Trench prefabricated part with iron mine solid waste as main raw material and preparation method of ditch prefabricated part

Abstract

The invention aims to provide a ditch prefabricated part taking iron mine solid waste as a main raw material and a preparation method of the ditch prefabricated part in order to solve the problems existing in the existing technology for preparing a cementing material or concrete by using the solid waste and provides the ditch prefabricated part taking the iron mine solid waste as the main raw material and the preparation method of the ditch prefabricated part. According to the invention, based on the double salt effect and the four-coordination isomorphism effect theory of silicon, slag and desulfurized fly ash are used as binding materials, and waste rock of an iron mine is used as aggregate to prepare the channel prefabricated member. The prefabricated part uses a large amount of industrial solid waste, can show good compressive strength without cement clinker, not only can improve the utilization rate of the mine solid waste and the desulfurized fly ash, but also can reduce carbon emission and effectively reduce the production cost, and can be used as an agricultural water delivery ditch and a building material. And the prefabricated member is a good substitute for conventional cement concrete prefabricated members.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of solid waste resources and building materials, and in particular relates to a ditch prefabricated part and a preparation method thereof. Background Art

[0002] Iron ore waste rock is the ore waste slag produced by the stripping of surrounding rocks during the mining process, and is an important component of industrial solid waste. The storage of a large amount of waste rock not only occupies land, but also brings environmental and safety risks, causing great environmental and economic pressure on enterprises. In recent years, my country has vigorously developed infrastructure construction, and the market demand for sand and gravel is huge, but the price of natural sand and gravel has risen due to restrictions on mining, and the "blasting" sand and gravel production is extremely polluting. Therefore, processing iron ore waste rock into sand and gravel aggregate not only realizes the resource utilization of waste rock, but also reduces the production cost of concrete. At the same time, with the increasing consumption of coal resources in my country, a large amount of SO2 gas is brought in every year. Now flue gas desulfurization has entered a rapid development stage. Desulfurization ash is a solid waste produced by semi-dry and dry flue gas desulfurization. Desulfurization ash contains a large amount of CaSO3 and Ca(OH)2, which is unstable and expands after hydration, which will cause safety hazards to cement products. Therefore, desulfurization ash is only used as an admixture, and most of it is mainly stacked and abandoned, which not only occupies a large amount of land, but also causes serious secondary pollution to the environment.

[0003] In the prior art, research has been conducted on the preparation of concrete or cementitious materials from solid waste, for example:

[0004] CN116924711A "A kind of all-solid waste cementitious material and its preparation method and application" proposes a cementitious material: 30-70 parts of solid sulfur ash, 10-35 parts of active components, 0-14 parts of carbide slag, 0-30 parts of fine coal gangue, and 0-6 parts of desulfurization ash. The amount of desulfurization ash added in this patent is low, and it mainly plays the role of alkaline excitation.

[0005] CN116282984A "All-solid waste cementitious material, new roadbed material and preparation method thereof" discloses a cementitious material: 10%-18% desulfurization ash, 20%-40% steel slag powder, 35%-55% slag powder and 8%-12% construction waste powder. The maximum amount of desulfurization ash in this patent is only 18%, which makes it difficult to use desulfurization ash on a large scale.

[0006] CN115448680A discloses "A low-carbon fast demoulding prefabricated part prepared from solid waste-based cementitious materials containing cement, fly ash and desulfurized gypsum and a preparation method thereof", which uses water cement, fly ash and desulfurized gypsum to form a synergistic coupling mechanism to prepare cementitious materials, and then mixes with aggregate, water and admixtures to obtain concrete, and obtains prefabricated parts after curing. The weight proportion of cement in this invention is 100 to 150 parts, and the "two grinding and one burning" production process of cement will emit a large amount of carbon dioxide, which runs counter to our country's vision of "carbon peak" and "carbon neutrality".

[0007] CN114292081A discloses "A cement-free low-carbon concrete and its preparation method", which uses 20-60 parts of coal gasification slag, 30-50 parts of steel slag, 10-30 parts of gypsum, and 0-15 parts of lime kiln dust. It does not use cement, reduces the carbon emission of concrete, and provides a corresponding preparation method for medium and low strength concrete prefabricated parts. However, steel slag is a metallurgical solid waste with high grinding energy consumption, and its large-scale use will increase the production cost of concrete.

