CN111485043A - Dephosphorization process and device for liquid steel slag - Google Patents
Dephosphorization process and device for liquid steel slag Download PDFInfo
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- CN111485043A CN111485043A CN202010483512.3A CN202010483512A CN111485043A CN 111485043 A CN111485043 A CN 111485043A CN 202010483512 A CN202010483512 A CN 202010483512A CN 111485043 A CN111485043 A CN 111485043A
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
- C21B3/06—Treatment of liquid slag
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- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05B—PHOSPHATIC FERTILISERS
- C05B17/00—Other phosphatic fertilisers, e.g. soft rock phosphates, bone meal
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0006—Making spongy iron or liquid steel, by direct processes obtaining iron or steel in a molten state
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/0066—Preliminary conditioning of the solid carbonaceous reductant
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
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Abstract
The invention discloses a dephosphorization process of liquid steel slag, belonging to the technical field of recycling of solid waste of smelting steel slag, comprising the following steps: s1, transporting the liquid steel slag; s2, carrying out primary reaction; s3, carrying out secondary reaction; s4, carrying out tertiary reaction; s5, recycling the liquid steel slag with dephosphorization and deferrization manganese; and S6, discharging the gasified phosphorus. The process method can realize dephosphorization of the steel slag in a high-temperature molten state and a liquid state, so that the dephosphorization of the steel slag is continuous and stable, the process is simple, the automatic operation can be realized, and the closed pollution-free clean production can be realized.
Description
Technical Field
The invention belongs to the technical field of recycling of solid waste of smelting steel slag, and particularly relates to a dephosphorization process and device for liquid steel slag.
Background
With the high yield of steel in China in successive years, steel slag becomes the largest industrial solid waste, and the stockpiling quantity is huge, so that a systematic comprehensive solution needs to be formed urgently, reduction, recycling and harmlessness are realized, and finally efficient conversion and cyclic utilization are realized. "
In fact, in the steelmaking process, in order to remove sulfur and phosphorus in molten steel, reduce molten steel splashing, protect a furnace lining and reduce the content of molten steel terminal oxygen, quicklime and dolomite are added into a steelmaking furnace for slagging, and the slag is smelted first. The steel-making must produce the steel slag as a byproduct, but the comprehensive utilization rate of the steel slag is only 20 percent, and a large amount of steel slag is abandoned, occupies land and pollutes the environment.
The steel slag is recycled as a sintering raw material, an iron-making flux and a steel-making return raw material in an iron and steel plant in the most efficient and convenient way. The internal recycling of the steel plant has the advantages of shortening the flow, reducing the consumption of slag charge and saving the energy consumption of heating and melting the slag charge. The addition of the quicklime and the dolomite is reduced in the steelmaking process, the scrap steel ratio is increased, the transportation cost is greatly reduced, and the benefit of steel slag utilization is maximized.
However, if the steel slag is used as a sintering raw material and a blast furnace flux, phosphorus in the raw material and the flux cannot be removed in the process of sintering the mineral powder and smelting the blast furnace, and the phosphorus is completely converted into molten iron, so that the phosphorus is enriched in the molten iron. In the process of steelmaking, in order to remove phosphorus, the consumption of quicklime in smelting is increased, and then more slag is produced in the steelmaking link.
Because the sintering and iron-making links have no phosphorus removal capability, the phosphorus enrichment of molten iron limits the recycling of the steel slag in steel plants. Research and development of a dephosphorization process and a device for steel slag are urgent to solve the problem of recycling in a steel slag factory, and are one of approaches for recycling the steel slag.
The dephosphorization of the steel slag is carried out at home and abroad, a plurality of researches and experiments are carried out, a solid chemical thermodynamics and kinetic foundation is laid for the chemical reaction of the dephosphorization of the steel slag, the removal rate of phosphorus in the steel slag can reach more than 90 percent during the experiment, and the steel slag dephosphorization agent has a better dephosphorization effect. But currently only stays in the laboratory stage and does not go to the industrial stage.
The research and experiment of experts and scholars on the dephosphorization of the steel slag mainly comprises the dephosphorization in the sintering process, the dephosphorization by leaching flotation, the dephosphorization by silicothermic reduction and the dephosphorization by carbothermic reduction.
Adding steel slag, pyrolusite and CaCl during sintering of mineral powder2Dephosphorizing, finally reacting phosphorus in raw material with Cl to produce gas PCl3Discharging to achieve the purpose of dephosphorization. But discharging PCl3Low boiling point of gasToxic, irritant and strongly corrosive, and can cause environmental pollution.
