JP6447323B2 - How to recycle roll waste - Google Patents

Description

  The present invention removes oil from roll debris (polishing debris, cutting debris) generated during grinding or cutting of metal working rolls used in steel manufacturing processes such as hot rolling rolls and cold rolling rolls of steel. The present invention relates to a method of reducing, removing, or further reducing and removing a grindstone component from roll scraps and recycling it as a roll raw material for metal working or a stainless steel raw material.

  Metal working rolls used in the steel manufacturing process are periodically ground and cut to maintain a good surface condition. At that time, polishing scraps and cutting scraps, which are roll scraps, are generated.

  Since both polishing scraps and cutting scraps contain valuable metals such as nickel, chromium, molybdenum, tungsten, vanadium in addition to iron, it is desired to reuse them. However, since both the grinding scraps and the cutting scraps have a special shape and are small in size, it is not easy to handle them as metal scraps. For example, when polishing scraps are put into a melting furnace described later, there is a problem that polishing scraps having a special shape and size are easily scattered from the melting furnace.

  Moreover, when reusing abrasive scraps and cutting scraps, the most common conventional technique is to put them into a melting furnace (component adjustment and refining process) for manufacturing metal working rolls together with raw materials such as iron alloys. There is. However, since polishing scraps and cutting scraps contain oil, they are included in these when they are put into a melting furnace such as an arc furnace or induction furnace as part of the raw material for a metal processing roll. It is not preferable in terms of work safety due to the flames caused by the oil. Therefore, in order to reuse abrasive scraps and cutting scraps as raw materials for metal processing rolls, it is possible to improve the ease of handling of abrasive scraps and cutting scraps, and to remove oil contained in abrasive scraps and cutting scraps, Alternatively, reduction is required.

  The techniques disclosed in the following Patent Documents 1 to 4 are known as techniques for facilitating handling of polishing scraps and cutting scraps, and techniques for separating (reducing or removing) oil from metal scraps.

  In Patent Document 1, although it is not a steel manufacturing process, cutting scraps of the same metal material are mixed with abrasive sludge (also referred to as polishing scraps) such as aluminum, and compressed to be briquetted (agglomerated or molded). It is described that the handling is easy.

  Patent Document 2 describes that metal cutting scraps are mixed with roll cutting scraps and agglomerated by compression to facilitate handling and use as an iron source. Patent Document 2 also describes that oil content is squeezed out and reduced by compression.

  In Patent Document 3, although it is not a steel manufacturing process, after pulverizing aluminum dairy powder (a kind of cutting waste) to which moisture and oil have adhered, it is put into a drying furnace, and moisture and It is described that oil is reduced by evaporation and pyrolysis.

  Although it is not a metal cutting waste, in order to separate fats and oils from a metal processed product (intermediate product), a technique for separating and removing oil using a solvent (also referred to as an extractant) has been studied. For example, in Patent Document 4, in order to separate oil applied during processing or oil applied for rust prevention from metal processed products such as metal processed metal parts, a hydrocarbon-based cleaning agent is sprayed onto the metal processed products. And performing degreasing cleaning. In Patent Document 4, it is described that the degreasing waste liquid generated at the time of degreasing and cleaning is regenerated in a distillation facility, and a cleaning device for cleaning a metal workpiece and a distillation for regenerating the degreasing waste liquid. A vacuum degreasing and cleaning facility that has an apparatus has been proposed.

JP 2003-277842 A JP 2007-16256 A JP 2009-144994 A JP-A-7-166385

Iron and steel, Vol.80 (1994) No.7, pp.N386 to pp.N389

  In Patent Document 1, it is considered that handling easiness of polishing sludge is improved by briquetting the polishing sludge. However, in patent document 1, there is no description about separation and removal of oil contained in polishing sludge and cutting waste. Moreover, the grindstone component mixed at the time of grinding | polishing is not examined. Usually, the oil concentration in the polishing sludge is 3 to 15% by mass, and it is considered that it is difficult to sufficiently reduce the oil concentration even if the oil content can be squeezed out to some extent only by the described compression.

  In Patent Document 2, it is considered that the ease of handling of the roll grinding waste is improved by agglomerating the roll grinding waste. Patent Document 2 describes that moisture is reduced by agglomerating roll scraps, but it is also described that oil is not reduced as much as moisture. Specifically, in the example of Patent Document 2, the oil content is reduced to only 2.5% by mass, and in the method described in Patent Document 2, there is a limit in reducing the oil content, and the oil content is charged into the melting furnace. In this case, it cannot be said that the oil content is sufficiently reduced until the generation of flame, smoke, etc. can be avoided.

  In Patent Document 3, evaporation and thermal decomposition are performed for oil removal. When this method is applied to polishing scraps of metal processing rolls, the polishing scraps of metal processing rolls are composed of fine particles and contain 3 to 15% by mass of oil. During evaporation and pyrolysis, most of the metal processing roll abrasive debris is oxidized. Therefore, in order to use the polishing scraps of the metal processing roll from which oil has been removed as a raw material for the metal processing roll, it is necessary to perform a reduction process for reducing the polishing scraps after removing the oil. Processing cost becomes high.

  In patent document 4, it examines only for the metal processed goods to which the oil component adhered, and about the correspondence method with respect to the metal scrap to which moisture, a grindstone component, etc. have adhered like the polishing scrap of a metal processing roll. Not considered.

  In addition, various metal components are included in the metal processing roll used in the steel manufacturing process, and the metal components included differ depending on the type of the metal processing roll (for example, Non-Patent Document 1 is described). For each material of the work roll for hot strip rolling. Therefore, the metal components contained in the polishing scraps and cutting scraps generated from the metal processing roll are also various and diverse. Therefore, since the metal components are various and diverse, it is difficult to effectively reuse the polishing scraps and cutting scraps because complicated sorting is required for the polishing scraps and cutting scraps. Moreover, even if it is the cutting waste with a big size, when the cutting waste containing various metal components is mixing, the technique which isolate | separates cutting waste in addition to oil separation was not disclosed.

  Therefore, an object of the present invention is generated when polishing or cutting a metal working roll used in a steel manufacturing process, and because it contains a large amount of oil and is fine, roll scraps that are difficult to handle are thrown into a melting furnace. The present invention is to provide a method for recycling roll scraps that can be safely and effectively reused as a raw material for rolls for metal processing.

  As described above, the metal components contained in the polishing scraps and cutting scraps generated from the metal processing roll are various and diverse. However, it is not realistic to finely separate the abrasive scraps and cutting scraps from the small size of each component. Therefore, the present inventor has sought a method for effectively separating polishing scraps and cutting scraps in order to efficiently reuse the polishing scraps and cutting scraps generated from the metal processing rolls as metal processing roll raw materials. It was.

  Under such circumstances, the present inventor has intensively studied effective separation, and as a result, the metal working roll used in the steel manufacturing process basically includes Fe, Cr, Ni, and Mo which are metal components. In addition, it can be roughly divided into a metal processing roll containing one or more metal components of W and V, which are expensive and precious, and a metal processing roll which does not contain any metal component of W or V. I found out that I can do it. Furthermore, the present inventor also presents metal processing rolls containing Nb and Co, which are metal components, among the metal processing rolls. These rolls include one or more metals selected from W and V. They also found that they often contain ingredients.

