Top-blown oxidation-reduction method for refining furnace
Technical Field
The invention belongs to the technical field of metal metallurgy, and particularly relates to a top-blown oxidation-reduction method of a refining furnace.
Background
The flash converting process is suspension reaction, the sulfur content of the blister copper is high (about 0.1%), the refining furnace can utilize the gap for pre-oxidation (about 2 hours) only after 300t of feeding, and the reduction can be carried out only after 3 hours of formal oxidation after the feeding is finished. When the sulfur content of blister copper is higher than 0.1%, the oxidation time is longer.
The oxidation-reduction mode of the refining furnace at the present stage is mainly to build oxidation-reduction ports, prefabricate and finalize the design oxidation-reduction ports and the like, the brick body and the oxidation-reduction gun are immersed below the copper liquid, and the blown compressed air and the reducing agent are in direct contact with the copper liquid to generate oxidation-reduction reaction. The scouring wear of the brick body in the area is particularly serious, the service life of the brick body is only about 1 month, and the service life of the brick body can be reduced after the oxidation-reduction time is prolonged. Meanwhile, the refining furnace is heated by a dilute oxygen combustion system, natural gas and oxygen are blown in from the end wall to keep warm and heat, and the flame position can also change when the refining furnace is positioned at different operation positions due to the fact that the hearth of the refining furnace is large, so that the burning loss of the cylinder bricks at the position close to the end is serious, and the service life of the refining furnace is influenced.
Disclosure of Invention
In order to solve the problems, the invention provides a top-blowing oxidation-reduction method for a refining furnace, which is used for carrying out oxidation-reduction on a blister copper melt in the refining furnace by top blowing, so that the copper content in slag of the smelting furnace is reduced, and the service life of equipment is prolonged.
The invention is realized by the following technical scheme:
a method of refining furnace top-blown oxidation-reduction comprising the steps of:
(1) Inserting a top-blowing spray gun into the refining furnace from a spray gun hole of the refining furnace body through a lifting device, and then connecting the top-blowing spray gun with a gas supply metal hose to complete equipment installation; the lifting device is connected with the winch through a lifting steel wire rope;
(2) When the crude copper melt in the converting furnace enters the refining furnace, oxygen is blown by using a top-blowing spray gun to carry out combustion supporting and heat preservation, and when the crude copper melt fed into the refining furnace body for the first time reaches more than 300t, a crude copper melt sample is taken to carry out analysis on the oxygen and sulfur content;
(3) Calculating the time and gas flow of the oxidation according to the oxygen and sulfur content in the blister copper melt, then introducing compressed air and oxygen-enriched air into a top-blowing spray gun to oxidize, and continuously adjusting the height of the top-blowing spray gun according to the height of the blister copper melt liquid level to ensure that the distance between the top-blowing spray gun and the blister copper melt liquid level is 50-150 mm;
(4) After the feeding is finished, taking a blister copper melt sample for observation, and judging whether the oxidation needs to be continued or not according to the appearance and the section state of the blister copper melt; after the oxidation of the blister copper melt is finished, introducing natural gas through a top-blowing spray gun to perform top-blowing reduction;
(5) Switching the top-blowing spray gun to heat preservation after reduction is finished, and adjusting the position of the top-blowing spray gun to be at a height of 0.8-1.2 m from the liquid level of the blister copper melt by a winch in the process of rotating the refining furnace body to discharge copper;
(6) The condition of the top-blowing spray gun is detected from the spray gun holes at regular intervals, when the height of the top-blowing spray gun does not meet production requirements, the top-blowing spray gun is pulled out through a winch and replaced by a new top-blowing spray gun, and then the gun head of the old top-blowing spray gun is welded for one section again after being cut off, so that the top-blowing spray gun is repaired for use.
According to the invention, oxygen-enriched air and natural gas are continuously supplied into the furnace from the top of the refining furnace to carry out oxidation reduction on the blister copper melt, so that the sulfur content of blister copper is reduced, the direct contact between a top-blowing spray gun and the blister copper melt is avoided, the use frequency of an oxidation reduction port and a furnace mouth brick body is reduced, and the service life of equipment is prolonged.
Further, the top-blowing spray gun comprises a nitrogen cooling outer pipe, an intermediate gas pipe, a central inner pipe and a pipeline joint;
the middle gas pipe, the nitrogen cooling outer pipe and the central inner pipe are coaxially arranged in sequence from outside to inside; the pipeline joint is connected with the air supply metal hose;
the nitrogen cooling outer tube is filled with nitrogen for cooling;
the intermediate gas pipe is filled with oxygen for oxidation and combustion supporting during oxidation and heat preservation, and is filled with dilution during reduction, so that the reduction utilization rate of natural gas is improved.