The flotation method is to utilize phosphorus mainly as solid solution 2CaO & Si2·3Ca·P2O is in the form of solid solution in 2 CaO. SiO2Middle, 2 CaO. SiO2The density of the particles in the slag is small, the particles are easy to float upwards, and 2CaO & SiO can be separated out when the liquid steel slag is slowly cooled2The nucleation becomes larger, the density is lower than that of the rest slag liquid, the floating is separated from the slag liquid, and the phosphorus is solid-melted in 2 CaO. SiO2Neutralizing 2CaO SiO2Crystallizing and floating together and separating slag and liquid. But the cooling is slow, the separation is incomplete, and the phosphorus removal rate is low.
The Chinese patent application number 201510318286.2, the name of the invention is: the invention relates to a steel slag dephosphorization recycling method, which is used for crushing, magnetically separating and levigating steel slag to obtain steel slag magnetic separation powder. Leaching magnetic separation powder by using citric acid-NaOH-HCl buffer solution to obtain phosphorus-containing filtrate and low-phosphorus steel slag, drying the low-phosphorus steel slag, and returning to sintering, ironmaking or steelmaking for cyclic utilization, wherein the leaching rate of phosphorus in the steel slag magnetic separation powder can reach 92%. However, the invention only removes phosphorus from part of the steel slag, namely the magnetic separation powder, and the magnetic separation powder just contains solid solution 2CaO & Si2·3Ca·P2O is low. In addition, the steel slag is crushed, magnetically separated, ground and dried, so that the energy consumption is high and the flow is long.
Another patent application No. 201811183045.1 entitled: a recycling method for removing phosphorus from biomass ash slag modified converter steel slag comprises the steps of adding biomass ash below 200 meshes into molten steel slag, preserving heat for 60-90min at 1723-1823K, cooling at the speed of 3-5K/min, slowly cooling to room temperature, crushing, grinding and leaching, wherein the leaching temperature is 298-323K, and the leaching time is 60-150 min.
Carbothermal reduction and silicothermal reduction: one form of carbothermic reduction is to crush and grind the cold solid steel slag, add carbon or silicon reducing material and mix them evenly, and dephosphorize the steel slag by microwave heating or induction furnace heating and high temperature carbothermic reduction. The steel slag utilized by microwave heating or induction heating is cold solid steel slag, and cold massive powdery steel slag needs to be heated up to
1400-1800 ℃, so the energy consumption is high, the working procedure is relatively complex, the production efficiency is low and the cost is high.
Another form is the use of molten steel slag. Reducing agent (carbon powder or Si) is added in the process of splashing slag and protecting the converter, the reducing agent (carbon powder or Si powder) is blown into the liquid steel slag by the high-pressure nitrogen of the splashing slag, and the reaction between solid (reducing agent) -gas (nitrogen) -liquid (slag) is carried out, so that the phosphorus in the liquid slag enters a gas phase for removal through the reaction. Phosphorus in the liquid steel slag is removed in the converter, equipment is not added, and energy consumption is saved. However, slag splashing and furnace protection need to be cooled after tapping is finished, the viscosity of liquid slag is increased, the temperature of the slag is reduced to be close to the melting point of 1350-1400 ℃, and dephosphorization is limited by the heat transfer viscosity at the moment; slag splashing time is generally 2-4min, and dephosphorization reaction is insufficient. The gasified phosphorus is easy to dissolve in the molten iron, molten iron is stored in the converter during slag splashing, the slag layer is thin, the gasification dephosphorization rate is low, and the proportion of the phosphorus in the molten iron remaining in the converter is large.
The dephosphorization of the cold-state solid steel slag requires crushing, grinding and uniformly mixing the reducing agent and the steel slag, and the carbon heat or silicon heat reduction also requires heating to the temperature of 1400 ℃ and 1700 ℃, so that the energy consumption is high; the adoption of flotation and leaching needs a large amount of leaching liquid, the flow is long, the reaction is slow, and the leaching waste liquid is difficult to treat. The method is not economical for large-scale dephosphorization of the steel slag.
The hot liquid steel slag dephosphorization does not need to be levigated and externally added with heat, has good dynamic conditions during slag splashing, but has short reaction time, mainly depends on gasification dephosphorization, and most of phosphorus is absorbed by molten iron and remains in the furnace.