[0008] CN112225497A discloses "A novel tailings, waste rock aggregate fly ash geopolymer concrete material and its preparation method", which uses slag and fly ash as cementitious materials, and tailings and waste rock instead of natural sand for concrete preparation. Alkali activators are used to activate the activity of fly ash and part of slag is added to prepare cementitious materials, and tailings and waste rock are used to replace natural sand and stone to prepare concrete, which can make use of a large amount of solid waste. However, in this invention, water glass and NaOH are added as alkaline activators, and solid NaOH needs to be dissolved before being added to concrete, which complicates the preparation process of concrete. Summary of the invention

[0009] The purpose of the present invention is to address the problems existing in the existing technology of using solid waste to prepare cementitious materials or concrete, and to provide a ditch prefabricated component using iron mine solid waste as the main raw material and a preparation method thereof. The present invention relies on the theory of complex salt effect and silicon's four-coordinate isomorphism effect, and uses slag and desulfurization ash as cementitious materials and iron mine waste rock as aggregate to prepare ditch prefabricated components. The prefabricated component uses a large amount of industrial solid waste and can show good compressive strength without the need for cement clinker. It can not only improve the utilization rate of mine solid waste and desulfurization ash, but also reduce carbon emissions and effectively reduce production costs. Moreover, the prefabricated component can be used as an agricultural water ditches and a building material, and is a good substitute for conventional cement concrete prefabricated components.

[0010] One of the technical solutions of the present invention is a ditch prefabricated component using iron ore solid waste as the main raw material, which is made of the following raw materials in parts by weight:

[0011] 450-576 parts of cementitious material;

[0012] 773-900 parts of waste rock fine aggregate;

[0013] 1067-1150 parts of waste stone coarse aggregate;

[0014] 150-158 parts of water;

[0015] Water reducing agent 2.55-3 parts.

[0016] Furthermore, in the above-mentioned ditch prefabricated part, the cementitious material comprises the following raw materials in weight percentage: 60-65% slag powder and 35-40% desulfurized ash; optimally, the cementitious material comprises the following raw materials in weight percentage: 60% slag powder and 40% desulfurized ash.

[0017] Furthermore, in the above-mentioned ditch prefabricated part, the specific surface area of ​​the cementitious material is 500m 2 / kg~650m 2 / kg.

[0018] Furthermore, in the above-mentioned ditch prefabricated parts, the slag powder in the cementitious material is granulated blast furnace slag powder; the slag powder complies with the standard requirements of GB / T18046-2017 "Granulated blast furnace slag powder used in cement, mortar and concrete".

[0019] Furthermore, in the above-mentioned ditch prefabricated part, the desulfurized ash in the cementitious material is a by-product of flue gas desulfurization; the specification of the desulfurized ash is: particle size D90 is 20-40μm or specific surface area is 500-800m 2 / kg.

[0020] Furthermore, in the above-mentioned ditch prefabricated part, the waste rock fine aggregate is a fine aggregate with a particle size less than 4.75 mm prepared by crushing waste rock in the Anshan-type iron ore mining process.

[0021] Furthermore, in the above-mentioned ditch prefabricated part, the waste rock coarse aggregate is a coarse aggregate with a particle size of not less than 4.75 mm prepared by crushing waste rock in the Anshan-type iron ore mining process.

[0022] Furthermore, for the above-mentioned ditch prefabricated parts, the water reducer is a polycarboxylate-based high-efficiency water reducer, which complies with GB / T33892-2020 "Concrete Admixtures".

[0023] The second technical solution of the present invention is that the method for preparing the above-mentioned ditch prefabricated component comprises the following steps:

[0024] (1) Mix slag powder and desulfurized ash in proportion by weight and grind to a specific surface area of ​​500m 2 / kg~650m 2 / kg, to obtain a gelling material;

[0025] (2) mixing the cementitious material prepared in step (1) with waste rock fine aggregate, waste rock coarse aggregate, a water reducing agent and water in proportion by weight to obtain a concrete mixture;

[0026] (3) The concrete mixture prepared in step (2) is poured into a mold for molding, and then cured for 2-3 days under outdoor film covering conditions and then demolded to obtain a prefabricated ditch component.

[0027] The present invention proposes to use slag and desulfurized ash as a cementitious material after mixing and grinding in a certain proportion. In this system, the desulfurized ash is one of the main raw materials of the cementitious material, and the amount of the mixed amount is as high as 40%. The hydration product is mainly ettringite, which is a kind of cementitious material with extremely low solubility (10 -111.4 )'s complex salt can drive the hydration reaction to proceed continuously and generate more hydration products, fundamentally solving the problem of the difficulty in utilizing desulfurization ash.

