JP2010017668A - Method for treating slurry generated in iron mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively treat various slurries generated in an iron mill with high efficiency. <P>SOLUTION: Various slurries generated in an iron mill are divided into regulation-requiring slurry requiring at least either pH regulation or solid content concentration regulation and regulation-nonrequiring slurry not requiring both of pH regulation and solid content concentration regulation. This regulation-nonrequiring slurry is fed to a slurry receiving tank 11, and the regulation-requiring slurry is fed to a raw water tank 12, and is mixed with yard waster water. Next, the mixture in the raw water tank 12 is transferred to a neutralization tank 13, is subjected to pH regulation with a neutralizer, and is thereafter transferred to a flocculation tank 14, and a solid content is flocculated using a flocculant. The flocculated solid content is precipitated in a precipitation tank 15, and is subjected to solid-liquid separation into precipitate-containing slurry and a supernatant liquid. The precipitate-containing slurry is fed to the slurry receiving tank 11, and is mixed with the regulation-nonrequiring slurry, and moisture is removed by a dehydrator 17. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for treating various slurries generated in an ironworks.

  In the steelworks, various slurries having different properties (hereinafter, such various slurries may be collectively referred to as various slurries) are discharged. For example, various types of slurries with different liquidity, solid content concentration, solid content particle size, etc. are discharged as well as different types of liquid and solid content constituting the slurry. And the various slurry discharged | emitted is collect | recovered, and it collects in one place and dehydrates.

  Here, an example of a conventional method for treating various slurries will be described with reference to FIG. First, the collected various slurries are collected in the slurry receiving tank 31. And it moves to the neutralization tank 32 and throws in a neutralizer and adjusts pH. The various slurries subjected to such pretreatment are sent to a dehydrator 33 and separated into a dehydrated cake and a dehydrated filtrate. The dehydrated filtrate is sent to the coagulation tank 34, and a flocculant is added to agglomerate a small amount of solid content remaining in the dehydrated filtrate.

Then, the dehydrated filtrate containing the solid content that is easily aggregated and precipitated is transferred from the aggregation tank 34 to the precipitation tank 35 and allowed to stand to precipitate the solid content. When the solid content is sufficiently precipitated, the precipitate and the supernatant are separated into solid and liquid. That is, the supernatant liquid may be sent to the treated water tank 36 and thereafter discharged to the natural world, or may be used for cooling water or the like. The slurry containing a large amount of precipitate is returned to the slurry receiving tank 31 and processed together with various newly collected slurries.
Japanese Patent Laid-Open No. 11-319891 JP 2008-114142 A

Some of the various types of slurry discharged in the steelworks are preferably pretreated before dehydration depending on their properties. For example, it is preferable to neutralize (pH adjustment) the acidic or basic slurry as a pretreatment. Therefore, as described above, a neutralization tank for adjusting the pH of the collected various slurries is provided.
Further, in the dehydration treatment, it is preferable to set the operating conditions of the dehydrator to an optimum value depending on the properties of the slurry such as the solid content concentration and the particle size of the solid content, but the properties of the various slurries discharged are different each time. Therefore, it has been difficult to set the operating conditions of the dehydrator to an optimum value according to the properties of the slurry. Therefore, with regard to the solid content concentration, the collected various slurries are diluted in a large buffer tank (solid concentration) so that the dehydrator can be operated under a constant operating condition no matter what solid content slurry is discharged. The properties of the various slurries may be smoothed by adjustment, but this requires an additional facility (buffer tank), which increases the construction cost of the various slurry processing facilities. When the concentration of solid content is not adjusted, the dehydrating performance of the dehydrator may not be sufficiently exhibited depending on the properties of the slurry.
As described above, the conventional processing of various slurries has to be improved in terms of processing performance and cost.
Then, this invention makes it a subject to solve the problem which the above prior arts have, and to provide the method of processing various slurry generated in an ironworks efficiently and cheaply.