  Therefore, polishing scraps that are one of metal processing roll scraps include a group of polishing scraps (α group) containing Fe, Cr, Ni, and Mo, and not including any of W and V, Fe, Cr, Collected and separated and separated into groups of abrasive scraps (β group) containing Ni and Mo and containing any one or more of W and V, and removing moisture and oil in each group Then, after reducing and removing the oil, the scraps from each group are put into a melting furnace for manufacturing each metal processing roll used in the steel manufacturing process as part of a raw material such as iron alloy. Invented the invention.

  Further, the inventor of the above-mentioned separated α group polishing scraps contains main components of austenitic stainless steel and duplex stainless steel (austenitic / ferritic), which are a kind of stainless steel. It has been found that the α group polishing scraps after removal can be charged as a part of raw materials into a melting furnace for producing these stainless steels.

  Furthermore, the present inventor conducted further studies and collected cutting scraps, which are another type of metal processing roll scraps, in two groups, α and β, as well as polishing scraps, and additionally pulverized them. It can be put into the melting furnace as a part of the raw material without mixing oil to the cutting waste by mixing the same group of abrasive scrap after oil removal with the cutting waste after crushing I found.

  In addition, when the present inventor examined the operational safety when reusing abrasive scraps and cutting scraps, as described in detail below, in order to avoid problems such as flame and smoke in the melting furnace, When putting into a melting furnace, the knowledge that it was preferable to make the oil content contained in the input raw material containing grinding | polishing waste and cutting waste into 0.1 mass% or less was acquired. Furthermore, as the investigation continued, the present inventor found that in the metal processing roll used in the steel manufacturing process, the amount of roll scrap generated was about 10% of the production amount of the metal processing roll. When considering using roll scraps (polishing scraps, cutting scraps) as a raw material to replace part of the alloy iron, etc., which is the raw material for processing rolls, it is possible to use up to about 10% of the total raw material. Derived that it is reasonable. Based on such results, the present inventor found that the oil content in the alloyed iron contained in the input raw material is zero, so the oil concentration in the polishing scrap and cutting waste used as the input raw material is 1% by mass. It has been found that the following is preferable. That is, the present inventor, based on the above-described original investigation, in order to reuse abrasive scraps and cutting scraps as a raw material for metal processing rolls safely, effectively, and at low cost, It had the original knowledge that it was preferable to reduce the oil concentration contained in the cutting waste to 1% by mass or less.

  In order to solve the above-described problems, the present invention has the following configuration.

(1) Generated when polishing a metal processing roll used in the steel process, and contains polishing scraps containing oil and moisture, including Fe, Cr, Ni, and Mo, but not including any of W and V A separation management process of polishing waste, which is separated and managed as a first polishing waste and a second polishing waste containing Fe, Cr, Ni, and Mo and containing any of W and V,
Moisture removal step of the polishing scraps by drying the separated first polishing scraps and the second polishing scraps to remove moisture,
The first scrap and the second scrap after removal of moisture are each washed with a solvent to remove the oil component of the scrap,
A metal component recovery step of polishing scraps in which the first polishing scraps and the second polishing scraps after oil removal are respectively put into a melting furnace to recover metal components;
A method for recycling roll waste, comprising:

(2) It is generated when polishing a metal processing roll used in an iron and steel process, and polishing scraps containing oil and water contain Fe, Cr, Ni, and Mo, but do not contain any of W and V. A separation management process of polishing waste, which is separated and managed as a first polishing waste and a second polishing waste containing Fe, Cr, Ni, and Mo and containing any of W and V,
Moisture removal step of polishing waste, wherein the separated first polishing waste and the second polishing waste are each dried to remove moisture,
The first scrap and the second scrap after removal of moisture are each washed with a solvent to remove the oil component of the scrap,
A first cutting that occurs when cutting a metal working roll used in the steel process and contains oil, Fe, Cr, Ni, and Mo, but does not include any of W and V. Cutting waste separation management process for separating and managing waste and second cutting waste containing Fe, Cr, Ni, and Mo, and including any of W and V,
A crushing step of cutting waste for crushing the separated first cutting waste and the second cutting waste, respectively,
A first mixing step of mixing the first polishing waste after oil removal and the first cutting waste after crushing, the second polishing waste after oil removal, and the second after crushing A mixing step including at least one of a second mixing step of mixing the cutting scraps of
Melting the first polishing waste and the first cutting waste after the first mixing step and / or the second polishing waste and the second cutting waste after the second mixing step. A metal component recovery process for polishing scraps and cutting scraps, which is put into a furnace and recovers metal components,
A method for recycling roll waste, comprising:

(3) The above-mentioned (1), further comprising a polishing waste molding step of molding the first and second polishing scraps after oil removal between the oil removal step and the metal component recovery step. ) Recycling method for roll waste as described in).

(4) Between the mixing step and the metal component recovery step, the first polishing waste and the first cutting waste after mixing, or the second polishing waste and the second after mixing. The method for recycling roll waste according to (2) above, further comprising a molding step of forming cutting waste.

(5) The roll according to (2) or (4), wherein in the crushing step, the first cutting waste and the second cutting waste are crushed to a size of 5 mm to 40 mm. How to recycle trash.

(6) After the oil removal step, the method further includes a magnetic separation separation step of the polishing scraps that separates the first and second polishing scraps into magnetized and non-magnetized materials using magnetism,
The method for recycling roll waste according to any one of (1) to (5) above, wherein the separated magnetic deposit is used in a subsequent step.

(7) In the metal component recovery step,
From the first polishing scraps, or the first polishing scraps and cutting scraps, a metal component as a metal processing roll raw material or a stainless steel raw material is recovered,
In the above (1) to (6), the second polishing scrap, or the metal component as the roll material for metal processing, is recovered from the second polishing scrap and the cutting scrap. The method for recycling roll waste according to any one of the above.

(8) The method for recycling roll waste according to any one of (1) to (7) above, wherein in the oil removal step, the oil is removed until the oil concentration becomes 1% by mass or less. .

(9) The method for recycling roll waste according to (6) or (7) above, wherein in the oil removal step, the oil is removed until the oil concentration becomes 0.5% by mass or less.

  According to the present invention, metal processing that occurs when polishing or cutting a metal processing roll used in a steel manufacturing process, and that has a large amount of oil and is fine, makes it difficult to handle roll scraps into a melting furnace. It can be reused safely and effectively as a raw material for rolls.

It is a figure explaining the form of the oil content, grindstone powder, water | moisture content, and metal powder contained in grinding | polishing waste. It is a figure for demonstrating the flow of the recycling method of the roll waste of the 1st Embodiment of this invention. It is a figure for demonstrating the oil-separation apparatus used by embodiment of this invention. Residual oil concentration in the polishing debris, Al ₂ O ₃ concentration of the recovered magnetically attached material in, or is a diagram showing the relationship between the non-magnetically attached quantity concentration. It is a figure for demonstrating the flow of the recycling method of the roll waste of the 2nd Embodiment of this invention. It is the figure which showed the relationship between the magnitude | size after crushing of cutting waste, and bulk specific gravity.

