阅读说明：本技术 一种脱碳煤矸石粉及其制备方法和作为混凝土掺合料的应用 (Decarbonized coal gangue powder, preparation method thereof and application of decarbonized coal gangue powder as concrete admixture ) 是由 汪洪波 蒋明刚 孙星海 刘泽 王栋民 于 2021-09-07 设计创作，主要内容包括：本发明提供了一种脱碳煤矸石粉及其制备方法和作为混凝土掺合料的应用,属于建筑材料技术领域。本发明采用浮选的方式,能够去除煤矸石粉中的可燃性碳组分,在混凝土中,可燃性碳组分为非活性组分,会引起混凝土开裂,本发明通过对煤矸石中的可燃性碳组分进行去除,能够使所得脱碳煤矸石粉烧失量满足混凝土掺合料标准,能够用于代替混凝土中的水泥,从而促进煤矸石的资源化应用,缓解煤矸石粉体过剩的问题,同时,碳煤矸石粉成本低廉,能够降低混凝土的成本。本申请通过控制煤矸石矿浆的浓度为70～90g/L,捕收剂的用量为50～350g/L,能够有效的提高浮选脱碳效果,使脱碳煤矸石粉烧失量满足混凝土掺合料标准。(The invention provides decarburization gangue powder, a preparation method thereof and application of the decarburization gangue powder as a concrete admixture, and belongs to the technical field of building materials. The method adopts a flotation mode, so that the combustible carbon component in the coal gangue powder can be removed, and the combustible carbon component in the concrete is an inactive component which can cause the concrete to crack. This application is through the concentration of control gangue ore pulp for 70 ~ 90g/L, and the quantity of collector is 50 ~ 350g/L, can effectual improvement flotation decarbonization effect, makes decarbonization coal gangue powder ignition loss satisfy concrete admixture standard.)

1. A preparation method of decarburized gangue powder comprises the following steps:

(1) mixing coal gangue powder with water to obtain coal gangue pulp, wherein the concentration of the coal gangue pulp is 70-90 g/L;

(2) mixing the coal gangue pulp with a foaming agent and a collecting agent for flotation, and drying and ball-milling precipitates obtained by flotation in sequence to obtain decarburized coal gangue powder; and taking the volume of the coal gangue pulp as a reference, wherein the using amount of the collecting agent is 50-350 g/L.

2. The method according to claim 1, wherein the gangue powder has a particle size of 0.5mm or less.

3. A method of preparation according to claim 1 wherein the collector is N9858 and/or N9836.

4. A preparation method according to claim 1 or 3, wherein the amount of the collector is 150-300 g/L.

5. The method of claim 1, wherein the foaming agent is a No. 2 oil foaming agent and/or a PAS-12 high efficiency foaming agent.

6. The preparation method of claim 1 or 5, wherein the amount of the foaming agent is 12-15 g/L based on the volume of the coal gangue pulp.

7. The preparation method of claim 1, wherein the rotation speed of the ball mill is 300-360 r/min, and the time is 120-150 min.

8. The decarburized gangue powder prepared by the preparation method according to any one of claims 1 to 7, wherein the ignition loss of the decarburized gangue powder is 4 to 8 wt%.

9. The use of the decarburized gangue powder of claim 8 as an admixture for concrete.

10. The use according to claim 9, wherein the decarburized gangue powder replaces 10 to 40 wt% of cement in the concrete.

Technical Field

The invention relates to the technical field of building materials, in particular to decarburization gangue powder, a preparation method thereof and application of the decarburization gangue powder as a concrete admixture.

Background

The gangue is a mixed rock mass discharged in the process of coal mine shaft building and production, and comprises gangue discharged in the process of coal mine shaft tunneling, gangue stripped in the process of open pit coal mining and gangue discharged in the process of washing and selecting processing. The production amount of the coal gangue accounts for 10-25% of the coal mining amount. Estimated by the waste rock discharge amount accounting for 20% of the raw coal production, more than 2 hundred million tons of newly increased waste rocks are generated every year, and the rest parts are naturally mixed and stored nearby except about 8000 ten thousand tons of comprehensively utilized waste rocks.

