JP2015021141A - Collapse prevention device for briquetted article, calcination reduction apparatus and calcination reduction method for steel by-product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a collapse prevention device for a briquetted article capable of reducing generated powder and sufficiently removing volatile substance such as moisture, and a calcination reduction apparatus and a calcination reduction method for a steel by-product.SOLUTION: The collapse prevention device for a briquetted article is provided in which powdery substance is molded into a briquette by a briquetting machine 22, a briquetted article 21a is transferred by transfer means 23a, 23b, and the briquetted article is prevented from collapsing when the briquetted article is charged into a box 24 for transferring the briquette. The collapse prevention device for a briquetted article includes a slope 30 which can absorb impact due to falling of the briquetted article and is provided downstream from the transfer means and immediately above the box for transferring the briquette. After charging the briquette into the box for transferring the briquette, the briquette is charged into a calcination box, the briquette is heated and calcined, and the calcined briquette is charged into an arc type electric furnace together with coke, thereby reducing valuable metal.

Description

  The present invention relates to a method for recovering valuable metals contained in industrial waste. In particular, steel by-products such as iron, nickel, chromium, manganese and other valuable metals, pickling sludge, annealing scales, etc. are made into briquettes, and the briquettes are not collapsed by subsequent handling. The present invention relates to an apparatus for preventing the collapse of a briquette molded product that suppresses the amount of powder generated. Further, the present invention relates to a steel by-product roasting and reducing device provided with the briquette molded product collapse prevention device. Furthermore, the present invention relates to a method for roasting and reducing steel by-products using the steel by-product roasting and reducing apparatus.

  Steel by-products such as steelmaking dust, slag, pickling sludge, and scales during annealing contain valuable metals such as iron, nickel, chromium, and manganese, and many recovery methods have been proposed. It has been. As one of the methods, a method has been proposed in which these by-products are mixed with a carbon source such as coal or coke, molded into a briquette shape, and heated in an arc electric furnace for reduction treatment (for example, Patent Documents). 1 and 2).

  Separately, by-products are mixed with carbon sources such as coal and coke, formed into briquettes, once baked to remove volatile components such as moisture, and then heated in an arc electric furnace. Thus, a reduction method has been proposed (see, for example, Patent Documents 3 to 6).

  In these methods, depending on the components of the raw material, there may be a problem in operation such as hanging on a shelf or blowing up that is considered to be accompanied by an arc electric furnace. Moreover, the meltability and fluidity | liquidity of slag were not appropriate, and there also existed a problem that the recovery rate of valuable metals fell.

  In the method of heating and reducing in an arc type electric furnace after performing the above-mentioned roasting, a method of adding aluminum ash is disclosed in order to effectively recover valuable metals (for example, patent document) 7), since the reaction in the electric furnace was too intense, it was difficult to control the furnace, and there were problems such as shelf hanging.

  The problem of shelves arises due to the powder that is generated when the briquettes collapse. That is, since the powder is preferentially melted, this promotes the sintering and may form a dome-shaped shelf. If it collapses, the moisture contained in the raw material rapidly expands, so-called steam explosion may occur, which is a problem to be prevented.

  For such a problem, a technique for stabilizing the operation is disclosed by defining each raw material mixing ratio of steel by-products such as steelmaking dust, slag, pickling sludge, and scale during annealing (for example, , See Patent Document 8).

  A technique for ensuring the strength of briquettes by defining the particle size distribution of the raw materials within a preferable range is disclosed. Alternatively, a method of operating stably by defining the power input amount and a technique for dropping the briquette so that the briquette does not collapse are also disclosed (see, for example, Patent Documents 9 to 12).

  Although it can be said that the operation has been stabilized by the technical development as described above, the powder was generated at a rate of 13% or more. Even at 13%, the shelf hanging problem has not been completely solved, and new technology development has been desired with the aim of further reducing powder generation.

JP-A-8-260014, JP 2003-247026 A JP-A 61-15929 JP-A 61-177331 JP 61-177332 A JP-A 61-177337 Japanese Patent Laid-Open No. 10-330822 Japanese Patent Publication No. 2008-31548 Japanese Patent Publication No. 2008-240138 Japanese Patent Publication No. 2008-308755 Japanese Patent Publication No. 2008-31549 Japanese Patent Publication No. 2009-7632

  In the method where steel by-products are mixed with charcoal, charged in an arc electric furnace, heated and reduced to recover valuable metals, stable and safe operation is achieved without increasing production costs. Ensuring the recovery rate of valuable metals is an issue. In view of this problem, an object of the present invention is to provide a briquette molded product collapse prevention device capable of reducing powder generated from briquettes and sufficiently removing volatile substances such as moisture. And Furthermore, the present invention provides an apparatus for roasting and reducing steel by-products provided with this apparatus, and a method for roasting and reducing iron by-products using the roasting and reducing apparatus.

  In order to solve the above-mentioned problems, the inventors have eagerly studied a mechanism for generating shelf suspension in an arc electric furnace (submerged type). As a result, it was found that the shelf suspension is generated by a mechanism as shown in FIG. That is, the raw material charged in the arc electric furnace causes a shelf hanging phenomenon due to excessive progress of partial sintering. When it collapses, a so-called steam explosion may occur in which water contained in the raw material rapidly expands. Furthermore, the relationship with the amount of powder contained in the raw material was investigated. As a result, it has been clarified that shelf suspending is caused by excessive sintering because raw materials are easily sintered when powder is present.

