KR20110117353A - Preparation method for c12a7 mineral using rotary kiln - Google Patents

Abstract

The present invention comprises the steps of mixing a calcium oxide source and an aluminum oxide source to produce a mixture; And the mixture comprising calcined at 900 ~ 1500 ℃ were charged into a rotary kiln; without relates to a method of producing C ₁₂ A ₇ based mineral containing, and energy saving is excellent, the pre-firing to form the pellets C ₁₂ A ₇ By distilling the minerals into the clinker, the existing process is dramatically shortened.

Description

Preparation method of C12A7 mineral using rotary kiln {Preparation method for C12A7 mineral using rotary kiln}

The invention is used to be associated with the production of C ₁₂ A ₇ based mineral, C ₁₂ A ₇ based mineral is iron steel-making flux / sintering aid for, shotcrete cement class approval for such.

CaO-Al ₂ O ₃ -based bicomponent minerals include five compounds of CA ₆ , CA ₂ , CA, C ₁₂ A ₇ and C ₃ A from the Al ₂ O ₃ side. Of these, CA ₆ is not used in cement because it is not reactive with water.

CA ₂ , CA, C ₁₂ A ₇ , and silver are used as constituent minerals in alumina cement.

Among the CaO-Al ₂ O ₃ -based minerals, C ₁₂ A ₇ is mainly used as a flux / sintering aid for steelmaking and cemented cement for shotcrete due to the mineralization characteristics of lower melting point than other minerals and the hydration characteristics which quench when reacted with water. It is used for various purposes. In particular, as shown in FIG. 1, low melting point characteristics are expressed in the range of about 48 to 54% of Al ₂ O ₃ , and when Fe ₂ O ₃ is added, it depends on the content of Fe ₂ O ₃ , as shown in FIG. 2. It can be seen that the melting point of the C ₁₂ A ₇ mineral is further lowered to 1335 ℃. Therefore, the amount of heat of melting required for the manufacture of conventional C ₁₂ A ₇ minerals is reduced, thereby ensuring economic feasibility.

Meanwhile, in Korean Patent No. 0464184, CaO raw material and Al ₂ O ₃ raw material are mixed, and the mixture is melted in an electric furnace and then 10 to 50 kg / in the high pressure air stream sprayed at a pressure of 3 to 10 kgf / cm ² from a rotary cooler. Aqueous C ₁₂ A ₇ beads prepared by spraying min water together to form a glassy phase of 10 mm or less are pulverized to have a specific surface area of 5000 cm ² / g or more as a ble inch. _Although a representative method for producing ₁₂ A ₇ is disclosed, this has a problem of raising the temperature to the melting temperature, and also requires a large amount of cooling water in the cooling process.

In addition, Korean Patent No. 0937399 pulverizes and mixes a lime source and an alumina source, and then prepares pellets and heats them at 1000 ° C. or higher. Although a method of manufacturing a clinker is disclosed, a process for preparing pellets is included in advance, and there is a disadvantage in that baking is performed two or more times.

In addition, Japanese flux products (product name Calsip et al.-manufactured by Yabashi 石灰 工業 株 式 會, etc.) are eco-friendly because they do not contain fluorite, but they have the disadvantage of being molded into pellets. The rate of dephosphorization is known to be slow.

However, C ₁₂ A ₇ based mineral, so is characterized to be generated from a temperature lower than the melting temperature of the CaO source and the Al ₂ O ₃ source, depending on the generating conditions usually begins to produce at about 900 ℃, CaO source and the Al ₂ By firing using a rotary kiln without melting the O ₃ source, it is possible to complete the production method of the present invention with excellent energy saving and low carbon dioxide generation.

An object of the present invention is to provide a method for producing a C ₁₂ A ₇ -based mineral, which is more energy-saving than the melting method and generates a small amount of carbon dioxide.

Method for producing a C ₁₂ A ₇ mineral of the present invention comprises the steps of mixing a calcium oxide (CaO) source and aluminum oxide (Al ₂ O ₃ ) source to prepare a mixture; And putting the mixture into a rotary kiln and baking at 900 to 1500 ° C.

The method for producing C ₁₂ A ₇ mineral of the present invention is characterized in that the source of calcium oxide (CaO) is at least one selected from the group consisting of limestone, quicklime, hydrated lime, marble, nitrite, and waste lime.

