CN116065018A - A high-quality pelletizing method with stainless steel ash and carbon for improving element yield - Google Patents

Abstract

The invention discloses a high-quality ball-making method of stainless steel ash mixed with carbon for improving the yield of elements. The method includes the following steps: (1) The ratio of materials in the ball: the digested stainless steel 300 series dedusting ash, stainless steel oxidation Iron sheet, CDQ dust, organic binder, inorganic binder and water are mixed according to the mass ratio of 70:5:15:2:3:5; (2) Prepare materials; (3) Mix with water; (4) stuffing; (5) initial pressure; (6) final pressure: the pellets from the initial pressure enter the ball conveying belt through the inclined chute at the bottom of the roller briquetting machine, and feed the final briquetting machine. The balls enter and exit the ball belt through the inclined sieve plate at the bottom of the ball briquetting machine, and the crushed and powdered materials are transported to the initial pressure feeding belt through the under-screen return belt to continue the initial pressure, and the cycle is like this; (7) Transshipment.

Description

A high-quality pelletizing method with stainless steel ash and carbon for improving element yield

technical field

The invention relates to the technical field of iron and steel metallurgy, in particular to a high-quality pelletizing method for stainless steel ash mixed with carbon for improving element yield.

Background technique

There is a considerable amount of dust removal in the process of stainless steel making, among which there is a 300 series dust removal dust whose typical composition is shown in the table below.

.

The particle size of the dust removal ash above is extremely fine, and contains high iron oxide and chromium oxide. If it can be reused in the metallurgical process, chromium and iron metal can be reduced and used, which will help reduce the cost of the enterprise while disposing of solid waste. At present, domestic stainless steel enterprises mainly adopt the following two modes for the disposal of stainless steel dust:

First, set up a special silo, together with stainless steel pickling sludge, produce sintered ore in sintering batching, and supply it to the steelmaking process. Most domestic stainless steel enterprises are independent stainless steel production lines with unified design and one-time construction of sintering, ironmaking, steelmaking, and steel rolling. This recycling mode can make full use of valuable elements and has more significant economic and environmental benefits. However, for iron-making and steel-making blast furnaces that are successively built and put into operation while they are under construction, since there are no uniform multiple independent production lines connecting firing-iron-steel-rolling, the blast furnace is cross-supplied to carbon steel or steelmaking after tapping. The stainless steel steelmaking system cannot realize that the chromium-nickel hot metal is exclusively used for stainless steel steelmaking. After a part of the molten iron is supplied to carbon steel, not only the chromium and nickel elements in it cannot be used, but also the quality risk of carbon steel products is increased. This will only reflect the environmental benefits, but not the economic benefits. The difficulty in sintering is the problem of fine dust and shed materials.

Second, build a cold-pressed ball production line in the stainless steel factory of the enterprise, and cold-press the dust and stainless steel mud together, and then use it for stainless steel electric arc furnaces and P-removing converters. When using an electric arc furnace, because nickel-iron blocks and high-carbon ferrochrome are used as metal materials, coke and carbon powder are added to form a high-carbon molten pool, which can reduce most of the nickel and iron in the dust removal dust, and the Chromium achieves 50-60% reduction. Although the economy is not as good as that used in sintering, it realizes that solid waste does not leave the factory, does not diffuse and self-circulates, which is a relatively reasonable method that takes into account both economic and environmental benefits.

In addition, in order to provide enough heat for the AOD furnace in the post-treatment process of the electric arc furnace, it is often necessary to add a part of coke while using high-carbon ferronickel and ferrochromium, so as to increase the carbon in the molten pool while the electric arc furnace is blowing oxygen to generate heat. content, so that AOD furnace has sufficient burning exothermic agent during argon oxygen refining, increases the temperature of AOD furnace molten pool, and improves the effect of decarburization and chromium preservation. Although lump coke has high strength and suitable particle size, it is easy to add through the silo, but the price is often more than 2,000 yuan, which is not economical.

