12％、SO₃2-5 percent, and the activity requirement of the national standard above S95 level is met after grinding.

4. The composite admixture for utilizing solid wastes of iron and steel works as claimed in claim 1, wherein said steel slag comprises the following components in percentage by weight: SiO 2₂ 15％～25％、CaO 30％～40％、Al₂O₃ 3％～8％、Fe₂O₃ 10％～25％、MgO 10％～15％、SO₃0.2-2% and the loss on ignition is less than or equal to 8%.

5. The admixture as defined in claim 1, wherein said fly ash is used in the steel plantThe ratio meter comprises the following components: SiO 2₂ 40％～55％、CaO 5％～10％、Al₂O₃ 25％～40％、Fe₂O₃ 2％～10％、SO₃2-5 percent and the ignition loss is less than or equal to 10 percent.

6. The admixture for compounding solid wastes of steel and iron works as defined in claim 1 wherein said tower bottom ash comprises the following components in weight percent: SiO 2₂ 3％～5％、CaO 25％～40％、Al₂O₃ 0％～3％、Fe₂O₃ 3％～10％、SO₃15-25 percent and the ignition loss is less than or equal to 30 percent.

7. The admixture for compounding solid wastes of iron and steel works as claimed in claim 1, wherein said chemical activator is selected from the group consisting of anhydrous sodium sulphate: ammonium alum: isopropanolamine: ester quaternary ammonium salt: the modified polyol is prepared from the following components in percentage by mass (4-8): (2-6): (0.1-0.5): (0.2-0.6): (0.1-0.3), wherein the modified polyol is prepared by mixing ethylene glycol: diethylene glycol: pentaerythritol: glycerol is prepared from the following raw materials in a mass ratio of (1-3): (2-4): (1-2): (3-6) mixing.

8. The method for preparing the composite admixture utilizing the solid wastes of the iron and steel plant as claimed in any one of claims 1 to 7 is characterized by comprising the following steps:

respectively carrying out chemical component analysis on the slag, the steel slag, the fly ash and the tower bottom ash;

the ingredients ensure the chemical composition of the mixture: SiO 2₂ 29％～34％、CaO 35％～40％、Al₂O₃ 10％～18％、Fe₂O₃1.5％～3％、SO₃2.5-4 percent of the total weight of the coal, and the ignition loss is less than or equal to 2.5 percent;

crushing the slag and the steel slag respectively, controlling the particle size to be less than 5mm, and putting the crushed slag, the fly ash and tower bottom ash into a mill;

adding a chemical activating agent to grind for 30-40 min while grinding, and controlling the specific surface area to be more than or equal to 450m by a powder concentrator²and/Kg, obtaining the composite admixture.

Technical Field

The invention belongs to the technical field of industrial waste residue resource utilization, and particularly relates to a composite admixture utilizing solid wastes of an iron and steel plant and a preparation method thereof.

Background

In the process of steel production, steel plants generate a lot of solid wastes with low hydration activity besides slag, such as steel slag, furnace slag, tower bottom ash, low-grade fly ash, construction waste, iron tailings and the like.

Slag is a byproduct obtained by discharging slag into water and quenching in the iron-making process, and chemical components of the slag are CaO and SiO₂、Al₂O₃And MgO component more than 80%, and small amount of Fe₂O₃、MnO₂And TiO₂The mineral composition is mainly silicate and aluminosilicate, and contains a large amount of substances with amorphous vitreous structures, and the mineral composition has high potential hydration activity. For years, the slag micro powder is used as a high-quality auxiliary cementing material for preparing cement and concrete due to the excellent characteristics of the slag micro powder, the demand of the slag micro powder is increased year by year along with the increase of the cement and concrete yield, the phenomenon of shortage of supply and demand even occurs in some regions, and the price of the slag micro powder in some regions is even comparable with that of the cement.

The steel slag is solid waste discharged in the steel-making process and is rich in C₃S and C₂S and other minerals are similar to the industrial waste residue of the inferior portland cement clinker, but the mineral waste residue is poor in grindability and stability, and the resource utilization is difficult to realize on a large scale. The low-grade fly ash is fine ash captured from coal-fired flue gas, and comprises SiO as main component₂、Al₂O₃、Fe₂O₃、Fe₂O₃、CaO、TiO₂And the like, the particles are coarse, even a certain amount of unburned carbon powder is contained, and the hydration activity is poor. The tower bottom ash is solid powder generated by flue gas desulfurization, has complex components andand most of the components are extremely unstable calcium sulfite, so that the comprehensive utilization is difficult, most of the components are used for stacking or landfill disposal, but secondary pollution is caused and a large amount of sulfur resources are lost. Compared with slag, the hydration activity of the steel slag, the fly ash, the tower bottom ash and the like is very low, the production added value is low, the treatment is difficult, and the burden which troubles the development of the major industry of steel enterprises is gradually formed.

