KR800001054B1 - Method for the manufacture of light aggregate from coal mine muck - Google Patents

Abstract

Method for excluding the partial combustibles in the coal refuse as the high temp. oxidizes the crushed refuse of -0.5mm in size of the coal preparation. After mixing and moulding the crushed shale of -0.5 mm in size and refuse with each other at the ratio of 80:20 or 70:30, the light aggregate is dried and put in the roaster of deoxidizing atmosphere at the 1000≰C, and is produced by sintering for 10-15 min, after heating to 1200≰C(at 8-13≰C/min). By this method is added to the shale at the radio of 20-39%.

Description

Manufacturing method of lightweight aggregate using coal mine waste

The present invention removes some of the combustible components contained in the waste-rock by subjecting it to high-temperature oxidation of the waste-rock, which has been pulverized to a particle size of 0.5 mm or less after coal briquettes, and then pulverized to a particle size of 0.5 mm or less. Mixed red spot shell with waste rock at 80:20 or 70:30, granulated and dried, put into a furnace of reducing atmosphere of 1000 ℃ and heating rate is 8 ~ 13 In the manufacturing process by heating up to 1200 ℃ at 10 ℃ / min and firing for 10 to 15 minutes, the method of producing aggregate using coal mine waste-rock is characterized by adding 20-30% by weight of red spot shell as solvent and blowing agent. It is about.

Recently, various kinds of artificial lightweight aggregates are known as the weight of the structure is required due to the high and large structures of the building. However, the conventional artificial lightweight aggregates are mostly added to various types of fluxes and foaming agents to expandable clay, expandable shale and other raw materials at high temperature. This lightweight aggregate is made by plastic manufacturing, and the lightweight aggregate has a porous surface, so it has high absorbency, which makes it difficult to determine the capacity ratio between cement and water in concrete construction. Too light, deteriorated strength, of course, there was a difficult problem in concrete construction.

The present invention is used for mining in coal mines without the use of expensive foaming agents or melters by using a waste coal mine that has been calculated in large quantities in the coal mines, giving problems such as difficulty in disposal place and high disposal cost. It is possible to manufacture high-quality foam lightweight aggregates more economically than the conventional one by adding reddish shell (shale), which is discarded at the time of output, to be useful as a lightweight aggregate suitable for construction of high-rise large-scale buildings. When the present invention will be described in detail as to enable the advantage of one stone two trillion to reduce the waste-rock treatment cost and remove the mineral sea by utilizing the simultaneous coal mine waste-rock.

When coal is mined, it is inevitably mined with coal, and then the waste stone discarded for beneficiation is crushed to a particle size of 0.5mm or less and air oxidized at 600 to 800 ° C for 1 to 1 hour and 30 minutes, which is unnecessary for the production of lightweight aggregate. When combustible components are removed in advance and excavated from coal mines as a flux and blowing agent, the ground waste shells which are discarded to a particle size of 0.5 mm or less are mixed in a weight ratio of 80:20 or 70:30, and then an appropriate amount of water is added. As a granulator, it is manufactured into particles having a particle size of 20 mm or less, and then dried in a drying furnace maintained at about 110 ° C. for 1 to 2 hours, and then placed in a reducing atmosphere furnace maintained at about 1000 ° C. for a temperature increase rate of 8∼. After heating up to 1200 degreeC at 13 degreeC / min, heat-processing for about 10 to 15 minutes, it is left to cool, it is screened, and the lightweight aggregate of this invention is obtained.

In the production of the present invention, the foaming action of the aggregate is due to the reaction characteristics at high temperatures of the carbon powder and various minerals contained in the waste-rock, but the foaming action is strongly related to the atmosphere in the furnace during firing and especially the rate of temperature rise.

That is, there example carbon in the form of inorganic and organic matter in the muck the Fe ₂ O ₃ contained in the inorganic form of pyrolysis and to promote the foaming sikieo generate CO ₂ gas of carbon in organic form tailings as Fe ₃ O ₄ to Fe It serves to reduce the CO ₂ gas generated at this time to encourage the foaming action.

The mineral components contained in the waste-rock are shown in Table 1.

TABLE 1

Among the components contained in the waste-rock, foaming is promoted by basic components such as Fe ₂ O ₃ , CaO and MgO, and components which lower the melting temperature are Na ₂ O, K ₂ O and Fe ₂ O ₃ .

