JPS5933646B2 - Manufacturing method of sintered raw material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing sintering raw materials, particularly blending powdered iron, which improves air permeability during the sintering process, improves the reduction and pulverizability of the sintered ore itself, and , its purpose is to improve productivity.

The sintering method has been widely known as a pretreatment method for blast furnace raw materials.

Generally, as shown in Figure 1, this method first charges blending powder iron (B powder), limestone, coke powder, and return ore separately into a blending tank 1, and then cuts out appropriate amounts of each raw material from each blending tank and blends them. After that, it is sent to the primary mixer 2 for water addition, mixing, and granulation, and then sent to the secondary mixer 3 as necessary.
Further granulation is performed.

The raw material granulated in this way is charged from the hopper 4 to the endless pallet of the sintering machine 5, and the coke mixed in the raw material is ignited by the ignition furnace 6. The raw material is sintered by more forced suction and ventilation.

However, in such a method, the raw material is mainly water granulated in the primary mixer 2 immediately before being charged into the sintering machine 5, so water as a binder does not completely and uniformly permeate the raw material. First, the permeability (granulation) is poor, the productivity is poor, and the reduction pulverization index, which is a quality index of the finished product, is poor, and in order to improve this, the amount of coke powder used as fuel has to be increased. be.

In addition to this, each sintering raw material also serves as the basis for the quality of sintered ore.
However, due to resource trends and the balance of supply and demand, it is not always possible to obtain raw materials with optimal conditions. Development is required.

The present invention was proposed as a result of repeated studies in view of the current situation, and in particular, by adding water in advance to the sintering raw material before charging it into the mixing tank and granulating it, The purpose is to improve granulation properties, improve air permeability during the sintering process, and improve productivity.

The present invention will be described below as a blending powder iron (B) as a sintering raw material.
Taking powder powder as an example, powder raw materials used for sintering are generally piled up at the rough ore yard from the ship via an unloader, and then mixed with other brands of raw materials in an appropriate ratio to obtain powder B. is charged into the blending tank 1 shown in FIG.

However, the present invention is characterized in that water is added in advance to the powder raw material before it is charged into the blending tank 1, and the powder is granulated.

Figure 2 shows a schematic diagram of Poso, in which powder raw materials are
When the coarse ore is stored in a yard 13 through conveyors 11 and 12, a humidity control mixer 14 is installed in the middle of the process, and granulation is performed by spraying water from a water nozzle 15.

Further, each raw material stored in the rough ore yard 13 is mixed in a predetermined ratio and then stored in the blending yard 16, but in the present invention, the conveyor 17, Another humidity control mixer 19 may be installed between 1B and granulation may be performed by spraying water from the water spray nozzle 20* here as well (note that 21 in FIG. 2 is a blender dust cutter).

As shown in FIG. 3, it can be seen that when the raw materials charged into the blending tank are granulated in advance using a humidity control mixer, the granulation index of various brands is significantly improved.

In addition, in FIG. 3, the SKF index and the SP index are each expressed by the following formulas.

PS index -100 (-0,25 mm of completely dry particle size) = () Then, the amount of water added in the humidity control mixer is controlled to be the optimum amount for granulation.

Specific examples are shown in Table 1 and FIG.

As seen in these data, the appropriate amount of moisture added varies depending on the brand, with A being 3.2 to 4.5% and B being 3.
．． The optimum content is 8 to 5.4%, and the optimum content of C is 5.0 to 7.2%.

In other words, the appropriate moisture content is the maximum air permeability moisture of each brand x (0,7~
1.0).

Figure 5 shows an example of a system for controlling moisture content, in which the raw material conveyor 30
．． A hopper 32 is provided in the middle of 31, and this hopper 32
A moisture meter 33, such as a neutron moisture meter, is installed in the conveyor 31, and a weighing device 34 is installed in the middle of the conveyor 31. This adjusts the amount of water sprinkled.

In addition, as another example, the outlet conveyor 35 of the humidity control mixer 40,
An intermediate hopper 38 equipped with a moisture meter 37 may be installed between the humidity control mixer 40 and the moisture control mixer 40 to provide feedback to the water spray nozzle 41 so that the raw material carried out from the humidity control mixer 40 has a predetermined moisture content.

On the other hand, in the present invention, adding binders such as quicklime and slaked lime during granulation using a humidity control mixer improves air permeability (granulation properties).
will be significantly improved.

As shown in FIG. 5, such a binder may be cut out from a hopper 39 provided on the inlet side of the humidity control mixer 40, or it may be dissolved in water and sprayed with water from a water spray nozzle 41.

FIG. 6 shows the effect of this binder addition, and the conditions of a=d in the figure are as shown in the table below.

The amount of this binder added is not particularly limited, but it is usually added in an amount of 1 to 3%.

In this case, the weighing device 34 shown in FIG. 5 and the binder supply hopper 39 may be linked to control the feed amount to always be at a predetermined ratio to the amount of raw material conveyed.

In the present invention, it is more effective if the water added is warm water.

In this case, the water temperature is recommended to be 50°C or higher, preferably 80 to 90°C.

According to the present invention as explained above, the obtained sintering raw material has improved air permeability during the sintering process, and at the same time, the reduction powdering rate has been improved, and the productivity has been increased. It is effective.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing a general sintering process, Figure 2 is a schematic diagram for explaining the method of the present invention, and Figure 3 is a diagram showing the effect of granulation using a humidity control mixer in the present invention. graph, 4th
The figure is a graph showing the appropriate moisture content for granulation of various brands, FIG. 5 is a schematic diagram showing a system for controlling moisture content in the present invention, and FIG. 6 is a graph showing the effect of adding a binder. In the figure, 1 is a blending tank, 13 is a rough ore yard, 14°19.40
1 is a humidity control mixer, and 15, 20, and 41 are water nozzles.

Claims (1)

[Claims] 1. A sintering raw material characterized in that water is added in advance to the powdered raw material to be sintered and the powder is granulated before being charged into a mixing tank installed before a primary mixer. manufacturing method. 2. A method for producing a sintering raw material, which comprises adding moisture and a binder in advance and granulating the powdered raw material to be sintered before charging it into a mixing tank installed before a primary mixer. 3. Method for producing a sintered raw material according to item 1 or 2 above, characterized in that when adding moisture, the moisture content is controlled to be optimal for granulation according to the brand of the powder raw material. The method for producing a sintered raw material according to the above item 1 or 2, characterized in that: