WO2017063250A1

WO2017063250A1 - Production method for hot-delivering oxidized pellets in shaft furnace to sealed ferrochrome electric furnace

Info

Publication number: WO2017063250A1
Application number: PCT/CN2015/095074
Authority: WO
Inventors: 姜海洪
Original assignee: 福建鼎信实业有限公司
Priority date: 2015-10-14
Filing date: 2015-11-19
Publication date: 2017-04-20
Also published as: CN106591527A

Abstract

A production method for hot-delivering oxidized pellets in a shaft furnace to a sealed ferrochrome electric furnace comprises: producing oxidized pellets in a shaft furnace; delivering the oxidized pellets to a grading station; and after being mixed with auxiliary materials, delivering to a furnace top feeding system of the sealed ferrochrome electric furnace by means of a feeding device which is capable of realizing hot delivery, during a delivery process of the feeding device, the temperature of the oxidized pellets being 300-800°C.

Description

Production method for heat transfer to closed ferrochrome electric furnace by using shaft furnace oxidized pellet

Technical field

The invention relates to a new method for producing and preparing high carbon ferrochrome, in particular to a production method for heat transfer to a closed ferrochrome electric furnace using a shaft furnace oxidized pellet.

Background technique

High-carbon ferrochrome is mainly used for smelting stainless steel such as AOD, VOD, and double-blown converter. The smelting methods of high-carbon ferrochrome include shaft furnace method, electric furnace method, and plasma furnace method. At present, there is a production method in the world that uses a shaft furnace oxidized pellet to be cooled to a closed ferrochrome electric furnace, and the method has the problems of high energy consumption and high production cost.

The oxidized pellets sintered in the shaft furnace are sent to the ferrochrome electric furnace for high-carbon ferrochrome smelting to produce high-carbon ferrochrome alloy, which has not been reported in the world and belongs to the company. The method focuses on the hot delivery process. The method has the advantages of safety, economy, energy saving and environmental protection. The process flow is smooth, the main economic indicators reach the international advanced level, the high yield and high efficiency of the ferrochrome electric furnace are ensured, and the ferrochrome is greatly reduced. Cost of production.

Summary of the invention

In order to effectively solve the above problems, the present invention provides a production method for heat transfer to a closed ferrochrome electric furnace using a shaft furnace oxidized pellet.

The specific technical scheme of the present invention is as follows: a production method for using a shaft furnace to oxidize pellets to be sent to a closed ferrochrome electric furnace for producing high carbon ferrochrome, wherein the method comprises the following steps: Sintered into oxidized pellets at a temperature of about 1100 ° C, and then directly heated to a closed ferrochrome furnace through a hot tank car. At this time, the pellet temperature is between 300 ° C and 800 ° C, making full use of its heat energy. To achieve the highest efficiency link between the shaft furnace oxidized pellets and the closed ferrochrome electric furnace, achieving the goal of environmental protection and high efficiency.

Further, the production method includes the following steps:

A) weigh the appropriate proportion of chromium powder ore and bentonite in the batching station, and place the chromium powder ore and bentonite in a grinding mill to finely grind into powder;

B) the finely ground powdered chromium ore and bentonite are conveyed to a disc pelletizer by a belt conveyor to add water to form a finished pellet.

C) The finished green pellets are sent to the shaft furnace through a belt conveyor, and the green pellets are sintered at 1000-1200 ° C. The sieved objects in the sintering process are returned to the batching station through the belt conveyor and the forklift. After the sintering, the finished pellets are obtained;

D) sending the finished pellets to the batching station together with the auxiliary materials, and then feeding them to a sealed ferrochrome electric furnace for smelting to obtain high carbon ferrochrome;

The auxiliary material includes coke and silica, and is mixed with the pellets at a heat transfer temperature of 300 ° C to 800 ° C.

Further, the mass ratio of the chromium fine ore, bentonite, coke and silica is 70-80:0.5-2:10-20:3-5.

Further, the oxidized pellets are first sent to the batching station, mixed with the auxiliary materials, and then sent to the top charging system of the closed ferrochrome electric furnace through the feeding device capable of realizing the heat feeding, in the conveying process of the feeding device The temperature of the oxidized pellets is 300-800 °C.