The method for producing C ₁₂ A ₇ mineral of the present invention is characterized in that the aluminum oxide (Al ₂ O ₃ ) source is at least one selected from the group consisting of bauxite, aluminum hydroxide, aluminum dross and refined spent catalyst.

Method for producing a C ₁₂ A ₇ mineral of the present invention is characterized in that it further comprises a slag of the steelmaking and steelmaking process in the mixture.

In the method for producing C ₁₂ A ₇ mineral of the present invention, 1 to 50 parts by weight of slag of the steelmaking and steelmaking process is mixed with 100 parts by weight of the mixture of the calcium oxide (CaO) source and the aluminum oxide (Al ₂ O ₃ ) source. It is characterized by.

Method for producing a C ₁₂ A ₇ mineral of the present invention is characterized in that the firing temperature of the firing step is 1150 ~ 1350 ℃.

Method for producing a C ₁₂ A ₇ -based mineral of the present invention is characterized in that the C ₁₂ A ₇ -based mineral is a solid clinker.

The present invention does not melt the calcium oxide (CaO) source and aluminum oxide (Al ₂ O ₃ ) source for the production of C ₁₂ A ₇ minerals, so the energy saving is excellent, cement using a rotary kiln without the formation of pellets before firing By using a kiln to provide a method for producing C ₁₂ A ₇ -based minerals by clinker, the existing process is greatly shortened.

1 shows a eutectic state diagram of 12CaO 7Al ₂ O ₃ in the atmospheric state.
2 is a graph showing a state diagram of CaO-C ₁₂ A ₇ -C ₂ F system.
Figure 3 shows the X-ray diffraction pattern of the refined slag.
Figure 4 shows the X-ray diffraction pattern of the 1200 ℃ baked product of Example 1.
Figure 5 shows the X-ray diffraction pattern of the calcined product of Example 1250 ℃.
Figure 6 shows the X-ray diffraction pattern of the fired 1300 ° C of Example 1.
FIG. 7 shows the X-ray diffraction pattern of the 1350 ° C. calcined product of Example 1. FIG.
8 is a photograph of a 1200 ° C. fired product of Example 1. FIG.
9 is a photograph of a 1250 ° C. fired product of Example 1. FIG.
10 is a photograph of a 1350 ° C. fired product of Example 1. FIG.
FIG. 11 shows the X-ray diffraction pattern of the fired product to which the refined slag of Example 2 was added 10%.
12 shows the X-ray diffraction pattern of the fired product to which the refined slag of Example 2 was added 20%.
FIG. 13 shows an X-ray diffraction pattern of a fired product to which refined slag of Example 2 is added 30%.
14 is a photograph of a fired product to which 10% refined slag of Example 2 is added.
15 is a photograph of a fired product to which the refining slag of Example 2 is added 20%.
16 is a photograph of a fired product to which the refined slag of Example 2 is added 30%.
17 is a photograph of a fired product to which the refined slag of Example 3 is added 30%.
18 shows the X-ray diffraction pattern of the fired product to which the refined slag of Example 3 was added 30%.
19 is a photograph of a fired product to which refined slag of Example 3 is added 40%.
20 is a photograph of a fired product to which refined slag of Example 3 is added 50%.
21 shows the X-ray diffraction pattern of the fired product to which the refined slag of Example 3 was added 40%.
22 shows the X-ray diffraction pattern of the fired product to which the refined slag of Example 3 was added 50%.
Fig. 23 shows the X-ray diffraction analysis pattern when 50% of the refined slag of Example 4 was added and calcined at 1150 ° C.

Method for producing a C ₁₂ A ₇ mineral of the present invention comprises the steps of mixing a calcium oxide (CaO) source and aluminum oxide (Al ₂ O ₃ ) source to prepare a mixture; And putting the mixture into a rotary kiln and baking at 900 to 1500 ° C .;

The calcium oxide (CaO) source of the present invention can be used as, but not limited to, all industrial by-products based on calcium oxide, such as limestone, quicklime, hydrated lime, marble, niche or waste lime.

As the aluminum oxide (Al ₂ O ₃ ) source of the present invention, materials containing aluminum oxide as the main component such as bauxite and aluminum hydroxide, and all industrial by-products containing aluminum oxide as the main mineral such as aluminum dross and refined waste catalyst can be used. However, it is not limited thereto.