Under the background condition, the method combines the actual situation of steel enterprises, compounds the easily obtained solid wastes (such as steel slag, tower bottom ash, low-grade fly ash, construction waste, iron tailings, stone chips and the like) with the slag to prepare the economical composite admixture, replaces S95 slag micro powder, can relieve the problem of mineral powder supply shortage to a certain extent, can improve the comprehensive utilization rate of the solid wastes, reduce environmental pollution, change waste into valuables, save social resources while improving the economic value of the slag, and has great economic benefit and environmental benefit.

The patent CN 112358215A provides a multi-solid waste cement coupling admixture and a preparation method thereof, although the preparation method also adopts a chemical activation mode, the preparation method needs a thermal activation process, the production process is complex, the energy consumption is high, and the preparation cost is high. The patent "a steel slag powder-ferromanganese slag powder composite admixture and preparation technology thereof" (CN 111302691A) provides a steel slag powder-ferromanganese slag powder composite admixture and a preparation technology thereof, the preparation technology is that steel slag and ferromanganese slag are respectively ground to certain fineness, the grinding equipment investment of the technology is large, the production efficiency is not high, and the obtained composite admixture meets the standard of GB/T20491-2017 "steel slag powder used in cement and concrete", has low activity and limited application; in addition, the steel slag content is too high, and the risk of poor volume stability of the product at the later stage exists.

Disclosure of Invention

The invention aims to provide an economical composite admixture prepared by utilizing solid wastes of a steel plant and a production method thereof. The composite admixture mainly adopts solid wastes in the production process of steel enterprises, can not only utilize the solid wastes such as steel slag, low-grade fly ash, tower bottom ash and the like as resources, increase the supply of mineral powder and reduce the production cost of the mineral powder, but also is beneficial to smoothening the relationship between main products and byproduct wastes in the production process of steel and promotes the development of major industry.

In order to achieve the purpose, the technical scheme is as follows:

the composite admixture utilizing the solid wastes of the steel plant comprises the following components in parts by weight:

80-90 parts of slag, 5-10 parts of steel slag, 3-9 parts of tower bottom ash, 1-5 parts of fly ash and 1-3 parts of chemical activating agent; the slag, the steel slag, the tower bottom ash and the fly ash are all from solid waste of a steel plant.

According to the scheme, the mixture consisting of the slag, the steel slag, the tower bottom ash and the fly ash comprises the following components in percentage by weight:

SiO₂ 29％～34％、CaO 35％～40％、Al₂O₃ 10％～18％、Fe₂O₃ 1.5％～3％、SO₃2.5-4 percent and the ignition loss is less than or equal to 2.5 percent.

According to the scheme, the slag comprises the following components in percentage by weight: SiO 2₂ 30％～35％、CaO 35％～40％、Al₂O₃ 8％～20％、Fe₂O₃ 0.1％～2％、MgO 6％～12％、SO₃2-5 percent, and the activity requirement of the national standard above S95 level is met after grinding.

According to the scheme, the steel slag comprises the following components in percentage by weight: SiO 2₂ 15％～25％、CaO 30％～40％、Al₂O₃ 3％～8％、Fe₂O₃ 10％～25％、MgO 10％～15％、SO₃0.2-2% and the loss on ignition is less than or equal to 8%.

According to the scheme, the fly ash comprises the following components in percentage by weight: SiO 2₂ 40％～55％、CaO 5％～10％、Al₂O₃ 25％～40％、Fe₂O₃ 2％～10％、SO₃2-5 percent and the ignition loss is less than or equal to 10 percent.

According to the scheme, the tower bottom ash comprises the following components in percentage by weight: SiO 2₂ 3％～5％、CaO 25％～40％、Al₂O₃ 0％～3％、Fe₂O₃ 3％～10％、SO₃15-25 percent and the ignition loss is less than or equal to 30 percent.

According to the scheme, the chemical activator is prepared from anhydrous sodium sulphate: ammonium alum: isopropanolamine: ester quaternary ammonium salt: the modified polyol is prepared from the following components in percentage by mass (4-8): (2-6): (0.1-0.5): (0.2-0.6): (0.1-0.3), wherein the modified polyol is prepared by mixing ethylene glycol: diethylene glycol: pentaerythritol: glycerol is prepared from the following raw materials in a mass ratio of (1-3): (2-4): (1-2): (3-6) mixing.