Although the second method of stainless steel dust removal is feasible, due to the characteristics of full powder and high calcium oxide materials that are not easy to form balls, there is also the problem of high cost of pressing balls (the high cost is mainly reflected in the high ratio of binder, the bonding The cost of the agent is high and difficult to lower) and the powder loading rate is large, and it is easy to raise dust. At the same time, the reduction of metal oxides is carried out only by carbon in the molten pool, the reducing atmosphere is insufficient, the reduction kinetics conditions are not ideal, the yield of iron and nickel, especially the yield of chromium is not high, and there is still a lot to improve the yield. big space. At present, there is no relevant technical application to solve the above problems in the domestic application field of stainless steel dust removal ash pelletizing

Contents of the invention

Aiming at the above technical problems, the present invention provides a method for high-quality pelletizing of stainless steel ash mixed with carbon for improving element yield.

In order to achieve the above object, the technical solution of the present invention is specifically as follows:

A high-quality pelletizing method for stainless steel ash mixed with carbon for improving element yield, comprising the following steps:

(1) Ratio of materials in the ball: Digested stainless steel 300 series dust, stainless steel oxide scale, CDQ dust, organic binder, inorganic binder and water according to the mass ratio of 70:5:15:2: 3:5 ratio for proportioning;

(2) Material preparation: stainless steel 300 series dust is digested by special equipment and weighed with a weighing hopper, and the material is fed to the closed feeding belt by electric vibration, and then fed to the mixer; the stainless steel oxide scale is fed to the closed feeding belt Mixer; the organic binder and inorganic binder are placed in the storage bin respectively, weighed with a weighing hopper, fed to the closed feeding belt by electric vibration, and then fed to the mixer; CDQ dust is collected from a small The loader feeds into the cone bin through the reserved side-opening temporary feeding inlet, and the cone bin feeds the material to the weighing hopper with electric vibration, then feeds the material to the closed feeding belt with electric vibration, and then feeds the material to the mixer;

(3) Mixing with water: the rollers of the mixer should rotate no less than 100 times to ensure that the material, water and binder are fully dispersed and mixed to eliminate raw material lumps, and then add water according to the humidity of the material while stirring, so that the material is fully wetted ;

(4) Stuffed material: the mixed material is transported to the large cone bin by a belt conveyor, and the material is firstly picked up from the bottom by electric vibration, and the upper material is guaranteed to be stuffed for more than 3 hours, so as to promote the further dispersion and mixing of material, water and binder;

(5) Initial pressure: The stuffed material is fed by the feeding belt conveyor to the ball pressing machine for the first pass, and the top of the ball pressing machine is equipped with a screw forced feeder to ensure the ball socket on the surface of the roller. fill rate;

(6) Final pressure: The pellets that come out of the initial pressure enter the ball conveying belt through the inclined chute at the bottom of the roller briquetting machine, and feed the final briquetting machine. , crushed and powdered materials are transported to the initial pressure feed belt through the under-screen return belt to continue the initial pressure, and so on;

(7) Transshipment:

1) Outgoing: Multiple sets of outbound belts are connected to convey the finished balls, and finally the initial ball pile is piled up into a cone through the elevation-angle-adjustable ball outbelt conveyor. The balls are raised and the belt moves sideways to form a ring-shaped girder-shaped ball pile. After more than 12 hours of air-drying and aging hardening, it is then shoveled to the large ball pile to continue air-drying;

2) The pellets in the large pellet pile are taken according to the principle of first-in-first-use, and the pellets are transported to the ground warehouse through equipment;

3) The pellets in the ground bin are fed by electric vibration to the auxiliary material feeding belt to the steelmaking distribution platform, and are distributed by the distribution trolley to the high-level feed bin above the electric arc furnace for standby.

Wherein, in the step (6), according to comprehensive consideration of pellet heat transfer, mass transfer, easy pelletization, easy demoulding and production efficiency, the pellets are oval-shaped with a thick middle and thin sides, with a length of 40 mm and a width of 40 mm. 25mm, 15mm thick.

Wherein, in the step (3), the mixer adopts a large wheel mill mixer.

Among them, in 1) of the above step (7), in the production line with sufficient space, more sets of belts are used to connect to control the distance of the ring-shaped ball pile, and a quarter of a ring-shaped short beam is created by raising the belt. Radial storage from the inside to the outside reduces tipping and further reduces debris.

Wherein, in 2) of the step (7), the equipment is used to transport the pellets to the ground warehouse, which is specifically to use a loader to load them into a well-sealed vehicle with a stretchable tarpaulin and transport them to the ground warehouse of stainless steel steelmaking auxiliary materials, and then start the dust removal Then dump.