  A method for recycling roll scraps (polishing scraps, cutting scraps) generated during processing of a metal processing roll used in a steel process according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, polishing scraps and cutting scraps used in the following embodiments will be described. Metal working rolls used in the steel manufacturing process are regularly cut and polished in order to maintain a good surface condition. Specifically, the term “polishing” refers to polishing the surface of a metal working roll using a grindstone or the like in a grinder such as a grinder, and polishing scraps are generated when polishing is performed. Since polishing is performed using an oil for polishing, 3-15% by mass of oil is contained in the polishing waste, and a grindstone component (main components are Al ₂ O ₃ , SiO ₂ , SiC) is 3-15. May be included by mass. Further, the polishing scraps are often very fine with a diameter of 500 μm or less.

Further, the cutting means that a metal working roll is formed by a lathe used for rough cutting, and cutting waste is generated when cutting is performed. Since cutting is performed using cutting oil, the cutting waste may contain 0.5 to 2% by mass of oil. Further, the cutting waste is often thin, warped, or curled. Therefore, the bulk specific gravity of the cutting waste is as small as 0.1 to 0.5 g / cm ³ .

  Oils contained in abrasive scraps and cutting scraps are mainly abrasive oils and cutting oils, but also include various processing oils such as heat treatment oils, rust prevention oils, rolling oils, lubricating oils, greases, etc. Also good. Moreover, in many cases, these polishing scraps and cutting scraps are stored outdoors, and moisture due to rainwater adheres to them. Specifically, as shown in FIG. 1, in the polishing scrap 10, the metal powder 100 and the grindstone powder 110 are covered with an oil component 120. Further, the cutting waste does not include grinding stone powder, but the oil content 120 and the moisture 130 have substantially the same form as the polishing waste.

(First embodiment)
Next, the recycling method of the roll waste of 1st Embodiment using the grinding | polishing waste produced | generated when grind | polishing the metal processing roll is demonstrated using FIG. FIG. 2 is a diagram illustrating a flow of the roll scrap recycling method according to the first embodiment. As shown in FIG. 2, in the roll scrap recycling method of the first embodiment, a separation management process, a moisture removal process, an oil removal process, and a metal component recovery process are sequentially performed.

(Separation management process)
First, in the separation management step, polishing scraps generated during polishing of the metal processing roll include a group of polishing scraps including Fe, Cr, Ni, Mo and not including any of the metal components of W and V ( (α group) and a group of polishing scraps (β group) containing Fe, Cr, Ni, Mo and one or more metal components of W, V.

  Further, the separation management process will be described in detail.

  As described above, the metal working roll used in the steel process includes, in addition to Fe, Cr, Ni, Mo, a metal working roll containing one or more metal components of W, V, Fe, It can be roughly divided into rolls for metal processing that contain Cr, Ni, Mo and do not contain any of the metal components W and V. Among metal processing rolls, there are also metal processing rolls containing Nb and Co, but these metal processing rolls are often metal processing rolls containing either W or V. .

  In addition, a type of stainless steel includes austenitic stainless steel and duplex stainless steel (austenite / ferrite), and the metal working roll of this stainless steel material contains Fe, Cr, Ni, and may contain Mo. . Furthermore, the metal processing roll may contain a small amount of W, V, Nb, and Co, but there are few types.

  Therefore, in this embodiment, polishing scraps of metal processing rolls used in the steel process, α group polishing scraps (including Fe, Cr, Ni, and Mo, but not including W and V), Separately managed into β-group polishing scraps (containing Fe, Cr, Ni, and Mo and including one or more of W and V). By doing in this way, it becomes possible to hold the metal components of W and V, which are expensive metals, in the β group polishing scraps at a high content without thinning, and is used in the steel process. As a raw material for the metal processing roll, it is possible to efficiently recover the metal component. That is, the α group polishing scraps can efficiently recover metal components as raw materials for metal working rolls or stainless steel used in the steel process. In addition, since the generation amount of polishing scrap of the metal processing roll is very small, about 1/10 compared to the production volume of the metal processing roll, and even smaller than the production volume of stainless steel, metals other than the above components are used. Even if the component is mixed in a small amount in the raw material of the metal working roll, the influence on the metal working roll or stainless steel produced from the raw material is small. Therefore, in the first embodiment, it is only necessary to classify into the α group polishing scraps and the β group polishing scraps, and it is not necessary to subdivide into three or more groups.

  Moreover, since it only classifies into the (alpha) group grinding | polishing waste and (beta) group grinding | polishing waste, the separation process of 1st Embodiment can be implemented easily. For example, in factories that process or mold metal processing rolls, collection boxes have often been installed in the past, so that abrasive scraps generated when processing or molding metal processing rolls are expressed as α, β By installing a collection box that collects for each group of polishing scraps, it is possible to easily recover for each of the α and β group polishing scraps. In addition, a recovery line for recovering α group polishing waste and a recovery line for recovering β group polishing waste according to the metal processing roll to be polished is installed at the metal processing roll processing site. However, the separation may be performed, and the method is not particularly limited.

(Moisture removal process)
Next, the moisture removal process will be described. In the moisture removal step, moisture is removed from each of the separated polishing scraps at 100 to 120 ° C. and normal pressure. As a method of drying and removing, for example, a drying machine such as a hot stove or a rotary kiln can be used. Moreover, since the drying time of polishing waste differs depending on the state of the polishing waste, the dryer to be used, and the like, it is preferable to determine by experimenting in advance, but the drying time is about 15 to 60 minutes.

(Oil removal process)
Next, the oil removal process will be described.

  Polishing waste contains 3-15 mass% of oil. However, as described above, when putting the polishing scraps into the melting furnace, it is necessary to reduce the oil content in the polishing scraps to 1% by mass or less. As described above, in view of safe operability, it is preferable to make the oil concentration of the polishing scrap almost zero.

  In order to make the oil concentration of polishing scraps almost zero, a method of incinerating polishing scraps in a combustion furnace and burning the oil as in Patent Document 3 can be considered. However, in this method, since the metal component in the polishing scrap is almost oxidized, it is necessary to reduce it again. Therefore, in the oil removal process of the present embodiment, a method of removing oil using a solvent is used. According to this method, since the oil component is removed with almost no oxidation of the metal components in the polishing scraps, there is no need to perform reduction. Specifically, for example, each group of polishing scraps is washed with a solvent having a boiling point of 30 ° C. or higher and lower than 250 ° C. to remove oil from the polishing scraps. Then, in order to volatilize the solvent adhering to the polishing scraps, the solvent is heated to the boiling point or higher of the solvent, and the solvent adhering to the polishing scraps is removed from the polishing scraps. As the solvent, lipophilic solvents are preferable, and specific examples include alkane substances having 5 to 14 carbon atoms, diethyl ether, ethyl formate, ethyl acetate, benzene, toluene, xylene, kerosene, cyclodecane, decene and the like. Examples of the solvent product include NS Clean 100, NS Clean 110, NS Clean 200 (manufactured by JX Nippon Oil & Energy Corporation), Daphne Cleaner SD3 (manufactured by Idemitsu Kosan Co., Ltd.), and the like.

