JPH0670261B2 - Agglomerated ore manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an agglomerated ore that prevents bursting of raw pellets.

[Prior Art] An agglomerated ore is generally manufactured as follows. Mix powdered iron ore, serpentine and other solvent media and crushed agglomerated ore and return granules of 4 mm or less generated during sizing, mix with mixer, granulate with primary pelletizer, then secondary pelletizer or drum With a mixer, the surface of this granulated material is subjected to secondary granulation by coating solid fuel such as powdered coke, char, pulverized coal, etc., to produce 5-10 mm raw pellets, which are endless moving great type Charge into a sintering machine and fire.
The fired product is crushed to a predetermined size, cooled, and sized to produce an agglomerated ore of 4 mm or more.

Since the raw pellets are rapidly heated during drying and ignition, if the raw pellets contain iron ore that is prone to thermal cracking, the thermal cracking of the iron ore and vaporization of the internal moisture cause bursting (burst). ), There is a phenomenon of pulverization. If the bursting of the raw pellets occurs frequently, the breathability of the charging layer deteriorates. The cause of deterioration of air permeability is deterioration of granulation property other than bursting. Then, this deterioration of air permeability can only be grasped by a decrease in the temperature of a plurality of air boxes and an increase in the negative pressure of the main blower on the side of the sinter mine ore, and then an operation action is usually taken.

[Problems to be Solved by the Invention] The deterioration of the air permeability of the raw pellet layer charged in the sinter is grasped by the decrease in the temperature of a plurality of wind boxes and the increase in the negative pressure of the main blower on the slag discharge side of the sinter. In the conventional method, it cannot be seen that the pallet loaded with raw pellets having poor air permeability deteriorates in air permeability until 30 to 35 minutes have passed after passing through the ignition furnace. Further, in the conventional method, it is not known whether the cause of the deterioration of the air permeability is due to the bursting of the raw pellets or other causes, and therefore it takes more time to investigate the cause. Therefore, there is a problem that the production rate and the quality are degraded while the cause of the deterioration of the air permeability is determined.

[Means for Solving the Problem] The present invention is intended to solve the above problems, in which powdered iron ore, solvent medium and return ore are mixed, primary granulation is performed, and the granulated product is obtained. An agglomerated ore that continuously coats an agglomerated ore composed of an aggregate of fired pellets by coating the surface with powdery solid fuel to make green pellets, charging the raw pellets into an endless moving great type firing furnace In the manufacturing method, the noise level at the time of raw pellet ignition is detected by a noise sensor installed in the ignition furnace, and when the noise level exceeds a certain value, the amount of binder added is increased or dried, and the ignition condition is changed. Is a method for producing agglomerated ore.

[Function] The burst noise of the raw pellets may be loud or small. Therefore, the noise sensor provided in the ignition furnace should detect the bursting of the raw pellets passing through the ignition furnace as the noise level. You can That is, when the raw pellets pass through the ignition furnace, it is possible to detect the deterioration of the air permeability due to the bursting of the raw pellets, so that the operation action can be taken quickly.