First, a calcium oxide source and an aluminum oxide source, which are starting materials, are ground and mixed or ground after mixing to an average particle size of 0.01 to 1 mm. The mixing ratio is 40:60 to 60:40 in the weight ratio of calcium oxide (CaO) and aluminum oxide (Al ₂ O ₃ ), preferably in the molar ratio of 1: 0.4 to 0.8, and more preferably in the molar ratio of 1: 0.5. To 0.7, most preferably 12: 7.

In the present invention, in order to increase the production of C ₁₂ A ₇ minerals, refining slag, blast furnace slag, etc., slag generated as waste in the steelmaking and steelmaking processes, which are main components, may be used. Preferably, refining slag whose main component is a C ₁₂ A ₇ -based mineral is used. The slag of the steelmaking and steelmaking processes is mixed in an amount of 1 to 50 parts by weight based on 100 parts by weight of a mixture of a calcium oxide (CaO) source and an aluminum oxide (Al ₂ O ₃ ) source.

Calcium (CaO) source and an aluminum oxide (Al ₂ O ₃₎ mixture of the source begins to generate the C ₁₂ A ₇ based mineral at above 900 ℃ in the rotary kiln, and, C ₁₂ from above 1000 ℃ A ₇ based mineral As the formation of more increases, the C ₁₂ A ₇ -based mineral is mainly produced at 1230 ° C or higher. The solid clinker is also formed at 1350 ° C. or lower, preferably 1300 ° C. or lower, and more preferably 1280 ° C. or lower.

When the slag of the steelmaking and steelmaking process is added to a mixture of a calcium oxide (CaO) source and an aluminum oxide (Al ₂ O ₃ ) source, C ₁₂ A ₇ minerals are produced at lower temperatures as the amount of added slag increases. At 1200 ° C or higher, the main product mineral is a C ₁₂ A ₇ -based mineral. In addition, when 1 to 25 parts by weight of the slag of the steelmaking and steelmaking process is added to 100 parts by weight of the mixture of a calcium oxide (CaO) source and an aluminum oxide (Al ₂ O ₃ ) source, clinker is formed at 1300 ° C. or less. When added to 35 parts by weight to form a clinker at 1275 ℃ or less, when added to 35 to 50 parts by weight to form a clinker at 1250 ℃ or less.

Hereinafter, the present invention will be described in detail by way of examples. However, the following examples are merely to illustrate the present invention, but the content of the present invention is not limited thereto.

Limestone (CaO content 49.5 wt%) was used as a calcium oxide (CaO) source, and bauxite (85.6 wt% Al ₂ O ₃ content) was used as aluminum oxide (Al ₂ O ₃ ). In addition, in order to increase the production of C ₁₂ A ₇ minerals were refined slag (CaO content 50.0% by weight, Al ₂ O ₃ content 36.3% by weight) was mixed and fired. Figure 3 shows the XRD pattern of the refining slag, the refining slag was confirmed that the C ₁₂ A ₇ mineral is the main component.

Example 1

Limestone and bauxite were mixed by controlling the CaO content of the mixture to 40 to 60 wt% and the Al ₂ O ₃ content to 40 to 60 wt%. The mixture was pulverized so that 90 µm residues were around 10%. The mixture was then calcined in rotary kilns for 30 minutes at firing temperatures 1200, 1250, 1300, and 1350 ° C.

4 is an X-ray diffraction pattern of a fired product at 1200 ° C., FIG. 5 is an X-ray diffraction pattern of a fired product at 1250 ° C., FIG. 6 is an X-ray diffraction pattern of a fired product at 1300 ° C., and FIG. Each of the patterns is shown. FIG. 8 is a photograph of a 1200 ° C. calcined product, FIG. 9 is a photograph of a 1250 ° C. calcined product, and FIG. 10 is a photograph of a 1350 ° C. calcined product, respectively.

As shown in FIG. 4, it was confirmed that some C ₁₂ A ₇ -based minerals were formed even at 1200 ° C., and from 1250 ° C. of FIG. 5, the main minerals were C ₁₂ A ₇ -based minerals. It was confirmed that C ₁₂ A ₇ -based minerals were produced even at ℃.

It was confirmed that the calcined product was released in the form of unmelted clinker in the rotary kiln up to a calcination temperature of 1250 ° C. (FIGS. 8 and 9), and was completely melted at 1300 ° C. (FIG. 10).

Example 2

Limestone and bauxite were mixed under controlled CaO content of 40-60% and Al ₂ O ₃ content of 40-60%. Then, refined slag was added to 10, 20, 30% of the mixture based on foreign soil. After mixing again, the mixture was pulverized such that 90 µm residue was around 10%. The mixture was pulverized so that 90 µm residues were around 10%. The mixture was then calcined for 30 minutes at a sintering temperature of 1300 ° C. in a rotary kiln.

It can be seen that when the refining slag is added at 10% and 20% under firing conditions at 1300 ° C., C ₁₂ A ₇ minerals are produced (FIGS. 11 and 12), and C ₁₂ A ₇ minerals are produced even when 30% is added. It could be confirmed (Fig. 13). The big difference between the molten and unmelted clinker states is that the intensity of C ₁₂ A ₇ -based mineral peaks around 18 degrees is observed higher in the melt. But no big difference was found.

In addition, at 1300 ° C. firing conditions, when 30% of the refined slag is added, it exists in a molten state (FIG. 16), but less than 30% of 10% and 20% added are present in a complete clinker state (FIGS. 14 and 15). Therefore, it was confirmed that C ₁₂ A ₇ minerals were produced well in the three-component system calcined by adding refined slag to limestone and bauxite.

Example 3

The firing temperature of the three-component (limestone, bauxite, and scouring slag) mixture was tested at 1275 ° C. This lowers the firing temperature to produce no molten phase, i.e. a solid clinker. At this time, whether or not C ₁₂ A ₇ mineral is produced is examined. In addition, the content of refined slag was increased by 40% and 50%.

When 30% of the refined slag was added, melting was not observed when the firing temperature was lowered to 1275 ° C. (FIG. 17), and C ₁₂ A ₇ -based minerals were excellently produced (FIG. 18). In other words, when the firing temperature is lowered, C ₁₂ A ₇ -based minerals can be produced without the formation of a molten phase.

This has the advantage that the firing temperature can be lowered, and thus may be accompanied by a reduction in input fuel.

When 40% and 50% of the content of refined slag was added, some molten and total molten phases were observed (FIGS. 19 and 20). It is also assumed that if the firing temperature is lowered, C ₁₂ A ₇ -based minerals will be produced.

Example 4

When 50% of refined slag is added in a mixture of three-component (limestone, bauxite, and refined slag) and calcined at 1150 ° C., minerals having different C ₁₂ A ₇ minerals as shown in the X-ray diffraction pattern as shown in FIG. 23. It is also because we can confirm that it exists together with.

Claims (7)

Mixing a calcium oxide (CaO) source with an aluminum oxide (Al ₂ O ₃ ) source to produce a mixture; The method of C ₁₂ A ₇ based mineral containing; and the step of putting the mixture into a rotary kiln (rotary kiln) and baked at 900 ~ 1500 ℃.
The method of claim 1 wherein the production of C ₁₂ A ₇ based mineral, characterized in that the calcium oxide (CaO) oxide source is at least one selected from limestone, quick lime, slaked lime, marble, you dilution, and the group consisting of tailings circuit.
The method of claim 1, wherein the aluminum oxide (Al ₂ O ₃₎ source of the bauxite, process for producing aluminum hydroxide, aluminum dross and C ₁₂ A ₇ based mineral, characterized in that at least one selected from the group consisting of essential oils Catalyst .
Wherein the first to third according to any one of items, C ₁₂ A method of producing a mineral-based ₇ further comprising a slag of iron and steel making process to the mixture.
5. The method of claim 4, C _12, characterized in that the slag of iron and steel making process with respect to the mixture of 100 parts by weight of the calcium oxide (CaO) source with a source of aluminum oxide (Al ₂ O ₃₎ 1 to 50 parts by weight of mixture A ₇ Method for producing minerals.
The method of claim 5, wherein the firing temperature of the firing step is 1150 ~ 1350 ℃ characterized in that the manufacturing method of C ₁₂ A ₇ mineral.
The method of claim 6, wherein the C ₁₂ A ₇ The method of producing a mineral-based C ₁₂ A ₇ based mineral, characterized in that the solid phase of the clinker.

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