JPS593950B2 - How to make quicklime - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of quicklime from limestone and/or dolomite.

Limestone is a natural mineral resource mainly composed of calcium carbonate, and dolomite is a composite of calcium carbonate and magnesium carbonate, respectively, and the present invention is a method for producing quicklime by calcining these minerals.

Traditionally, quicklime was produced by burning limestone in a vertical kiln or a rotary kiln.

In the case of a vertical needle, the diameter is approximately 100mm! The raw materials were completely fired by using the above-mentioned natural raw stones and by using coal, especially anthracite, with a diameter of 30 to 50 mm to prevent the furnace from clogging.

However, in this method, since the raw materials are in large chunks, it takes time to fire them, tends to result in incomplete firing, and since it is a batch method, the production volume is limited to, for example, 30 tons per batch, which is extremely inefficient.

On the other hand, when using a rotary kiln, the raw ore is burned in a heavy oil burner, resulting in large amounts of oil consumption and increased costs.

The present invention was developed to solve the above-mentioned drawbacks of the prior art, and its main purpose is to streamline the quicklime sintering method to save energy.

To explain this in more detail, the present invention is a method of performing continuous operation by combining a vertical preheating furnace and a rotor kiln. The materials to be fired, which were intimately mixed with the crushed material, were charged into 20 to 50 parts of the ore, and fired at about 800 Q - about 1000 °C while supplying sufficient air, and about 70 parts of the whole were fired. Transfer to the rotary kiln below.

Inside the rotary kiln, the flame from the burner is radiated to maintain the temperature of the contents at about 1000°C to complete the firing.

In order to carry out this method efficiently, it is necessary to granulate the raw materials and solid fuel, mix the materials homogeneously, introduce sufficient air, and gradually move the materials downward without causing blockage. Firing temperature is approximately 800'-1000 by performing in a vertical preheating furnace.
It is necessary to carry out firing within the range of ℃.

Then, the firing speed is adjusted so that about 70 pieces of the total are fired in the vertical preheating furnace.

As mentioned above, pulverized coal is ejected from a burner installed at the rear of the rotary kiln, and the ignited flame maintains the firing temperature at approximately 1,000°C. It is another object of the present invention to make effective use of resources, and the rotation speed of the rotary kiln can be adjusted to adjust the residence time of the firing material, thereby completing the firing.

An embodiment of the present invention will be described with reference to the accompanying drawings. Reference numeral 1 denotes a hopper into which a natural ore material containing limestone and/or dolomite as a main component is crushed in advance into small pieces of 20% to 50% and then charged.

Forming the ore raw material into small agglomerates is necessary to facilitate calcination as described above and also to increase the capacity of the preheating furnace.

2 is also a hopper into which 2X or less granular or powdered coal or coke is charged.

Next, the finely granulated ore raw material and powdered coal or coke are mixed homogeneously in Step 3 to increase combustion efficiency.

Furthermore, the use of powdered coal is inexpensive and easily available.

Next, the mixed raw materials and powdered coal or coke are put into the preheating furnace 4.

The preheating furnace must first be ignited, but after that the combustion continues all the time, so you can simply put it into the furnace.

The preheating furnace currently being tested is a furnace with a diameter of 6 m and a height of 20 m, which reaches a combustion rate of about 70 inches in day and night, and will be gradually transferred to the rotary kiln 5 below.

In the rotary kiln 5, the contents are completely burned with a burner 6 from the rear while rotating the kiln to prevent uneven firing to produce quicklime.

This burner 6 prevents the firing temperature from dropping, and its fuel may be conventional heavy oil, but as mentioned above, pulverized coal can be used to save costs and petroleum resources. .

The burned quicklime is discharged from the rotary kiln and is sieved by a wire mesh 7 with a mesh size of 10% square arranged below into lumpy quicklime with a size of 10% or more and powdery quicklime with a size of less than 10%.

The sifted quicklime in the form of lumps of 10 or more is used as is, and the powder quicklime of less than 10 is hydrated and used as slaked lime.

As described above, one feature of the present invention is the use of a preheating furnace and a rotary kiln in combination, which enables continuous operation, resulting in fuel cost savings and increased production.

In addition, natural raw materials and powdered coal can be crushed to a certain particle size and mixed homogeneously to increase combustion efficiency and effectively utilize fuel, making it suitable for the era of resource conservation.

[Brief explanation of the drawing]

The figure is an overall view for explaining the present invention. 1... Raw material hopper, 2... Coal hopper, 3... Mixing section, 4... Preheating furnace, 5... Rotary kiln, 6 ...Burner, I...Wire mesh.

Claims (1)

[Claims] 1. Powdered or granular ore containing limestone and/or dolomite as a main component is crushed to 20 to 50 parts, and the mixture ratio with the ore is 5 to 10 parts.Powder or granule selected from coal and coke of solid fuel are homogeneously mixed, and the mixed material is calcined in a vertical preheating furnace for about 70 inches at a power firing temperature range of 800° to 1000°C with sufficient air passing through, and then heated in a rotary kiln. A method for producing quicklime, which is characterized in that the calcination is completed by the flame of a burner, and the product is cooled and collected.