Further, the lifting device comprises a lifting steel wire rope, a lifting guide rail, a pulley and a winch; one end of the lifting steel wire rope is connected with the top-blowing spray gun through a lifting lug, and the other end of the lifting steel wire rope penetrates through a pulley at the top of the lifting guide rail to be connected with the winch.
The lifting wire rope is tensioned or loosened through the rotation of the winch, so that the top-blowing spray gun is lifted. The pulley can use fixed pulley or movable pulley, installs at lifting rail top, and lifting rail is mainly as structural support, makes through calculating selection channel-section steel or I-steel, uses the bolt to fix on welded base, conveniently dismantles the change.
The beneficial effects of the invention are as follows:
1. according to the invention, oxygen-enriched air is continuously supplied into the refining furnace from top-blown oxidation of the refining furnace, and the raw copper melt is subjected to surface oxidation by using the feed and the waiting materials, so that the sulfur content of the raw copper is reduced, and the oxidation time is shortened.
2. According to the invention, the top-blowing oxygen-enriched air and the reducing agent are blown through the refining furnace, the top-blowing spray gun is positioned above the copper liquid, the brick body of the furnace body and the top-blowing spray gun are not in direct contact with the blister copper melt, the use frequency of the oxidation-reduction port and the brick body at the furnace mouth is reduced, erosion and scouring are reduced, the service life of the brick body in a vulnerable area is prolonged, the efficient long-period stable operation of the refining furnace is realized, the overhaul and maintenance frequency is reduced, and the material and overhaul cost are saved.
3. The top-blowing spray gun can realize oxidation-reduction operation, can realize copper liquid heat preservation and temperature rise through natural gas combustion, and the combustion flame is in direct contact with the blister copper melt, so that the heat utilization rate is improved; meanwhile, the heat radiation to the hearth can be controlled by adjusting the height of the top-blowing spray gun, so that the temperature uniformity of the hearth is realized, the burning loss of the brick body is reduced, and the service life of the refining furnace is prolonged.
4. The invention can control the formal oxidation time of the refining furnace within 2h by a top-blowing oxidation-reduction technology, and the single-furnace operation period of the refining furnace can be controlled within 22h, thereby realizing the matching with the high-load production of a flash converting system.
Drawings
Fig. 1 is a schematic view of the overall installation structure of the present invention.
Fig. 2 is a schematic view of a top-blowing lance structure according to the present invention.
Reference numerals: the device comprises a 1-refining furnace body, a 2-blister copper melt, a 3-top blowing spray gun, a 301-nitrogen cooling outer pipe, a 302-middle gas pipe, a 303-center inner pipe, a 304-pipeline joint, a 4-lifting steel wire rope, a 5-lifting guide rail, a 6-pulley and a 7-winch.
Description of the embodiments
The invention is further described below with reference to the accompanying drawings.
Examples
A method of refining furnace top-blown oxidation-reduction comprising the steps of:
(1) Installation of equipment
As shown in fig. 1, a top-blowing lance 3 is inserted into a refining furnace from a lance hole of a refining furnace body 1 through a lifting device, and then the top-blowing lance 3 is connected with a gas supply metal hose to complete equipment installation; the lifting device is connected with the winch 7 through a lifting steel wire rope 4;
the top-blowing spray gun 3 is shown in fig. 2, and comprises a nitrogen cooling outer pipe 301, an intermediate gas pipe 302, a central inner pipe 303 and a pipeline joint 304; the middle gas pipe 302, the nitrogen cooling outer pipe 301 and the center inner pipe 303 are coaxially arranged in sequence from outside to inside; the pipeline joint 304 is connected with a gas supply metal hose; the nitrogen cooling outer tube 301 is filled with nitrogen for cooling; the middle gas pipe 302 is filled with oxygen for oxidation and combustion supporting during oxidation and heat preservation, and is filled with oxygen for dilution during reduction, so that the reduction utilization rate of natural gas is improved;
one end of the lifting steel wire rope 4 is connected with the top-blowing spray gun 3 through a lifting lug, and the other end of the lifting steel wire rope penetrates through a pulley 6 at the top of the lifting guide rail 5 to be connected with the winch 7.
