KR101964794B1 - Red mud composition for efflorescence reduction - Google Patents

Abstract

The present invention relates to a red mud composition for efflorescence reduction to reduce efflorescence of red mud. More specifically, the present invention relates to a red mud composition for reducing efflorescence occurring when red mud is applied to various fields such as a flooring material, a building material, a road pavement or a block, etc.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a red mud composition for reducing bleaching,

The present invention relates to a red mud composition for reducing the whitening phenomenon for reducing whitening of red mud. More specifically, the present invention relates to a red mud composition for improving the whitening phenomenon occurring when red mud is applied to various fields such as flooring, building materials, road pavement or block.

Red mud is an industrial by-product generated in the process of producing aluminum hydroxide (Al (OH) ₃ ) and aluminum oxide (Al ₂ O ₃ ) from bauxite raw mineral. In Korea, aluminum hydroxide is extracted by the Bayer method, that is, by extracting aluminum hydroxide by adding sodium hydroxide to a raw mineral having a large amount of alumina, and the remaining sludge is called a red mud. Called scarlet clay, and is discharged in a sludge state of high viscosity having a water content of usually about 30 to 50 wt%.

Most red mud chemical composition is SiO ₂ , Al ₂ O _3, and Fe ₂ O ₃ , and red ocher similar to yellow ocher is expressed due to Fe ₂ O ₃ , and is commonly referred to as red mud. And about 10.0% of Na ₂ O which acts as a cause of white pigmentation. This is because sodium hydroxide (NaOH) is used as an extract in the process of extracting aluminum from the ore of bauxite, so that the unrecovered sodium hydroxide solution is present in a large amount in the residue redmud. As a result, the pH of the redmud is 11.0 .

Red mud is producing more than 120 million tons of sludge annually and more than 40 million tons of dry powder in the world, and the amount is increasing every year. Domestic sludge red mud is emitted at an annual output of 200,000 tons, but there is no way to treat red mud itself, so it is not only limited to building materials, but also there is no fundamental treatment. Especially, the place of loading red mud around the world is not enough, and leaking water leaks cause environmental problems such as damage to nearby crops and human life. Therefore, the treatment of red mud sludge is urgent, and research for reducing the whitening phenomenon occurring when applying to construction materials is urgent.

In Korean Patent Laid-Open Publication No. 10-2018-0084218 (Aug. 20, 2018), there has been a study to improve the waterproofing property of cement pigment including coconut oil to suppress whitening phenomenon. However, since it contains oil, there is a disadvantage that oil may migrate to the surface and stickiness may occur on the surface.

Korean Patent Laid-Open Publication No. 10-2018-0084218 (Aug. 25, 2018)

It is an object of the present invention to provide a new white light reducing agent for reducing the whitening phenomenon of red mud.

Also, it is an object of the present invention to provide a new whiteness reducing agent which does not cause surface migration such as oil and does not affect the strength change upon construction with the building material.

Also, it is an object of the present invention to provide a red mud composition for reducing the whitening phenomenon, which can be manufactured in various forms such as liquid sludge, powdery form, and granular form, and which is easy to apply to construction materials and the like.

One aspect of the present invention for achieving the above object is to provide a red mud composition for reducing bleaching, comprising a bleaching agent and red mud which are selected from coffee grounds and ground coffee beans or a mixture thereof.

One aspect of the present invention also provides a construction material selected from flooring, building materials, road pavements and blocks comprising a red mud composition for reducing bleaching.

The red mud composition of the present invention has the effect of significantly reducing whitening of red mud without lowering the strength of the applied body.

1 is a photograph showing a red mud block in which whitening has occurred.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described more fully hereinafter with reference to the accompanying drawings, It should be understood, however, that the invention is not limited thereto and that various changes and modifications may be made without departing from the spirit and scope of the invention.

Unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention is merely intended to effectively describe a specific embodiment and is not intended to limit the invention.

Also, the singular forms as used in the specification and the appended claims are intended to include the plural forms as well, unless the context clearly indicates otherwise.

One aspect of the present invention provides a red mud composition for reducing bleaching, comprising a bleaching agent and red mud which are either selected from coffee grounds and ground coffee beans or a mixture thereof.

The red mud composition may be powder, granule or liquid sludge, but is not limited thereto.

The whitening agent may be contained in an amount of 0.1 to 60% by weight, based on the solid content in the composition, but is not limited thereto.

The coffee grounds may be obtained by extracting coffee from ground coffee beans and then drying the remaining coffee grounds.

The coffee grounds may be those obtained by baking after drying.

The red mud composition for reducing bleaching can be used for flooring, building material, road pavement or block.

Another aspect of the present invention provides a construction material selected from a flooring material, a building material, a road pavement, and a block including the red mud composition for reducing the whitening phenomenon.

Another embodiment of the present invention provides a method for reducing bleaching of red mud by adding the red mud composition for reducing bleaching phenomenon to a construction material.