The preparation method of the composite admixture by utilizing the solid wastes of the steel plant comprises the following steps:

respectively carrying out chemical component analysis on the slag, the steel slag, the fly ash and the tower bottom ash;

the ingredients ensure the chemical composition of the mixture: SiO 2₂ 29％～34％、CaO 35％～40％、Al₂O₃ 10％～18％、Fe₂O₃ 1.5％～3％、SO₃2.5-4 percent of the total weight of the coal, and the ignition loss is less than or equal to 2.5 percent;

crushing the slag and the steel slag respectively, controlling the particle size to be less than 5mm, and putting the crushed slag, the fly ash and tower bottom ash into a mill;

adding a chemical activating agent to grind for 30-40 min while grinding, and controlling the specific surface area to be more than or equal to 450m by a powder concentrator²and/Kg, obtaining the composite admixture.

Compared with the prior art, the invention has the advantages and beneficial effects that:

the economical composite admixture prepared by utilizing the solid wastes of the steel plant takes the solid wastes of the steel plant, such as slag, steel slag, fly ash, tower bottom ash and the like as main production raw materials, can consume a large amount of solid wastes, comprises the steel slag, the tower bottom ash and the like with low hydration activity which are difficult to treat, and simultaneously can reduce the production cost of slag powder and increase the supply of S95 slag powder.

The reasonable raw material composition of the composite admixture is designed based on the chemical components of all raw materials, the activity of slag is not lower than S95 grade, and the hydration activity of the admixture is improved by means of physical and mechanical grinding control of fineness, sulfate excitation of tower bottom ash, alkali excitation of chemical activating agent and the like, so that the waste of activity of high-activity slag powder is avoided, and the utilization value of low-activity solid waste is improved.

Drawings

FIG. 1 is the XRD pattern of the 7d hydration product corresponding to neat paste of example 2 of the present invention;

FIG. 2 is an XRD pattern of a 28d hydration product corresponding to neat paste in example 2 of the present invention;

FIG. 3 is an SEM image of a hydration product corresponding to neat slurry 7d of example 2 of the invention;

FIG. 4 is an SEM image of a hydration product of neat paste 28d of example 2 of the invention.

Detailed Description

The following examples further illustrate the technical solutions of the present invention, but should not be construed as limiting the scope of the present invention.

The invention prepares the economical composite admixture which meets the requirements of national standard S95 slag powder by compounding high-activity slag and low-activity solid waste of a steel plant and utilizing the means of mechanical grinding activation, synergistic excitation among components, excitation of an additional activating agent and the like.

The slag, the steel slag, the tower bottom ash and the fly ash adopted in the concrete embodiment are all from solid wastes of a steel plant, and the components in parts by weight are as follows: 80-90 parts of slag, 5-10 parts of steel slag, 3-9 parts of tower bottom ash, 1-5 parts of fly ash and 1-3 parts of chemical activating agent.

Wherein, the slag comprises the following components in percentage by weight: SiO 2₂ 30％～35％、CaO 35％～40％、Al₂O₃ 8％～20％、Fe₂O₃ 0.1％～2％、MgO 6％～12％、SO₃2-5 percent, and the activity requirement of the national standard above S95 level is met after grinding.

The steel slag comprises the following components in percentage by weight: SiO 2₂ 15％～25％、CaO 30％～40％、Al₂O₃3％～8％、Fe₂O₃ 10％～25％、MgO 10％～15％、SO₃0.2-2% and the loss on ignition is less than or equal to 8%.

The fly ash comprises the following components in percentage by weight: SiO 2₂ 40％～55％、CaO 5％～10％、Al₂O₃25％～40％、Fe₂O₃ 2％～10％、SO₃2-5 percent and the ignition loss is less than or equal to 10 percent.

The tower bottom ash comprises the following components in percentage by weight: SiO 2₂ 3％～5％、CaO 25％～40％、Al₂O₃0％～3％、Fe₂O₃ 3％～10％、SO₃15-25 percent and the ignition loss is less than or equal to 30 percent.

The chemical activator is prepared from sodium sulfate: ammonium alum: isopropanolamine: ester quaternary ammonium salt: the modified polyol is prepared from the following components in percentage by mass (4-8): (2-6): (0.1-0.5): (0.2-0.6): (0.1-0.3), wherein the modified polyol is prepared by mixing ethylene glycol: diethylene glycol: pentaerythritol: glycerol is prepared from the following raw materials in a mass ratio of (1-3): (2-4): (1-2): (3-6) mixing.