  Before the raw material is charged into the arc electric furnace, a preheating step such as roasting may be performed. However, the powder also hinders briquette heating efficiency in the roasting process. As shown in FIG. 2, if there is no powder, ventilation is good, the whole briquette is heated well, and moisture is removed by evaporation by 80 to 100%. However, if there is powder, the powder stays at the bottom, and when it is roasted by a burner, it starts to melt and forms a clumped clinker, which inhibits heating and drying of the briquettes present on the top. As a result, it is brought into an arc electric furnace with moisture and becomes a source of steam explosion. Furthermore, the powder that has not become a clinker is brought into the arc electric furnace as it is, and causes the sintering phenomenon described above. Thus, suppression of powder is an important issue.

  As a result of intensive investigations on the occurrence location, it was found that the powder generated by the mechanism shown in FIG. In other words, it was found that when briquettes were loaded from the belt conveyor into the briquette transfer box, the biggest cause was collapse due to the impact caused by the dropping. Therefore, in the present invention, when powdery substances such as steel by-products are formed into briquettes with a bunker, and the briquette molded products are transferred by a transfer means such as a belt conveyor and are inserted into the briquette transfer box. An apparatus for preventing the briquette molded product from collapsing, characterized in that it is provided with a slope that can absorb an impact caused by dropping of the briquette molded product on the downstream side of the transfer means and immediately above the briquette transfer box. This is an apparatus for preventing the collapse of briquette molded products.

  The slope of the briquette molded product collapse prevention device includes a mechanism that moves up and down according to the height of briquette filling in the briquette transfer box. It is.

  Further, the slope of the apparatus for preventing the collapse of the briquette molded product is a spiral shape, and the apparatus for preventing the collapse of the briquette molded product.

  The spiral slope is an apparatus for preventing the collapse of a briquette molded product, comprising a guide for preventing the fall of the briquette molded product at the outer edge of the slope.

  The spiral slope is an apparatus for preventing the collapse of a briquette molded product, wherein the sliding surface of the briquette molded product is made of a wire.

  The sliding surface of the spiral slope is an apparatus for preventing the collapse of a briquette molded product, wherein the slope is inclined with respect to the spiral shaft portion from the outer edge portion of the slope.

  The spiral slope is an apparatus for preventing the collapse of a briquette molded product, characterized in that the spiral shaft portion rotates in a horizontal plane and moves up and down in the vertical direction, so that the briquette falling portion which is the lower end of the slope rotates and moves up and down. .

  An apparatus for preventing the collapse of a briquette product, wherein the amount of rotation of the spiral slope in the horizontal plane and the amount of elevation in the vertical direction coincide with the inclination of the spiral slope.

  The sliding surface of the spiral slope is an apparatus for preventing the collapse of a briquette molded product, which is inclined by 30 to 45 degrees with respect to a horizontal plane.

  Furthermore, the slope of the apparatus for preventing the collapse of the briquette molded article is provided with a mechanism capable of moving in a horizontal plane in accordance with the position where the briquette is dropped.

  Furthermore, the briquette transfer box is made of steel having a length of 1100 to 1300 mm, a width of 1100 to 1300 mm, and a height of 700 to 900 mm.

  Preferably, the transfer means is a belt conveyor, which transports briquette molded articles at a belt speed of 30 to 60 m / min, and moves the belt conveyor in the transport direction at an installation height of 1000 to 2000 mm directly above the briquette transfer box. An apparatus for preventing the collapse of a briquette molded product, wherein the movable range is 300 to 1000 mm.

  Preferably, the powdery substance is a steel byproduct, and the steel byproduct is steelmaking dust, pickling sludge, and a scale material.

  And it is characterized by comprising a briquetting machine for briquetting steel by-products, a briquette molded product collapse prevention device, a briquette roasting device, and a submerged arc electric furnace as described above. It is a roasting reduction device for steel by-products.

  Furthermore, steel by-products are briquetted together with coke in a bunker, and then the briquette is loaded into the briquette transfer box using the briquette molded product collapse prevention device described above, and then the briquette is roasted. A roasting reduction method for steel by-products, which is replaced with a baking box, where briquettes are heated and roasted, and the roasted briquettes are charged into an arc electric furnace together with coke to reduce valuable metals. is there. The steel by-product is a method of roasting and reducing steel by-product, wherein the steel by-product is steelmaking dust, pickling sludge, and scale material.

  According to the present invention, when a briquette is formed by a bunker, and the briquette is inserted into the briquette transfer box from the transfer means, the collapse prevention device suppresses the collapse of the briquette molded product, thereby preventing powder generation. It becomes possible to reduce. As a result, the raw material can be sufficiently heated in the roasting step, and moisture can be removed effectively. Ultimately, the shelf hanging in the reduction process of the arc electric furnace is reduced, stable operation is realized, and high productivity can be obtained.

  Furthermore, according to the present invention, a high recovery rate of valuable metals is obtained, and it is possible to stably produce valuable metals such as Fe, Ni, Cr, and Mn from steelmaking dust, pickling sludge, and scale materials that have been discarded as industrial waste. Since metal can be secured, a part of these raw materials can be compensated, which can contribute to the reduction of manufacturing costs and the preservation of the global environment.