The inventors of the present invention have studied to reduce whitening phenomenon of red mud. As a result, it has been surprisingly found that the whitening phenomenon is improved by mixing any one selected from coffee grounds and pulverized coffee beans or a mixture thereof, Thereby completing the invention. Further, the present inventors have found that the addition of any one selected from coffee grounds and ground coffee beans or a mixture thereof does not cause whitening phenomenon as well as strength deterioration, thereby completing the present invention.

In one embodiment of the present invention, the red mud composition for reducing whitening may include a whitening reducing agent which is red mud, a coffee grounds, and any one selected from ground coffee beans or a mixture thereof. In addition, if necessary, it may further comprise, as an additive, any one or a mixture of two or more selected from water, an emulsifier, an antifoaming agent, a thickener, a suspending agent, a dispersant, an excipient and a solubilizing agent.

In one embodiment of the present invention, the red mud composition may be powder, granule or liquid sludge, and its form is not limited.

Red mud is usually obtained as an industrial by-product in the process of producing aluminum hydroxide (Al (OH) ₃ ) and aluminum oxide (Al ₂ O ₃ ) from boric acid ore and has a stickiness of 30 to 50 wt% Sludge. Therefore, in the case of using without any pretreatment such as drying, it may be made of a liquid slurry.

Further, water may be further added to adjust the viscosity of the liquid slurry as required. In order to improve the dispersibility and stability of dispersion, an emulsifier, a defoaming agent, a thickener, a suspending agent, a dispersant And solubilizing agents, and the like.

In addition, the sludge-state red mud may be dried and used in powder form, in which case a red mud composition in powder or granules may be provided. The granules may further contain additional excipients for the preparation thereof, but the present invention is not limited thereto.

In one aspect of the present invention, the whitening agent may be any one selected from coffee grounds and ground coffee beans, or a mixture thereof. The inventors of the present invention have found that when the liquid coffee is used, the whitening effect can not be achieved, but when the liquid coffee is extracted and the remaining coffee ground is added, the whitening phenomenon is improved and the present invention is completed .

More specifically, the coffee grounds are obtained by extracting coffee from the ground coffee beans and then drying the remaining coffee grounds. In addition, it is possible to use ground coffee beans. On the other hand, it is confirmed that the improvement of whitening phenomenon is further improved when the coffee grounds obtained by drying the coffee residue after extracting coffee from the ground coffee beans are used.

The drying is performed to remove the moisture of the coffee residue remaining after extracting the coffee. The drying is preferably performed at a temperature of 20 to 100 캜, though it is not limited, and it is preferable to dry until the moisture content becomes less than 10%. The effect of reducing bleaching can be further increased by drying until the water content becomes less than 10% as compared with the presence of water.

Further, by performing the baking after drying the above-mentioned coffee grounds, the effect of reducing the whitening can be improved, the degree of powdering can be increased, the addition amount can be further increased, and the strength of the applied product can be prevented from decreasing .

The firing may be performed at a temperature of 200 to 700 ° C, more specifically, 300 to 500 ° C. It may also be carried out for 1 to 10 hours, more particularly for 2 to 8 hours.

The content of the whitening reducing agent is preferably within a range that does not impair the inherent physical properties of red mud, and the content thereof is not limited. Specifically, for example, the content of the whitening reducing agent is 0.1 to 60 wt% In the range of 1 to 50% by weight, more specifically 5 to 40% by weight, based on the total weight of the red mud, The whitening phenomenon reduction effect can be achieved.

In one embodiment of the present invention, the red mud composition for reducing the whitening phenomenon can be used as a construction material such as a block after molding, drying or sintering itself.

Alternatively, the red mud composition for reducing the whitening phenomenon may be mixed with a cement composition, a concrete composition or the like to be applied to a flooring, a building material, a road pavement, and the like.

At this time, the content of the red mud composition for reducing bleaching phenomenon when mixed with the cement composition, concrete composition and the like is not limited, but it can be used in the range of 10 to 500 kg / m < 3 & It is preferable because it can satisfy the physical properties such as the strength of the sieve.

The red mud composition for reducing the whitening phenomenon according to an embodiment of the present invention has the effect of preventing environmental pollution by making red mud that is an industrial by-product applicable to various fields, and by improving the whitening phenomenon, It is possible to apply the present invention to an application.

Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the following examples and comparative examples are merely examples for explaining the present invention in more detail, and the present invention is not limited by the following examples and comparative examples.

1) Bleaching test

The specimens of 5 × 5 × 5 cm were prepared and cured for 28 days at a temperature of 20 ° C. and a relative humidity of 60%. After curing for 28 days, the side of the specimen was sealed with paraffin and immersed in distilled water for 14 days in a constant temperature and humidity chamber at 7 ℃ and 50% relative humidity.

The whitening area was photographed after 14 days immersion in the thermo-hygrostat, and the whitening area was calculated and quantified using the 'paintnet' program. Fig. 1 is a photograph of a specimen in which whitening occurred.