Wherein, in 2) of the step (7), the equipment is used to transport the pellets to the ground bin. Specifically, the loader is used to feed the pellets to the feed bin, and the feed bin is electrically vibrated to feed the feed to the conveyor belt under the bin, and the conveyor belt The batch is delivered directly to the warehouse of the steelmaking process.

The beneficial effects of the present invention are:

1. Fully consider the physical and chemical properties of materials, deeply grasp the key points of briquetting technology, fully consider the process characteristics of electric arc furnace, and realize the improvement of the strength of stainless steel dust pellets with reliable principles, low cost and convenient operation. With the reduction of dust, the reduction and recovery rate of valuable metal elements in the pellets is further improved. At the same time, cheap carbon can be used to replace the high-priced lump coke that was originally added to the stainless steel electric arc furnace to increase the carbon content of the molten pool. The overall economic Significant improvement in efficiency.

2. With brand-new ideas, meticulous design and operating procedures, the efficient utilization of difficult-to-handle solid waste such as stainless steel dust, iron oxide scale, and CDQ dust is realized, which reduces the environmental protection pressure of the enterprise and improves the enterprise's efficiency. The healthy and high-quality development of enterprises.

3. After successful application, it can set up a model in the metallurgical industry, which has a demonstration effect and can drive the solid waste utilization of metallurgical enterprises, with economic, social and environmental benefits.

4. The present invention can solve the problem that the quality of the binder stainless steel dedusting ash is not high, there are many broken materials, the loading powder rate is large, it is easy to raise dust, the reduction kinetics is not ideal, the yield of Inconel is not high, and the problem of using coke The problem of high cost of carbon distribution and heating. This process fully considers the physical and chemical properties of materials, deeply grasps the key points of briquetting technology, fully considers the process characteristics of electric arc furnace, and realizes the improvement of the strength of stainless steel dust removal ash pellets and the reduction of powder and dust in the reverse transportation process with low investment and relatively simple operation. At the same time, the reduction recovery rate of valuable metal elements in the pellets is improved, and at the same time, the powdery cheap carbon (CDQ dust removal dust) is used to replace the expensive lump coke. The synergy between agglomeration and metal yield improvement has been realized, and the combination of dust removal ash utilization and carbon powder utilization has significantly improved overall economic benefits. At the same time, solid waste resources are fully utilized through the use of characteristics and reasonable collocation, which reduces the burden of solid waste management on enterprises, and promotes cost reduction, efficiency increase and high-quality development of iron and steel enterprises, especially stainless steel enterprises.

5. The present invention makes full use of the characteristics of each material by analyzing the characteristics of each material, reasonably designing and proportioning the dosage form, the oxide in the dust removal dust is in close contact with carbon, the ball is oval, thick in the middle and thin on both sides, and The size of 40mm long, 25mm wide and 15mm thick takes into account the heat transfer and mass transfer effects, improves the reduction kinetics conditions, and provides the main way to increase the reduction rate of metal oxides and metal yield. The method uses the reducing agent function of carbon, and turns the powder into an easy-to-use pellet material, which replaces the lump coke required by the process.

6. The carbon material of the present invention selects CDQ dedusting ash that is not easy to use because the metallurgical process is too thin to replace lump coke, which reduces the oxygen potential of the iron molten pool, and brings into play the metal oxide reducing agent and the pellet surface, The role of the reducing atmosphere builder on the slag surface, the combination of two binders with different properties and different strengths can more reliably maintain the high strength of the pellets.

7. The present invention adopts a special pelletizing method to ensure the strength of pellets. In terms of material preparation, each material involved in briquetting has a special storage bin and participates in batching after weighing, which ensures the purity of the material and accurate measurement. The improvement of ball quality and metallurgical performance has laid the foundation; the mixing adopts a large-scale wheel-mill mixer for more than 100 laps, and then uses a large-scale electric vibration feeding cone warehouse for stuffing (awakening), and adopts a forced feeding function The initial pressure of the roller briquetting machine with a shallower ball socket ensures the full dispersion, mixing and wetting of the material, water, and binder, and further lays the foundation for the improvement of the quality of the briquetting ball and the improvement of metallurgical properties; The final pressure of the roller briquetting machine for feeding and deeper ball sockets ensures the filling rate of materials in the ball sockets and the improvement of the density of the balls, which is another guarantee mechanism for the quality and metallurgical performance of the balls.