It is a figure which shows blowing up typically. It is a figure which shows the roasting state of the briquette in a roasting box. It is a schematic diagram which shows the briquette insertion from the transfer means in a prior art to the box for briquette transfer. (A) is a schematic diagram which shows the briquette insertion to the box for briquette transfer from the transfer means in one Embodiment of this invention, (b) is a schematic diagram which shows the slope for collapse prevention. (A) is a schematic diagram showing immediately after the start of charging briquette charging from the transfer means to the briquette transfer box in another embodiment of the present invention, (b) is a charging after a predetermined time from (a) It is a schematic diagram which shows the middle. It is a schematic diagram which shows the briquette insertion from the transfer means in the other embodiment of this invention to the box for briquette transfer. It is a schematic diagram which shows the briquette insertion from the transfer means in the other embodiment of this invention to the box for briquette transfer. It is a schematic diagram which shows the briquette insertion from the transfer means in the other embodiment of this invention to the box for briquette transfer. (A) is a schematic diagram which shows the briquette insertion from the transfer means in the other embodiment of this invention to the box for briquette transfer, (b) is a schematic diagram which shows the helical slope for collapse prevention. It is the perspective view which showed typically the helical slope part for the collapse prevention in embodiment of FIG. (A)-(c) shows the change with progress of time. It is the top view which showed typically the helical slope part for the collapse prevention in embodiment of FIG. (A)-(c) shows the change with progress of time.

  The apparatus for preventing collapse of a briquette molded product according to the present invention is basically based on a method of recovering valuable metals Fe, Ni, Cr and Mn from steel byproducts, and this valuable metal recovery method will be described later. Mixing steel by-products with a specific composition such as moisture, fats and oils and carbonaceous materials (coke) into a briquette with a machine, and then roasting the briquette in a roasting box, After further mixing carbonaceous materials and limestone and / or silica sand, this mixture is charged into an arc electric furnace (submerged type) and heated to reduce valuable metals and separate them into metal and slag. .

  Here, the briquette molded product collapse prevention device of the present invention is located on the downstream side of the belt conveyor and directly above the transfer box when the briquette is transferred by the belt conveyor and the briquette is loaded into the briquette transfer box. By installing a slope on which briquettes can be placed and filling the box via this slope, the impact caused by the fall of the briquette is absorbed and the collapse of the briquette is suppressed, resulting in the generation of powder. It is to reduce.

First Embodiment FIG. 3 is a schematic diagram showing the arrangement of a conventional dumper, transfer means, and briquette transfer box, and FIG. 4 is a schematic diagram in which the apparatus for preventing collapse of a briquette molded product according to the present invention is arranged in addition to FIG. Shown in As shown in FIG. 3, the powdery substance (steel by-product) is mixed with a carbonaceous material and moisture at a predetermined ratio, and is compression-molded by the forming machine 22 to form a briquette 21 a. The briquette 21a is transferred by transfer means 23 such as a belt conveyor, and is filled in the briquette transfer box 24 at the most downstream side. At this time, conventionally, the transfer box 24 is filled in a state of being projected from the transfer means 23 in the horizontal direction. Since the briquette molded product 21a is simply in a compressed state, there is a problem that a part of the briquette molded product 21a is destroyed due to the impact of the collision at the time of projection and powder is formed.

  In the first embodiment of the present invention shown in FIG. 4, in addition to the apparatus configuration of the conventional example, a slope 30 for preventing the collapse of the briquette molded product is located on the most downstream side of the transfer means 23 and immediately above the briquette transfer box 24. Is provided. The slope 30 includes an impact absorbing portion 30b made of a flat plate member and a shaft portion 30a connected to the upper end of the impact absorbing portion. The shaft portion 30a is held by a holding means (not shown) at the upper end thereof.

  According to the first embodiment of the present invention, the briquette molded product 21a projected from the transfer means 23 once collides with the impact absorbing portion 30b, then slides down the slope of the impact absorbing portion 30b, and the briquette transfer box 24 is dropped. Filled in. At this time, the shock absorbing portion 30b functions as a cushioning material, and is dropped using a slope instead of free-falling as in the prior art, so that the impact and powder generation when filling the box 24 is reduced. There is an effect that can be done.

  Since the slope 30 of the briquette molded product collapse prevention device of the present invention suppresses the impact caused by the fall of the briquette 21a, immediately after the briquette is placed in the briquette transfer box 24, the briquette is placed on the iron plate on the bottom of the box. It is the most time to be wary of the collapse to hit directly. Therefore, at the beginning, the lower end of the slope (the briquette falling end) should be lowered from the bottom surface to a height of 100 to 300 mm.

  In addition, the inclination angle with respect to the horizontal surface of the shock absorbing portion 30b of the slope 30 is preferably 15 to 50 °, and the width of the shock absorbing portion 30b is preferably in the range of 200 to 500 mm.

Second Embodiment FIG. 5 shows a schematic diagram of a second embodiment of the present invention. As shown to Fig.5 (a), the collapse prevention apparatus 31 of the briquette molded product of 2nd Embodiment is the slope (impact absorption part 30b + shaft part 30a) 30, and the wire 31c connected to the upper end of the shaft part 30a. A pulley 31b for hanging the wire 31c, an elevating means 31d to which the other end of the wire 31c is connected, and a housing 31a for holding them.

  In the initial stage of filling the briquette molded product 21a into the briquette transfer box 24, as described in the first embodiment, the briquette falling end of the slope 30 is lowered from the bottom surface to a height of 100 to 300 mm. Since the filling of the briquette 21a proceeds and the filling height rises, as shown in FIG. 5 (b), the lifting / lowering means 31d is operated accordingly, and the slope 30 is raised.

  In this way, the height of the slope 30 can always be maintained at the optimum position in accordance with the filling height of the briquette. According to the present embodiment, not only the impact on the projected briquette 21a itself can be reduced, but also the briquette that has already been filled can be reduced from receiving an impact from a newly filled briquette. It is preferable.

