JPH03183730A - Manufacture of quicklime by sintering machine - Google Patents

Abstract

PURPOSE:To improve the quality and productivity of quicklime by charging a mixture of limestone and coke breeze to a recessed part formed in the topmost layer part of a pallet in a Dwight-Lloyd sintering machine and sintering the mixture by heat in an ignition furnace. CONSTITUTION:In a sintering stage by using a Dwight-Lloyd sintering machine, a recessed part is formed in the topmost layer part of a pallet 1 in the sintering machine as well as the part in which heating temp. of the central part in the breadwise direction is made uniform. A mixture 9 of limestone and coke breeze is charged to the recessed part. Next, the mixture 9 is sintered by heat in an ignition furnace to obtain quicklime.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for producing quicklime in the uppermost layer of a sintering machine pallet in a process of sintering raw materials for a blast furnace using a Dwight Lloyd sintering machine. The present invention relates to a method for improving the quality and productivity of quicklime.

<Prior art> Figure 1 shows a schematic diagram of a sintering operation for blast furnace raw materials using a Dwight Lloyd sintering machine. The sintering raw material 2 cut out from the ore feed hopper 4 is stacked and supplied on top. Raw material 2 is the ignition device! It is ignited at f15, and the coke powder in the sintering raw material is combusted by ventilation from the main blower 14, and the sintering raw material is brought to the bottom of the pit and becomes sintered ore. The sintered ore is crushed by a crusher 5, cooled by a cooler 6, and the sieved ore is classified by a machine 7. The product on the sieve with a particle size of 8 to 16 mm is returned to the bedding hopper 3 as bedding ore 1O, and the remainder is transported to the blast furnace as product 13. On the other hand, the classified particles having a particle diameter of 5H or less are returned to the ore feed hopper 4 after being mixed with new raw material 12 by a ξ mixer 8 as a return wire 11.

Generally, as a means to improve the air permeability of the raw material 2 on the pallet, a binder may be mixed into the raw material.
Quicklime (Cab) is commonly used as a binder.

As a method for producing this CaO at low cost, JP-A-5B-
Publication No. 133331 discloses that limestone (CaCOs) powder 9 is cut out from a lime pumper 19, layered on top of the raw material 2, and an ignition device is created! The heat in f15 causes the reaction of the following formula to occur: CaCO3' CaO-+-COg+ΔH--
(1) (ΔH: enthalpy difference) A method for producing quicklime powder from limestone powder has been proposed.

However, when firing limestone, the temperature distribution in the width direction of the pallet is not uniform, and the sides are lower than other parts, so if you aim at the bottom of the pit on the side, the limestone on the center side will be more likely to be overfired. If the aim was to focus on the center side, there would be a lot of unfired material on the side sides, which caused problems in terms of production efficiency and quality.

<Problems to be Solved by the Invention> An object of the present invention is to provide a method for producing quicklime using a sintering process with higher efficiency and higher quality than before.

Means for Solving the Problems〉 That is, the present invention provides a sintering process using a Dwight Lloyd type sintering machine, in which a mixture of limestone powder coke is charged into the top layer of a sintering machine pallet, and When producing quicklime powder from limestone by the heat in the furnace, a recess is formed in the uppermost layer of the pallet at the center in the width direction where the heating temperature is almost uniform, and the mixture is loaded into the recess. This is a method for producing quicklime using a sintering machine.

Kusaku Kawa> In the sintering machine shown in FIG.
The distribution of retention times of C or higher was measured. The results are shown in FIGS. 2 and 3, respectively.

By the way, limestone decomposes at temperatures above 900°C, so
The holding time at 00°C or higher determines productivity.

According to this, a substantially uniform heating temperature was obtained in the widthwise central portion of the pallet, and a uniform state was also obtained in the time period during which the temperature was maintained at 900° C. or higher.

In the present invention, the central SJ having this almost uniform heating temperature
Since a recess is formed in advance in area 1 and a mixture of limestone powder and coke powder, which are the raw materials, is loaded therein, the entire raw material is uniformly heated, and quicklime of uniform quality is efficiently produced. be able to.

Next, an example of a specific device for carrying out the above-mentioned loading is shown in FIG.
, is partially controlled by gate set 1G. This gate set 16 is a combination of a large number of gates, and is a device that enables partial control of the raw material layer thickness in the valent width direction. The width of the limestone to be charged into the area where the firing conditions are uniform is determined by the gate cellar mesh 6 in advance.
A recess is formed as shown in the figure, and then a mixed raw material 9 of coke powder and limestone powder is loaded into the recess from a limestone hopper 19 using a drum feeder 20.

Next, the present invention will be explained in more detail based on examples.

<Example> Raw materials were loaded into the recesses of the uppermost layer of a sintering machine pallet using a gate set and a drum feeder in the following nest production to produce quicklime.

Pallet width: 3500+w Coke blending ratio: 12.5% Layer thickness: 30mm Loading width: 1700+w Limestone surface temperature by ignition furnace: 1050"c Particle size distribution of limestone Particle size distribution of limestone component coke MS: 1.59m Other conditions Table 1 shows the comparison results between the conventional method and the present invention, which are the same but charge the entire width of the pallet.

As is clear from the table, when the present invention is adopted, the decomposition rate of CaC0 increases from 53% to 72% compared to the conventional method, and the reactivity of quicklime increases from 105% to 177% in terms of quality. has improved.

Table 1: Reactivity: Emulsify 50 g of sample in 2000 cc of warm water at 40°C, perform neutralization titration with 4N hydrochloric acid, and after 5 minutes,
The amount of N hydrochloric acid used (*ff1) is as follows.

<Effect of the invention> In the process of charging coke powder and limestone powder to the top layer of a sintering machine pallet and bottoming out the limestone using the heat in the ignition furnace, the heating temperature is uniform in the width direction of the pallet. Since quicklime is produced by loading limestone, productivity and quality of quicklime can be improved.

Therefore, when compared with the conventional method, it has become possible to significantly reduce costs in producing quicklime.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the quicklime production process on a sintering machine, Figure 2 is a measurement diagram showing the distribution of heating temperature in the width direction of the pallet, and Figure 3 is the distribution of retention time of limestone decomposition heat in the width direction of the pallet. FIG. 4 is an explanatory diagram of a specific device for carrying out the present invention, and FIG. 5 is a schematic diagram of a raw material loading recess in the pallet width direction. 1...Pallet, 2...Sintering raw material, 3.
...Bed ore hopper 4...Ore feed hopper 5...
Crusher, 6... Cooler 7... Sieving machine, 8... Mixer 9... Limestone powder + coke powder, IO... Bed ore, 11... Return ore, 12
...New raw materials, 13...Products, 14...
・Blower, 15...Ignition device, 16...
Gate set, 17...Blended raw materials, 18...Drum chute, 19...Limestone hopper 20...Drum feeder, 21...Chute. Patent source Kawasaki Steel Co., Ltd.Bullet position in the width direction 22 Position in the width direction

Claims (1)

[Claims] In the sintering process using a Dwight Lloyd sintering machine,
When charging a mixture of limestone powder and coke powder to the top layer of a sintering machine pallet and generating quicklime powder from limestone powder using the heat in the ignition furnace, the heating temperature at approximately the widthwise center of the top layer of the pallet A method for producing quicklime using a sintering machine, comprising: forming a recess in a portion where the mixture is uniform; and filling the mixture into the recess.