As shown in Table 1 below, the whitening grades are classified into five grades according to whitening area.

White flag grade Percentage of whitening area Ⅰ No occurrence Ⅱ Less than 10% Ⅲ Less than 10% ~ 30% IV 30% to less than 50% V More than 50%

2) Compressive strength

The compressive strength was measured at 28 days according to KS L 5105. The unit is MPa

The red mud sludge used in Examples and Comparative Examples was generated from KC Co., Ltd. located in Daebul Industrial Complex, Yeongam-gun, Jeonnam, and the composition table thereof is shown in Table 2 below. The water content was 50% by weight and the pH was 11.

ingredient Content (wt%) SiO ₂ 38.8 Al ₂ O ₃ 16.1 Fe ₂ O ₃ 22.8 Na ₂ O 10.0 CaO 3.4 Other 8.9

The coffee grounds were obtained by pulverizing coffee beans, extracting the liquid coffee, and drying the remaining residue at 50 DEG C for 24 hours.

The fired coffee grounds were obtained by firing the coffee grounds obtained at the above-mentioned temperature for 3 hours at 400 ° C.

[Example 1]

90% by weight of Red Mud sludge shown in Table 1, 9% by weight of water and 1% by weight of coffee grounds were homogenized using a homogenizer at 4000 rpm for 10 minutes to prepare a redmud composition in a liquid slurry state.

10 parts by weight of the prepared red mud composition, 100 parts by weight of fine aggregate and 50 parts by weight of mixed water were blended with 100 parts by weight of cement to prepare a mortar specimen molded into a block form. At this time, folklore cement was usually used for cement, standard yarn for fine aggregate was used, and water for mixing was used.

The whitening grade and compressive strength of the prepared specimens were measured and are shown in Table 3 below.

[Example 2]

A specimen was prepared in the same manner as in Example 1 except that 81% by weight of red mud sludge, 9% by weight of water and 10% by weight of coffee residue were used in Example 1.

The whitening grade and compressive strength of the prepared specimens were measured and are shown in Table 3 below.

[Example 3]

A specimen was prepared in the same manner as in Example 2 except that 20 parts by weight of the red mud composition was used in Example 2.

The whitening grade and compressive strength of the prepared specimens were measured and are shown in Table 3 below.

[Example 4]

A specimen was prepared in the same manner as in Example 1 except that fired coffee grounds were used in place of the coffee grounds in Example 1.

The whitening grade and compressive strength of the prepared specimens were measured and are shown in Table 3 below.

[Example 5]

A specimen was prepared in the same manner as in Example 2 except that fired coffee grounds were used in place of the coffee grounds in Example 2.

The whitening grade and compressive strength of the prepared specimens were measured and are shown in Table 3 below.

[Example 6]

A specimen was prepared in the same manner as in Example 3, except that the fired coffee grounds were used in place of the coffee grounds in Example 3.

The whitening grade and compressive strength of the prepared specimens were measured and are shown in Table 3 below.

[Comparative Example 1]

With respect to 100 parts by weight of Red Mud sludge in Table 1, 15 parts by weight of water was homogenized by stirring using a homogenizer at 4000 rpm for 10 minutes.

The specimens were prepared in the same manner as in Example 1, and the degree of whitening and the compressive strength of the specimens were measured and shown in Table 3 below.

White flag grade Compressive strength (MPa) Example 1 Ⅲ 24.1 Example 2 Ⅱ 23.7 Example 3 Ⅰ 22.1 Example 4 Ⅰ 24.5 Example 5 Ⅰ 25.4 Example 6 Ⅰ 24.0 Comparative Example 1 V 24.5

As shown in FIG. 1, it was found that the test piece according to Comparative Example 1 was severely whitened, but the whitening phenomenon was reduced in Examples 1 to 6.

In Examples 1 to 3, the whitening phenomenon was reduced as the content of the coffee grounds was increased, but the compressive strength was slightly lower than that of Comparative Example 1.

However, as shown in Examples 4 to 6, it was confirmed that when the fired coffee residue was used, the compressive strength was maintained even though the whitening phenomenon reduction effect was excellent as the content increased.

Claims (8)

A red mud composition for reducing whitening phenomenon, comprising a whitening reducing agent and red mud obtained by extracting coffee from a ground coffee bean and then drying and firing the remaining coffee grounds. The method according to claim 1,
Wherein the red mud composition is a powder, granule or liquid sludge. The method according to claim 1,
Wherein the whitening reducing agent comprises 0.1 to 60% by weight of the solid content in the composition. delete delete The red mud composition for reducing bleaching of any one of claims 1 to 3 is used for flooring, timber, road pavement or block. A construction material selected from a flooring, building material, road pavement and block comprising a red mud composition for reducing bleaching of any one of claims 1 to 3. A method for reducing whitening of red mud by adding a red mud composition for reducing bleaching of any one of claims 1 to 3 to a construction material.

Images