  At this time, the slope 30 of the anti-collapse device may be raised by using the lifting means 31d as human power, but personnel must be arranged. Therefore, it is a desirable embodiment to have a mechanism that rises as the briquette is filled into the briquette transfer box 24. It is better to use a motor for the power to raise.

Third Embodiment A schematic diagram of a third embodiment of the present invention is shown in FIG. As shown in FIG. 6, the briquette molded product collapse prevention device 31 of the third embodiment includes a slope 30 (impact absorbing portion 30b + shaft portion 30a), a wire 31c connected to the upper end of the shaft portion 30a, and a wire 31c. , A lifting / lowering means 31d to which the other end of the wire 31c is connected, a casing 31a for holding them, and a horizontal movement means 31e provided at the bottom of the casing 31a. As the horizontal movement means 31e, a known means such as operating a wheel and an axle with a motor or the like can be adopted.

  According to the second embodiment described above, it is possible to always maintain the height of the slope 30 at the optimum position according to the filling height of the briquette 21a as described above, but the slope 30 is moved in the horizontal direction. Therefore, the briquette 21a is filled in a mountain shape centering on the position where the slope 30 is first installed. Therefore, the filling height may be uneven in the horizontal direction in the briquette transfer box 24, and it may be necessary to level it. On the other hand, according to the third embodiment, since the horizontal movement means 31e is provided at the lower part of the casing 31a of the briquette molded product collapse prevention device 31, the collapse prevention device in a direction where the briquette filling height is insufficient. 31 can be moved in the horizontal direction, and the briquette molded product 21a can be more uniformly filled without manually leveling the piles of briquettes.

4th Embodiment The schematic diagram of 4th Embodiment of this invention is shown in FIG. As shown in FIG. 7, the briquette molded product collapse preventing device 31 of the fourth embodiment includes a slope 30 (impact absorbing portion 31b + shaft portion 31a), shaft rotating means 31f connected to the upper end of the shaft portion 31a, It comprises a wire 31c connected to the shaft rotating means 31f, a pulley 31b for hanging the wire 31c, an elevating means 31d to which the other end of the wire 31c is connected, and a housing 31a for holding them. The shaft rotating means 31f can be, for example, a motor.

  According to the fourth embodiment, as in the third embodiment, as described above, the briquette filling height can be prevented from being biased in the horizontal direction in the second embodiment. Specifically, the slope 30 can be rotated to an arbitrary position by 360 degrees by operating the shaft rotating means 31f. Thus, the slope of the shock absorbing portion 310b of the slope 30 can be filled in a desired direction in which the briquette 21a should be filled, and the briquette molded product 21a can be further added without leveling the briquette pile manually. It can be filled uniformly.

  Furthermore, as shown in FIG. 8, it is also possible to employ a configuration in which both the horizontal direction moving means 31e of the third embodiment and the shaft rotating means 31f of the fourth embodiment are provided. According to this embodiment, it is possible to fill the briquette 21a by moving the slope 30 to any location in the briquette transfer box 24 and arbitrarily selecting the falling direction.

Fifth Embodiment FIG. 9 shows a schematic diagram of a fifth embodiment of the present invention. As shown in FIG. 9, the briquette molded product collapse prevention device 31 of the fifth embodiment includes a spiral slope 32, a shaft rotation means 31 f connected to the upper end of the shaft portion 32 b of the spiral slope 32, and a shaft rotation. It comprises a wire 31c connected to the means 31f, a pulley 31b for hanging the wire 31c, an elevating means 31d to which the other end of the wire 31c is connected, and a housing 31a for holding them. The spiral slope 32 of the fifth embodiment includes a shaft portion 32b and a briquette sliding surface 32a formed in a spiral shape around the shaft portion 32b.

  A briquette supply chute 25 for supplying briquette 21a to the spiral slope 32 is provided at the most downstream portion of the transfer means 23, and the briquette supply chute 25 has a briquette sliding surface 32a of the spiral slope at the tip. It is arranged so as to be in contact with or close to.

  In the first to fourth embodiments described above, briquette 21a that has been transported by the belt conveyor 23 is released from the belt conveyor 23 with a momentum, although briquette collapse and powder generation are suppressed more than before. And collides with the slope 30. On the other hand, in the fifth embodiment, since it is directly supplied to the inclined surface 32a of the spiral slope 32 without being projected through the briquette supply chute 25, the momentum due to the momentum of the briquette 21a, that is, the inertia is generated. It can be suppressed and is more preferable. The briquette 21a once discharged from the belt conveyor 23 is preferably rotated along the spiral while reducing the momentum. Therefore, the inclination angle of the spiral slope is preferably 30 to 45 degrees, and the spiral slope is preferable. The width is preferably in the range of 200 to 500 mm.

  The operation of the briquette molded product collapse prevention device 31 according to the fifth embodiment will be described with reference to FIGS. FIG. 10 is a perspective view showing step by step the briquette filling process in the fifth embodiment, and FIG. 11 is a corresponding plan view. A briquette supply chute 25 is installed on the downstream side of the transfer means 23, and the downstream end of the briquette supply chute 25 is located on the briquette sliding surface 32 a of the spiral slope 32 of the collapse prevention device 31 for the briquette molded product. The position is adjusted to be close.

