JPS6244990Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a device for dissolving mill scale using a hydrochloric acid solution, and is particularly applicable to concentrated waste hydrochloric acid generated when recovering hydrochloric acid from the hydrochloric acid pickling waste liquid (hereinafter referred to as waste hydrochloric acid) in a steel material pickling line. Therefore, we propose a device for dissolving mill scale.

Generally, waste hydrochloric acid generated from a steel pickling line is sent to a hydrochloric acid recovery facility, where it is thermally decomposed and hydrochloric acid is recovered. In this hydrochloric acid recovery process, water in the waste hydrochloric acid is evaporated in an intermediate washer using hot air flowing from a sintering furnace to form concentrated waste hydrochloric acid, and this concentrated waste hydrochloric acid is sprayed from the top of the roasting furnace.
The composition of concentrated waste hydrochloric acid consists of total iron and total hydrochloric acid, and the total hydrochloric acid contains free hydrochloric acid.By roasting this concentrated waste hydrochloric acid, the hydrochloric acid is recovered and a constant amount is amount of ferric oxide is produced. This iron oxide is also effectively used as a raw material for ferrite. The best way to increase the production of ferric oxide for ferrite without adding any existing equipment is to dissolve mill scale in the aforementioned free hydrochloric acid to increase the total iron concentration. The technology of this melting device such as mill scale is well known, but
During this dissolution process, oil and light scale components adhering to the mill scale are entrained in the dissolving solution, resulting in various problems as described below.

(i) It adheres and floats inside packed towers and tanks, worsening operational conditions.

(ii) It adheres and settles inside the piping, causing poor fluid flow.

(iii) The liquid pumped by pumps is defective.

In order to prevent the above-mentioned problems with the equipment, floating light scale components and attached oil components in the mill scale must be removed before charging into the melting device. Conventionally, in this case, a method has generally been adopted in which mill scale is placed in a hot water washing tank that can be stirred, heated while being stirred, and then the floating scale and oil are separated. Here, the separated floating scale and oil pass through wastewater sedimentation treatment equipment, where the floating scale is returned to the iron source and the oil is recovered as scum oil. The mill scale that has been washed with hot water is then charged to the melting equipment using a Telfu crane.

FIG. 1 shows an example of a conventional mill scale dissolving apparatus, in which mill scale 2 is placed in a warm water washing tank 1, and washing water 3 is supplied inside. When the cleaning water is heated by the heater 4 installed at the bottom of the hot water washing tank and the mill scale is stirred by pressurized air or power stirring 5, the light scale and oil content 6 in the mill scale are transferred to the inner surface of the hot water washing tank. Float. This suspended matter is sent to a wastewater treatment facility by a wastewater pump 7 for treatment. The deoiled mill scale is loaded into a melting device 9 using a Telfu crane 8.
Dissolve with concentrated waste hydrochloric acid solvent 10.

As described above, in the conventional technology, mill scale is cleaned before it is dissolved, and the process for such hot water washing equipment is complicated, resulting in high equipment investment costs, operation and maintenance costs, and Maintenance is also difficult.

Another method for cleaning mill scale is a method of incinerating oil by heating with a burner, but this method is also expensive in processing costs, as is the case with the hot water washing method.

The present invention solves the problems of the conventional technology as explained above, and when melting mill scale, it eliminates the need for cleaning treatment such as hot water washing before charging into the melting equipment. The mill scale with scale and oil still attached is charged into the dissolving device, and concentrated waste hydrochloric acid is continuously supplied to free and entrain the light scale and oil in the overflowing dissolving solution.
The object of the present invention is to provide a device that easily separates and removes these floating scales and oil.