Disclosure of Invention
The invention aims to provide a dephosphorization process and a dephosphorization device for liquid steel slag, which fully utilize high-temperature liquid steel slag for steelmaking, remove phosphorus elements in the liquid steel slag in the flowing process of the liquid steel slag, and return the processed liquid steel slag to a furnace to be used as a return slag material for steelmaking so as to realize effective recovery of the steel slag.
In order to achieve the purpose, the invention adopts the following technical scheme:
the dephosphorization process of the liquid steel slag comprises the following steps:
s1, transporting the liquid steel slag by using a slag pot, and then pouring the liquid steel slag in the slag pot into a dephosphorization device by using hoisting equipment;
s2, injecting the preheated fuel into the dephosphorization device through the material feeding tank by using an air compressor, and simultaneously injecting the mineral powder into the dephosphorization device through the material feeding tank, controlling the fuel to burn at the moment to heat the liquid steel slag in the dephosphorization device, and simultaneously carrying out primary reaction on the mineral powder and the liquid steel slag;
s3, allowing the liquid steel slag after the primary reaction treatment to flow into a carbon reduction bed at the lower part in the dephosphorization device under the action of a high potential difference, and performing secondary reaction with carbon in the carbon reduction bed;
s4, blowing gas into the bottom of the furnace body of the dephosphorization device to react with the liquid steel slag for three times during the reaction treatment period;
s5, continuously sinking the liquid steel slag after the three-time reaction treatment in the dephosphorization device, discharging iron and manganese in the liquid steel slag through an iron discharge port at the bottom of the dephosphorization device, and discharging the liquid steel slag after dephosphorization and ferromanganese removal through a slag discharge port at the bottom of the dephosphorization device for recycling;
s6, in the reaction treatment process, the gasified phosphorus generated in the reaction is discharged through a smoke outlet at the top of the dephosphorization device, and is prepared into a phosphate fertilizer for recycling after enrichment and recovery.
Further, the fuel in step S2 is at least one of fuel gas, fuel oil, coal or coke.
Further, the mineral powder in step S2 is at least one of clay, sand, kaolin, fly ash, coal powder, red mud, and furnace top ash.
Further, the gas in step S4 is carbon monoxide, carbon dioxide, nitrogen, argon, or blast furnace gas.
The liquid steel slag dephosphorization device comprises a furnace body, wherein a water-cooled wall and a refractory material are arranged on the inner wall of the furnace body, and the refractory material is arranged on the inner wall of the water-cooled wall; the top of the furnace body is sequentially provided with a slag liquid inlet, a top combustion port and a smoke exhaust port from left to right; two side burners are symmetrically arranged on the left side wall and the right side wall of the furnace body; a cavity enclosed in the refractory material is a slag pool, a carbon reduction bed is arranged in the center of the slag pool, and bottom blowing is arranged right below the carbon reduction bed; the bottom of the furnace body is also provided with an iron tap hole and a slag discharge hole.
Furthermore, the external ports of the slag liquid inlet, the top combustion, the smoke outlet, the side combustion, the iron discharging port, the slag discharging port and the bottom blowing are all arranged outside the furnace body, and the internal ports are all arranged in a slag pool of the furnace body.
Furthermore, the slag liquid inlet, the top combustion port, the smoke exhaust port and the side combustion internal port are all arranged above the carbon reduction bed in the slag pool; the iron tap hole, the slag discharge hole and the internal port of the bottom blowing are all arranged below the carbon reduction bed in the slag bath.
Further, the carbon reduction bed comprises a frame and contents, the contents are filled in the frame, the frame is made of slag-corrosion-resistant high-fire-resistant ceramic materials, and the contents are at least one of ferrosilicon, graphite and coke.