[0028] Compared with the prior art, the advantages of the present invention are:

[0029] (1) The cementitious materials of the present invention are slag and desulfurized ash. Not using cement at all can effectively reduce the problem of carbon dioxide emissions caused by cement production, and can also significantly reduce production costs.

[0030] (2) Slag is easy to grind. Desulfurized ash is a nano-particle solid waste. The preparation of cementitious materials only requires simple mixing and grinding to reach 500m 2 / kg~650m 2 / kg specific surface area, low grinding energy consumption.

[0031] (3) The concrete aggregate of the present invention uses coarse aggregate and fine aggregate made from waste stone, does not contain natural sand, has low cost and is beneficial to environmental protection.

[0032] (4) The cementitious material of the all-solid waste concrete of the present invention uses slag powder and desulfurized ash as raw materials. Among them, desulfurized ash, as an alkaline component, provides the necessary alkaline environment for the system reaction. The slag and desulfurized ash synergistically hydrate to produce silicon tetracoordinate isomorphism effect and double salt effect. Moreover, under the condition of low water-cement ratio, a large number of silicon, aluminum and oxygen bonds on the surface of waste rock aggregate are broken and rebonded, so that concrete with a compressive strength greater than 40MPa can be prepared without adding clinker.

[0033] (5) The entire production process has no secondary pollution, which can achieve the goal of environmental protection and energy saving, and at the same time realize the comprehensive utilization of waste resources.

[0034] (6) The production process is simple, the operation flow is simple, and the production does not require a large amount of land resources. Only slight changes to the components of the traditional concrete production process are required, and the investment and production management costs are low.

[0035] (7) The solid waste admixture amount of the present invention is 100%, which can greatly improve the utilization rate of mine solid waste. DETAILED DESCRIPTION

[0036] Example 1

[0037] A method for preparing a ditch prefabricated part using iron ore solid waste as the main raw material:

[0038] 1. Preparation of cementitious materials

[0039] 1) Dry and grind the slag to a particle size D90 of 35 μm or a specific surface area of ​​450 m 2 / kg;

[0040] 2) Dry and grind the desulfurized ash to a particle size D90 of 30 μm or a specific surface area of ​​500 m 2 / kg;

[0041] 3) The above-mentioned materials are mixed and ground into powder according to the following proportions: 60% slag and 40% desulfurized ash to a specific surface area of ​​530m 2 / kg, to obtain a gelling material.

[0042] 2. Preparation of precast concrete parts

[0043] 1) Weigh a certain weight of waste rock fine aggregate and waste rock coarse aggregate, dry them to constant weight, and calculate the moisture content;

[0044] 2) Weigh each raw material according to the dry basis mass in Table 1, where the water reducer is measured by dry basis mass, mix the aggregate and cementitious material evenly according to the proportion, pour into the silo, then start the self-falling drum mixer to feed, rotate, and stir for 3 minutes, and then reverse the drum mixer to discharge the material, and then put the concrete raw materials into the prefabricated mold. After loading, use a vibrator to vibrate out the bubbles inside, and at the same time, scrape the surface of the prefabricated part flat, and then cover and water it outdoors for 2-3 days, demould and continue to maintain, and obtain the prefabricated part. The properties of the prefabricated part are shown in Table 2.

[0045] Table 1 Precast parts mix ratio data table (Concrete material consumption per cubic meter: kg / m 3 )

[0046]

[0047]

[0048] Table 2 Compressive strength of prefabricated parts at different ages in Example 1

[0049]

[0050] Example 2

[0051] A method for preparing a ditch prefabricated part using iron ore solid waste as the main raw material:

[0052] 1. Preparation of cementitious materials

[0053] 1) Dry and grind the slag to a particle size D90 of 35 μm or a specific surface area of ​​450 m 2 / kg;

[0054] 2) Dry and grind the desulfurized ash to a particle size D90 of 30 μm or a specific surface area of ​​570 m 2 / kg;

[0055] 3) The above-mentioned materials are mixed and ground into powder according to the following proportions: 60% slag and 40% desulfurized ash to a specific surface area of ​​580m 2 / kg, to obtain a gelling material.