Further, the loading device comprises a material tank, the material tank is a sandwich structure, the inner tank adopts OCr19Ni9, the interlayer is insulated by nano-insulation material, and the outer wall is welded by Q345B, and the material tank is provided with a guide wheel.

Further, the loading device further comprises a tank conveyor truck for transporting the tank from the receiving point to the lifting hole, and a crane for transporting the tank to the top of the furnace system.

Further, the top charging system comprises a furnace top silo, a material tube, a material tube insulation suspension and a magnetic isolation cast steel nozzle; the furnace top silo is disposed at an upper part of the ferrochrome electric furnace, and one end of the material tube is connected The top of the furnace silo is connected to the magnetically cast steel nozzle at the other end, and the material tube is connected to the upper platform of the ferrochrome electric furnace through the insulation of the material pipe.

Further, the furnace top silo is welded by Q235B, and the top of the furnace silo is knotted with refractory material;

The material of the material pipe is 0Cr18Ni9, the wall thickness is 12mm, and the material pipe is covered with heat insulation material; the material of the magnetic isolation steel casting material is ZG30Cr26Ni5.

The beneficial effects of the invention are as follows: after the raw and auxiliary materials are formed into balls, they are sintered into oxidized pellets at a temperature of about 1100 ° C in a shaft furnace, and then directly heated to a closed ferrochrome through a hot material tanker. The electric furnace, at this time, the pellet temperature is between 300 °C and 800 °C, making full use of its thermal energy to achieve the highest efficiency link between the shaft furnace oxidized pellets and the closed ferrochrome electric furnace, achieving the goal of environmental protection and high efficiency.

DRAWINGS

Figure 1 is a schematic flow chart of the present invention.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Rather, the invention is to cover any alternatives, modifications, and equivalents and embodiments of the invention. Further, in order to provide a better understanding of the present invention, the specific details are described in detail in the detailed description of the invention. The invention may be fully understood by those skilled in the art without a description of these details.

The invention provides a production method for using a shaft furnace oxidized pellets to be sent to a sealed ferrochrome electric furnace, the method applying a high carbon ferrochrome preparation system, the apparatus comprising a grinding machine and a pelletizing machine , shaft furnace, batching station, hot delivery system and ferrochrome electric furnace, wherein the grinding machine is used for finely grinding chrome powder ore and bentonite into powder, and adding water to the pelletizing machine for peening, and then passing The shaft furnace is sintered at 1100°C-1300°C, and other auxiliary materials (coke, silica, etc.) are mixed together at the batching station, transported to the top of the furnace through the hot tanker, and finally put into the ferrochrome furnace. The high-carbon ferrochrome smelting is carried out, and the molten iron and slag produced by the smelting are periodically discharged, and the molten iron is sent to the steel making workshop; the slag is transported by the automobile.

In the application of the hot tank car, the coke and silica-added pellets are directly sent to the closed ferrochrome electric furnace. At this time, the pellet temperature is between 300 ° C and 800 ° C, and the heat energy is fully utilized to realize the shaft furnace oxidized pellet. Linked to the highest efficiency of a closed ferrochrome electric furnace, achieving environmentally-friendly and high-efficiency goals, adding coke and silica before the heat transfer process, and controlling the mass ratio of chromium ore, bentonite, coke and silica to 70-80:0.5-2: 10-20: 3-5, at this ratio, preliminary mixing of oxidized pellets, coke and silica during the heat transfer process can be achieved, and the preliminary mixing achieves the following technical effects:

The cohesive ratio of the pellet surface area to the fine coke is 20-30:5-8; and the fine coke penetrates into the surface of the pellet by 3-5 mm, and the bonding ratio of the pellet surface area to the fine silica is 20-30. : 1-1.5; and the fine coke penetrates into the surface of the pellet by 1-2mm, and under the premise of the above effects, entering the ferrochrome electric furnace for smelting, the smelting cost can be reduced, and the smelting speed is accelerated, not only Environmental protection.

Specifically, the ferrochrome electric furnace includes a furnace body, a furnace cover, a combined electrode column assembly, a short net, a furnace top feeding, a flue, a water cooling system, a hydraulic system, a transformer, and a furnace front device.