Compared with the prior art, the invention has the beneficial effects that:
the process method can realize dephosphorization of the steel slag in a high-temperature molten state and a liquid state, so that the dephosphorization of the steel slag is continuous and stable, the process is simple, the automatic operation can be realized, and the closed pollution-free clean production can be realized; the complex treatment of traditional steel slag such as slag pan, slag tank car transportation, tank stuffiness, water sprinkling, crushing, magnetic separation and the like is changed, the operation of re-crushing, levigating, mixing, sintering or melting, re-heating to 1400-1600 ℃ or even 1800 ℃ is avoided, and the use of a melting furnace, microwave heating, electric arc or induction heating equipment is further saved; and the problems of low dephosphorization rate, overlong time consumption and unclear phosphorus-iron separation caused by that a part of gasified phosphorus is extruded in a steel tapping gap during slag splashing or is stored in a reducing agent at the bottom of the furnace by utilizing the impulsive force of slag but not uniformly mixed during slag tapping are solved. The carbon reduction bed arranged in the device changes the mode and the speed of mutual diffusion of phosphorus and carbon in the steel slag, promotes slag liquid to carry out dephosphorization in the flowing process and gas-liquid countercurrent exchange dephosphorization gasification, thereby ensuring continuous dephosphorization and optimizing the whole process flow. The invention directly carries out the carbothermic reduction reaction on the steel slag with high heat discharged from the furnace, obviously reduces the energy consumption and heat consumption of the whole process, realizes the separation and recovery of 100 percent of iron in the slag, and the recovered iron has low phosphorus content; the removal rate of phosphorus is as high as more than 80 percent, and the recovery rate of phosphorus is high; the dephosphorized steel slag can be returned to a converter or a hot metal ladle in a liquid state to be directly reused as a slag material for desulfuration and dephosphorization; the method effectively reduces the heat consumption of the slag, saves the addition of the quick lime, the dolomite and the fluorite, and can increase the addition of the scrap steel, so that the heat of the slag and the slag can be recycled together in the steel plant, the integral production cost is reduced, and the method has great popularization and application values.
Drawings
FIG. 1 is a schematic process flow diagram of example 1 of the present invention.
Fig. 2 is a schematic view of the overall structure of the dephosphorization apparatus according to the present invention.
In the figure: 1. placing an iron notch; 2. a carbon reduction bed; 3. a water cooled wall; 4. side burning; 5. a refractory material; 6. a slag pool; 7. A slag liquid inlet; 8. a smoke outlet; 9. top combustion; 10. a furnace body; 11. a slag discharge port; 12. and (4) bottom blowing.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
Example 1
The dephosphorization process of the liquid steel slag comprises the following steps:
s1, transporting the liquid steel slag by using a slag pot, and then pouring the liquid steel slag in the slag pot into a dephosphorization device by using hoisting equipment;
s2, injecting the preheated fuel into the dephosphorization device through the material feeding tank by using an air compressor, and simultaneously injecting the mineral powder into the dephosphorization device through the material feeding tank, controlling the fuel to burn at the moment to heat the liquid steel slag in the dephosphorization device, and simultaneously carrying out primary reaction on the mineral powder and the liquid steel slag;
s3, allowing the liquid steel slag after the primary reaction treatment to flow into a carbon reduction bed at the lower part in the dephosphorization device under the action of a high potential difference, and performing secondary reaction with carbon in the carbon reduction bed;
s4, blowing gas into the bottom of the furnace body of the dephosphorization device to react with the liquid steel slag for three times during the reaction treatment period;
s5, continuously sinking the liquid steel slag after the three-time reaction treatment in the dephosphorization device, discharging iron and manganese in the liquid steel slag through an iron discharge port at the bottom of the dephosphorization device, and discharging the liquid steel slag after dephosphorization and ferromanganese removal through a slag discharge port at the bottom of the dephosphorization device for recycling;
s6, in the reaction treatment process, the gasified phosphorus generated in the reaction is discharged through a smoke outlet at the top of the dephosphorization device, and is prepared into a phosphate fertilizer for recycling after enrichment and recovery.
The fuel in step S2 is coal.
The mineral powder in step S2 is pulverized coal.
The gas in step S4 is carbon dioxide or blast furnace gas.
Referring to fig. 1, the liquid steel slag dephosphorization apparatus comprises a furnace body 10, wherein a water-cooled wall 3 and a refractory material 5 are arranged on the inner wall of the furnace body 10, and the refractory material 5 is arranged on the inner wall of the water-cooled wall 3; the top of the furnace body 10 is sequentially provided with a slag liquid inlet 7, a top burner 9 and a smoke outlet 8 from left to right; two side burners 4 are symmetrically arranged on the left side wall and the right side wall of the furnace body 10; a cavity enclosed in the refractory material 5 is a slag pool 6, a carbon reduction bed 2 is arranged in the center of the slag pool 6, and a bottom blowing device 12 is arranged right below the carbon reduction bed 2; the bottom of the furnace body 10 is also provided with an iron tap hole 1 and a slag discharge hole 11.