As shown in FIGS. 10 (a) and 11 (a), in the initial stage of briquette charging, the elevating means 31d and the shaft rotating means are arranged so that the briquette supply chute 25 is connected to the vicinity of the upper portion of the spiral slope 32. The height of the spiral slope 32 in the vertical direction is set by appropriately operating 31f. At this time, the lower end portion of the spiral slope 32 is located at a height indicated by H ₁ from the bottom surface of the briquette transfer box 24.

When the supply of the briquette molded product 21a is started, the briquette molded product 21a is supplied from the transfer means 23 via the briquette supply chute 25 to the spiral slope 32 along the direction indicated by the arrow A, and slides on the sliding surface 32a. The briquette transfer box 24 is filled. Since the height H ₁ of the lower end portion of the helical slope 32 height close to the bottom surface of the briquette transport boxes, there is an effect that it is possible without disrupting the briquettes 21a, to fill.

  If the elevating means 31d and the shaft rotating means 31f are operated as appropriate when the filling height of the briquette reaches a predetermined height, the spiral slope 32 rotates in the direction indicated by the arrow B around the shaft portion. , Rising in the direction indicated by arrow C. At this time, the ratio of the amount of rotation B of the spiral slope 32 in the horizontal plane (by the shaft rotating means 31f) and the amount of vertical rise C of the spiral slope 32 (by the elevating means 31d) is determined as the slip of the spiral slope. If it sets so that it may correspond with the inclination of the surface 32a, the sliding surface 32a will not be displaced apparently. For this reason, the position of the sliding surface 32a itself into which the briquette supply chute 25 is inserted and whose tip is in contact with or close to the surface does not appear to rise, so that the briquette supply chute 25 does not hinder the rise of the spiral slope 32.

This state is shown in FIGS. 10 (b) to (c) and FIGS. 11 (b) to (c). As shown in FIG. 10 (b) ~ (c) , the rotation and elevation of helical slope, slope lower end height increases, the height from the bottom surface is _changed with _{H 2,} H _3, H ₄ (H ₁ <H ₂ <H ₃ <H ₄ ).

  Thus, like the first to fourth embodiments, the lower end of the slope can be raised following the increase in the briquette filling height. At the same time, as shown in FIGS. 11A to 11C, the lower end of the slope is also moving in the circumferential direction. Thereby, since a filling position can be changed also in the horizontal surface in the box for briquette transfer, the filling of briquette does not shift to one place but can be filled more uniformly.

  Also, as shown in FIGS. 10 and 11, the spiral slope 32 appears to be spiral when the ratio of the amount of rotation in the horizontal plane to the amount of vertical rise matches the slope of the sliding surface 32a. The slope 32 itself is not displaced, and only the upper and lower ends of the slope appear to rise while rotating. Therefore, the briquette supply chute 25 inserted on the spiral slope 32 does not hinder the rotation of the spiral slope 32, and its position is not changed throughout the steps (a) to (c). There is an effect that it is not necessary to adjust the position of the briquette supply chute 25 every 32 operations.

  In the fifth embodiment, the briquette sliding surface of the spiral slope can be configured by a flat plate member, but as shown in FIG. 10, it is preferable to configure it by a wire rod because friction between the briquette and the sliding surface is reduced. . Further, it is preferable because the powder generated slightly from the briquette can be sieved downward without remaining on the sliding surface.

  Further, as shown in FIG. 9, when a guide 32c is provided on the outer peripheral portion of the sliding surface or an inclination is provided from the outer peripheral portion of the sliding surface 32a toward the shaft portion 32b, the briquette 21a is placed outside the helical slope 32 by centrifugal force. It is preferable that it can be prevented from falling. When providing an inclination from the outer peripheral part of the sliding surface toward the shaft part, the inclination is preferably 1 to 10 degrees.

  When the briquette transfer box is made of steel having a length of 1100-1300 mm, a width of 1100-1300 mm, and a height of 700-900 mm, the apparatus of the present invention obtains the best embodiment. The reason is that if the size of the briquette transfer box is such that length × width × height exceeds 1300 mm × 1300 mm × 900 mm, transport by forklift becomes difficult. Moreover, when length x width x height is less than 1100 mm x 1100 mm x 700 mm, the conveyance efficiency is lowered, and as a result, productivity is lowered. For this reason, the size of the briquette transfer box is defined such that length × width × height is 1100 to 1300 mm × 1100 to 1300 mm × 700 to 900 mm. Preferably, length × width × height is 1150 to 1250 mm × 1150 to 1250 mm × 750 to 850 mm.

  The belt conveyor is transported at a belt speed of 30 to 60 m / min. When the belt speed of the belt conveyor is less than 30 m / min, the briquette transport efficiency is lowered, and as a result, the productivity is lowered. Moreover, when it exceeds 60 m / min, the momentum of a briquette will become high too much and it will hit a slope strongly and will become easy to collapse. Therefore, it was set to 30 to 60 m / min. Preferably, it is 40-50 m / min.

  The installation height is preferably 1000 to 2000 mm immediately above the briquette transfer box. If the installation height of the belt conveyor is less than 1000 mm, there is a risk of contact with the belt conveyor when the briquette transfer box is lifted and transported by a forklift, and if it is 2000 mm or more, the fall distance becomes large and the briquette's momentum increases. The impact will increase. Therefore, 1000-2000 mm is preferable. More preferably, it is 1200-1800 mm, More preferably, it is 1400-1600 mm.

  It is more preferable that the range in which the belt conveyor can be moved in the transport direction is 300 to 1000 mm. The reason why this should be done is that if the belt conveyor can be moved in the carrying direction, the position of the briquette molded product collapse prevention device can be finely adjusted after the briquette transfer box is installed.

