阅读说明：本技术 一种混凝土用降粘增强的球形镍渣材料的制备方法 (Preparation method of viscosity-reduction-enhanced spherical nickel slag material for concrete ) 是由 罗翔 夏焕超 郑常伟 贺希 于 2021-10-09 设计创作，主要内容包括：本发明公开了一种混凝土用降粘增强的球形镍渣材料的制备方法,包括以下步骤：1)用高压冷空气将熔融镍渣吹入空冷区进行冷却,熔融镍渣迅速冷却,形成球形细颗粒的形状；2)按粒径大小将球形镍渣分为三个等级,第一级为0-0.3mm,第二级为0.3-0.85mm,第三级为0-4.75mm；3)将三个等级的球形镍渣分别与天然骨料硅质砂混合后形成混合骨料；4)将水、混合骨料与水泥混合后,得含球形镍渣混凝土材料。本发明利用雾化冷却工艺形成的球形镍渣来降低混凝土粘度增强力学性性能,该方法操作便捷,成本低廉,可大规模应用,另,利用球形SNS实现混凝土高流动度、高减水率、高强度增长,可行性极高。(The invention discloses a preparation method of a viscosity-reduction enhanced spherical nickel slag material for concrete, which comprises the following steps: 1) blowing the molten nickel slag into an air cooling area by using high-pressure cold air for cooling, and rapidly cooling the molten nickel slag to form spherical fine particles; 2) the spherical nickel slag is divided into three grades according to the particle size, wherein the first grade is 0-0.3mm, the second grade is 0.3-0.85mm, and the third grade is 0-4.75 mm; 3) respectively mixing the three grades of spherical nickel slag with natural aggregate siliceous sand to form mixed aggregate; 4) and mixing the water, the mixed aggregate and the cement to obtain the spherical nickel slag-containing concrete material. The method reduces the viscosity of the concrete by using the spherical nickel slag formed by the atomization cooling process to enhance the mechanical property, is convenient to operate, has low cost, can be applied in a large scale, and realizes high fluidity, high water reducing rate and high strength increase of the concrete by using the spherical SNS, thereby having extremely high feasibility.)

1. A preparation method of viscosity-reduction enhanced spherical nickel slag material for concrete is characterized by comprising the following steps: the method comprises the following steps:

1) blowing the molten nickel slag into an air cooling area by using high-pressure cold air for cooling, and rapidly cooling the molten nickel slag to form spherical fine particles;

2) the spherical nickel slag is divided into three grades according to the particle size, wherein the first grade is 0-0.3mm, the second grade is 0.3-0.85mm, and the third grade is 0-4.75 mm;

3) respectively mixing the three grades of spherical nickel slag with natural aggregate siliceous sand to form mixed aggregate;

4) and mixing the water, the mixed aggregate and the cement to obtain the spherical nickel slag-containing concrete material.

2. The method for preparing the viscosity-reduction-enhanced spherical nickel slag material for concrete according to claim 1, wherein the viscosity-reduction-enhanced spherical nickel slag material comprises the following steps: the mass ratio of the mixture of the spherical nickel slag and the natural aggregate siliceous sand in the step 3) is 1: 4-3: 2.

3. the method for preparing the viscosity-reduction-enhanced spherical nickel slag material for concrete according to claim 1, wherein the viscosity-reduction-enhanced spherical nickel slag material comprises the following steps: the mass ratio of the mixed aggregate to the cement in the step 4) is 3: 1.

4. the method for preparing the viscosity-reduction-enhanced spherical nickel slag material for concrete according to claim 1, wherein the viscosity-reduction-enhanced spherical nickel slag material comprises the following steps: the mass ratio of the water to the cement in the step 4) is 0.42-0.50.

5. The method for preparing the viscosity-reduction-enhanced spherical nickel slag material for concrete according to claim 1, wherein the viscosity-reduction-enhanced spherical nickel slag material comprises the following steps: the specific operation of the step 4) is as follows: and (3) slowly stirring cement and water in a cement stirrer for 80-100 s, slowly adding the mixed aggregate within the last 30s of the slow stirring process, and finally quickly stirring for 110-130 s.