The preparation process of the composite admixture of the invention is as follows:

respectively carrying out chemical component analysis on the slag, the steel slag, the fly ash and the tower bottom ash;

the ingredients ensure the chemical composition of the mixture: SiO 2₂ 29％～34％、CaO 35％～40％、Al₂O₃ 10％～18％、Fe₂O₃ 1.5％～3％、SO₃2.5-4 percent of the total weight of the coal, and the ignition loss is less than or equal to 2.5 percent;

crushing the slag and the steel slag respectively, controlling the particle size to be less than 5mm, and putting the crushed slag, the fly ash and tower bottom ash into a mill;

adding a chemical activating agent to grind for 30-40 min while grinding, and controlling the specific surface area to be more than or equal to 450m by a powder concentrator²and/Kg, obtaining the composite admixture.

Table 1 shows the parts by weight of each solid waste of the composite admixtures obtained in examples 1, 2 and 3.

TABLE 1

Examples	Slag of mine	Steel slag	Fly ash	Tower bottom ash	Activating agent
						Example 1	80.0	9.0	3.0	6.0	2.0
Example 2	84.0	7.0	3.0	5.0	1.0
						Example 3	85.0	8.0	1.0	4.5	1.5

The compound admixtures corresponding to the examples in table 1 and the mixture of cement are mixed with standard sand in a weight ratio of 1:3, cement mortar is obtained according to a water-cement ratio of 0.5, and then the test result of slag powder mortar test is carried out according to the GB/T18046-2017 granulated blast furnace slag powder for cement and concrete. For comparison, a reference group S using pure ordinary silica cement as a binding material, and a control group S0 using 50% ordinary silica cement and 50% slag powder as a binding material were prepared. Table 2 reflects that the strength of the composite admixtures of examples S1-S3 mostly exceeded that of the reference group S, and S1-S3 all exceeded that of the control group S0.

TABLE 2 test results of the mortar strength of each example, reference group and control group

The data results in table 2 are shown in table 3, after being processed according to the activity calculation method in the standard GB/T18046-2017 granulated blast furnace slag powder for cement and concrete. It can be seen that the activity indexes of 7d and 28d of examples S1-S3 both meet the technical requirements of S95 in GB/T18046-2017 granulated blast furnace slag powder for use in cement and concrete Standard, compared with the cement mortar S group and S0 group using pure ordinary portland cement and S95 slag powder.

TABLE 3 test results of Activity indexes of examples, reference group, and control group

Meanwhile, selecting the example 2 in the table 1, preparing a pure slurry test block according to GB/T1346-2011 Standard test method for water consumption, setting time and stability of standard consistency of cement, preparing a sample after standard maintenance for 7d and 28d, and respectively measuring phases of hydration products of different ages by an XRD diffractometer, wherein the phases are shown in the figure 1 and the figure 2; the microscopic appearances of the fresh sections of the samples of different hydration ages are respectively observed by a Scanning Electron Microscope (SEM) in a vacuum mode, and are shown in figures 3 and 4.

According to the figure1 and 3, it can be seen that the 7d hydration products of example 2 corresponding to neat paste are mainly acicular ettringite, flocculent C-S-H gel and flaky Ca (OH)₂. Besides the hydration reaction of ordinary cement, the chemical activator is alkaline, which can make OH^-Crystals are precipitated by increasing the concentration, and ettringite, C-S-H gel and the like are generated by the reaction with active silica, alumina and sulfate ions in the mineral admixture (i.e. alkali excitation). As the hydration reaction proceeded, substantially no Ca (OH) flakes were observed in the hydrated product of sample 28d, as shown in FIGS. 2 and 4₂But the ettringite and C-S-H gel are obviously increased. The potential activity of the mineral admixture is slowly excited along with the continuous progress of the hydration reaction, the amount of calcium hydroxide is continuously consumed, ettringite is formed in a system as a framework, C-S-H gel and other hydration products are filled in the framework and pores, the structure is more compact, and the macro-expression shows that the mechanical property is obviously improved.

The cost of producing the composite admixture of examples 1-3, as compared to the cost of the S95 pure slag powder, is shown in Table 4, based on the current raw material price. The price of each raw material at present is respectively: the slag is 230 yuan/t, the steel slag is 25 yuan/t, the tower bottom ash is 25 yuan/t, the fly ash is 100 yuan/t, the activating agent is 1200 yuan/t, the formula cost of each embodiment is respectively 214.75 yuan/t for S1, 217.75 yuan/t for S2, 218.93 yuan/t for S3, the formula cost is respectively reduced by 15.25 yuan/t, 12.25 yuan/t and 11.07 yuan/t compared with the formula cost of S95 slag powder, the production cost is reduced, low-activity solid waste is consumed, the slag powder yield is improved, and the economic effect is obvious.

TABLE 4 formulation costs for examples 1-3 corresponding to composite admixtures

While the foregoing is directed to the preferred embodiment of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.