In the process of dissolving mill scale, the inventor of the present invention
When we conducted a thorough study to streamline this process, we discovered that the traditional method of separating and removing light scale and oil during hot water washing before dissolving mill scale was inefficient and costly. As a result of various research and tests, we found that the concentrated waste hydrochloric acid containing free hydrochloric acid used to dissolve mill scale has a high temperature of 90℃ or more, and instead of the conventional pretreatment of hot water washing, we can directly use concentrated waste hydrochloric acid. Theoretically speaking, if the mill scale is brought into contact with the mill scale, the heat of reaction will be added and high-temperature pickling will be effective, and the experimental results also show that the oil and light scale adhering to the mill scale can be easily separated into the dissolved solution. It has been confirmed that the oil and light scales are separated and removed through such mill scale dissolution treatment, which would be extremely advantageous and achieve the purpose of the present invention. I found out that.

The present invention was developed based on this knowledge, and includes a dissolving device that charges and fills mill scale with light scale and oil still attached, and continuously supplies concentrated waste hydrochloric acid to dissolve the mill scale. , a separation device consisting of a continuous magnetic separation tank and an oil separation tank that separates and removes light scale and oil accompanying the solution discharged from the dissolution device, and a mill to which light scale and oil remain attached. This is a mill scale melting device that directly and continuously melts scale.

In the following, the device of the present invention will be described with reference to the drawings of preferred embodiments. FIG. 2 is an explanatory diagram of the dissolving apparatus, in which mill scale is directly charged and filled into the dissolving apparatus 9 using a Telfu crane, a solvent 10 of concentrated waste hydrochloric acid is supplied upward from the bottom, and the mill scale in the dissolving apparatus is While dissolving the scale, it overflows from the dissolving device as a dissolving solution 11. This solution contains light scale, which is the oil that had adhered to the mill scale. In these separations, floating scale is first removed in a continuous magnetic separation tank 12, but at this time, some of the oil that adheres thereto is also removed. Next, the oil flows into the oil separation tank 13, and the oil 14 floating on the surface of the solution is discharged based on the difference in specific gravity, and then the scale remaining in the solution is removed using a magnet (not shown).

There is also a filtration method as an alternative method, but this method can be adopted depending on the liquid properties of the solvent liquid.
Further, in the above embodiment, the solvent is continuously supplied from the bottom in an upward flow, but it is also possible to continuously supply the solvent in a downward flow from the top.

The mill scale that is dissolved in the device of this invention is metal powder such as pure iron, ferric oxide, and triiron tetroxide, and rust, and the solvent is scale such as hydrochloric acid and iron chloride containing suspended hydrochloric acid. It is a soluble liquid.

As is clear from the above explanation, in the mill scale dissolving apparatus of the present invention, the packed tower is supplemented with the necessary amount of light scale and mill scale with oil attached, as mill scale dissolution progresses. There is no need to control the progress of the process between the hot water washing machine and the packed tower as in the conventional method (see FIG. 1). In addition, in terms of cleaning mill scale, which is a raw material, the present invention uses heat-concentrated waste hydrochloric acid, which is extremely efficient, and removes floating scale from the dissolved solution containing oil and light scale that overflows from the dissolving device. As can be seen from Figure 2, oil separation can be carried out continuously and automatically, and the effects of the present invention are extremely remarkable.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional mill scale dissolving device, and FIG. 2 is a schematic diagram of a mill scale dissolving device according to an embodiment of the present invention. 1...Hot water washing tank, 2...Mill scale, 3...
...Washing water, 4...Heater, 5...Stirring device, 6
...Light scale and oil, 7...Drain pump, 8
... Telfah Crane, 9 ... Melting equipment, 10
... Concentrated waste hydrochloric acid, 11 ... Dissolved liquid, 12 ... Continuous magnetic separation tank, 13 ... Oil separation tank, 14 ...
Oil content, 15...scale, 15'...light scale.

Claims (1)

[Scope of utility model registration request] In a continuous mill scale dissolution device using concentrated waste hydrochloric acid generated when hydrochloric acid is recovered from hydrochloric acid pickling waste, mill scale with light scale and oil still attached is charged and filled, and the concentrated waste hydrochloric acid is continuously supplied. A mill scale dissolution device consisting of a dissolution device for dissolving the mill scale, and a separation device consisting of a continuous magnetic separation tank and an oil separation tank for separating and removing light scale and oil accompanying the dissolved solution discharged from the dissolution device. Device.