8. The present invention adopts multiple groups of ball-out belts to connect and convey the finished balls, and at the end, the elevation-angle-adjustable ball-out belt conveyor is used to pile up a conical initial ball pile, and the subsequent balls roll down with the initial ball pile as a slope to reduce breakage; Lift the belt while discharging the ball and move it to one side to form a ring-shaped mountain beam pile, which is convenient for preliminary air-drying and shoveling to a large pile for further air-drying; for a production line with sufficient space, more sets of belt connections are used to control the distance of the ring-shaped ball pile. The belt makes a quarter-circle low beam and piles up radially from the inside to the outside; the pellets in the big ball pile are taken according to the principle of first-in-first-use, the above method reduces the breakage rate of the balls and reduces the amount of powder , It creates conditions for reducing dust during transportation and use and avoiding losses caused by suction by the dust removal system.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are exemplary only, and are not intended to limit the scope of the present invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concept of the present invention.

A high-quality pelletizing method for stainless steel ash mixed with carbon for improving element yield, comprising the following steps:

(1) Ratio of materials in the ball: Digested stainless steel 300 series dust, stainless steel oxide scale, CDQ dust, organic binder, inorganic binder and water according to the mass ratio of 70:5:15:2: 3:5 ratio for proportioning;

(2) Material preparation: stainless steel 300 series dust is digested by special equipment and weighed with a weighing hopper, and the material is fed to the closed feeding belt by electric vibration, and then fed to the mixer; the stainless steel oxide scale is fed to the closed feeding belt Mixer; the organic binder and inorganic binder are placed in the storage bin respectively, weighed with a weighing hopper, fed to the closed feeding belt by electric vibration, and then fed to the mixer; CDQ dust is collected from a small The loader feeds into the cone bin through the reserved side-opening temporary feeding inlet, and the cone bin feeds the material to the weighing hopper with electric vibration, then feeds the material to the closed feeding belt with electric vibration, and then feeds the material to the mixer;

(3) Mixing with water: the rollers of the mixer should rotate no less than 100 times to ensure that the material, water and binder are fully dispersed and mixed to eliminate raw material lumps, and then add water according to the humidity of the material while stirring, so that the material is fully wetted ;

(4) Stuffed material: the mixed material is transported to the large cone bin by a belt conveyor, and the material is firstly picked up from the bottom by electric vibration, and the upper material is guaranteed to be stuffed for more than 3 hours, so as to promote the further dispersion and mixing of material, water and binder;

(5) Initial pressure: The stuffed material is fed by the feeding belt conveyor to the ball pressing machine for the first pass, and the top of the ball pressing machine is equipped with a screw forced feeder to ensure the ball socket on the surface of the roller. fill rate;

(6) Final pressure: The pellets that come out of the initial pressure enter the ball conveying belt through the inclined chute at the bottom of the roller briquetting machine, and feed the final briquetting machine. , crushed and powdered materials are transported to the initial pressure feed belt through the under-screen return belt to continue the initial pressure, and so on;

(7) Transshipment:

1) Outgoing: Multiple sets of outbound belts are connected to convey the finished balls, and finally the initial ball pile is piled up into a cone through the elevation-angle-adjustable ball outbelt conveyor. The balls are raised and the belt moves sideways to form a ring-shaped girder-shaped ball pile. After more than 12 hours of air-drying and aging hardening, it is then shoveled to the large ball pile to continue air-drying;

2) The pellets in the large pellet pile are taken according to the principle of first-in-first-use, and the pellets are transported to the ground warehouse through equipment;

3) The pellets in the ground bin are fed by electric vibration to the auxiliary material feeding belt to the steelmaking distribution platform, and are distributed by the distribution trolley to the high-level feed bin above the electric arc furnace for standby.

Wherein, in the step (6), according to comprehensive consideration of pellet heat transfer, mass transfer, easy pelletization, easy demoulding and production efficiency, the pellets are oval-shaped with a thick middle and thin sides, with a length of 40 mm and a width of 40 mm. 25mm, 15mm thick.

Wherein, in the step (3), the mixer adopts a large wheel mill mixer.