The combined electrode column is disposed inside the furnace body, the electrode column assembly includes upper and lower portions, and the upper portion of the electrode column assembly includes an electrode lifting device, an electrode pressing device, a heating assembly, an upper holding cylinder, and a pressure release The platform and the hydraulic pipeline, the lower part of the electrode column assembly comprises a lower holding cylinder, a water cooling protection screen, a conductive copper tube, a bottom ring, a contact component, a high temperature resistant gas sealing pad, and a water cooling pipe.

The short net system and the ferrochrome electric furnace form a low-voltage circuit to provide electric energy required for electric furnace smelting, and the ferrochrome electric furnace includes three single-phase transformers, and the single-phase transformer passes through the short net system and the electrode column The short net system comprises a conductive copper tube, a water-cooled cable, a water-cooled compensator, an insulating suspension device, a cast copper connecting body, and a water cooling device. The three single-phase transformers and the short nets are all symmetrically distributed at 120°. The furnace cover is used to seal the furnace, reduce heat loss, and improve working conditions in the smelting section. The furnace cover includes an antimagnetic center portion and an edge portion, the edge portion encloses the antimagnetic center, the edge portion is welded by Q245R, and the central antimagnetic center portion is welded by O6Cr18Ni11Ti, the furnace cover For the full water-cooled structure, the inside of the furnace cover is coated with refractory material, and the furnace cover is provided with 13 material tube holes, 3 motor holes, 2 furnace pressure measuring ports, 2 flue gas outlets and safety explosion-proof valves. The furnace cover is further provided with a motor sealing guide.

The flue is used for feeding the furnace gas generated in the furnace during the production of the ferrochrome electric furnace into the dust removal system, or directly discharging the furnace gas when the dust removal system is abnormal, and the flue is a water-cooled structure welded by the steel plate.

The water cooling system is used for water-cooling a furnace cover, a furnace body, an electrode system, a flue butterfly valve, a transformer system, and a hydraulic system, and the water cooling system includes three water-cooled distributors, one for each water-cooled distributor water supply pipe Mechanical pressure measuring instrument, thermometer, and set the thermal resistance in the return pipe.

The top charging system comprises a furnace top silo and a material tube.

The hydraulic system includes a pump station, an electrode platen device, and an actuator.

The furnace body comprises a furnace shell, a furnace bottom steel and a furnace outlet, the furnace bottom steel is arranged at the bottom of the furnace shell, and the furnace shell is welded by a material of Q245R steel plate, and the furnace bottom steel It is a 45b I-beam, and the furnace shell is provided with two outlets, and the furnace shell is surrounded by a wall water cooling system.

The furnace bottom air cooling device is configured to reduce the temperature of the furnace bottom to improve the service life of the furnace shell and the lining, the bottom air cooling device comprises a plurality of wind turbines and a wind pipe, and the air outlet direction of the air duct faces the Bottom.

The circuit transformer system includes three 12000 kVA single-phase transformers for power supply.

The electrode position indicator is a relative position of the display electrode in the furnace wall.

The furnace front equipment includes an exit trolley, a ladle, a slag pack, a furnace front screen, a front exhaust system, and an open plugging machine.

The loading equipment includes a tank, a tank conveyor, a 20-ton electric double-girder bridge crane, and a 3-ton electric hoist.

The invention also provides a preparation method of high carbon ferrochrome, which comprises the following steps:

A) Weigh the appropriate proportion of chromium ore and bentonite in the batching station, and place the chromium ore and bentonite in a grinding machine for fine grinding into powder.

The chromium powder ore has a particle size of less than 1 mm and a moisture content of not more than 8%.

Among them, bentonite requires a particle size of less than 140 microns and accounts for more than 95%.

B) The finely pulverized chromium powder ore and bentonite are conveyed by a belt conveyor to a disc pelletizer for ball formation to obtain a finished green pellet.

C) The finished green pellets are sent to the shaft furnace through a belt conveyor, and the green pellets are sintered under the condition of about 1100 ° C, and the sieved objects in the sintering process are returned to the batching station through the belt conveyor and the forklift. The finished pellets are obtained after sintering.