[0056] 2. Preparation of precast concrete parts

[0057] 1) Weigh a certain weight of waste rock fine aggregate and waste rock coarse aggregate, dry them to constant weight, and calculate the moisture content;

[0058] 2) Weigh each raw material according to the dry basis mass in Table 3, where the water reducer is measured by dry basis mass, mix the aggregate and cementitious material evenly according to the proportion, pour into the silo, start the self-falling drum mixer to feed, rotate, and stir for 3 minutes, and then reverse the drum mixer to discharge the material. Put the concrete raw materials into the prefabricated mold, and after loading, use a vibrator to vibrate out the bubbles inside, and at the same time, scrape the surface of the prefabricated part flat, and then cover and water it outdoors for 2-3 days, demould and continue to maintain, and obtain the prefabricated part. The properties of the prefabricated part are shown in Table 4.

[0059] Table 3 Precast parts mix ratio data table (Concrete material consumption per cubic meter: kg / m 3 )

[0060] Cementitious materials Waste rock fine aggregate Waste rock coarse aggregate water Water reducing agent 500 850 1150 156 2.55

[0061] Table 4 Compressive strength of prefabricated parts at different ages in Example 2

[0062]

[0063] Example 3

[0064] A method for preparing a ditch prefabricated part using iron ore solid waste as the main raw material:

[0065] 1. Preparation of cementitious materials

[0066] 1) Dry and grind the slag to a particle size D90 of 35 μm or a specific surface area of ​​450 m 2 / kg; 2) Dry and grind the desulfurized ash to a particle size D90 of 30 μm or a specific surface area of ​​630 m 2 / kg;

[0067] 3) Mix the above mentioned materials in the following proportions: 60% slag, 40% desulfurized ash and grind to a specific surface area of ​​600m 2 / kg, to obtain a gelling material.

[0068] 2. Preparation of precast concrete parts

[0069] 1) Weigh a certain weight of waste rock fine aggregate and waste rock coarse aggregate, dry them to constant weight, and calculate the moisture content;

[0070] 2) Weigh each raw material according to the dry basis mass in Table 5, where the water reducer is measured by dry basis mass, mix the aggregate and cementitious material evenly according to the proportion, pour into the silo, start the self-falling drum mixer to feed, rotate, and stir for 3 minutes, and then reverse the drum mixer to discharge the material. Put the concrete raw materials into the prefabricated mold, and after loading, use a vibrator to vibrate out the bubbles inside, and at the same time, scrape the surface of the prefabricated part flat, and then cover and water it outdoors for 2-3 days, demould and continue to maintain, and obtain the prefabricated part. The properties of the prefabricated part are shown in Table 6.

[0071] Table 5 Precast parts mix ratio data table (Concrete material consumption per cubic meter: kg / m 3 )

[0072] Cementitious materials Waste rock fine aggregate Waste rock coarse aggregate water Water reducing agent 550 828 1070 158 2.55

[0073] Table 6 Compressive strength of prefabricated parts at different ages in Example 3

[0074]

[0075] Example 4

[0076] A method for preparing a ditch prefabricated part using iron ore solid waste as the main raw material:

[0077] 1. Preparation of cementitious materials

[0078] 1) Dry and grind the slag to a particle size D90 of 35 μm or a specific surface area of ​​450 m 2 / kg;

[0079] 2) Dry and grind the desulfurized ash to a particle size D90 of 30 μm or a specific surface area of ​​720 m 2 / kg;

[0080] 3) The above-mentioned materials are mixed and ground into powder according to the following proportions: 60% slag and 40% desulfurized ash to a specific surface area of ​​640m 2 / kg, to obtain a gelling material.

[0081] 2. Preparation of precast concrete parts

[0082] 1) Weigh a certain weight of waste rock fine aggregate and waste rock coarse aggregate, dry them to constant weight, and calculate the moisture content;

[0083] 2) Weigh each raw material according to the dry basis mass in Table 7, where the water reducer is measured by dry basis mass, mix the aggregate and cementitious material evenly according to the proportion, pour into the silo, start the self-falling drum mixer to feed, rotate, and stir for 3 minutes, and then reverse the drum mixer to discharge the material. Put the concrete raw materials into the prefabricated mold, and after loading, use a vibrator to vibrate out the bubbles inside, and at the same time, scrape the surface of the prefabricated part flat, and then cover and water it outdoors for 2-3 days, demould and continue to maintain, and obtain the prefabricated part. The properties of the prefabricated part are shown in Table 8.

