JPH0353754Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for treating hot metal desulfurization slag in pig iron factories and foundries, and specifically, desulfurization slag (waste slag) after hot metal desulfurization treatment. In particular, it relates to a processing device for harmlessly processing residual calcium carbide (CaC ₂ ).

[Prior Art] Conventionally, the sulfur content contained in hot metal has an adverse effect on the material quality of products, and is a major impediment to the carbon spheroidization process, especially when melting ductile cast iron. It must be removed in advance. Sulfur removal treatment (hereinafter referred to as "desulfurization") is performed by applying a commercially available desulfurization agent mainly composed of calcium carbide to the ladle 15a from the tap bucket 14a of a hot metal furnace such as a cupola as shown in Fig. 2A. At the same time, _N2 gas is injected from the porous plug 16a fitted into the bottom of the ladle to vigorously bubble the molten metal and bring it into sufficient contact. At this time, the sulfur in the molten metal is separated and transferred to the molten slag floating on top of the molten metal, so if this slag is scraped off from above the molten metal as shown in FIG. 2B, desulfurization is completed.

[Problem that the invention aims to solve] Molten slag is made by turning input materials such as calcium carbide into slag at high temperatures, and it contains a large amount of sulfur that has migrated from the molten iron, which poses undesirable safety and environmental problems in the workplace. arise.

That is, desulfurization slag, especially calcium carbide, comes into contact with molten iron and has the following composition.

These include calcium oxide (CaO), calcium sulfide (CaS), calcium phosphide (Ca ₃ P ₂ ), unreacted calcium carbide (CaC ₂ ), and others.
In particular, calcium carbide and calcium phosphide react rapidly when they come into contact with atmospheric moisture or other moisture.

C ₂ H ₂ , or acetylene gas, is an explosive gas and is dangerous because it easily ignites and burns with the residual heat of the desulfurization slag that is discarded _.
P, or hydrogen phosphide, also known as phosphine, is a toxic gas and has a foul odor.

Therefore, it is not preferable to dispose of the desulfurization slag as it is, so on-site construction methods have been added to eliminate CaC ₂ and Ca ₃ P ₂ in the slag. In order to achieve this purpose, the charged calcium carbide desulfurization agent should completely react with the sulfur in the hot metal to eliminate residual calcium carbide (CaC ₂ ). Considering the contact efficiency with the desulfurizing agent and the treatment time, it is inevitable that the calcium carbide desulfurizing agent remains unreacted in the slag. Calcium phosphide (Ca ₃ P ₂ ) is also caused by phosphorus (P) as an impurity introduced during the calcium carbide manufacturing process, and this cannot be avoided, so there is no way to solve the problem. Not yet reached.

In order to solve the above-mentioned problems, the present invention aims to provide a separate device that completely processes the generated slag without depending on the reaction in the ladle.

[Means for Solving the Problems] The desulfurization slag processing device according to the present invention has a box whose four circumferences are hermetically formed with double inner and outer walls separated by a hollow part, and a lower bottom of the box. A hollow box whose top surface is a perforated plate is removably locked to the box body, and a circulating cooling water supply/discharge port is installed in the hollow part of the box body, and a compressed air supply port is installed in the bottom hollow box. This solved the problem mentioned earlier.

[Operation/Example] The operation of the present invention will be explained with reference to FIG. 1 showing an example. In the figure, the processing apparatus 1 forms a box body 5 with an inner wall 3 and an outer wall 4 that are vertically arranged in a double manner with a hollow portion 2 in between. A hollow box 7 whose only upper surface is a perforated plate 6 is mounted on a hinge 8 at the bottom of the box 5.
It is removably locked. A cooling water supply port 9 and a drain port 10 are attached to the box body 5, while a compressed air supply port 11 is attached to the hollow box 7 at the bottom. In addition, in the example shown in this figure,
A partition wall 12 is erected in the middle, and a hollow portion 13 is formed by a double structure similar to the surrounding side walls. In practical terms, it is preferable that the walls be slightly sloped at the bottom, as shown in the figure.