Iron contained in the waste-rock is present in a divalent or trivalent state. Iron-containing minerals are brown iron, hematite, rhomborite and iron sulfide. These iron oxides react with oxygen and carbonic acid in a high temperature reducing atmosphere as follows. As a source of gas and foaming, the iron ore (FeCO ₃ ) is ferrous oxide to produce carbon dioxide gas, and iron sulfide to foam by generating SO ₂ gas.

On the other hand, CaO and MgO exist mainly in the form of Calcite and dolomite, so they decompose at high temperature and generate carbon dioxide gas to encourage foaming.

In the present invention, reducing the firing atmosphere promotes the generation of gas, as well as reducing the ferric oxide to ferrous oxide when firing in the reducing atmosphere, thereby significantly reducing the melting temperature of 2FeO and SiO _2. This has the advantage of lowering the firing temperature. The reaction that takes place inside the furnace when firing waste-rock proceeds in the following order.

That is, 1) water removal 2) combustion of organic materials 3) decomposition of composition 4) interaction between minerals of each component 5) redox reaction.

Therefore, when the heating rate is increased, the reaction of each of these steps becomes more closely, and there is an advantage in that some of the processes are overlapped to lower the foaming and firing temperature.

However, if the heating rate is too fast, the gas is generated so rapidly that it cannot be trapped inside the aggregate, which leads to cracks. Aggregate surfaces may crack, and when sequenced, gas is generated before the aggregate surface becomes vitrified and gas is not trapped inside the aggregate. It does not become an expandable aggregate, and therefore, the heating rate is about 8 to 13 ° C / min of the present invention.

In the present invention, the addition of the red spot shell is most important for the production of light weight aggregates. In the firing process of the raw materials, the surface is vitrified at a predetermined temperature and at the same time, gas is generated inside, so that the generated gas is trapped inside the aggregate and is dense. It should be lightened by giving porosity.

Generally, the components contributing to the vitrification of the surface are Fe ₂ O ₃ CaO and R ₂ O, and the components generating gas (encouraging foaming) are CaCO ₃ , MgCO ₃ , Fe ₂ O ₃ , Fe ₃ O ₄ , FeS ₂ hydrous silicates and organics.

However, in the coal waste-rock, Fe ₂ O ₃ , CaO and R ₂ O components are less than the content necessary for the production of lightweight aggregate. If the plastic is processed as it is, the gas is generated and sunrise before the surface of the aggregate is vitrified and gas is not captured in the aggregate. Light weight is not achieved.

To compensate for this drawback, components of Fe ₂ O ₃ , CaO and R ₂ O must be supplemented. In this case, the addition of the red spot shell (part of the excavated waste-rock to coal mine) is similar to Kaolin in the red spot shell, but Sericite, which contains a large amount of alkali metals, is a main component, which is insufficient in the coal waste-rock, that is, Fe ₂ O ₃ , CaO, R ₂ By adding 20-30% of red spot shell to replenish O and hydrous silicate, it increases the expansion and foaming of raw materials, lowers the firing temperature, and increases the strength of the assembled aggregate (Green Pellet) to easily light weight aggregate from crushed coal. It can be manufactured.

Table 2 shows the specific gravity and absorption of the punctate shell and waste-rock.

TABLE 2

In addition, the use of waste-rock has the advantage that the problem of waste-rock treatment and treatment plant in the coal mine is solved, and the lightweight aggregate of the present invention is a foamed lightweight aggregate, but the absorption is less easy to combine cement and easy to set the mixing ratio of water and cement, etc. It can be usefully provided to build a more rigid structure.

EXAMPLE

The mixture of granules and shells as a flux and foaming agent is mixed with 25% by weight of coal, and then put into a reducing atmosphere furnace maintained at 1000 ° C and heated to 1200 ° C at a temperature rise rate of 13 ° C / min and calcined for 15 minutes. A lightweight aggregate having a water absorption of 1.9 to 2.4% is obtained.

When the concrete strength using the light weight aggregate obtained in the embodiment of the present invention compared with the steel gravel under the same conditions, the steel product 200kg / ㎠ exhibited an excellent effect of 190kg / ㎠.

Both test tables are shown in Table 3.

TABLE 3

Claims (1)

Light weight aggregate manufacturing method of light aggregate using coal mine waste, characterized in that easy to manufacture lightweight aggregate from coal mine waste by adding and processing 20-30% by weight of red spot shell with flux and foaming agent on coal waste stone which is insufficient as raw material.