The external ports of the slag liquid inlet 7, the top combustion 9, the smoke outlet 8, the side combustion 4, the iron tap hole 1, the slag discharge hole 11 and the bottom blowing 12 are all arranged outside the furnace body 10, and the internal ports are all arranged in the slag pool 6 of the furnace body 10.
The inner ports of the slag liquid inlet 7, the top combustion 9, the smoke outlet 8 and the side combustion 4 are all arranged above the carbon reduction bed 2 in the slag pool 6; the internal ports of the iron tap hole 1, the slag discharge hole 11 and the bottom blowing hole 12 are all arranged below the carbon reduction bed 2 in the slag bath 6.
The carbon reduction bed 2 is composed of a frame and contents, the contents are filled in the frame, the frame is made of slag corrosion resistant high-fire-resistant ceramic materials, and the contents are graphite.
The dephosphorization device is characterized in that a heating section is arranged above a carbon reduction bed 2 in a slag pool 6, a carbon thermal reduction section is arranged in the middle of the carbon reduction bed 2, a precipitation section is arranged below the carbon reduction bed 2, fuel, coal and mineral powder and coal powder are fed into the heating section in the slag pool 6 by a feeding tank through side combustion 4 and top combustion 9 by utilizing an air compressor, simultaneously steel slag generated by steelmaking is also fed into the heating section in the slag pool 6 through the slag tank, under the combustion heat release action of the fuel, the molten steel slag is heated to form flowing liquid steel slag, the added coal powder can be combusted to release heat on one hand, and SiO contained in the other hand2Can make P2O5Ca from steel slag3(PO4)2Is replaced by (C) and the reaction equation is 3SiO2+Ca3(PO4)2＝P2O5+3CaSiO3(ii) a Then the flowing liquid steel slag flows into the graphite gaps in the carbon reduction bed 2 under the action of the high head difference to perform reduction reaction with the carbon in the carbon reduction bed 2, and the reaction equation is 5C + P2O5＝5CO+1/2P4、FeO+C＝Fe+CO、 1/3Fe2O3+ C-2/3 Fe + CO, MnO + C-Mn + CO; meanwhile, the gas-blast furnace gas is blown upwards by the bottom blowing 12 of the furnace body 10, so that the phosphorus, iron and manganese oxides in the liquid steel slag can be reduced in sequence, and the reaction equation is as follows: p2O5+5CO＝P2+5CO2FeO + CO ═ Fe + CO, CO + C ═ 2 CO; carbon dioxide can be blown in, the blowing direction of carbon dioxide gas and liquid realize reverse flow, slag liquid is stirred, phosphorus vapor is prevented from contacting liquid iron, the phosphorus vapor is difficult to dissolve in the iron liquid, the phosphorus vapor is driven to float upwards, the phosphorus vapor escapes along with the gas before being absorbed by the iron liquid, the recovery rate of phosphorus is improved, and the phosphorus content of iron is reduced; then the liquid steel slag enters a precipitation section in the slag pool 6, iron and manganese are precipitated at the bottom of the furnace body 10, and then the liquid steel slag is controlled to be discharged from the iron tap hole 1 regularly, and the purified liquid steel slag is taken as slag water and discharged from the slag discharge hole 11 of the furnace body 10 to return to steel making, so that the consumption of alkaline solvent and the heat consumption of slagging are reduced; or atomizing to obtain powderHeat is collected and sintering is carried out; the gasified phosphorus generated in the period is discharged through the smoke outlet 8, the gasified phosphorus can exchange heat with the air heat exchanger to realize heat recovery, and then the gasified phosphorus is dedusted and discharged or is enriched and recovered to be used as a phosphate fertilizer; the air heat exchanger is driven by the air compressor to work, and the recovered heat can be used for preheating materials of the top fuel 9, the side fuel 4 and the material feeding tank, so that the overall cost is further reduced.