  In addition, if the collapse prevention apparatus of the briquette molded product demonstrated as mentioned above is used, as shown in the Example mentioned later, the amount of powder generation is suppressed to less than 13%.

The present invention also provides a steel by-product roasting and reducing apparatus provided with the briquette molded product collapse prevention apparatus.
Specifically, it is composed of a machine for briquetting steel by-products, a briquette molded product collapse prevention device, a briquette roasting device, and a submerged arc electric furnace as described above. This is a roasting and reducing apparatus for steel by-products. By reducing the powder, roasting briquettes becomes efficient and effective, the briquettes can be dried, and 90% or more of the briquettes in the roasting box can be heated to 800 ° C. When this briquette is charged into an arc electric furnace and reduced, stable operation can be performed without causing a shelf hanging phenomenon.

Furthermore, a method for roasting and reducing steel by-products using the above apparatus is also provided.
The steel by-product is briquetted together with coke in a clustering machine, and then the briquette is charged into the briquette transfer box using the briquette molded product collapse prevention apparatus described above. In this way, the briquette transfer box loaded with briquettes is transported by a forklift, and the process proceeds to the roasting process described below.

  First, the briquette is replaced with a roasting box, and the briquette is heated and roasted. As a specific briquette roasting process, the upper part of the roasting box is sealed with a duct, and the lower part is ignited with a burner while sucking it using a wind blower, so-called roasting treatment is performed to volatilize water. As a result, the average moisture content of briquettes in the roasting box can be 6 wt% or less, and preferably the average moisture content of briquettes of 70 wt% or more in the roasting box can be 5 wt% or less. Furthermore, the briquette strength after roasting is specifically 50 kgf / piece or more, and the generation of powder when charged in an arc electric furnace can be suppressed. Thus, since the briquette after roasting can suppress generation | occurrence | production of powder and the moisture content can also be reduced, it can prevent a shelf hanging phenomenon in the reduction | restoration process by an arc electric furnace.

As a specific valuable metal recovery process, the roasted briquette is charged into a submerged arc electric furnace and heated to separate it into a metal part and a slag part, such as Fe, Ni, Cr, Mn, etc. Collect valuable metals. Moreover, at the time of charging to an electric furnace, limestone and / or quartz sand can be added as appropriate for the purpose of adjusting the amount of slag and basicity (CaO / SiO ₂ ), and depending on the composition of the raw material, carbonaceous materials can be added as appropriate. . In particular, on the slag side, a sufficient amount of slag can be ensured by using the reducing and recycling raw material having the above chemical components, and the meltability and fluidity can be controlled in a preferable region. Although the most desirable slag composition is not particularly limited, it contains CaO, SiO ₂ , Al ₂ O ₃ , MgO at 80% by mass or more, and the ratio of CaO / SiO ₂ is 0.8 to 1.4, preferably 1.0. 1.2, the content of _Al 2 _{O 3} is in the range of 0.6 to 7.0 wt%. Furthermore, as an important point in this reduction step, it is desirable to control the concentration of Cr ₂ O ₃ that is relatively difficult to reduce to 5% or less. This can be achieved by suppressing the powder as described above. In other words, briquette roasting becomes efficient and effective, briquettes can be dried, and more than 90% of the briquettes in the roasting box can be heated to 800 ° C, enabling stable operation without causing the shelf hanging phenomenon. This is because the reduction efficiency increases.

The steel by-product is preferably a steelmaking dust, pickling sludge, or a scale material.
1. Steelmaking dust: Steelmaking dust is generated in the refining process of stainless steel, and in order to ensure the content of valuable metals Fe, Ni, Cr and Mn, and also in the steel by-products, SiO ₂ , Al ₂ O ₃ , MgO In order to control the concentration within a suitable range, the blending ratio is preferably 10 to 50% by weight.

2. Pickling sludge: Pickling sludge is generated in an annealed pickling line, and in order to ensure the content of valuable metals Fe, Ni, Cr and Mn, and also suitable for CaO, F and S concentrations in steel by-products. In order to control to the range, the blending ratio was specified to be 5 to 30% by weight. Further, since the pickling sludge contains a large amount of S, if the S content is too high, desulfurization becomes difficult, so the mixing ratio of the pickling sludge is preferably limited to 30% by weight or less.

3. Scale material: The scale material is produced by hot rolling, continuous casting or the like, and is a raw material containing valuable metals Fe, Ni, Cr, and Mn. Since this raw material has a relatively coarse particle size, it acts as an aggregate when it is briquetted. Therefore, in order to ensure the content of valuable metals Fe, Ni, Cr and Mn and to exhibit the effect as an aggregate, the blending ratio of the scale material is preferably 30% by weight or more.

  In addition, for briquette molding, moisture and oil are required for the purpose of connecting particles. Moisture is necessary to secure an initial briquette strength of 20 kgf / piece or more after molding and before roasting. The moisture content is preferably 10 to 26% by weight because briquette strength cannot be obtained if the moisture content is too low or too high. In addition, this content rate is a ratio with respect to the total weight of said solid raw material. For example, it is 150-260 kg with respect to the raw material 1t.

  The oil is preferably added to supplement the initial briquette strength after molding and before baking. If the oil content is too high, briquette strength cannot be obtained. In addition, this content rate is a ratio with respect to the total weight of said solid raw material. For example, with respect to the raw material 1t, it is 30 kg or less.