  In order to solve the above problems, the present invention has the following configuration. That is, the processing method of the slurry generated in the steelworks according to the present invention is the need for adjustment of the various slurries generated in the steelworks, the adjustment slurry that requires at least one of pH adjustment and solid content concentration adjustment, and the adjustment that does not require the both adjustments. The slurry is divided into slurry, and the both slurries are incorporated into a treatment process of the yard drainage discharged from the yard where the iron ore is stacked, and the slurry is treated together with the yard drainage. After mixing with waste water and adjusting the pH of the mixture, a flocculant is added to agglomerate the solid content, the agglomerated solid content is precipitated and separated into a supernatant and a slurry containing the precipitate. It is characterized in that a dehydration process is performed by mixing the slurry that does not require adjustment with a slurry containing.

  The method for treating a slurry generated in a steelworks according to the present invention can efficiently and inexpensively treat various slurries generated in the steelworks.

  First, a conventional yard drainage treatment process will be described with reference to FIG. In an ironworks, iron ore (for example, powdered ore) carried by an ore carrier is stacked in a mountain shape on a yard provided outdoors. However, because fine iron ore stacked on the yard may be scattered by the wind and cause dust pollution, water is sprayed on the iron ore stacked in a mountain shape to suppress dust generation. May be in a wet state.

  Then, since fine iron ore is washed away by watering, the yard watering containing floating substances (hereinafter referred to as SS) is discharged from the yard. Since this yard sprinkling may contain SS exceeding the discharge standard, in order to discharge the yard sprinkling to the natural world such as a river, it is necessary to perform a process for removing the SS. In addition, even if it rains on iron ore loaded on the yard, rainwater containing SS is discharged from the yard, so it is necessary to perform a process for removing SS as in the case of the yard watering. There is. Therefore, in the steelworks, a processing facility for processing yard sprinkling and rainwater including SS (in the present invention, yard sprinkling and rainwater including SS discharged from the yard is referred to as “yard drainage”) is provided. .

  Yard drainage discharged from a yard not shown is collected in the raw water tank 21. And the yard drainage of the raw | natural water tank 21 is moved to the neutralization tank 22 through piping, and neutralizing agents, such as slaked lime, are thrown in and pH adjustment is carried out. Next, since SS particles are fine and difficult to precipitate, the pH-adjusted yard drainage is transferred to the agglomeration tank 23, and a flocculant is added to cause aggregation. Then, the yard drainage containing SS that has been easily aggregated and precipitated is transferred from the aggregation tank 23 to the precipitation tank 24 through a pipe and allowed to stand to precipitate SS.

  When SS is sufficiently precipitated, the precipitate and the supernatant are separated into solid and liquid. That is, the supernatant liquid is sent to the treated water tank 25, and the slurry containing a large amount of precipitate is sent to the dehydrator 27 via the slurry storage tank 26 to remove moisture. And the dehydrated filtrate discharged | emitted from the dehydrator 27 is returned to the raw | natural water tank 21, and is processed with a new yard drainage. Further, the dehydrated cake discharged from the dehydrator 27 is discarded or recycled. In addition, the supernatant liquid sent to the treated water tank 25 may be discharged to the natural world, or may be used for cooling water or the like.

Next, an embodiment of the method for treating a slurry generated in an ironworks according to the present invention will be described in detail with reference to FIG. The processing facility of FIG. 1 is a processing facility for processing various slurries and yard wastewater generated in the steelworks, and is a process for incorporating the various slurries into the conventional yard drainage treatment process as shown in FIG. It is.
The various slurries generated in the steelworks are divided into a slurry requiring adjustment that requires at least one of pH adjustment and solid content concentration adjustment, and a slurry that does not require adjustment of pH and solid content concentration. The adjustment-free slurry is sent to the slurry receiving tank 11 and temporarily stored. The various slurries generated in the steelworks often contain iron ore powder and limestone powder generated from raw material processing equipment, blast furnace dust collectors, converter dust collectors and the like as solids.