Technical Field

The invention belongs to the technical field of waste residue treatment, and particularly relates to a viscosity-reduction-enhanced spherical nickel residue material for concrete.

Background

Nowadays, in the course of rapid industrialization, the demand of crude steel is gradually increased with increasing consumption, the crude steel yield reaches 17.8 hundred million tons in 2020, while the metallurgical yield in china reaches 49% of the world metallurgical yield in 2017. However, different types of by-products, metallurgical wastes including Spherical Nickel Slag (SNS), are produced during metallurgical processes depending on the production process. The world ferrous metallurgical waste production in 2019 is estimated to be between 1.9 and 2.8 million tons, depending on the current production levels of the crude metallurgy. The generation of such waste in large quantities poses serious environmental problems such as pollution of soil and groundwater and occupation of large land resources. In addition, about 25% to 30% of the worldwide metallurgical material is produced in an electric arc furnace in such a way that about 70 kg of slag is produced for each ton of metallurgical product produced. And because of different raw materials and cooling processes, various types of nickel slag such as air quenching, water quenching, high-pressure quenching and the like are formed. Such huge metallurgical waste residue needs reasonable research of planning, carries out economic effectual comprehensive utilization, otherwise simply handles or directly discharges into natural environment, not only seriously pollutes the environment, but also can cause the waste of land resource, consequently rationally handles metallurgical waste residue and becomes the problem that needs to solve at present urgently.

However, there are many factors that have to be considered in how to make a rational use of metallurgical slag, including the form of application, the particle size distribution, the crush value index and, most importantly, the stability.

The application of the metallurgical waste residues as aggregates in building materials is common and large in consumption, and the production process and the cooling mode of the metallurgical waste residues are different, so that the application mode is also multiform: (1) directly taking materials, and directly using air-cooled or water-quenched slag as coarse aggregate. Although the method greatly reduces the disposal cost, the method is too dependent on the properties of the metallurgical slag, and the stability problems of insufficient strength and cracking and expansion are easy to occur. (2) And (3) coating improvement, namely processing the metallurgical slag, and coating a layer of cementing material on the outer surface of the metallurgical slag. The shell structure formed by the method effectively improves the strength of the waste residue aggregate. (3) Crushing as fine aggregate, artificial fine aggregate instead of natural sand is an effective way to deal with environmental problems, but also has problems of poor stability and poor gradation. (4) The waste slag powder, other cementing materials and an excitant are mixed according to a proportion design, and the stability problem can be well solved by using the granulated particles as aggregates. (5) In recent years, a novel cooling process is provided, SNS fine aggregates can be obtained by omitting the crushing process and cost, and the novel cooling process is also an application mode of few waste residue fine aggregates.

Along with the industrialization process of China, the volume of modern buildings is continuously increased, and the research on ultra-high-strength concrete (UHPC) materials is gradually strengthened. Because the UHPC has excellent high strength and high durability, the use of the ultra-high strength concrete can greatly reduce the dead weight of the building and improve the height of the building in the same basic design; the sectional area of the structural member of the beam plate column under the same bearing requirement condition is reduced, and further the usage amount of concrete in unit building area is reduced; correspondingly, the use space in the limited building area is increased, and a large amount of concrete and steel are saved. Because of the high durability, the service life of the building can be greatly prolonged, and the building material meets the green economic technical policy of saving materials and energy in the current building material development of China, thereby becoming the key for the development of the green technology of the current building material. Although the economic and technical advantages of UHPC are obvious, high compactness is obtained due to the high amount of gelling material and low water-to-gel ratio which are often required in the production of UHPC. The UHPC slurry has the advantages that due to the high ultra-fine powder consumption and the extremely low water-to-gel ratio of UHPC, the consumption of additives mainly comprising a water reducing agent is remarkably increased, the thickness of a slurry particle water film layer is reduced, and the residue of gap liquid additives is increased, so that the UHPC slurry has high viscosity and is gradually increased along with the increase of the consumption of the water reducing agent, the UHPC slurry has high standing fluidity loss, is not easy to pump for construction, has large shrinkage and has large cracking risk. Therefore, the low-viscosity ultra-high-strength concrete technology is the future trend of the concrete technology development.

