KR100554741B1 - A Method of Preparing Calcium-Magnesium Inorganic Fertilizer Made From Dolomite Waste Firebrick Of Steel Making - Google Patents

Abstract

Calcium-magnesium-based inorganic fertilizer manufacturing method using dolomite waste refractory brick for steelmaking, calcium-magnesium-based inorganic fertilizer is prepared by the hydration reaction of water 370 ~ 400kg per 1000kg of dolomite waste refractory brick.

Fertilizer manufacturing using dolomite waste refractory bricks discarded after being used in steel making facilities as a raw material has no burden of first raw material cost, and is effective in preventing acidification of soil, and third, due to resource preservation and reduction of waste landfill. It contributes to the extension of landfill life and environmental protection. Fourth, it does not require any heat source or energy except for the power source of machinery during the manufacturing process. Therefore, a high quality calcium-magnesium mineral fertilizer is provided at a low cost.

Waste Refractory Brick, Calcium-Magnesium Mineral Fertilizer, Hydration Reaction

Description

Method of Preparing Calcium-Magnesium Inorganic Fertilizer Made From Dolomite Waste Firebrick Of Steel Making}             

1 is a schematic view showing a manufacturing facility of a calcium-magnesium mineral fertilizer,

2 is a detail of the screen of FIG.

        Description of the main parts of the drawing

1 .... Hydration tank 2 .... Tank support post

3 .... fertilizer discharge hopper 4 .... tank bottom opening hook

5 .... tank bottom 6 .... screen

7 .... Fertilizer Outlet

The present invention relates to a method for producing calcium-magnesium mineral fertilizer using dolomite waste firebrick for steelmaking.

In general, inorganic fertilizers used for agriculture are manufactured by processing raw materials, such as pre-firing, by using by-products from other industries, or other agricultural waste, food waste, livestock waste, phosphorus dolomite It has been prepared to add.

Korean Patent Publication No. 2001-35406 discloses a method for fertilizing organic wastes, namely agricultural wastes, food wastes, livestock wastes, slaughter wastes, manure, and sewage sediment sludges in a 3: 1 to 2: 1 weight ratio. It is disclosed. However, the small dolomite is difficult to manufacture raw materials because it needs to be manufactured and used as a dolomite of a certain size by calcining a mineral called dolomite and requires a separate dolomite source. In addition, various manufacturing apparatus for stirring and mixing are required in the manufacturing process, which requires a lot of equipment investment, which is uneconomical in consideration of the market price of fertilizer compared to dolomite raw material cost and facility investment cost. Moreover, after fertilizer production, secondary wastewater may be generated.

In Korean Patent Application No. 1996-67563, fertilizer is manufactured using converter slag of steel mill, but its application is limited due to the low content of magnesium oxide and calcium oxide and basicity of slag. In addition, it requires energy because it requires a grinding process.

Conventional methods require a separate mine or production process to procure the raw material of inorganic minerals required for the production of inorganic fertilizers, and also increases the production cost due to the purchase of a separate raw material.

Accordingly, an object of the present invention is to provide a method for producing calcium-magnesium mineral fertilizer using dolomite refractory brick for steelmaking.

It is another object of the present invention to provide a method for producing a calcium-magnesium mineral fertilizer without additional processing by using a dolomite refractory brick for steelmaking by a hydration reaction.

Still another object of the present invention is to provide a method for producing calcium-magnesium-based inorganic fertilizers, which is effective in preventing acidification of soil by reducing waste generation by using waste refractory bricks used in steelmaking facilities and containing a large amount of mineral components.

According to the invention,

Provided is a method for preparing calcium-magnesium inorganic fertilizer, characterized by hydrating 370 to 400 kg of water per 1000 kg of dolomite waste refractory brick and dolomite waste refractory brick.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

Although there are some differences depending on the type of material, the dolomite refractory brick is generally composed of the components shown in Table 1 below.

TABLE 1

division Component (wt%) CaO 40-60 MgO 60-40 Al2O3 a very small amount SiO2 a very small amount

As can be seen in Table 1, since the dolomite refractory brick contains a large amount of calcium oxide and magnesium oxide, high quality calcium-magnesium-based inorganic fertilizers can be prepared using the same.