[Examples] Examples of the present invention will be described in detail below. FIG. 2 is an explanatory diagram of steps and equipment from the raw material storage tank to the sintering machine.
In FIG. 2, coarse iron ore in storage tanks 1 and 2, pellet feed of fine powder in storage tank 3, serpentine as a solvent in storage tank 4, agglomerated ore in storage tank 5 is generated during crushing and sizing. 4 mm
A predetermined amount of the returned ore and quick lime as a binder in the storage tank 6 is cut out, water is added and mixed by the mixer 7, and the mixed product is primary granulated by the primary desk pelletizer 8 while adding water. The primary granules granulated by the primary desk pelletizer 8 are sieved by a pellet screen 9a having a mesh size of 4 mm, and the granules having a particle diameter of -4 mm are returned to the primary desk pelletizer 8 and re-granulated. Granules with a particle size of +4 mm are sieve mesh 25 mm
The granulated product having a particle size of -25 mm is sieved with a pellet screen 9b of No. 2 and is charged into a secondary desk pelletizer. In the secondary desk pelletizer, the solid fuel in the storage tank 11 (powder coke,
Char, pulverized coal, etc.) is added at the same time as water to coat the surface of the primary granulation product with a solid fuel such as powder coke and secondary granulation. This gives raw pellets with a particle size of 5-10 mm. The raw pellets thus obtained are transferred via the primary storage tank 12 to the pallet 18 of the great-type sintering machine 13.
After being dried in a drying furnace 14 that uses high-temperature exhaust gas from a sintering machine supplied by a circulation fan 16, the ignition furnace 15
The surface of the layer is ignited with. On the other hand, after the drying furnace 14, the main blower 17 sucks the gas or the atmosphere downward from the surface of the raw pellet layer through the raw pellet layer charged in the pallet 18. Then, the combustion zone generated on the surface of the raw pellet layer progresses downward with the movement of the pallet, the entire height of the raw pellet layer is sintered before the slag discharge section of the sinter, and is continuously discharged from the slag section. The discharged sintered body is sent to a crushing and sizing process.

The present invention, in the above equipment, provided with a noise sensor 20 in the ignition furnace 15, to detect the noise level at the time of ignition of the raw pellets, when the noise level exceeds a certain value, the addition amount of binder such as quick lime increases Alternatively, the furnace temperature of the drying furnace 14 is raised or the furnace temperature of the ignition furnace 15 is lowered.

FIG. 1 is a block diagram for carrying out the method of the present invention, and 20 is a noise sensor provided in the ignition furnace. The noise sensor 20
It is attached to a gap where noise in the ignition furnace leaks or a sound tube provided to penetrate the ignition furnace wall. Reference numeral 21 denotes a calculator, which is a noise level value (or noise level value x number of times / minute) for performing an operation action or an action sequence. For example, if the set noise level is exceeded, (1) the amount of quicklime added is increased.

(2) If the noise level does not decrease even after the set time elapses after the action of (1), the temperature of the drying furnace is raised.

Etc., and the action amount has been entered. 22 is a controller for the quick lime cutting device, 23 is a controller for the drying furnace temperature, and 24 is a controller for the ignition furnace temperature.

The measurement value signal measured by the noise sensor 20 is transmitted to the calculator 21. The calculator 21 determines the presence / absence of an action, an action item, etc. based on the measured value, and implements an operation action through the corresponding controller.

[Advantage of the Invention] The present invention detects the bursting of raw pellets by the noise sensor provided in the ignition furnace to carry out the operation action. Therefore, the operation action is performed 1 to 2 hours earlier than the conventional method. Can be taken during the time
It is possible to prevent a decrease in production rate and a decrease in quality.

[Brief description of drawings]

FIG. 1 is a block diagram for carrying out the method of the present invention, and FIG. 2 is an explanatory diagram of steps and equipment from a raw material storage tank to a sintering machine. 13 ... Sintering machine, 14 ... Drying furnace, 15 ... Ignition furnace, 18 ... Pallet, 20 ... Noise sensor, 21 ... Calculator, 22 ... Quicklime cutting device controller, 23 ... Drying furnace temperature controller, 24 ... Ignition furnace temperature Controller.

Continued Front Page (72) Inventor Hideaki Inoue 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Yuko Kano Examiner, Nihon Kokan Co., Ltd.

Claims (1)

[Claims] 1. A powdery iron ore, a solvent, and a return ore are mixed and primary granulated, and the surface of the granulated product is coated with powdered solid fuel,
In a method for producing an agglomerated ore, in which a raw pellet is produced, the raw pellet is charged into an endless moving great type firing furnace, and an agglomerated ore comprising an aggregate of the fired pellets is continuously produced, is provided in an ignition furnace. A method for producing agglomerated ore, comprising detecting a noise level at the time of igniting raw pellets with a noise sensor, and increasing the amount of binder added or drying and changing the ignition condition when the noise level exceeds a certain value.