Among them, in step (7) of 1), in the production line with sufficient space, more sets of belts are used to control the distance of the ring-shaped ball pile, and a quarter of a ring-shaped low beam is created by raising the belt, and the inner Radial stacking to the outside can reduce overturning and further reduce the amount of debris.

Among them, in step (7) of 2), the equipment is used to transport the pellets to the ground warehouse, which is specifically to use a loader to load them into a well-sealed vehicle with a stretchable tarpaulin and transport them to the stainless steel steelmaking auxiliary material ground warehouse, and then start dust removal. dump.

Among them, in step (7) of 2), the equipment is used to transport the pellets to the ground bin. Specifically, the loader is used to feed the pellets to the feed bin, and the feed bin is electrically vibrated to feed the feed to the conveyor belt under the bin, and the conveyor belt directly feeds the pellets Delivered to the warehouse of the steelmaking process.

Among them, the function design of each material:

Stainless steel 300 series dedusting ash: Valuable elements Cr, Ni, Fe are provided in the form of oxides, and part of CaO is provided in the form of slaked lime, which can save the amount of lime in the electric arc furnace, and realize partial carbonation and solidification by the action of hourly ash and carbon dioxide in the air. Knot is an auxiliary pellet strength guarantee mechanism;

Carbon material: CDQ dust removal ash is selected, which comes from the dust collection system of the CDQ process in the coking plant, and the particle size is below 100 mesh, accounting for more than 80%. Here, it is used as a substitute for the original carbon matching material of stainless steel electric arc furnace - lump coke to reduce the oxygen potential of iron molten pool, and at the same time, it is used as a reducing agent for metal oxides in dust removal ash and a reducing atmosphere creating agent for furnace gas near the pellet surface and slag surface;

The organic binder is the main pellet strength guarantee mechanism. Through the unique age hardening characteristics of organic agents, it can guarantee the high late strength of the pellets; it decomposes after heating to create a reducing atmosphere;

Inorganic binder ensures that the freshly pressed wet balls have a certain strength, which is convenient for the balls to have unlucky conditions in a short period of time after pressing, and is an auxiliary pellet strength guarantee mechanism;

Water is an accelerator that enables the base material and binder particles to fully contact, and an inducer that enables organic and inorganic binders to play a bonding role.

The present invention can restore and improve the principle of metal recovery:

The basic reaction for reducing chromium oxide in dust removal dust with solid carbon at a high temperature below 1600 °C in an electric arc furnace is:

2/3Cr ₂ O ₃ +2C=4/3Cr+2CO (1) ∆Gϴ=516890-339.5T The reaction start temperature is 1250℃;

2/3Cr ₂ O ₃ +26/9C=4/9Cr3C2+2CO (2) ∆Gϴ=478234-347.15T The reaction start temperature is 1100℃;

2/3Cr ₂ O ₃ +18/7C=4/21Cr7C3+2CO (3) ∆Gϴ=482281-343.54T The reaction start temperature is 1130℃;

2/3Cr ₂ O ₃ +54/23C=4/69Cr23C6+2CO (4) ∆Gϴ=494369-341.72T The reaction start temperature is 1175℃.

It can be seen that the reaction temperature for forming chromium carbides is lower than that of pure chromium, and the reaction temperature for forming carbides with high carbon content is lower than that of carbides with low carbon content, so the formation of carbides with high carbon content is easier to give priority to conduct. Since chromium and carbon have the property of forming stable carbides, the reduction of chromium oxides with a carbon reducing agent yields chromium carbides in the form of Cr ₂₃ C ₆ , Cr ₇ C ₃ , and Cr ₃ C ₂ . According to the principle of iron and steel metallurgy, it can be known that the reduction temperature of Fe ₂ O ₃ is about 900 ° C, so the iron oxide in the dust removal dust is preferentially reduced at a lower temperature than Cr ₂ O ₃ . Melt with chromium carbide to form composite carbides (Cr, Fe) ₃ C ₂ , (Cr, Fe) ₇ C ₃ , (Cr, Fe) ₂₃ C ₆ and other binary carbides and enter the electric arc furnace molten pool. The formation of these complex carbides not only reduces the melting point of the alloy formed by iron, chromium and carbon, but also reduces the activity of Cr from the perspective of chemical balance, so that the reduction reaction can be carried out at a lower temperature, so dust removal The presence of medium iron is beneficial to the reduction of chromium oxide in the dust removal ash.