With the aging of the Chinese population, the intelligent application is realized in the construction industry, the traditional operation mode method is replaced, the demand is urgent, and the 3D concrete printing (3DPC) technology is generated. The total 3D printing market amount in China reaches 5182 hundred million yuan since 2019, and the 3D printing industry is a burst growth period in the five to ten years in the future. The method conforms to the policy guidance that the national and local governments vigorously promote the intelligent manufacturing process, the new concept and new state of 3D building printing contain huge business opportunities, huge market demands are being created, and the potential of applying new technologies to modify the traditional industry is also huge. But the 3DPC technology is not yet mature at present. Because of the requirement of rapid forming, hardening and strength increase, a plurality of additives are required to be used cooperatively, so that the required performances such as strength, printability, constructability and the like are met. The water reducing agent, the chemical fiber, the rubber powder, the thixotropic agent and the like contained in the additive cause the concrete printing material to have the problems of high viscosity, high loss of fluidity over time and the like as the UHPC, and are not beneficial to extrusion, conveying and operation time. In particular, the interlacing of the fibers in the cement paste makes the fluidity very poor.

Disclosure of Invention

The invention mainly solves the technical problem of providing a preparation method of viscosity-reduction-enhanced spherical nickel slag material for concrete, wherein the viscosity of the concrete is reduced by utilizing spherical nickel slag formed by an atomization cooling process to enhance the mechanical property, the method is convenient to operate, low in cost and applicable to large scale, and in addition, the high fluidity, high water-reducing rate and high strength of the concrete are increased by utilizing spherical SNS, and the feasibility is extremely high.

In order to solve the technical problems, the invention adopts a technical scheme that: a preparation method of viscosity-reduction enhanced spherical nickel slag material for concrete comprises the following steps:

1) blowing the molten nickel slag into an air cooling area by using high-pressure cold air for cooling, and rapidly cooling the molten nickel slag to form spherical fine particles;

2) the spherical nickel slag is divided into three grades according to the particle size, wherein the first grade is 0-0.3mm, the second grade is 0.3-0.85mm, and the third grade is 0-4.75 mm;

3) respectively mixing the three grades of spherical nickel slag with natural aggregate siliceous sand to form mixed aggregate;

4) and mixing the water, the mixed aggregate and the cement to obtain the spherical nickel slag-containing concrete material.

Further, the mass ratio of the mixture of the spherical nickel slag and the natural aggregate siliceous sand in the step 3) is 1: 4-3: 2.

further, the mass ratio of the mixed aggregate and the cement in the step 4) is 3: 1.

further, the mass ratio of the water to the cement in the step 4) is 0.42-0.50.

Further, the specific operation of step 4) is: and (3) slowly stirring cement and water in a cement stirrer for 80-100 s, slowly adding the mixed aggregate within the last 30s of the slow stirring process, and finally quickly stirring for 110-130 s.

The invention has the following beneficial effects:

1. in the optimization process, the ball effect generated by the spherical appearance of the SNS is utilized to replace the effect of the water reducing agent, the water requirement is reduced by 16%, and the fluidity can still reach 185 +/-5 mm; the sand is different from irregular angular silica sand, the physical appearance of the sand hardly generates stress at the tip end of an aggregate when bearing load, the generation and the expansion of microcracks are hindered, and the breaking strength of 3 days in the early stage in the scheme is improved by 43.8 percent to the maximum extent; and the compressive strength of the finished product is respectively improved by 26.3 percent, 20.5 percent and 13.3 percent in the curing ages of 3 days, 7 days and 28 days. In conclusion, the spherical SNS can play a role in improving the fluidity of concrete, reducing the viscosity of the concrete and increasing the compressive and flexural strength;

2. the invention mixes the spherical nickel slag with the natural sand in a grading way, reduces the internal friction force of the aggregate, and determines the influence of the particle grading on the fluidity and the mechanical property;

2. the method provided by the invention is convenient to operate and low in cost, can be applied to practical application, utilizes industrial metallurgical wastes, realizes efficient optimization of viscosity reduction and reinforcement, and can reduce natural resource exploitation and reduce the use cost of the additive.