Example 2
The dephosphorization process of the liquid steel slag comprises the following steps:
s1, transporting the liquid steel slag by using a slag pot, and then pouring the liquid steel slag in the slag pot into a dephosphorization device by using hoisting equipment;
s2, injecting the preheated fuel into the dephosphorization device through the material feeding tank by using an air compressor, and simultaneously injecting the mineral powder into the dephosphorization device through the material feeding tank, controlling the fuel to burn at the moment to heat the liquid steel slag in the dephosphorization device, and simultaneously carrying out primary reaction on the mineral powder and the liquid steel slag;
s3, allowing the liquid steel slag after the primary reaction treatment to flow into a carbon reduction bed at the lower part in the dephosphorization device under the action of a high potential difference, and performing secondary reaction with carbon in the carbon reduction bed;
s4, blowing gas into the bottom of the furnace body of the dephosphorization device to react with the liquid steel slag for three times during the reaction treatment period;
s5, continuously sinking the liquid steel slag after the three-time reaction treatment in the dephosphorization device, discharging iron and manganese in the liquid steel slag through an iron discharge port at the bottom of the dephosphorization device, and discharging the liquid steel slag after dephosphorization and ferromanganese removal through a slag discharge port at the bottom of the dephosphorization device for recycling;
s6, in the reaction treatment process, the gasified phosphorus generated in the reaction is discharged through a smoke outlet at the top of the dephosphorization device, and is prepared into a phosphate fertilizer for recycling after enrichment and recovery.
The fuel in step S2 is gas.
The mineral powder described in step S2 is kaolin.
The gas in step S4 is carbon monoxide.
Referring to fig. 1, the liquid steel slag dephosphorization apparatus comprises a furnace body 10, wherein a water-cooled wall 3 and a refractory material 5 are arranged on the inner wall of the furnace body 10, and the refractory material 5 is arranged on the inner wall of the water-cooled wall 3; the top of the furnace body 10 is sequentially provided with a slag liquid inlet 7, a top burner 9 and a smoke outlet 8 from left to right; two side burners 4 are symmetrically arranged on the left side wall and the right side wall of the furnace body 10; a cavity enclosed in the refractory material 5 is a slag pool 6, a carbon reduction bed 2 is arranged in the center of the slag pool 6, and a bottom blowing device 12 is arranged right below the carbon reduction bed 2; the bottom of the furnace body 10 is also provided with an iron tap hole 1 and a slag discharge hole 11.
The external ports of the slag liquid inlet 7, the top combustion 9, the smoke outlet 8, the side combustion 4, the iron tap hole 1, the slag discharge hole 11 and the bottom blowing 12 are all arranged outside the furnace body 10, and the internal ports are all arranged in the slag pool 6 of the furnace body 10.
The inner ports of the slag liquid inlet 7, the top combustion 9, the smoke outlet 8 and the side combustion 4 are all arranged above the carbon reduction bed 2 in the slag pool 6; the internal ports of the iron tap hole 1, the slag discharge hole 11 and the bottom blowing hole 12 are all arranged below the carbon reduction bed 2 in the slag bath 6.
The carbon reduction bed 2 comprises a frame and contents, the contents are filled in the frame, the frame is made of slag-corrosion-resistant high-fire-resistant ceramic materials, and the contents are ferrosilicon.
The overall procedure of this example 2 is the same as that of example 1, and the other operation modes are as follows: firstly, injecting water into a furnace wall water-cooled wall 3, installing a carbon reduction bed 2 in place, lowering a top burner 9 for ignition, simultaneously igniting a side burner 4, and preheating a furnace body 10 for baking; the furnace top is provided with an infrared temperature measuring thermocouple and a temperature measuring thermocouple, and the furnace bottom is provided with a pressure measuring point; when the temperature in the furnace body 10 reaches 1300 ℃ (the temperature is measured by a thermocouple), the slag tank is hoisted to introduce steel slag from the slag liquid inlet 7, and when slag liquid flows out from the iron tap hole 1 and the slag discharge hole 11, the slag tank is plugged by stemming; after the slag liquid is filled to about 2000mm in height, spraying kaolin into a side combustion 4 spray gun, adjusting top combustion 9 and side combustion 4, and opening a slag discharge port 11 for stemming and slagging when the temperature of the slag liquid reaches 1650 ℃; at this time, the balance of the introduced slag and the discharged slag is controlled, the slag level is stabilized at 2000mm, and finally, the slag water flowing out of the slag discharge port 11 is sampled and tested. The main chemical components and the weight percentages of the steel slag introduced from the slag liquid inlet 7 are shown in the following table 1:
TABLE 1
| Composition (I) | CaO | SiO2 | FeO | Fe2O3 | MgO | Al2O3 | MnO | P |
| Content (wt.) | 40.21 | 11.91 | 14.78 | 8.58 | 12.87 | 2.06 | 1.14 | 0.64 |
Through sampling and testing, the removal rate of phosphorus by carbothermic reduction is 96%, the residual phosphorus in the slag is 0.04%, the phosphorus in the ferro-manganese alloy is 0.637%, the phosphorus gasification rate is 80%, and the iron reduction rate is almost 100%.