  Further, since the appropriate amount of the solvent added to the polishing scraps of each group varies depending on the state of the polishing scraps and the like, it is preferable to determine by experimenting in advance, but approximately 0.1 kg to 1 kg with respect to 1 kg of polishing scraps. It is preferable to add the solvent. Further, since the appropriate contact time between the polishing scrap and the solvent varies depending on the state of the polishing scrap and the like, it is preferable that the contact time is approximately 3 to 15 minutes.

  The oil separation step of the present embodiment can be performed using an existing oil separation device, and the device to be used is not particularly limited. Below, an example of the oil-separation apparatus used by the oil-removal process of this embodiment is demonstrated. As shown in FIG. 3, the oil content separation device 20 mainly includes an oil content separation tank 25, a solvent supply device 22, a temperature adjustment device 21 that adjusts the temperature in the oil content separation tank 25, and an oil content separation tank 25. And a pressure adjusting device 26 for adjusting the pressure. In the oil separation device 20, batch processing is appropriate because the container 23 in which the separated polishing scraps 55 are put in and out of the oil separation tank 25.

  The separated grinding waste 55 is accommodated in the container 23. The polishing debris 55 put in the container 23 is put into the oil separation tank 25 at a normal pressure and a temperature not higher than the boiling point of the solvent. After charging, the solvent 56 is sprayed from the spray nozzle 22, which is an example of a solvent supply device, toward the polishing waste 55 in the container 23. And when the grinding | polishing waste 55 and the solvent 56 contact, the oil component contained in the grinding | polishing waste 55 is extracted to the solvent 56, and an oil component can be isolate | separated and removed from the grinding | polishing waste 55. FIG. After the oil separation / removal is completed, the inside of the oil separation tank 25 is depressurized by the pressure adjusting device 26, and the temperature adjusting device 21 is heated to a temperature equal to or higher than the boiling point of the solvent 56 under reduced pressure, whereby the containers 23 and 23 It is possible to volatilize the solvent remaining in the polishing scraps 55 in the inside and to almost separate the remaining solvent 56. In addition, when injecting the solvent 56, the container 23 containing the polishing scraps 55 may be intermittently vibrated to efficiently extract the oil content.

(Metal recovery process)
Next, the metal component recovery process will be described.

  A melting furnace (an arc furnace, an induction heating furnace, etc.) for manufacturing each metal processing roll used in the steel manufacturing process, together with other alloy raw materials, from each group of abrasive scraps from which oil has been removed in the oil removal process, or Then, it is put into a melting furnace (an arc furnace, an induction heating furnace, a converter, etc.) for producing stainless steel, and the metal components contained in the polishing scrap are collected for producing each metal processing roll. For example, the α group polishing scrap contains the main components of austenitic stainless steel and duplex stainless steel (austenite / ferrite), which are a kind of stainless steel, and therefore melts to produce these stainless steels. A metal component contained in polishing scraps may be collected in order to produce stainless steel by charging it into the furnace as part of the raw material.

(Magnetic separation process)
In addition, grinding scraps may contain a lot of grindstone components, and since the grindstone components become slag components when thrown into the melting furnace, when throwing grinding scraps into the melting furnace, each group It is preferable to remove the grindstone component contained in the polishing scraps in advance. Therefore, in 1st Embodiment, you may perform the magnetic separation process which isolate | separates a grindstone component after an oil content removal process.

As shown in FIG. 1 described above, in the polishing scrap, the metal powder and the grindstone powder are covered with oil, and the oil is further covered with moisture. In many cases, the metal powder has magnetism, but the grindstone component is mainly composed of Al ₂ O ₃ , SiO ₂ , and SiC and has almost no magnetic adhesion. Therefore, the grindstone powder and the metal powder are not fixed. However, the viscosity of the oil is higher than that of water, and the oil with high viscosity loosely binds the metal powder and the grindstone powder, so it is difficult to separate the metal powder and the grindstone powder. In addition, the particle size of the metal powder and the grindstone powder is as small as 500 μm or less, which makes it more difficult to separate them when they are covered with oil.

  Therefore, by performing the magnetic separation process on the polishing scraps of each group that has been dehydrated in the moisture removing process and removed in the oil removing process, the magnetic properties that become the metal component that is the raw material of the metal processing roll can be obtained. Grinding stone powder having no magnetic adhesion can be separated from the metal powder. The magnetic separator used for magnetic separation can be a general magnetic separation device.

Polishing by oil separation, residual oil content of abrasive scraps after removal of oil and moisture, and Al ₂ O ₃ concentration in magnetic deposits (metal powder) recovered by magnetic separation, and residual oil content of polishing scraps, and magnetic separation FIG. 4 shows the relationship with the separation rate of non-magnetized articles (mainly grinding stone powder) separated from scrap. Since the Al ₂ O ₃ component is not included in the metal processing roll and is included only in the grindstone, the Al ₂ O ₃ concentration in the magnetic deposit decreases as the separation rate of the non-magnetic deposit in the polishing scrap increases. did. According to FIG. 4, when the residual oil content in the polishing scrap was 0.5% by mass or less, the Al ₂ O ₃ concentration in the magnetic deposit was drastically decreased. This is because, as shown in FIG. 1, in the polishing debris before removing the oil, the residual oil loosely binds the grindstone powder and the metal powder, so even if magnetic separation is performed, the grindstone powder and the metal It is difficult to separate into powder. However, from the results shown in FIG. 4, it is understood that when the oil concentration of the polishing scrap is 0.5 mass% or less, the grindstone powder and the metal powder can be easily separated by magnetic separation. That is, in order to separate the grindstone powder by magnetic separation, it is preferably performed after removing the oil component, and more preferably after the oil concentration of the polishing scrap is set to 0.5% by mass or less.

The residual oil content of the polishing scraps was obtained by bringing a solvent into contact with the polishing scraps from which the oil and moisture had been removed, extracting the residual oil components with a solvent, volatilizing the solvent, and setting the remaining amount as the residual oil content. Further, the Al ₂ O ₃ concentration in the magnetized material was quantified by analyzing the Al concentration in the acid solution by ICP (Inductively Coupled Plasma) analysis after dissolving the whole amount of the magnetized material with acid. Further, after grinding the scraps from which the oil was completely removed with milk, the magnetized material was collected with a neodymium magnet, and the mass (A) of the non-magnetized material that could not be collected with the neodymium magnet was measured. On the other hand, by extracting the oil content of the polishing scraps with a solvent, the concentration of the oil content in the polishing scraps is changed, and the magnetized material is removed by the neodymium magnet in a state where the polishing scraps of each oil concentration are not crushed with milk. The mass (B) of the non-magnetized material that was separated and could not be recovered with a neodymium magnet was measured. The non-magnetized substance separation rate in FIG. 4 is the ratio of B to A.

(Molding process)
In addition, since the grinding | polishing waste which isolate | separated the water | moisture content and oil consists of fine particle | grains, when throwing into a melting furnace, it is easy to scatter. Therefore, a molding process for molding polishing scraps of each group may be performed between the oil removal process and the metal component recovery process to prevent the polishing scraps from being scattered. By molding the polishing scraps of each group, the polishing scraps are hardly scattered and the metal component can be recovered more effectively.