Drawings

FIG. 1 is a schematic view of a spherical SNS material;

FIG. 2 is a grading curve image of a spherical SNS material and a siliceous sand material;

FIG. 3 is an XRD image of a spherical SNS material;

FIG. 4 is an image of an interfacial scanning electron microscope of spherical SNS material and cement slurry (a 3000 times mirror; b 5000 times mirror);

FIG. 5 is a SNS autoclaving pulverization rate inspection result chart.

Detailed Description

The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention.

Example 1

Weighing siliceous sand, and simultaneously weighing 42.5# cement with the total mass of the siliceous sand being 1/3;

weighing tap water according to the water-cement ratio of 0.50, placing the tap water in a stirring pot, mixing cement, uniformly stirring, adding siliceous sand, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 2

Weighing a spherical SNS material and siliceous sand according to a mass ratio of 1:4, wherein the spherical SNS material is selected from a grade of 0-0.3mm, and uniformly mixing; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.47, placing the tap water in a stirring pot, mixing cement, uniformly stirring, adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 3

Weighing a spherical SNS material and siliceous sand according to a mass ratio of 2:3, wherein the spherical SNS material is selected from a grade of 0-0.3mm, and uniformly mixing; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.46, placing the tap water in a stirring pot, mixing cement, uniformly stirring, then adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 4

Weighing a spherical SNS material and siliceous sand according to a mass ratio of 3:2, wherein the spherical SNS material is selected from a grade of 0-0.3mm, and uniformly mixing; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.46, placing the tap water in a stirring pot, mixing cement, uniformly stirring, then adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 5

Weighing a spherical SNS material and siliceous sand according to a mass ratio of 1:4, wherein the spherical SNS material is selected from a grade of 0.3-0.85mm, and uniformly mixing; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.45, placing the tap water in a stirring pot, mixing cement, uniformly stirring, then adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 6

Weighing a spherical SNS material and siliceous sand according to a mass ratio of 2:3, wherein the spherical SNS material is selected from a grade of 0.3-0.85mm, and uniformly mixing; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.44, placing the tap water in a stirring pot, mixing cement, uniformly stirring, then adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 7

And (3): weighing a spherical SNS material and siliceous sand in a mass ratio of 2, wherein the spherical SNS material is selected from a grade of 0.3-0.85mm and is uniformly mixed; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.43, placing the tap water in a stirring pot, mixing cement, uniformly stirring, then adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 8

Weighing a spherical SNS material and siliceous sand according to a mass ratio of 1:4, wherein the spherical SNS material is selected from a grade of 0-4.75mm, and uniformly mixing; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.46, placing the tap water in a stirring pot, mixing cement, uniformly stirring, then adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 9

Weighing a spherical SNS material and siliceous sand according to a mass ratio of 2:3, wherein the spherical SNS material is selected from a grade of 0-4.75mm, and uniformly mixing; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.44, placing the tap water in a stirring pot, mixing cement, uniformly stirring, then adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

Example 10

Weighing a spherical SNS material and siliceous sand according to a mass ratio of 3:2, wherein the spherical SNS material is selected from a grade of 0-4.75mm, and uniformly mixing; simultaneously weighing 42.5# cement with the total mass of the mixed aggregate of 1/3;

weighing tap water according to the water-cement ratio of 0.42, placing the tap water in a stirring pot, mixing cement, uniformly stirring, then adding mixed aggregate, fully stirring, and testing the fluidity of the mixture in time; and (3) forming by using a 40X 160mm triple die, curing for 24 hours in a curing box, demolding, putting into room-temperature water, curing for 3 days, 7 days and 28 days, and testing the flexural strength and the compressive strength of the material respectively.

TABLE 1 spherical SNS Components

FIG. 3 is an XRD pattern of a spherical SNS material, and from the results of Table 1, it is understood that the main phases thereof are quartz and forsterite, which means that the activity of nickel slag is not high.