Coal gangue becomes an industrial waste which has the largest inventory and annual output and occupies the largest stacking area in China. The gangue piles not only occupy a large amount of land, but also cause serious pollution to underground water around the gangue piles because salts rich in the gangue are leached and dissolved in rainwater to permeate into the underground water due to natural precipitation. And pyrite (FeS) contained in the coal gangue₂) Is easy to be oxidized by air, and the released heat can promote the coal contained in the coal gangue to be weathered to spontaneous combustion, and SO released during spontaneous combustion₂Severely polluting the air.

At present, most of the coal gangue is used for power generation, cement raw fuel, brick making, underground filling, land reclamation, road building and the like, but the total consumption is low and the utilization rate is not high. Because the coal gangue powder has high carbon content and the ignition loss does not meet the concrete admixture standard (the ignition loss is less than 8 percent required by the concrete admixture standard), the coal gangue powder can not be used as the concrete admixture.

Disclosure of Invention

In view of the above, the present invention aims to provide a decarburized coal gangue powder, a preparation method thereof and an application thereof as a concrete admixture. The method provided by the invention can effectively remove the combustible carbon component in the coal gangue powder, and the obtained decarbonized coal gangue powder has low ignition loss and can be used as a concrete admixture.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of decarburized coal gangue powder, which comprises the following steps:

(1) mixing coal gangue powder with water to obtain coal gangue pulp, wherein the concentration of the coal gangue pulp is 70-90 g/L;

(2) mixing the coal gangue pulp with a foaming agent and a collecting agent for flotation, and drying and ball-milling precipitates obtained by flotation in sequence to obtain decarburized coal gangue powder; and taking the volume of the coal gangue pulp as a reference, wherein the using amount of the collecting agent is 50-350 g/L.

Preferably, the particle size of the coal gangue powder is less than or equal to 0.5 mm.

Preferably, the collector is N9858 and/or N9836.

Preferably, the using amount of the collector is 150-300 g/L.

Preferably, the foaming agent is No. 2 oil foaming agent and/or PAS-12 high-efficiency foaming agent.

Preferably, the volume of the coal gangue pulp is taken as a reference, and the amount of the foaming agent is 12-15 g/L.

Preferably, the rotation speed of the ball milling is 300-360 r/min, and the time is 120-150 min.

The invention provides the decarburized gangue powder prepared by the preparation method, wherein the ignition loss of the decarburized gangue powder is 4-8 wt%.

The invention provides application of the decarburized coal gangue powder as a concrete admixture.

Preferably, the decarburized gangue powder replaces 10-40 wt% of cement in the concrete.

The invention provides a preparation method of decarburized coal gangue powder, which comprises the following steps: (1) mixing coal gangue powder with water to obtain coal gangue pulp, wherein the concentration of the coal gangue pulp is 70-90 g/L; (2) mixing the coal gangue pulp with a foaming agent and a collecting agent for flotation, and drying and ball-milling precipitates obtained by flotation in sequence to obtain decarburized coal gangue powder; and taking the volume of the coal gangue pulp as a reference, wherein the using amount of the collecting agent is 50-350 g/L. The method adopts a flotation mode, so that the combustible carbon component in the coal gangue powder can be removed, and the combustible carbon component in the concrete is an inactive component which can cause the concrete to crack. This application is through the concentration of control gangue ore pulp for 70 ~ 90g/L, and the quantity of collector is 50 ~ 350g/L, can effectual improvement flotation decarbonization effect, makes decarbonization coal gangue powder ignition loss satisfy concrete admixture standard.

Meanwhile, the preparation method provided by the invention is simple to operate and suitable for industrial mass production.

Drawings

FIG. 1 is a fitting curve of the ignition loss of the decarburized gangue powder obtained under different ore concentration and different collector usage amounts.

Detailed Description

The invention provides a preparation method of decarburized coal gangue powder, which comprises the following steps:

(1) mixing coal gangue powder with water to obtain coal gangue pulp, wherein the concentration of the coal gangue pulp is 70-90 g/L;

(2) mixing the coal gangue pulp with a foaming agent and a collecting agent for flotation, and drying and ball-milling precipitates obtained by flotation in sequence to obtain decarburized coal gangue powder; and taking the volume of the coal gangue pulp as a reference, wherein the using amount of the collecting agent is 50-350 g/L.