In the present invention, the fertilizer is prepared based on the slaking of calcium oxide (CaO) and magnesium oxide (MgO), that is, the main components of the refractory brick, that is, a hydration reaction at room temperature. Therefore, it does not require a separate heat source, not only does not consume energy, but also does not require complex and diverse equipment, and thus, economical production of calcium-magnesium fertilizer can be economically produced, and the amount of waste generated is reduced.

As raw materials for fertilizer production, dolomite waste refractory bricks (hereinafter referred to simply as 'fire refractory bricks'), which are used in steelmaking facilities and are disposed of and disposed of, are used. In addition, any kind and form of waste refractory brick can be used, and the type, form, etc. of the dolomite waste refractory brick are not particularly limited.

However, in order to manufacture high quality calcium-magnesium mineral fertilizers (hereinafter referred to simply as 'mineral fertilizers'), dolomite waste refractory bricks contain 40-60 wt% of CaO and 40-60 wt% of MgO. It is preferable to use what is present.

The dolomite waste refractory brick is waterified to prepare a calcium-magnesium mineral fertilizer. First, the waste fire brick dismantled used in the steelmaking facility is collected and the double slag and now (Steel, the metal component that solidified during the steelmaking process solidified and attached to the fire brick) are separated and the fire is fired. Collect only bricks. Hydrate the reaction by adding 370 ~ 400kg of water per 1000kg of waste refractory brick. Allow 48 hours for hydration to occur. In less than 48 hours, the refractory bricks are not fully hydrated, so it is desirable to allow sufficient hydration for more than 48 hours.

The amount of water added to the waste refractory bricks is based on the stoichiometric calculations of the following formulas of hydration of calcium oxide and magnesium oxide. Water should be supplied in a sufficient amount required for the hydration reaction of calcium oxide and magnesium oxide in the refractory bricks.In addition, if excess water is supplied, excess water should be dehydrated and dried again after the hydration reaction. It is preferable not to perform a separate dehydration drying process by adding an appropriate amount of water.

The appropriate amount of water is calculated by calculating the theoretical equivalent weight of the hydration equations according to the following reaction equations ① and ②.

CaO + H2O → Ca (OH) 2 ............... Equation①

MgO + H2O → Mg (OH) 2 .......... Equation②

The amount of water required for hydration of calcium oxide and magnesium oxide is as follows according to the above reaction equations ① and ②. That is, the molecular weight of CaO is 56 and the H 2 O molecular weight, which is the amount of water required for the hydration of CaO, is 18, the molecular weight of MgO is 40, and the H 20 molecular weight, which is the amount of water required for the hydration of MgO, is 18.

Therefore, the theoretical amount of water required for the hydration of 1000 kg of dolomite waste refractory brick is 373 to 399 kg based on the following reaction formulas (3), (4) and (5).

CaO 600 ~ 400kg → Water 193 ~ 129kg .......

MgO 400 ~ 600kg → Water 180 ~ 270kg .........

Waste Fire Brick 1000kg → Water 373 ～ 399kg ......... Equation ⑤: Equation ③ + ④

On the other hand, the theoretical amount of calcium-magnesium mineral fertilizer produced by hydration reaction of 1000kg of waste refractory bricks with 370-400kg of water is 1,373-1,399kg based on the following equations ⑥, ⑦.

   CaO + H2O → Ca (OH) 2 ............... Equation ①

600 ~ 400kg + 193 ~ 129kg 793 ~ 529kg ........ Equation ③

    MgO + H2O → Mg (OH) 2 ............... Equation ②

400 ~ 600kg + 180 ~ 270kg 580 ~ 670kg ........ Formula ④

CaO, MgO + 2H2O → Ca (OH) 2, Mg (OH) 2 ....... Formula ⑥: Formula ① + ②

 1000kg + 373 ~ 399kg 1,373 ~ 1,399kg ...... Equation ⑦: Equation③ + ④

Fertilizer production by the hydration reaction is a stoichiometric calculation based on theoretical assumptions, and in the actual state, the solid solution produced by the sintering and the iron oxide (FeO) is produced by the molten steel of high temperature on the movable surface during the steelmaking operation of the fireproof brick. Since the rate of hydration is very slow or rarely occurring, the part is not available due to the inconsistent economic and time conditions for industrial use.