  As a molding method, there is a conventional method of compression molding by adding a binder such as bentonite to the polishing scraps. However, this method is not a preferable method because the added binder becomes a slag component when charged into the melting furnace. Therefore, as the molding method of the first embodiment, it is preferable to use a molding method in which only a compressive force is applied to the polishing scraps without using a hydraulic reciprocating piston compressor or the like without adding the binder to the polishing scraps. . In compression molding using polishing scraps, the particle size of the polishing scraps is 500 μm or less, so a large compressive force is required, and a compressive force of 5 MPa or more is required.

(Second Embodiment)
Next, the recycling method of the roll waste of 2nd Embodiment using the grinding | polishing waste and cutting waste which generate | occur | produced when grind | polishing the roll for metal processing is demonstrated using FIG. FIG. 5 is a diagram illustrating a flow of the roll scrap recycling method according to the second embodiment. As shown in FIG. 5, in the roll scrap recycling method of the second embodiment, the polishing waste and cutting waste separation management process, the polishing waste water removal process, the abrasive waste oil removal process, and the cutting waste. The pulverization step, the mixing step, and the metal component recovery step are sequentially performed. In addition, a series of processes related to the polishing scraps from the separation management process to the oil removal process and a series of processes related to the cutting scraps from the separation management process to the grinding process may be performed in parallel. In addition, these steps may be performed sequentially, and any series of steps may be completed before the mixing step is performed. In the second embodiment, the process from the polishing scrap separation process to the oil removal process through the moisture removal process is the same as that in the first embodiment, and thus the description thereof is omitted here.

(Cutting waste separation management process)
In the cutting waste separation management process, the cutting waste generated at the time of cutting of the metal working roll, including Fe, Cr, Ni, and Mo, and not including any of W and V in the same manner as the polishing waste. Collected separately into a group of scraps (α group) and a group of cutting scraps (β group) containing Fe, Cr, Ni, and Mo and any one or more of W and V. In addition, the amount of cutting scrap generated from the metal processing roll is very small, about 1/10 of the production amount of the metal processing roll, and even smaller than the production amount of stainless steel, even when combined with the polishing scrap. Even if a small amount of metal components other than the above-mentioned components are mixed in the raw material of the metal processing roll, the metal processing roll or stainless steel produced from the raw material has little influence. Therefore, also in the second embodiment, it is only necessary to separate into two pieces of the α group cutting waste and β group cutting waste, and it is not necessary to finely separate into three or more groups. Similarly to the first embodiment, for example, a collection box for collecting cutting waste generated when processing or molding a metal working roll for each of the α and β group cutting wastes is installed in the factory. Therefore, it can collect | recover easily for every cutting waste of (alpha) and (beta) group. Furthermore, as in the first embodiment, a collection line for separation may be installed in the factory, and the separation method is not particularly limited.

(Cutting process of cutting waste)
Next, the cutting waste crushing step will be described.

When mixing cutting scraps and polishing scraps into the melting furnace, the cutting scraps cut to a certain size are mixed with the polishing scraps, so that the polishing scraps enter the gaps of the cutting scraps and enter the melting furnace. Polishing scraps are less likely to scatter when thrown. Therefore, in this embodiment, it grind | pulverizes with respect to the cutting waste of each group. Cutting scraps generated when cutting metal processing rolls in machining are often slender, warped, or curled, so the bulk specific gravity of the cutting scraps is It is as small as 0.1 to 0.5 g / cm ³ . Therefore, by setting the size of the cutting waste to 40 mm or less, the bulk specific gravity of the cutting waste becomes 1.0 g / cm ³ or more on average, and the void of the cutting waste can be reduced. It becomes easy to be retained in the gap. Furthermore, by setting the size of the cutting waste to 20 mm or less, the bulk specific gravity of the cutting waste becomes 1.5 g / cm ³ on average, and the void of the cutting waste can be further reduced. It becomes easier to be retained. On the other hand, when the size of the cutting waste is 5 mm or less, the entanglement between the cutting wastes is reduced, and the polishing waste is less likely to be held in the gaps between the cutting wastes. It becomes easy. Therefore, in the pulverization step of the present embodiment, the size of the cutting waste of each group is preferably 5 mm to 40 mm, and more preferably 5 mm to 20 mm. For crushing the cutting waste, a crusher such as a rotary hammer crusher, a short axis crusher, or a biaxial crusher can be used. FIG. 6 shows the relationship between the crushing length (= sieve opening) and the bulk specific gravity when crushing the cutting waste. From this, it can be said that the bulk specific gravity is increased by reducing the crushing length (size). In addition, the magnitude | size after crushing of cutting waste is defined by the opening of the sieve used in order to sort out the cutting waste after crushing. For example, when sieving with a sieve having an opening length of 20 mm, the cutting waste under the sieve is referred to as 20 mm-sized cutting waste after crushing. The bulk specific gravity is the mass per unit volume, and in the case of roll scrap, it can be obtained by calculating from the roll scrap capacity and mass in the recovery box using the above-mentioned recovery box.

(Mixing process)
Next, the mixing process will be described. In the mixing step, the pulverized cutting scraps of each group and the same group of polishing scraps are mixed. That is, the α group cutting waste is mixed with the same α group polishing waste, and the β group cutting waste is mixed with the same β group polishing waste. In addition, since cutting scraps often have less oil than polishing scraps, they can be charged into the melting furnace as a part of raw materials by mixing with cutting scraps from which oil has been removed. Therefore, in this embodiment, it is not necessary to remove oil from the cutting waste.

  In addition, since the appropriate mixing ratio of cutting scraps and polishing scraps varies depending on the state of cutting scraps and polishing scraps, etc., oil and metal components contained in the polishing scraps are measured in advance, and the measurement results and production are attempted. It is preferable to determine according to the required characteristics of the metal working roll to be performed. In addition, it is preferable that the ratio of cutting waste and polishing waste is approximately 5 to 0.5 to 1 in terms of mass ratio.

(Metal recovery process)
Next, the metal component recovery process will be described. As in the first embodiment, the mixture of each group of the polishing scraps of each group from which oil has been removed in the mixing step and the crushed cutting scraps of each group, a melting furnace for producing a metal working roll, or It puts into the melting furnace for manufacturing stainless steel, and collect | recovers in order to manufacture the metal component contained in grinding | polishing waste and a cutting waste, respectively, in order to manufacture the roll for metal processing. For example, the α group polishing scraps and cutting scraps are mixed as a part of raw materials into a melting furnace for producing stainless steel such as austenitic stainless steel and duplex stainless steel (austenite / ferrite). The metal component contained in may be recovered to produce stainless steel.

  In addition, the oil content density | concentration of the cutting waste and the grinding | polishing waste which generate | occur | produced at the time of the process of the metal processing roll is 0.5-2 mass% and 3-15 mass%, respectively. However, in this embodiment, since the oil concentration contained in the polishing scraps can be made almost zero by the oil removal step, the mixing ratio of the cutting scraps and the polishing scraps also in the mixing of the polishing scraps and the cutting scraps. Although it depends, the oil concentration contained in the mixture can be less than 1% by mass.