  In addition, for briquetting, a carbon material is necessary as a heat source and a reducing agent. The carbonaceous material in the present invention is preferably blended in an amount necessary for the reduction reaction and as a heat source in the roasting step, in an amount of 10 to 20% by weight, that is, 100 to 200 kg with respect to 1t of the blended raw material.

In the present invention, by blending the above material composition in the above ratio, the chemical component in the raw material is at least one of FeO, MnO, NiO, Cr ₂ O ₃ : 27% by mass or more in total, Al ₂ O _3: 0.3 to 3.5 wt%, MgO: 2 to 7 wt%, CaO and SiO _2: 35 mass% in total less, F: 1 to 6 wt%, S: 0.1 to 2 wt% ZnO: 2 mass% or less, and thereby, slag obtained in an electric furnace can have characteristics suitable for operation.

  In addition, although each said structural component is described as an oxide except S and F, since it is complicated, such as a hydroxide, a fluoride, sulfide, and a sulfate, it is described as an oxide for convenience. . The valuable metals in the present invention are not particularly limited, but include at least iron, nickel, chromium, and manganese.

  As mentioned above, although the collapse prevention apparatus of the briquette molded product of the present invention has been described by exemplifying the technology for producing and transferring the powder of steel byproduct, the present invention is not limited to the field of steel byproduct, for example, Included in the present invention as long as it is a field related to the transport of metal powder and alloy powder compression molded products in powder metallurgy, resin powder molded products, and pharmaceutical and food compacted products. It is what is done.

Next, the effect of this invention is demonstrated using the Example of this invention.
Steelmaking dust, pickling sludge, and scale material were blended at the material composition ratio shown in Table 1, and carbonaceous material, moisture, and oil were mixed. The moisture and oil are externally mixed, and the mixing ratio is based on the weight of the mixed raw material as 100. Subsequently, it was molded into briquettes using a twin roll type machine. In addition, the carbon material was mix | blended with the weight of 100-200 kg with respect to the mix | blended raw material 1t as a part required for a reductive reaction, and a heat source in a roasting process. Three types of blends A, B, and C were prepared and used for verifying the effect.

  Next, the briquettes molded as described above and transported by the belt conveyor were charged into the briquette transfer box, and then charged into the roasting box from the briquette transfer box. The size of the briquette transfer box was 1200 mm × 1200 mm × 800 mm. And the upper part of the roasting box was sealed with a duct, and the lower part was heated with a burner for 20 to 30 minutes while being ignited while being sucked using a wind exhauster, and the roasting process was performed for 120 to 180 minutes. Thereby, while volatilizing a water | moisture content, the raw material particle | grains inside each briquette were sintered. Finally, the heated and dried briquette was put together with the carbonaceous material into the arc type electric furnace, and the reduction treatment was performed by heating with electricity. The obtained metal is an Fe—Ni—Cr—Mn alloy.

In the example described here, the following items in Table 2 were used for evaluation of each operation.
Amount of powder generated: A sieve having a mesh size of 20 mm was used to measure the weight under the mesh as the amount of powder.
Presence / absence of shelf suspension: During operation of the arc electric furnace, the presence or absence of shelf suspension was monitored.
When the Cr ₂ O ₃ concentration in the slag exceeds 5%, it was determined that the reduction was insufficient. For the analysis, a fluorescent X-ray analyzer was used.

<Conventional example>
As shown in FIG. 3, the briquette (formulation A) was charged into the briquette transfer box without using the briquette molded product collapse prevention device. The evaluation results are shown in Table 2.

<Invention Example 1>
As shown in FIG. 4, briquettes (formulation B) were charged into a briquette transfer box using a briquette molded product collapse prevention device. The slope angle was 35 ° with respect to the ground. In addition, the slope was raised manually and at the same time the briquette was smoothed using a scraper. The evaluation results are shown in Table 2.

<Invention Example 2>
As shown in FIG. 5, briquette (formulation C) was charged into a briquette transfer box using a briquette molded product collapse prevention device. The slope angle was 25 ° with respect to the ground. Also, the slope was automatically raised and lowered using a lifting motor, but because the charging position in the horizontal plane was fixed, a person used a scraper to level the briquette. The evaluation results are shown in Table 2.

<Invention Example 3>
As shown in FIG. 8, briquette (formulation A) was charged into the briquette transfer box using a briquette molded product collapse prevention device. The slope angle was 35 ° with respect to the ground. In addition, the slope was automatically raised and lowered using the lifting motor, and the briquette was leveled so that the charging position could be changed using the shaft rotation motor in order to make the charging position uniform in the horizontal plane. . The evaluation results are shown in Table 2.

<Invention Example 4>
As shown in FIG. 9, briquette (formulation B) was charged into a briquette transfer box using an apparatus for preventing the collapse of a briquette molded product having a spiral slope. The angle of the sliding surface of the spiral slope was 40 degrees with respect to the ground. Briquette by using a lifting means and a shaft rotation motor to rotate and raise the slope shaft part at a ratio matching the slope slope so that the charging position can be changed in the vertical and circumferential directions. Smoothed. The evaluation results are shown in Table 2.

<Invention Example 5>
FIG. 8, FIG. 2 (a), FIG. 1 (a) is an example which shows the roasting reduction apparatus of the steel byproduct of this invention, and the roasting reduction method of an iron byproduct. That is, the briquette (formulation A) which was molded by a bunker and transported by a belt conveyor was charged into a briquette transfer box. At that time, the briquette was loaded into the briquette transfer box using a briquette molded product collapse prevention device. The slope angle was 40 ° with respect to the ground. Also, the slope was automatically raised and lowered using a lifting motor, and in order to make the charging position uniform, the charging position was changed using a shaft rotation motor and the briquette was leveled. The evaluation results are shown in Table 2.