Therefore, after the completion of the hydration reaction, the waste refractory bricks in the movable surface side are in the form of plate- or wall-shaped waste refractory bricks. Therefore, they must be separated and disposed of separately. Generally, the solid solution of iron oxide (FeO) is used for total waste refractory. 10-15% by weight of the brick.

After completion of the hydration reaction, the reaction hydrate is separated by passing through a strainer to separate the solid and the non-hydrated solid solution contained in the waste refractory brick.

Most of the added water is required for the hydration reaction, but if the state of the hydrate is sludge due to too much moisture, a separate drying operation should be performed.

However, when only a theoretical amount of water is added according to the above hydration equation in order to mix an appropriate amount of water, the amount of waste refractory bricks remaining in an unhydrated solid solution without participating in the hydration reaction is 10 to 15% by weight. After completion of the reaction, the moisture content of the prepared calcium-magnesium inorganic fertilizer is about 5 to 10% by weight, so that it can be used as a fertilizer without additional drying.

1 shows a schematic diagram of a plant that can be used to prepare the calcium-magnesium mineral fertilizer of the present invention. An inorganic fertilizer is produced by reacting the waste refractory brick and water in the hydration reaction tank 1, and the fertilizer produced through the fertilizer preparation hopper 3 is discharged. On the other hand, the tank bottom (5) structure is the front and rear opening and closing so that the fertilizer produced after the reaction is completed by the magnetic force to the hopper (3). The non-hydrated mass by-products are separated by the screen 6 under the hopper and the fertilizer is discharged through the fertilizer outlet 7.

The fertilizer having a moisture content of 5-10% by weight of the total fertilizer prepared by the present invention is moist in the form of a powder and prevents the dust from being blown off by wind when sprayed on farmland or forests, and does not have a separate drying work during manufacturing. Energy is also saved because there is no need.

The fertilizer produced by the present invention can be applied by applying for the growth and nutrition of crops and forests on agricultural land and forest forests.

Hereinafter, the present invention will be described in detail through examples. The following examples illustrate the invention but do not limit the invention.

6 kg of dolomite waste refractory brick (including solid solution of movable surface iron oxide (FeO)) and 2.4 Kg of water were left to stand for about 48 hours. After 48 hours of completion of the hydration reaction, the remaining plate-shaped unhydrated and moist powdery calcium-magnesium mineral fertilizer were separated and the weights of each were shown in Table 2 below.

TABLE 2

Raw Material Input (kg) Output (kg) Waste Refractory Brick 6 Total amount of fertilizer Calcium-Magnesium Mineral Fertilizer 7 water 2.4 Water (H2O) 0.5 system 8.4 system 7.6 Unhydrated solid solution 0.9

Trace amounts of alumina (Al2O3) and silica (SiO2) in waste refractories are stable oxides during the hydration reaction of the dolomite refractory brick, so the amount does not change before and after the hydration reaction.

Therefore, the composition of the calcium-magnesium inorganic fertilizer prepared by the method of the present embodiment is shown in Table 3.

TABLE 3

division weight% Ca (OH) 2  50 Mg (OH) 2  42 Al2O3  0.6 SiO2  0.7 Water (H2O)  6.7

As can be seen in Table 3, the inorganic fertilizer prepared using the dolomite waste refractory brick is a high quality inorganic fertilizer having a calcium and magnesium content of 85 to 90% by weight or more.

Fertilizer manufacturing using dolomite waste refractory bricks discarded after being used in steelmaking facilities as a raw material has no burden of first raw material cost, and is effective in preventing acidification of soil, and thirdly, due to resource preservation and reduction of landfill volume. It contributes to the extension of landfill life and environmental protection. Fourth, it does not require any heat source or energy except for the power source of machinery during the manufacturing process. Therefore, a high quality calcium-magnesium mineral fertilizer is provided at a low cost.

Claims (4)

A method for producing a calcium-magnesium mineral fertilizer, characterized by hydrating 370 to 400 kg of water per 1000 kg of dolomite waste refractory brick and dolomite waste refractory brick. The method for preparing calcium-magnesium inorganic fertilizer according to claim 1, which is hydrated for at least 48 hours. The method of claim 1, wherein the calcium-magnesium-based inorganic fertilizer has a moisture content of 5-10% by weight of the total weight. The method for producing a calcium-magnesium inorganic fertilizer according to any one of claims 1 to 3, which does not require a separate drying step.

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