  In the present embodiment, as in the first embodiment, a molding step for molding a mixture of polishing scraps and cutting scraps is performed between the mixing step and the metal component recovery step, and scattering of the polishing scraps. You may make it prevent further. In the molding process of the second embodiment, cutting waste and abrasive waste are mixed and subjected to compression molding, whereby the cutting waste is deformed, the gap of the cutting waste is further reduced, and the polishing waste is sandwiched by the cutting waste. Since it becomes such a shape, it becomes easy to hold | maintain polishing waste in cutting waste. Moreover, in this embodiment, you may perform the magnetic separation process which isolate | separates a grindstone component after the oil removal process of grinding | polishing waste similarly to 1st Embodiment.

  According to the first and second embodiments, polishing scraps and cutting scraps generated during cutting and polishing of a metal working roll used in the steel process are separately managed in two predetermined groups based on the components of the metal working roll. Furthermore, by removing moisture and oil, and putting them into the melting furnace to recover valuable metal components, the oil is rich and fine. As a raw material for rolls for metal processing to be put in, it can be safely and effectively reused at low cost.

  Further, cutting and polishing of a metal processing roll are often performed at a metal processing roll manufacturing factory or a metal processing factory that performs metal processing. Specifically, cutting is performed at a metal processing roll manufacturing factory (a metal processing roll supplier), and polishing is performed at a metal processing factory (user of a metal processing roll). , Where it occurs. Furthermore, a manufacturing plant and a metal processing plant in which polishing scraps and cutting scraps are generated are often different from a metal processing roll manufacturing plant or a stainless steel manufacturing plant that reuses polishing scraps. However, according to the first and second embodiments, the metal components such as Fe, Cr, Ni, Mo, W, and V in the cutting scraps and polishing scraps can be used effectively. In addition, since the metal value of cutting scraps is highly appreciated, the cost of transporting between the above-mentioned factories is also relatively small, and polishing scraps and cutting scraps can be effectively reused between remote factories. It becomes like this.

  Hereinafter, the present invention will be described based on examples. In addition, this invention is not restrict | limited to the following Example.

  Based on the components of the rolling roll that is used when rolling rolls used in the hot rolling process, cold rolling process, and thick plate process are formed, polishing scraps and cutting scraps are used. , The α group (including Fe, Cr, Ni, and Mo but not including W and V) and the β group (including Fe, Cr, Ni, and Mo, and any one of W and V) Samples separated and managed) were prepared. For comparison, a sample was also prepared in which the generated roll scraps were not separated into the α group and the β group, but separated into only the polishing scraps and the cutting scraps.

  Thereafter, in order to determine the moisture content of the roll scrap, the roll scrap was dried at 110 ° C., and the mass of the roll scrap was measured, whereby the ratio of the mass difference due to drying to the initial mass was defined as the moisture content. Next, in order to determine the amount of oil remaining in the roll scrap, the roll scrap is immersed in a solvent, the oil adhering to the roll scrap is extracted with the solvent, the solvent is volatilized, and the remaining amount is defined as the oil amount. . Next, regarding the concentration of the metal component, the entire amount of roll scrap was acid-dissolved, and then the metal concentration in the acid solution was analyzed and quantified by ICP analysis.

  As a result, as shown in Table 1, unsorted polishing waste of the comparative sample and polishing waste of the example sample (β group), unsorted cutting waste of the comparative sample and cutting waste of the sample for the example (β group) When comparing (β group), it is found that W + V (mass% −dry) in the polishing waste (β group) and the cutting waste (β group) of the sample for example has a high concentration. On the other hand, when comparing the unsorted polishing scrap of the comparative sample and the polishing scrap of the example sample (α group), the unsorted cutting scrap of the comparative sample and the cutting scrap of the sample (α group), By sorting, it can be seen that W + V (mass% -dry) in the polishing waste (α group) and the cutting waste (α group) of the sample for Example has a low concentration.

  Using the polishing scraps and cutting scraps listed in Table 1, a metal raw material (molded body or mixture) was prepared by the methods shown in Examples 1 to 6 and Comparative Examples 1 to 3 below, and the components of the metal material and The bulk specific gravity is shown in Table 2. Furthermore, the obtained metal material was put into a melting furnace as a raw material for a metal working roll together with a normal raw material alloy iron. When only normal alloy iron is charged into the melting furnace, almost all of the metal components can be charged into the melting furnace (almost all of the metal is melted in the melting furnace). When a metal raw material containing “alloy iron and abrasive scraps” or “a mixture or molded body of alloy iron and cutting scraps and abrasive scraps” is put into the furnace, fine roll scraps (especially abrasive scraps) Is easy to scatter and is collected as dust collection dust in a dust collector installed at the top of the melting furnace. Therefore, by calculating back from the change in the amount of metal component in the dust collection dust, the ratio of the metal that was effectively used as the roll metal component or stainless steel component (melted in the melting furnace) of the metal in the roll scrap was estimated. did.

Example 1
The polishing scraps (α group) listed in Table 1 separated by separation management are dried at normal pressure and 110 ° C. for 20 minutes in the above-described water removal step to remove moisture, and then 0.3 kg relative to 1 kg of polishing scraps. Together with n-hexane, and put into an oil separation tank at normal pressure and room temperature to separate the oil for 5 minutes. After removing the oil from the polishing scraps, n-hexane was evaporated from the polishing scraps at 80 ° C.

  The moisture and oil content in the polishing scraps after evaporating n-hexane from the polishing scraps were measured, and both were 0% by mass, and the W and V contents were as low as 0.2% by mass. In order to produce a roll for metal processing, alloy iron: polishing scraps = 9: 1 (mass ratio), was put into a hopper and put into a melting furnace, the amount of scattering was large, but the flame was almost Without generation, about 30% by mass of metal could be used as the metal component of the metal working roll.

(Example 2)
The polishing scraps containing almost no oil after evaporating n-hexane from the polishing scraps in Example 1 were compressed at a pressure of 50 MPa using a hydraulic reciprocating piston compressor, and had a diameter of 90 mm and a thickness of 40 mm. A metal raw material (molded body) was prepared.

In the molded body, the moisture and oil contents were both 0% by mass, and the W and V contents were as low as 0.2% by mass. Moreover, the bulk specific gravity of the molded body was as large as 3.0 g / cm ³ . In order to manufacture a roll for metal processing, it was blended with an alloy iron: the above-mentioned molded body = 9: 1 (mass ratio), put into a hopper, and put into a melting furnace. It was possible to put it into the furnace with almost no flame, and the safety and effectiveness could be confirmed. Furthermore, the said molded object was able to be used as a metal component of the roll for metal processing. Moreover, in order to manufacture stainless steel, it mix | blended with alloy iron and scrap: the said molded object = 30: 1 (mass ratio), when this was put into a hopper and when it put into the melting furnace (arc electric furnace), grinding | polishing waste is It was able to be put into the furnace with almost no scattering and almost no fire, and safety and effectiveness could be confirmed. Furthermore, the said molded object was able to be used as a metal component of stainless steel.

Example 3
The cutting waste (α group) of the examples shown in Table 1 sorted by sorting management was cut to a size of 40 mm or less. Furthermore, the cutting scraps after cutting and the polishing scraps containing almost no oil after evaporating n-hexane from the polishing scraps in Example 1 were mixed to prepare a metal raw material (mixture). In addition, the mixing ratio of grinding | polishing waste and cutting waste was 2: 3 (mass ratio).