The hot metal F is received from the tap trough 14 of the hot metal furnace into the ladle 15, and at this time, a desulfurization agent D containing CaC ₂ +CaO as a main component is added at the same time and enters the ladle. A known porous plug 16 is installed at the bottom of the ladle 15.
is fitted, and an air supply pipe 17 for blowing out nitrogen gas is attached to the tip, from which nitrogen gas is vigorously injected into the hot metal. For this reason, the molten metal enters a boiling state (bubbling) and the reaction takes place rapidly, but as the receiving progresses, the surface of the molten metal gradually rises, and when it reaches the upper end of the ladle 15, the molten metal F
Only the molten slag S floating on the upper surface falls from the edge and flows down into the processing apparatus 1 placed below. The initial temperature of slag S is almost the same as that of hot metal.
The temperature is 1000°C or more, and it is a reddish-white liquid with high fluidity, but when it enters the processing device 1, it touches the surrounding inner walls and is rapidly cooled and accumulates while decreasing in temperature. When an appropriate amount of air accumulates and the temperature drops to an appropriate level, the air supply port 11 is opened to uniformly blow out an appropriate amount of air from the perforated plate 6 at the bottom over the entire surface. The flammable gas, which is rapidly being generated as the temperature falls, reacts violently with this ejected gas, and the combustion phenomenon begins. When the inflow of new slag from above and the ejection of air from below are in good balance, This phenomenon manifests itself best and lasts for a long time.

To achieve this balance, the blowing pressure and flow rate of compressed air must be well adjusted. The preferable range of the blowing pressure and flow rate is such that the desulfurization slag does not scatter and the compressed air and the desulfurization slag react without being too efficient. Therefore, the pressure and flow rate differ depending on the nozzle diameter and shape at the bottom of the vessel. Furthermore, when jetting is performed inside the vessel, the shape and dimensions of the combustion vessel and the relative positional relationship between the nozzle and the combustion vessel are important. There are also differences, so
Decisions must be made accordingly. Also, by blowing up compressed air, the calcium carbide inside the container burns with residual heat and generates heat, so this heat is absorbed by the cooling water circulating through the partition walls around the four sides, and the box body 5 due to the high temperature is absorbed. It is essential to prevent troubles such as deformation of the hollow box 7 and the occurrence of cracks caused by this. Also, considering that the lower limit of the temperature for desulfurization that can completely eliminate calcium carbide and calcium phosphide is about 300℃ to 600℃, there is no need to heat it to high temperatures when treating desulfurization slag with residual heat. .

When the reaction has sufficiently progressed, the slag has solidified and turned black, and the peculiar odor has almost disappeared, a saucer (noguchi box, not shown) is placed at the bottom of the apparatus, and the box 5 and hollow box 7 are When the lock is released, the slag S inside the box slides down the partition wall and moves into the receiving tray, and the entire receiving tray is transported to a predetermined disposal site for disposal. In this embodiment, the hinge 8
Since the two are engaged vertically, when the box body 5 is lifted up, the hinge 8 opens, and the hollow box 7 pivots around this hinge, so that the bottom part opens by itself. In addition, as mentioned above, the inner walls 3 on the four peripheries and the partition wall 12 in the middle
Since the slope is tapered downward, a unique effect of smooth sliding of the slag S is produced.

[Effects of the invention] As described above, the invention of the present application can significantly improve the working environment by easily disposing of the slag from the ladle, thereby contributing to the health and safety of workers. Naturally, it does not have any effect on the hot metal or its desulfurization treatment, and one of its advantages is that it is easy to implement, as it only requires ancillary work that overlaps with the continuous original work procedure. .

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the present application, and FIGS. 2A and 2B are front sectional views showing a conventional technique. 1... Processing device, 2... Hollow part, 3... Inner wall,
4... Outer wall, 5... Box body, 6... Perforated plate 7... Hollow part, 8... Hinge, 9... Water supply port, 10... Drain port, 11... Air supply port, D... Desulfurization agent, F... hot metal, S... slag.

Claims (1)

[Scope of utility model registration request] The four peripheries of the box are sealed with inner and outer walls that are erected twice across the hollow part, and a hollow box whose top surface is a perforated plate is removably locked to the bottom of the box. A desulfurizing slag processing device characterized in that a circulating cooling water supply/discharge port is installed in the hollow part of the body, and a compressed air supply port is installed in the hollow bottom box.