D) The finished pellets are sent to the batching station for batching together with the auxiliary materials, and the power supply furnace is used for smelting, and the ingredients are coke and silica.

Claims

A production method for using a shaft furnace oxidized pellets to be sent to a sealed ferrochrome electric furnace for producing high carbon ferrochrome, characterized in that the method comprises the fact that the raw and auxiliary materials are formed into balls, and are passed through a shaft furnace at about 1100 ° C. Sintered into oxidized pellets under temperature conditions, and then directly sent to a closed ferrochrome electric furnace through a hot material tanker. At this time, the pellet temperature is between 300 °C and 800 °C, and the heat energy is fully utilized to realize the shaft furnace. The highest efficiency link between oxidized pellets and closed ferrochrome furnaces achieves environmentally friendly and efficient goals.
The method for producing heat by using a shaft furnace oxidized pellets to a sealed ferrochrome electric furnace according to claim 1, wherein the production method comprises the following steps:

A) weigh the appropriate proportion of chromium powder ore and bentonite in the batching station, and place the chromium powder ore and bentonite in a grinding mill to finely grind into powder;

B) the finely ground powdered chromium ore and bentonite are conveyed to a disc pelletizer by a belt conveyor to add water to form a finished pellet.

C) The finished green pellets are sent to the shaft furnace through a belt conveyor, and the green pellets are sintered at 1000-1200 ° C. The sieved objects in the sintering process are returned to the batching station through the belt conveyor and the forklift. After the sintering, the finished pellets are obtained;

D) sending the finished pellets to the batching station together with the auxiliary materials, and then feeding them to a sealed ferrochrome electric furnace for smelting to obtain high carbon ferrochrome;

The auxiliary material includes coke and silica, and is mixed with the pellets at a heat transfer temperature of 300 ° C to 800 ° C.
The method for producing heat by using a shaft furnace oxidized pellets to a sealed ferrochrome electric furnace according to claim 2, wherein the mass ratio of the chromium powder ore, bentonite, coke and silica is 70-80:0.5 -2:10-20:3-5.
The method for producing heat by using a shaft furnace oxidized pellets to a sealed ferrochrome electric furnace according to claim 2, wherein the oxidized pellets are first sent to the batching station, mixed with the auxiliary materials, and then passed through The feeding device for realizing the hot delivery is sent to the top charging system of the closed ferrochrome electric furnace, and the temperature of the oxidized pellets is 300-800 ° C during the conveying process of the feeding device.
The method for producing heat by using a shaft furnace oxidized pellets to a sealed ferrochrome electric furnace according to claim 4, wherein the loading device comprises a material tank, the material tank is a sandwich structure, and the inner tank is used OCr19Ni9, the interlayer is insulated by nano-insulation material, and the outer wall is welded by Q345B. The tank is provided with a guide wheel.
The method for producing heat from a shaft furnace oxidized pellets to a sealed ferrochrome electric furnace according to claim 5, wherein the loading device further comprises a tank conveyor truck and a crane, the tank conveyor truck For transporting the tank from the receiving point to the lifting hole, the crane is used to transport the tank to the top charging system.
The method for producing heat from a shaft furnace oxidized pellets to a closed ferrochrome electric furnace according to claim 4, wherein the top charging system comprises a furnace top silo, a material tube, and a material tube insulation suspension And magnetic isolation cast steel nozzle;

The furnace top silo is disposed in an upper part of the ferrochrome electric furnace, one end of the material pipe is connected to the top of the furnace silo, and the other end is connected with a magnetic casting steel material nozzle, and the material pipe is connected to the ferrochrome through the material pipe insulation hanging On the upper platform of the electric furnace.
The method for producing heat by using a shaft furnace oxidized pellets to a sealed ferrochrome electric furnace according to claim 7, wherein the furnace top silo is welded by Q235B, and the top of the furnace silo is Junction refractory material;

The material of the material pipe is 0Cr18Ni9, the wall thickness is 12mm, and the material pipe is covered with heat insulation material; the material of the magnetic isolation steel casting material is ZG30Cr26Ni5.