  The water content in the mixture was 0.1% by mass and the oil content was 0.9% by mass, which was below the target oil content of 1% by mass. The W and V contents of the above mixture were as low as 0.2% by mass. Moreover, Al and Si content rate of the said mixture were 1.9 mass%, and became lower than 4.4 mass% of Example 2. This is because the grindstone component in the polishing waste is diluted with cutting waste that does not contain the grindstone component. In order to produce a roll for metal processing, alloy iron: mixture = 9: 1 (mass ratio) was blended, put into a hopper, and put into a melting furnace. About 4% by mass was scattered outside the furnace (most of the scattered material was abrasive scraps), but about 96% by mass of the total input material could be charged into the furnace and used as a metal component of a metal processing roll. I was able to. Although a flame was generated at the time of charging, there was no problem in operation.

(Example 4)
In Example 1, a neodymium magnet was brought close to the polishing scraps containing almost no oil after evaporating n-hexane from the polishing scraps, and the magnetized portions were magnetized and collected (magnetic separation process). Thereafter, the mass of the recovered magnetized component and the remaining non-magnetized component were measured. The amount of magnetic adhesion was 92.7% by mass with respect to the polishing scraps before separation by magnetic separation, and the remaining 7.3% by mass was non-magnetic adhesion. The concentration of Al ₂ O ₃ in the magnetic deposit was 0.4% by mass. Then, the cutting waste (α group) described in Table 2 was cut to a size of 30 mm or less by separation management, and the cutting waste after cutting and the abrasive waste collected by magnetic adhesion were mixed. The mixture was supplied to a hydraulic piston compressor, and compressed at a pressure of 50 MPa to prepare a metal raw material (molded body) having a diameter of 90 mm and a thickness of 40 mm. In addition, the mixing ratio of grinding | polishing waste and cutting waste was 2: 3 (mass ratio).

The water content in the molded body was 0.1% by mass and the oil content was 0.9% by mass, which was less than the oil content target value of 1% by mass. The W and V contents in the molded body were as low as 0.2% by mass. Moreover, Al and Si content rate in the said molded object were 0.3 mass%, and became lower than 1.9 mass% of Example 3. In addition, although 0.2 mass% of Si is contained in the metal working roll, Al and Si are mainly derived from the grinding stone components Al ₂ O ₃ and SiO ₂ . Therefore, since Al and Si in the molded body are lower than polishing scraps (α group) described in Table 1, it can be said that Al ₂ O ₃ and SiO ₂ can be separated by the magnetic separation process. Further, the bulk specific gravity of the molded body was as large as 2.8 g / cm ³ . In order to manufacture a roll for metal processing, alloy iron: molded body = 9: 1 (mass ratio), and when this was put in a hopper and put into a melting furnace, the size of the molded body was sufficient. It could be thrown into the furnace without scattering and could be used as a metal component of a metal working roll. Although a flame was generated at the time of charging, there was no problem in operation.

(Example 5)
In Example 1, a neodymium magnet was brought close to the polishing scraps containing almost no oil after evaporating n-hexane from the polishing scraps, and the magnetized portions were magnetized and collected (magnetic separation process). The amount of magnetic adhesion was 92.7% by mass, and the remaining 7.3% by mass was non-magnetized with respect to the polishing debris before magnetic separation. Then, using only the polishing scraps collected by magnetic adhesion, this was supplied to a hydraulic piston compressor and compressed with a pressure of 50 MPa to prepare a metal raw material (molded body) having a diameter of 90 mm and a thickness of 40 mm.

The water content in the molded body was 0% by mass and the oil content was 0% by mass, which was lower than the oil content target value of 1% by mass. The W and V contents in the molded body were 0.2% by mass, which was a low value. Moreover, Al and Si content rate in the said molded object were 0.3 mass%, and became lower than 1.9 mass% of Example 3. In addition, Al and Si are mainly derived from Al ₂ O ₃ and SiO ₂ as grindstone components. Therefore, since Al and Si in the molded body are lower than polishing scraps (α group) described in Table 1, it can be said that Al ₂ O ₃ and SiO ₂ can be separated by the magnetic separation process. Moreover, the bulk specific gravity of the molded body was as large as 3.0 g / cm ³ . In order to produce rolls for metal processing, alloy iron: molded body = 9: 1 (mass ratio) is blended, put into a hopper and put into a melting furnace, and the size of the molded body is sufficient. It was possible to use it as a metal component of a metal working roll without being fired and without causing a flame.

(Example 6)
After polishing waste (β group) shown in Table 1 separated by separation management is dried at atmospheric pressure and 110 ° C. for 20 minutes to remove moisture in the above-described water removal step, 0.3 kg against 1 kg of polishing waste is removed. Together with n-hexane, and put into an oil separation tank at normal pressure and room temperature to separate the oil for 5 minutes. After removing the oil from the polishing scraps, n-hexane was evaporated from the polishing scraps at 80 ° C. The oil content in the polishing scraps after evaporation was 0.05% by mass. A neodymium magnet was brought close to this polishing scrap, and the magnetized portion was magnetized and collected (magnetic separation process). The amount of magnetic adhesion was 90.5% by mass, and the remaining 9.5% by mass was non-magnetized with respect to the polishing debris before magnetic separation. Then, the cutting waste (beta group) of Table 2 sorted by the classification management was cut | disconnected so that it might become a size of 30 mm or less. Furthermore, the grinding scraps after cutting and the polishing scraps collected by magnetic adhesion were mixed. The mixture was supplied to a hydraulic piston compressor, and compressed at a pressure of 50 MPa to prepare a metal raw material (molded body) having a diameter of 90 mm and a thickness of 40 mm. In addition, the mixing ratio of grinding | polishing waste and cutting waste was 2: 3 (mass ratio).

The water content in the molded body was 0.2% by mass and the oil content was 0.6% by mass, which was lower than the oil content target value of 1% by mass. The W and V contents in the molded body were 9.0% by mass, which was a sufficiently high value. Moreover, Al and Si content rate in the said molded object were 0.3 mass%, and became lower than 1.9 mass% of Example 3. In addition, Al and Si are mainly derived from Al ₂ O ₃ and SiO ₂ as grindstone components. Therefore, since Al and Si in the molded body are lower than polishing scraps (β group) shown in Table 1, it can be said that Al ₂ O ₃ and SiO ₂ can be separated by the magnetic separation process. Moreover, the bulk specific gravity of the molded body was as large as 2.9 g / cm ³ . In order to produce a roll for metal processing, alloy iron: molded body = 9: 1 was blended, put in a hopper and put into a melting furnace, and since the size of the molded body was sufficient, there was almost no scattering. It could be put into the furnace and used as a metal component of a metal processing roll. Although a flame was generated at the time of charging, there was no problem in operation.

(Comparative Example 1)
Unsorted polishing scraps listed in Table 2 that are not separated and managed are supplied as they are to a hydraulic piston compressor and compressed at a pressure of 50 MPa to produce a metal raw material (molded body) having a diameter of 90 mm and a thickness of 40 mm. did.