  In Invention Example 5, the briquette transfer box was charged into the roasting box. The size of the briquette transfer box was 1200 mm × 1200 mm × 800 mm. And the upper part of the roasting box was sealed with a duct, and the lower part was heated with a burner for 20 to 30 minutes while being ignited while being sucked using a wind exhauster, and the roasting process was performed for 120 to 180 minutes. Thereby, while volatilizing a water | moisture content, the raw material particle | grains inside each briquette were sintered. Finally, the heated and dried briquette was put together with the carbonaceous material into the arc type electric furnace, and the reduction treatment was performed by heating with electricity. The obtained metal is an Fe—Ni—Cr—Mn alloy.

  In the field of transporting powdered compacted molded products and charging them into containers, it is promising because it can suppress the collapse of molded products and improve the yield.

DESCRIPTION OF SYMBOLS 1 ... Submerged arc electric furnace, 2 ... Raw material briquette for reduction | restoration recycling, 3 ... Electrode, 4 ... Slag part, 5 ... Reduction metal part, 6 ... Hole, 7 ... Shelf-lifting, 11 ... Unroasted briquette,
12 ... roasting box, 13 ... burner, 14 ... exhaust air, 15 ... ventilation in the box, 16 ... roasting briquette, 17 ... clinker, 21a ... briquette molded product, 21b ... powder, 22 ... dumper machine, 23 DESCRIPTION OF SYMBOLS Transfer means (belt conveyor), 24 ... Briquette transfer box, 25 ... Briquette supply chute, 30 ... Collapse prevention slope, 30a ... Shaft portion, 30b ... Shock absorber, 31 ... Collapse prevention device, 31a ... Housing, 31b ... pulley, 31c ... wire, 31d ... elevating means, 31e ... horizontal movement means, 31f ... shaft rotating means, 32 ... spiral slope, 32a ... briquette sliding surface, 32b ... shaft portion, 32c ... guide.

Claims (16)

A device for preventing the collapse of the briquette molded product when the powdery substance is molded into briquettes with a bundling machine, and the briquette molded product is transferred by a transfer means and inserted into a briquette transfer box,
An apparatus for preventing the collapse of a briquette product, comprising a slope that is capable of absorbing an impact caused by the fall of the briquette product, on the downstream side of the transfer means and directly above the box for briquette transfer.   The apparatus according to claim 1, wherein the slope includes a mechanism that moves up and down in accordance with a height at which the briquette molded product is filled into the briquette transfer box.   The apparatus according to claim 1 or 2, wherein the slope has a spiral shape.   The briquette molded product collapse prevention device according to claim 3, wherein the spiral slope includes a briquette molded product fall prevention guide at an outer edge of the slope.   The briquette molded product collapse prevention device according to claim 3 or 4, wherein the spiral slope has a sliding surface of the briquette molded product made of a wire.   The apparatus for preventing collapse of a briquette molded product according to any one of claims 3 to 5, wherein the sliding surface of the spiral slope is inclined with respect to the spiral shaft portion from the outer edge portion of the slope.   7. The spiral slope according to any one of claims 3 to 6, wherein the spiral shaft portion rotates and moves up and down, so that the briquette dropping portion which is the lower end of the slope rotates in the horizontal plane and moves up and down in the vertical direction. The briquette molded product collapse prevention device described.   The briquette molded product according to claim 7, wherein the amount of rotation of the spiral slope in a horizontal plane and the amount of elevation in the vertical direction coincide with the inclination of the spiral slope. Collapse prevention device.   The briquette molded product collapse prevention device according to any one of claims 3 to 6, wherein a sliding surface of the spiral slope is inclined by 30 to 45 degrees with respect to a horizontal plane.   The said slope is provided with the mechanism which can move in the horizontal surface according to the fall position of a briquette, The collapse prevention apparatus of the briquette molded product in any one of Claims 1-9 characterized by the above-mentioned.   The briquette molded product according to any one of claims 1 to 10, wherein the briquette transfer box has a length of 1100 to 1300 mm, a width of 1100 to 1300 mm, and a height of 700 to 900 mm. apparatus.   The transfer means is a belt conveyor, which transports the briquette molded product at a belt speed of 30 to 60 m / min, and can move the belt conveyor in the transport direction at an installation height of 1000 to 2000 mm directly above the briquette transfer box. 12. The briquette molded product collapse prevention device according to claim 1, wherein the range is 300 to 1000 mm.   The apparatus for preventing collapse of a briquette molded product according to any one of claims 1 to 12, wherein the powdery substance is a steel byproduct.   The briquette molded product collapse prevention device according to claim 13, wherein the steel by-products are steelmaking dust, pickling sludge, and scale material.   A briquetting machine for briquetting steel by-products, a briquette molded product collapse prevention device according to any one of claims 1 to 14, the briquette roasting device, and a submerged arc electric furnace. An apparatus for roasting and reducing steel by-products. Iron and steel by-products are briquette-formed with coke in a clustering machine, and then the briquette is loaded into the briquette transfer box using the briquette molded product collapse prevention device according to any one of claims 1 to 14, After that, the briquette is replaced with a roasting box, the briquette is heated and roasted, and the roasted briquette is charged with coke into an arc electric furnace to reduce valuable metals. Baking reduction method.

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