When the temperature of the electric arc furnace bath is further increased, the post-reduced Cr2O3 will decarburize the carbides that have been reduced, and the reaction is:

14/5Cr ₃ C ₂ +2/3Cr ₂ O ₃ =4/3Cr+ ₆ /5Cr 7 C ₃ +2CO (5)∆Gϴ=543609-309.45T The reaction start temperature is 1490℃

2Cr ₇ C ₃ +2/3Cr ₂ O ₃ =2/3Cr ₂₃ C ₆ +2CO (6) ∆Gϴ=621315-328.13T The reaction start temperature is 1620℃

1/3Cr ₂₃ C ₆ +2/3Cr ₂ O ₃ =9Cr+2CO (7) ∆Gϴ=655173-326.67T The reaction start temperature is 1730℃

The decarburization temperature of chromium oxide is relatively high. In the stainless steel electric arc furnace, the temperature can only reach above 1600°C before tapping, so the decarburization reaction of formula (5) is mainly carried out, and the reaction of formula (6) is rarely carried out. The reaction of (7) is only carried out in the high temperature zone of the arc (accounting for less than 20% of all decarburization reactions). The metal chromium or chromium carbide produced by the decarburization reaction is called a part of the electric arc furnace molten pool.

Finally, after electric arc impact, stirring of carbon powder injection and re-mixing during electric arc furnace tapping, a stainless steel mother liquor containing chromium, nickel, iron, carbon and other elements and a more uniform temperature is formed and mixed into the AOD refining furnace Carry out the follow-up process of decarburization, chromium preservation and impurity removal.

In summary, the reduction of stainless steel dust in the initial stage begins with the reduction of iron oxides. As the temperature increases (above 1200 ° C), the part of chromium oxides that is in contact with the reducing agent begins to slowly reduce, forming chromium, iron, and iron oxides. composite carbides. The chromium carbide formed by the reduction reaction, together with the carbonaceous reducing agent, continues to reduce the residual Cr ₂ O ₃ at a higher temperature (above 1600 ° C), and the carbide is decarburized. Since the main charge in the electric arc furnace is high-carbon nickel-iron block with a small amount of high-carbon ferro-chrome block, there are two types of reduction reactions after the metal material in the furnace melts and forms a molten pool. One is pellets in molten state (that is, slag Part of the phase) the reduction reaction of carbon in the interior to oxides, and the second is the reduction reaction of carbon in the molten pool to oxides in the slag phase (a part of the carbon in the molten pool also comes from the dissolution of carbon in the carbon pellets). Due to the extremely fine and close contact between oxides and carbon particles in the carbon pellets, the reduction reaction is mainly controlled by the diffusion of reduction products, while the transmission of carbon and metal oxides is not the main rate-controlling link in the entire reduction stage. The reduction kinetics conditions are improved, and the reduction rate of chromium and iron is increased. The formation of CO in the reduction process strengthens the reducing atmosphere above the molten pool and around the pellets, further promoting the improvement of the reduction rate of chromium and iron.

Material use of stainless steel dust removal ash with carbon pellets

On the basis of scientific pelletizing and transshipment, in order to maximize the yield of valuable metals in dust-removed carbon pellets, the following special feeding process is adopted under the support of reliable theory:

(1) When the scrap steel and iron block in the electric arc furnace are melted under the action of electric arc and oxygen lance and a molten pool appears, stainless steel dust removal ash and carbon pellets are added.

(2) Add a small amount of carbon pellets several times. For a 100-ton electric arc furnace, add 3 batches from the beginning of the molten pool to complete melting, each batch is 1 ton; after melting, add 3 batches Batch, 1 ton per batch, no pellets will be added 10 minutes before tapping.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (6)

1. A stainless steel ash carbon-matched high-quality pelletizing method for improving element yield, which is characterized by comprising the following steps:

(1) The material ratio in the ball is as follows: the digested stainless steel 300 series fly ash, stainless steel oxide scale, dry quenching fly ash, organic binder, inorganic binder and water are mixed according to the mass ratio of 70:5:15:2:3:5, proportioning the materials in proportion;