  On the other hand, the adjustment-needed slurry is sent to the raw water tank 12 where the yard drainage discharged from the yard not shown is collected and mixed with the yard drainage. Since the amount of yard drainage is extremely large compared to the adjustment required slurry, the adjustment required slurry is diluted at high magnification by the yard drainage, and the ratio of the solid content in the adjustment required slurry in the mixture of the adjustment required slurry and the yard drainage. Is extremely low. The solid content concentration of the adjustment slurry generated in the steelworks is different each time, but since it is diluted at a high magnification by the yard drainage as described above, no matter what the concentration adjustment slurry is discharged, The properties of the mixture are almost constant.

  Next, the mixture in the raw water tank 12 is transferred to the neutralization tank 13 through a pipe, and a pH is adjusted by introducing a neutralizing agent such as slaked lime. Since the solid content in the slurry to be adjusted and the SS in the yard drainage are fine and difficult to precipitate, the pH-adjusted mixture is transferred to the agglomeration tank 14, and a flocculant is added to agglomerate. The kind of the flocculant is not particularly limited, and general ones can be used. Then, the solid content and SS-containing mixture of the adjustment-needed slurry that has become easy to aggregate and settle are transferred from the aggregation tank 14 to the precipitation tank 15 through a pipe and allowed to stand, thereby precipitating the solid content and SS of the adjustment-needed slurry.

  When the solid content and SS of the slurry to be adjusted are sufficiently precipitated, the precipitate and the supernatant are separated into solid and liquid. That is, the supernatant liquid is sent to the treated water tank 16, and the slurry containing a large amount of precipitate is sent to the slurry receiving tank 11. Then, a slurry containing a large amount of precipitate and an adjustment-free slurry are mixed in the slurry receiving tank 11, and the mixed slurry is sent from the slurry receiving tank 11 to the dehydrator 17 to remove moisture. The dehydrated filtrate discharged from the dehydrator 17 is returned to the raw water tank 12 and processed together with new yard drainage and adjustment slurry. Further, the dehydrated cake discharged from the dehydrator 17 is discarded or recycled.

  The processing equipment (FIG. 1) of the present embodiment that processes the various slurries and yard wastewater as described above is combined with the conventional various slurry processing equipment (FIG. 2) and the conventional yard wastewater treatment equipment (FIG. 3). In comparison, there are various advantages as follows. For example, even if slurries having different properties such as solid content are discharged, the properties are smoothed by being diluted with yard drainage, so that the dehydrator can be operated under certain operating conditions. Therefore, various slurries generated in the steelworks can be processed efficiently.

In addition, since various types of slurry are incorporated and processed in the yard wastewater treatment facility, apparatuses and tanks common to the conventional various slurry treatment facilities and the conventional yard wastewater treatment facility can be integrated. Therefore, the total construction cost of the processing equipment can be reduced.
Specifically, conventionally, each of the various slurry processing equipment and the yard drainage processing equipment has been provided with a dehydrator. However, in this embodiment, only one dehydrator is required. Moreover, in order to dilute the adjustment-necessary slurry as described above and smooth the properties, a large buffer tank is required, but dilution is performed using a large tank that has conventionally treated yard wastewater. There is no need to add a new buffer tank.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of the processing method of the slurry generated in the steelworks which concerns on this invention, and is a systematic diagram explaining the structure of the processing equipment of various slurry. It is a systematic diagram explaining the structure of the processing equipment of the conventional various slurry. It is a systematic diagram explaining the structure of the processing equipment of the conventional yard drainage.

Explanation of symbols

11 Slurry receiving tank 12 Raw water tank 13 pH adjusting tank 14 Coagulation tank 15 Precipitation tank 16 Treated water tank 17 Dehydrator

Claims (1)

The various slurries generated in the steelworks are divided into the required adjustment slurry that requires at least one of pH adjustment and solid content concentration adjustment, and the adjustment-free slurry that does not require both adjustments, and from the yard where iron ore is stacked Incorporating both of the slurries into the processing process of the discharged yard wastewater, and processing with the yard wastewater,
The slurry to be adjusted is mixed with the yard drainage, and after adjusting the pH of the mixture, a flocculant is added to agglomerate the solids, and the agglomerated solids are precipitated to contain a supernatant and a precipitate. And the slurry containing this precipitate is mixed with the slurry that does not require adjustment to perform a dehydration process.

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