The water content in the molded body was 5.2% by mass and the oil content was 3.2% by mass. Both the water content and the oil content were lower than the unsorted polishing scrap, but exceeded the oil content target value of 1% by mass. The W and V contents in the molded body averaged 2.7% by mass, but fluctuated between 0.9 and 5.1% by mass. Thus, since the fluctuation | variation of W and V content rate was large, it was judged that it cannot be used as a roll raw material for metal processing containing W and V stably. Moreover, Al and Si content rate in the said molded object were 4.5 mass%. Moreover, the bulk specific gravity of the molded body was 2.2 g / cm ³ .

(Comparative Example 2)
Unsorted polishing scraps shown in Table 2 that are not separated and mixed with unsorted cutting scraps shown in Table 2 that are not separated and cut to a size of 100 mm or less were mixed to create a metal raw material. In addition, the mixing ratio of grinding | polishing waste and cutting waste was 2: 3 (mass ratio).

The water content in the mixture (mixture) was 4.2% by mass, and the oil content was 3.9% by mass, exceeding the target oil content value of 1% by mass. Although the average W and V content in the above mixture was 3.8% by mass, it varied greatly between 2.3 and 5.9% by mass. Therefore, as a roll material for metal working containing W and V stably, Judged that it can not be used. Moreover, Al and Si content rate in the said mixture were contained 2.3 mass%. The bulk specific gravity of the mixture was 0.4 g / cm ³ . This is thought to be because the gap in the mixture has increased because the size of the cutting scrap after cutting is as large as 100 mm. When alloy iron: mixture = 9: 1 (mass ratio) was mixed and put into a hopper, the mixture was charged into a melting furnace. As a result, about 5% by mass of the total charged raw material was scattered outside the furnace (most of the scattered raw material was About 95% by mass of the total input raw material can be charged into the furnace and used as the metal component of the metal processing roll. However, as mentioned above, the mixture contains W and V. It was thought that the rate fluctuation was large, it could not be used stably as a raw material for metal working rolls containing W and V, and a large flame was generated at the time of charging, and safety during operation could not be ensured.

(Comparative Example 3)
After the polishing scraps (α group) listed in Table 2 separated by separation management were dried at 110 ° C., the oil content was not separated, and a neodymium magnet was brought close to and magnetized and collected (magnetic separation process) ). Almost the entire amount was a magnetized component, and there was almost no non-magnetized component, and it was 1% by mass or less with respect to the polishing waste before magnetic separation. Then, using only the magnetically scraped polishing scraps, it was supplied to a hydraulic piston compressor and compressed with a pressure of 50 MPa to produce a metal raw material (molded body) having a diameter of 90 mm and a thickness of 40 mm.

The water content in the molded body was 0.2% by mass and the oil content was 4.3% by mass. Both the water content and the oil content were lower than the polishing scraps before the magnetic separation process, but exceeded the oil content target value of 1% by mass. The W and V contents in the molded body were as low as 0.2% by mass, and it was judged that they could not be used as a metal working roll raw material. Further, the content of Al and Si in the molded body was 4.2% by mass. This is because magnetic separation was performed without separating the oil component, and the oil component loosely combined the grinding stone powder and the metal powder, so the grinding stone component could not be separated even after performing the magnetic separation. This is thought to be because Al ₂ O ₃ and SiO _{2 that} were left were left. Moreover, the bulk specific gravity of the molded body was 1.8 g / cm ³ .

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 10, 55 Polishing waste 20 Oil content separation device 21 Temperature control device 22 Solvent supply device 23 Container 25 Oil content separation layer 26 Pressure control device 56 Solvent 100 Metal powder 110 Grinding stone powder 120 Oil content 130 Water

Claims (9)

A polishing scrap generated when polishing a metal processing roll used in a steel process and containing oil and moisture contains Fe, Cr, Ni, and Mo, but does not contain any of W and V. A polishing waste separation management process for separating and managing polishing waste and second polishing waste containing Fe, Cr, Ni, and Mo and containing any of W and V,
Moisture removal step of the polishing scraps by drying the separated first polishing scraps and the second polishing scraps to remove moisture,
The first scrap and the second scrap after removal of moisture are each washed with a solvent to remove the oil component of the scrap,
A metal component recovery step of polishing scraps in which the first polishing scraps and the second polishing scraps after oil removal are respectively put into a melting furnace to recover metal components;
A method for recycling roll waste, comprising: A polishing scrap generated when polishing a metal processing roll used in a steel process and containing oil and moisture contains Fe, Cr, Ni, and Mo, but does not contain any of W and V. A polishing waste separation management process for separating and managing polishing waste and second polishing waste containing Fe, Cr, Ni, and Mo and containing any of W and V,
Moisture removal step of polishing waste, wherein the separated first polishing waste and the second polishing waste are each dried to remove moisture,
The first scrap and the second scrap after removal of moisture are each washed with a solvent to remove the oil component of the scrap,
A first cutting that occurs when cutting a metal working roll used in the steel process and contains oil, Fe, Cr, Ni, and Mo, but does not include any of W and V. Cutting waste separation management process for separating and managing waste and second cutting waste containing Fe, Cr, Ni, and Mo, and including any of W and V,
A crushing step of cutting waste for crushing the separated first cutting waste and the second cutting waste, respectively,
A first mixing step of mixing the first polishing waste after oil removal and the first cutting waste after crushing, the second polishing waste after oil removal, and the second after crushing A mixing step including at least one of a second mixing step of mixing the cutting scraps of
Melting the first polishing waste and the first cutting waste after the first mixing step and / or the second polishing waste and the second cutting waste after the second mixing step. A metal component recovery process for polishing scraps and cutting scraps, which is put into a furnace and recovers metal components,
A method for recycling roll waste, comprising:   2. The method according to claim 1, further comprising a polishing waste molding step of molding the first and second polishing scraps after oil removal between the oil removal step and the metal component recovery step. How to recycle roll waste.   Between the mixing step and the metal component recovery step, the first polishing waste and the first cutting waste after mixing, or the second polishing waste and the second cutting waste after mixing. The method for recycling roll waste according to claim 2, further comprising a molding step of molding.   5. The method for recycling roll waste according to claim 2, wherein in the crushing step, the first cutting waste and the second cutting waste are crushed to a size of 5 mm to 40 mm. After the oil removal step, the first and second polishing scraps are further separated by a magnetic separation separation step of polishing scraps using a magnetism to separate magnetically and non-magnetized materials, respectively.
The method for recycling roll waste according to any one of claims 1 to 5, wherein the magnetically adhered product after separation is used in a subsequent step. In the metal component recovery step,
From the first polishing scraps, or the first polishing scraps and cutting scraps, a metal component as a metal processing roll raw material or a stainless steel raw material is recovered,
The metal component as a roll raw material for metal processing is recovered from the second polishing scraps or the second polishing scraps and cutting scraps. Recycling method for roll waste as described in 1.   The method for recycling roll waste according to any one of claims 1 to 7, wherein in the oil removal step, the oil is removed until the oil concentration becomes 1% by mass or less. The method for recycling roll waste according to claim 6 or 7, wherein in the oil removal step, the oil is removed until the oil concentration becomes 0.5 mass% or less.

Images