The coal gangue powder is mixed with water to obtain coal gangue pulp, and the coal gangue pulp is obtained. In the present invention, the method for preparing the gangue powder preferably comprises the following steps:

ball milling the coal gangue raw material to obtain coal gangue powder.

In the invention, the particle size of the coal gangue raw material is preferably 5-20 mm, and more preferably 10-15 mm. The invention has no special requirements on the source and the production place of the coal gangue raw material. In the invention, the ignition loss of the coal gangue raw material is preferably 10-30 wt%, and more preferably 15-20 wt%; the calcined coal gangue raw material preferably comprises the following components in percentage by mass: SiO 2₂ 57～60％，Al₂O₃ 25～28％，CaO 6～8％，Fe₂O₃6～7％，K₂1-2% of O and the balance of inevitable impurities.

In the invention, the particle size of the coal gangue powder is preferably less than or equal to 0.5mm, and more preferably 0.2-0.4 mm. The method has no special requirements on the ball milling mode, and the particle size of the coal gangue powder can meet the requirements.

The coal gangue powder is mixed with water to obtain coal gangue pulp, and the concentration of the coal gangue pulp is 70-90 g/L, preferably 75-85 g/L. The invention does not require special means for said mixing, as is known in the art, such as stirring.

After the coal gangue pulp is obtained, the coal gangue pulp, a foaming agent and a collecting agent are mixed for flotation, and precipitates obtained by flotation are sequentially dried and ball-milled to obtain decarburized coal gangue powder. In the invention, the collecting agent is preferably N9858 and/or N9836, and the using amount of the collecting agent is 50-350 g/L, preferably 150-300 g/L, and more preferably 200-250 g/L based on the volume of the coal gangue pulp. As a specific example of the present invention, the collector N9858 was purchased from nalco (china) environmental protection technical service, ltd, and the collector N9836 was purchased from nalco (china) environmental protection technical service, ltd.

In the present invention, the foaming agent is preferably No. 2 oil foaming agent and/or PAS-12 high efficiency foaming agent. In the present invention, the No. 2 oil foaming agent is a complex higher alcohol foaming agent with a chemical formula of ROH (R-alkyl), and as a specific embodiment of the present invention, the No. 2 oil foaming agent is commercially available from Zibo and Polychemist Co., Ltd. As an embodiment of the present invention, the PAS-12 high efficiency foaming agent is available from Naerco (China) environmental protection technical service, Inc.

The present invention preferably uses a flotation machine for said flotation. The present invention has no particular requirement for the specific operation of the flotation, and can be carried out using flotation operations well known to those skilled in the art.

In the present invention, after the flotation, the precipitate obtained by the flotation of the present invention is dried. In the invention, the drying temperature is preferably 80-120 ℃, and more preferably 100 ℃; the time is preferably 18 to 24 hours, and more preferably 20 to 22 hours.

In the invention, the rotation speed of the ball milling is preferably 300-360 r/min, and more preferably 330-350 r/min; the time is preferably 120 to 150min, and more preferably 130 to 140 min. In the invention, the ball-to-material ratio of the ball milling is 10-15: 1, and more preferably 12-14: 1. In the invention, the grain size of the decarbonized gangue powder obtained after ball milling is preferably less than or equal to 45 μm, and more preferably 20-40 μm.

The invention provides the decarburized gangue powder prepared by the preparation method, wherein the ignition loss of the decarburized gangue powder is 4-8 wt%, and preferably 5-6 wt%. In the invention, the density of the decarburized gangue powder is preferably 2.3-2.5 g/cm³The particle size is preferably 45 μm or less, and the specific surface area is preferably 600m or more²The water demand ratio is preferably 100-110%, the activity index of 7d is preferably more than or equal to 70%, and the activity index of 28d is preferably more than or equal to 80%.