Example 3
The dephosphorization process of the liquid steel slag comprises the following steps:
s1, transporting the liquid steel slag by using a slag pot, and then pouring the liquid steel slag in the slag pot into a dephosphorization device by using hoisting equipment;
s2, injecting the preheated fuel into the dephosphorization device through the material feeding tank by using an air compressor, and simultaneously injecting the mineral powder into the dephosphorization device through the material feeding tank, controlling the fuel to burn at the moment to heat the liquid steel slag in the dephosphorization device, and simultaneously carrying out primary reaction on the mineral powder and the liquid steel slag;
s3, allowing the liquid steel slag after the primary reaction treatment to flow into a carbon reduction bed at the lower part in the dephosphorization device under the action of a high potential difference, and performing secondary reaction with carbon in the carbon reduction bed;
s4, blowing gas into the bottom of the furnace body of the dephosphorization device to react with the liquid steel slag for three times during the reaction treatment period;
s5, continuously sinking the liquid steel slag after the three-time reaction treatment in the dephosphorization device, discharging iron and manganese in the liquid steel slag through an iron discharge port at the bottom of the dephosphorization device, and discharging the liquid steel slag after dephosphorization and ferromanganese removal through a slag discharge port at the bottom of the dephosphorization device for recycling;
s6, in the reaction treatment process, the gasified phosphorus generated in the reaction is discharged through a smoke outlet at the top of the dephosphorization device, and is prepared into a phosphate fertilizer for recycling after enrichment and recovery.
The fuel in step S2 is coke.
The mineral powder described in step S2 is sand.
The gas in step S4 is nitrogen.
Referring to fig. 1, the liquid steel slag dephosphorization apparatus comprises a furnace body 10, wherein a water-cooled wall 3 and a refractory material 5 are arranged on the inner wall of the furnace body 10, and the refractory material 5 is arranged on the inner wall of the water-cooled wall 3; the top of the furnace body 10 is sequentially provided with a slag liquid inlet 7, a top burner 9 and a smoke outlet 8 from left to right; two side burners 4 are symmetrically arranged on the left side wall and the right side wall of the furnace body 10; a cavity enclosed in the refractory material 5 is a slag pool 6, a carbon reduction bed 2 is arranged in the center of the slag pool 6, and a bottom blowing device 12 is arranged right below the carbon reduction bed 2; the bottom of the furnace body 10 is also provided with an iron tap hole 1 and a slag discharge hole 11.
The external ports of the slag liquid inlet 7, the top combustion 9, the smoke outlet 8, the side combustion 4, the iron tap hole 1, the slag discharge hole 11 and the bottom blowing 12 are all arranged outside the furnace body 10, and the internal ports are all arranged in the slag pool 6 of the furnace body 10.
The inner ports of the slag liquid inlet 7, the top combustion 9, the smoke outlet 8 and the side combustion 4 are all arranged above the carbon reduction bed 2 in the slag pool 6; the internal ports of the iron tap hole 1, the slag discharge hole 11 and the bottom blowing hole 12 are all arranged below the carbon reduction bed 2 in the slag bath 6.
The carbon reduction bed 2 is composed of a frame and contents, the contents are filled in the frame, the frame is made of slag corrosion resistant high-fire-resistant ceramic materials, and the contents are coke.
The processing steps of this example 3 are the same as those of example 2,
the main chemical components and the weight percentages of the steel slag introduced from the slag liquid inlet 7 are shown in the following table 2:
TABLE 2
| Composition (I) | CaO | SiO2 | FeO | MgO | Al2O3 | MnO | P2O5 | S |
| Content (wt.) | 47.3 | 15.79 | 19.89 | 10.89 | 1.11 | 2.3 | 2.62 | / |
Through sampling and testing, the removal rate of phosphorus by carbothermic reduction is 95%, the residual phosphorus in the slag is 0.05%, the phosphorus in the iron-manganese alloy is 2.15%, the phosphorus gasification rate is 82%, and the iron is reduced to be simple substance iron by 100%.
In conclusion, the device has the advantages of simple structure, short processing process and convenient operation; the dephosphorization rate is up to 96%, the residual phosphorus is low, and the recovery rate of the recovered phosphorus is high; the method can also realize the thermal recycling of the slag, save energy and resources, is the best way for reducing environmental pollution and improving economic benefit of steel plants, and achieves the effect of reducing the quantity from the source.