[0084] Table 7 Precast parts mix ratio data table (Concrete material consumption per cubic meter: kg / m 3 )

[0085] Cementitious materials Waste rock fine aggregate Waste rock coarse aggregate water Water reducing agent 450 773 1067 150 2.55

[0086] Table 8 Compressive strength of prefabricated parts at different ages in Example 4

[0087]

[0088] It can be seen from the above table that the prefabricated parts prepared by the present invention have excellent compressive strength and can meet the strength requirements of different strength grades.

[0089] Example 5

[0090] A method for preparing a ditch prefabricated component using iron mine solid waste as the main raw material, the raw material ratio and steps are the same as those in Example 1, the difference being that the cementitious material comprises the following raw materials in the following weight percentages: 65% slag powder and 35% desulfurized ash.

[0091] Example 6

[0092] A method for preparing a ditch prefabricated component using iron mine solid waste as the main raw material, the raw material ratio and steps are the same as those in Example 1, except that the cementitious material includes the following raw materials in percentage by weight: 62.5% slag powder and 37.5% desulfurized ash.

[0093] Since the slag, desulfurization ash, waste stone fine aggregate and waste stone coarse aggregate used in the present invention are all industrial solid wastes, these wastes are reprocessed to prepare cementitious materials and applied to all-solid waste concrete prefabricated parts, which not only solves the problems of pollution and carbon emissions caused by the large amount of cement used in this type of concrete, but also provides new ideas for the preparation of new raw materials for prefabricated parts.

[0094] At the same time, in order to solve the problem that the waste rock in the raw materials of Anshan-type iron ore contains a high amount of phyllite components, the present invention ensures the rationality and applicability of aggregate grading by adjusting the sand ratio.

[0095] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0096] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A ditch prefabricated part using iron ore solid waste as the main raw material, characterized in that: Made from the following raw materials in parts by weight: 450-576 parts of cementitious material; 773-900 parts of waste rock fine aggregate; 1067-1150 parts of waste stone coarse aggregate; 150-158 parts of water; Water reducing agent 2.55-3 parts.

2. The ditch prefabricated component using iron mine solid waste as the main raw material according to claim 1 is characterized in that: The cementitious material comprises the following raw materials in weight percentage: 60-65% slag powder and 35-40% desulfurized ash.

3. The ditch prefabricated component using iron mine solid waste as main raw material according to claim 1 or 2, characterized in that: The cementitious material comprises the following raw materials in weight percentage: 60% slag powder and 40% desulfurized ash.

4. The ditch prefabricated component using iron mine solid waste as the main raw material according to claim 1 is characterized in that: The specific surface area of ​​the gelling material is 500m 2 / kg~650m 2 / kg.

5. The ditch prefabricated component using iron mine solid waste as the main raw material according to claim 1 is characterized in that: The slag powder in the cementitious material is granulated blast furnace slag powder.

6. The ditch prefabricated component using iron mine solid waste as the main raw material according to claim 1 is characterized in that: The desulfurized ash in the cementitious material is a byproduct of flue gas desulfurization, with a particle size D90 of 20-40 μm or a specific surface area of ​​500-800 m 2 / kg.

7. The ditch prefabricated component using iron mine solid waste as main raw material according to claim 1 is characterized in that: The waste rock fine aggregate is a fine aggregate with a particle size of less than 4.75 mm prepared by crushing waste rocks in the Anshan-type iron ore mining and selection process.

8. The ditch prefabricated component using iron mine solid waste as the main raw material according to claim 1 is characterized in that: The waste rock coarse aggregate is a coarse aggregate with a particle size of not less than 4.75 mm prepared by crushing waste rock in the Anshan-type iron ore mining and selection process.

9. The ditch prefabricated component using iron mine solid waste as main raw material according to claim 1 is characterized in that: The water reducing agent is a polycarboxylate-based high-efficiency water reducing agent.

10. The method for preparing a ditch prefabricated component using iron mine solid waste as the main raw material according to claim 1, characterized in that: The steps include: (1) Mix slag powder and desulfurized ash in proportion by weight and grind to a specific surface area of ​​500m 2 / kg~650m 2 / kg, to obtain a gelling material; (2) mixing the cementitious material prepared in step (1) with waste rock fine aggregate, waste rock coarse aggregate, a water reducing agent and water in proportion by weight to obtain a concrete mixture; (3) The concrete mixture prepared in step (2) is poured into a mold for molding, and then cured for 2-3 days under outdoor film covering conditions and then demolded to obtain a prefabricated ditch component.

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