Table 2 shows the water-cement ratio and fluidity of each example

	Water cement ratio	Fluidity/mm
			Example 1	0.50	184
Example 2	0.47	183.5
			Example 3	0.46	184
Example 4	0.46	180.5
			Example 5	0.45	181.5
Example 6	0.44	185
			Example 7	0.43	182
Example 8	0.46	183.5
			Example 9	0.44	180
Example 10	0.42	185

Unlike the traditional cooling process, the SNS material treated by the atomization cooling process is in a regular spherical shape, and is a substance which is gray black in appearance and in a regular spherical shape. As shown in fig. 1, the physical appearance is characterized by serving as a key factor for reducing viscosity and increasing breaking strength by virtue of the ball effect and internal stress dispersion. As can be seen from Table 2, the water-cement ratio is reduced and the fluidity is maintained at 180mm or more as the replacement amount of SNS is increased, which shows that SNS plays a role in improving the fluidity and can replace the water reducing agent to achieve the effect of reducing the viscosity and increasing the fluidity.

Generally, controlling the water-cement ratio, an increase in fluidity is considered to be good fluidity. However, there is a possibility that the water-cement ratio increases and the strength decreases. According to the experimental scheme, the GB175-2007 is referred, the fluidity is controlled to be 180 +/-5 mm, the water-cement ratio is multiplied by 0.01, and the strength value is tested on the basis. When the fluidity of the control is consistent, the water demand is effectively reduced by adding the spherical nickel slag, and the purpose of increasing the flow can be achieved. In addition, the low water-cement ratio and the spherical close packing model are the key points for improving the mechanical property.

Table 3 shows the flexural strength of each example

Table 3 shows the flexural strength of each example, the flexural strength of the SNS spherical aggregate is improved by 43.8% to the maximum in 3 days in the early stage of the scheme, and the effect of stress dispersion of the SNS spherical aggregate in cement paste is proved.

Table 4 shows the compressive strengths of the examples

Spherical particles are the most ideal model for close packing, the spherical SNS conforms well to the model, and the grading is good when the view in FIG. 1 is taken, so that the close packing effect is favorable for the compressive strength of concrete. As can be seen from Table 4, the compressive strength of concrete was also significantly improved by SNS, which was improved by 26.3%, 20.5% and 13.3% at 3-day, 7-day and 28-day ages, respectively. FIG. 4 is a scanning electron microscope image of the third phase transition zone (ITZ) in concrete, it can be observed that the ITZ width between the SNS and the cement matrix is only 2 μm, and the narrower the ITZ width, the more favorable the strength of the concrete.

FIG. 5 shows SNS autoclaving pulverization rate censorship results

The pressure steaming pulverization rate adopts a stricter experimental condition, under the experimental condition, most of free CaO and MgO in the nickel slag can react, so that the pressure steaming pulverization rate can better reflect the destructive effect of unstable components in the nickel slag on nickel slag particles. SNS has no obvious change before and after autoclaving, the pulverization rate is only 1.86%, and the self-stability is good. As shown in FIG. 2, the grading curve for the spherical SNS conforms to the common sand in zone II of the project.

Table 5 shows the result of measurement of the autoclaving expansion ratio of the SNS-containing sample

The test piece used for the autoclave expansion ratio test was a prism of 25X 280 mm. As can be seen from Table 5, the change in the autoclave expansion ratio has no linear relationship with the particle size and the blending amount of SNS, but both do not exceed the limits. That means that the SNS fine aggregate of each particle size grade cannot cause transitional expansion and even cracking of the hardened mortar test piece when the doping amount is below 60%.

The Spherical Nickel Slag (SNS) fine aggregate produced by the atomization cooling process has the characteristics of regular spherical appearance, excellent gradation and low crushing value. Based on the characteristics, the spherical SNS has a ball effect in concrete, has the potential advantages of reducing viscosity and water demand, and the physical properties of the spherical SNS are more likely to strengthen the compression strength and the breaking strength of the concrete. And the purchasing cost of expensive additives and natural aggregates can be saved, and the indirect protection effect on the problem of mining damage of the environment is achieved. In addition, SNS is a by-product of the electric arc furnace, has low calcium-silicon ratio, and is treated by an atomization cooling process, so that the influence of free calcium oxide and magnesium oxide components on stability is reduced.

The harmless, quantitative-reduction and resource utilization means of the SNS and other metallurgical waste residues are the most potential disposal means, and the realization of resource utilization of the SNS in the fields of UHPC, 3DPC and the like is undoubtedly the most economical, effective, environment-friendly and imperative at present.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.