Claims (8)
1. The dephosphorization process of the liquid steel slag is characterized by comprising the following steps:
s1, transporting the liquid steel slag by using a slag pot, and then pouring the liquid steel slag in the slag pot into a dephosphorization device by using hoisting equipment;
s2, injecting the preheated fuel into the dephosphorization device through the material feeding tank by using an air compressor, and simultaneously injecting the mineral powder into the dephosphorization device through the material feeding tank, controlling the fuel to burn at the moment to heat the liquid steel slag in the dephosphorization device, and simultaneously carrying out primary reaction on the mineral powder and the liquid steel slag;
s3, allowing the liquid steel slag after the primary reaction treatment to flow into a carbon reduction bed at the lower part in the dephosphorization device under the action of a high potential difference, and performing secondary reaction with carbon in the carbon reduction bed;
s4, blowing gas into the bottom of the furnace body of the dephosphorization device to react with the liquid steel slag for three times during the reaction treatment period;
s5, continuously sinking the liquid steel slag after the three-time reaction treatment in the dephosphorization device, discharging iron and manganese in the liquid steel slag through an iron discharge port at the bottom of the dephosphorization device, and discharging the liquid steel slag after dephosphorization and ferromanganese removal through a slag discharge port at the bottom of the dephosphorization device for recycling;
s6, in the reaction treatment process, the gasified phosphorus generated in the reaction is discharged through a smoke outlet at the top of the dephosphorization device, and is prepared into a phosphate fertilizer for recycling after enrichment and recovery.
2. The process of dephosphorization of liquid steel slag according to claim 1, wherein said fuel in step S2 is at least one of fuel gas, fuel oil, coal or coke.
3. The dephosphorization process for liquid steel slag according to claim 1, wherein said mineral powder in step S2 is at least one of clay, sand, kaolin, fly ash, coal dust, red mud and furnace top ash.
4. The process of dephosphorization of liquid steel slag according to claim 1, wherein said gas in step S4 is carbon monoxide, carbon dioxide, nitrogen, argon or blast furnace gas.
5. The dephosphorization device of the liquid steel slag comprises a furnace body (10), and is characterized in that a water-cooled wall (3) and a refractory material (5) are arranged on the inner wall of the furnace body (10), and the refractory material (5) is arranged on the inner wall of the water-cooled wall (3); the top of the furnace body (10) is sequentially provided with a slag liquid inlet (7), a top burner (9) and a smoke outlet (8) from left to right; two side burners (4) are symmetrically arranged on the left side wall and the right side wall of the furnace body (10); a cavity enclosed in the refractory material (5) is a slag pool (6), a carbon reduction bed (2) is arranged in the center of the slag pool (6), and bottom blowing (12) is arranged right below the carbon reduction bed (2); the bottom of the furnace body (10) is also provided with an iron tap hole (1) and a slag discharge hole (11).
6. The dephosphorization apparatus for liquid steel slag according to claim 5, wherein the external ports of the slag liquid inlet (7), the top burner (9), the smoke outlet (8), the side burner (4), the tap hole (1), the slag discharge port (11) and the bottom blower (12) are all arranged outside the furnace body (10), and the internal ports are all arranged in the slag bath (6) of the furnace body (10).
7. The dephosphorization apparatus for liquid steel slag according to claim 6, wherein the internal ports of the slag liquid inlet (7), the top combustion (9), the smoke outlet (8) and the side combustion (4) are all arranged above the carbon reduction bed (2) in the slag bath (6); the internal ports of the iron tap hole (1), the slag discharge hole (11) and the bottom blowing hole (12) are all arranged below the carbon reduction bed (2) in the slag bath (6).
8. The dephosphorization apparatus for liquid steel slag according to claim 7, wherein said carbon reduction bed (2) is composed of a frame and a content, said content is filled in the frame, said frame is made of a slag-corrosion resistant high refractory ceramic material, and said content is at least one of ferrosilicon, graphite and coke.
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| CN112624070A (en) * | 2020-12-03 | 2021-04-09 | 钢铁研究总院 | Full utilization method of steel slag |
| CN113174455A (en) * | 2021-04-28 | 2021-07-27 | 东北大学 | Comprehensive utilization method for smelting reduction of high-iron red mud by side-top combined blowing |
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