The invention provides application of the decarburized coal gangue powder as a concrete admixture. In the invention, the decarburized gangue powder preferably replaces 10-40 wt% of cement in concrete, and more preferably 20-30 wt%. In the invention, when the decarburized coal gangue powder is used as a concrete admixture, 0.6-0.7 ton of the admixture can be prepared from 1 ton of the coal gangue, and the cost of each ton of the admixture is only about 50 yuan.

The decarburized gangue powder and the preparation method thereof and the application thereof as a concrete admixture according to the present invention will be described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.

Example 1

Using particle size<5mm of ground coal gangue particles are used as raw materials, the calcination test is carried out on the raw materials, the calcination temperature is 950 ℃, the time is 20min, the loss on ignition after calcination is 10-30%, and the components after calcination are as follows: SiO 2₂ 58％，Al₂O₃ 27％，CaO 7％，Fe₂O₃6％，K₂O1%, and the balance being other oxides.

The method for preparing the decarburized coal gangue powder by using the coal gangue particles comprises the following steps:

(1) grinding coal gangue particles to be less than 0.5mm in a ball mill, blending into ore pulp with the ore pulp concentration of 70-90 g/L, adding into a flotation machine, wherein the using amount of a foaming agent is 12g/L, and the foaming agent adopts No. 2 oil; the using amount of the collecting agent is 50-300 g/L, and N9858 is used as the collecting agent;

(2) and (3) drying the ore pulp after precipitation, wherein the drying temperature is 100 ℃, the drying time is 24 hours, putting the solid into a ball mill for ball milling, the ball milling speed is 300r/min, the ball-to-material ratio is 10:1, the ball milling time is 120min, and decarburizing the coal gangue powder.

The density of the obtained decarbonized gangue powder is 2.3-2.5 g/cm through detection³The particle size is less than or equal to 45 mu m, and the specific surface area is more than or equal to 600m²The water demand ratio is 100-110%, the activity index of 7d is more than or equal to 70%, and the activity index of 28d is more than or equal to 80%.

The ignition loss of the decarburized gangue powder obtained under different ore concentration and different collecting agent dosage is shown in table 1. The method for testing the ignition loss comprises the steps of taking 1g of coal gangue, igniting the coal gangue in a muffle furnace at 950 ℃ for 20min, taking out the coal gangue, drying the coal gangue to room temperature, and weighing the coal gangue to constant weight for multiple times.

TABLE 1 ignition loss (%)

According to the data in table 1, the ignition loss of the decarburized gangue powder obtained under different ore concentration and different collector usage is plotted, and the obtained fitting curve is shown in fig. 1.

The concrete equation of the fitting curve is as follows:

70g/L：Y＝2.99+0.032x-4.97x²；

80g/L：Y＝2.41+0.031x-4.57x²；

90g/L：Y＝2.12+0.027x-3.04x²；

x is the amount of the collector used (g/L) and Y is the loss on ignition (%).

As can be seen from figure 1, the method can reduce the ignition loss of the gangue powder to be below the standard of the concrete admixture, simultaneously gives a theoretical calculation equation of the decarburization effect, and adjusts the decarburization process parameters according to the properties of different raw materials in the actual production process, so that the ignition loss of the gangue admixture meets the national standard requirement.

Application example

The decarburized coal gangue micropowder prepared in example 1 is mixed with reference cement to prepare C20, C30 and C40 concrete, and the compressive strength of a concrete system is tested. Wherein, the mixing proportion of the C20, the C30 and the C40 concrete is shown in Table 2.

TABLE 2C 20, C30, C40 concrete mixing ratio

Examples of the C20 concrete applications are shown in Table 3.

TABLE 3C 20 concrete application examples

Examples of the C30 concrete applications are shown in Table 4.

TABLE 4C 30 concrete application examples

Examples of the C40 concrete applications are shown in Table 5.

TABLE 5C 40 concrete application examples

According to the data, the decarburized gangue powder provided by the invention is used as an admixture to prepare concrete with different strength grades such as C20-C40, the maximum doping amount of the concrete can reach 40% of the using amount of cement in the concrete, and the prepared concrete can meet the engineering quality requirements when being used for houses, roads, bridge buildings and the like.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.