(2) Preparing materials: the stainless steel 300 series dedusting ash is weighed by a weighing hopper after being digested by special equipment, is fed to a closed feeding belt by electric vibration, and is then fed to a mixer; stainless steel iron scales are fed to the mixer through a closed feeding belt; the organic binder and the inorganic binder are respectively placed in a storage bin, weighed by a weighing hopper, and fed to a closed feeding belt by electric vibration, and then fed to a mixer; adding dry quenching dust into a cone bin through a reserved side-opening temporary material adding inlet by a small loader, feeding the cone bin to a weighing hopper in an electric vibration mode, feeding the cone bin to a closed feeding belt in an electric vibration mode, and feeding the cone bin to a mixer;

(3) Adding water and mixing: the roller of the mixer rotates at least 100 circles to ensure that the materials, water and binder are fully dispersed and mixed so as to eliminate raw material blocks, and the materials are fully wetted by adding water according to the humidity of the materials while stirring;

(4) And (3) material blocking: the mixed materials are conveyed to a large cone bin through a belt conveyor, firstly, materials are taken from the bottom through electric vibration, and the upper materials are kept for choke-off materials for more than 3 hours, so that the materials, water and binder are further dispersed and mixed;

(5) Initial pressure: feeding the material after being closed to a twin-roll ball press by a feeding belt conveyor to carry out first-pass ball pressing, wherein a spiral forced feeder is arranged at the top of the twin-roll ball press to ensure the filling rate of ball sockets on the surface of the twin-roll;

(6) Final pressure: the initially pressed pellets enter a ball conveying belt through an inclined chute at the bottom of the double-roller ball press, the final-pressure ball press is fed, the finally pressed balls enter a ball discharging belt through an inclined screen plate at the bottom of the ball press, and crushed powder and powder are conveyed to the initially pressed feeding belt through an undersize return belt to continue initial pressing, and the circulation is performed;

(7) And (3) transferring:

1) Ball discharge: the multiple groups of ball outlet belts are connected and convey finished balls, finally, the finished balls are piled into an initial ball pile of a cone through an elevation angle adjustable ball outlet belt conveyor, the subsequent balls roll down in sequence by taking the initial ball pile as a buffer slope to reduce crushing, the balls are lifted up while moving to one side while being discharged, finally, an annular mountain beam type ball pile is formed, and after air drying and age hardening for more than 12 hours, the balls are shoveled to a large ball pile to continue air drying;

2) The pellets of the large ball pile are taken according to the principle of first production and first use, and are conveyed to a ground bin through equipment;

3) The pellets in the ground bin are fed to an auxiliary material feeding belt through electric vibration to a steelmaking distributing platform, and are distributed to a high-level bin above the electric arc furnace for standby by a distributing trolley.

2. The method for producing high-quality pellets with carbon-rich stainless steel ash for improving element yield according to claim 1, wherein in the step (6), the pellets are oval with thick middle and thin two sides, 40 mm long, 25 mm wide and 15 mm thick according to comprehensive consideration of heat transfer, mass transfer, easy balling, easy demolding and production efficiency of the pellets.

3. The method for producing high-quality pellets with carbon in stainless steel ash for improving element yield as claimed in claim 1, wherein in said step (3), a large-sized wheel mill type mixer is used as the mixer.

4. The method for producing high-quality balls with stainless steel ash and carbon for improving element yield according to claim 1, wherein in the step (7), in the production line with sufficient field, more groups of belts are used for connecting to control the distance of the annular ball pile, a quarter-circular short beam shape is produced by lifting the belts, and the radial piling is carried out from inside to outside, so that the overturning is reduced, and the crushed material amount is further reduced.

5. The method for producing high-quality balls from stainless steel ash for improving element yield according to claim 1, wherein in the step (7), 2), the pellets are transported to a ground bin by equipment, particularly a vehicle with telescopic tarpaulin, which is loaded to a well-sealed ground bin by a loader, are pulled to a stainless steel steelmaking auxiliary material ground bin, and dumping is carried out after dust removal is started.

6. The method for producing high-quality pellets with carbon in stainless steel ash for improving element yield according to claim 1, wherein in the step (7), the pellets are transported to a ground bin by equipment, particularly a loader is adopted to feed the pellets to the bin, the bin is electrically vibrated to a conveyor belt below the bin, and the conveyor belt directly conveys the pellets to the bin of a steelmaking process.