(2) Production conditions
When the blister copper melt 2 in the converting furnace enters the refining furnace, oxygen is blown by using the top-blowing spray gun 3 to perform oxidation combustion supporting and heat preservation, meanwhile, a sample of the blister copper melt 2 is taken to perform analysis on oxygen and sulfur content, the inside of the refining furnace body 1 is kept in a feeding state, and when the blister copper melt 2 in the refining furnace body 1 reaches 300t, sampling calculation is performed.
(3) Process calculation
According to the oxygen and sulfur content in the blister copper melt 2, the oxygen content of the blister copper is calculated to be 0.3%, the nitrogen pressure is 0.5MPa, the compressed air oxygen concentration is 21%, the pressure is 0.7MPa, the oxygen concentration is 100%, the pressure is 0.8MPa, the oxygen enrichment concentration is 40%, the oxygen utilization rate is 60%, the time required for feeding the blister copper to 650t is 6 hours, and the oxidation end point blister copper oxygen content is 0.8%;
the oxygen-enriched air quantity of 40% required for increasing the oxygen content of 650t crude copper from 0.3% to 0.8% is 10500Nm3, and the required oxygen and compressed air flow rates are 2500Nm respectively 3 And 8000Nm 3 The single top-blowing lance 3 is set up as follows: the flow rate of the cooling nitrogen was 100Nm 3 Per hour, compressed air flow rate 670Nm 3 /h, oxygen flow of 210Nm 3 And/h, the number of the top-blowing spray guns 3 is 2.
(4) Top-blown oxidation
And according to the data calculated by the process and the height of the liquid level of the blister copper melt 2, adjusting the height of the top-blowing spray gun 3 to enable the height of the top-blowing spray gun 3 from the liquid level of the blister copper melt 2 to be 100mm, and then performing top-blowing oxidation.
(5) Top-blown reduction
After the oxidation of the blister copper melt 2 is finished, introducing natural gas through a top-blowing spray gun 3 for top-blowing reduction; the crude copper melt 2 in the furnace is 300t, the oxygen content of the crude copper is 0.8%, the nitrogen pressure is 0.5MPa, the natural gas concentration is diluted to 50% by using nitrogen, the natural gas reduction utilization rate is 60%, and the reduction time is 2h;
the natural gas consumption required to reduce the oxygen content of 650t blister copper from 0.8% to 0.2% was 2700Nm 3 The single top-blowing lance 3 is set up as follows: the flow rate of the cooling nitrogen gas was 150Nm 3 /h, natural gas flow 675Nm 3 /h, nitrogen flow of 675Nm 3 And/h, the number of the top-blowing spray guns 3 is 2.
And according to the data calculated by the process and the height of the liquid level of the blister copper melt 2, adjusting the height of the top-blowing spray gun 3 to ensure that the height of the top-blowing spray gun 3 from the liquid level of the blister copper melt 2 is 150mm, and then performing top-blowing reduction.
(6) After the reduction is finished, the top-blowing spray gun 3 is switched to heat preservation, the refining furnace body 1 rotates to a copper discharging process, when the residual amount of the blister copper melt 2 in the furnace is 100t, the nitrogen pressure is 0.5MPa, the natural gas pressure is 0.5MPa, the oxygen pressure is 0.8MPa, the combustion oxygen-fuel ratio is 2.1, and the single top-blowing spray gun 3 in the heat preservation period is calculated as follows: the flow rate of the cooling nitrogen was 50Nm 3 /h, natural gas flow of 100Nm 3 /h, oxygen flow of 210Nm 3 The number of top-blowing spray guns 3 used is 2;
and adjusting the height of the top-blowing spray gun 3 according to the data calculated by the process and the height of the liquid level of the blister copper melt 2, so that the height of the top-blowing spray gun 3 from the liquid level of the blister copper melt 2 is 1m, and then performing top-blowing heat preservation.
(7) The condition of the top-blowing spray gun 3 is detected from spray gun holes at regular intervals, when the height of the top-blowing spray gun 3 does not meet production requirements, the top-blowing spray gun 3 is pulled out through a winch 7, a new top-blowing spray gun 3 is replaced, and then the gun head of the old top-blowing spray gun 3 is welded for one section again after being cut off, so that the top-blowing spray gun is repaired for use.
The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, the scope of which is defined by the claims. Various modifications and equivalent arrangements of parts may be made to the present invention within the spirit and scope of the invention, and such modifications and equivalents should be considered to fall within the scope of the invention.