JPH0435533B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for blowing high concentration oxygen and reaction gas when a part of the reaction air is replaced with high concentration oxygen in a flash smelting furnace, and a method for using high concentration oxygen. The present invention relates to the structure of a concentrate burner suitable for [Prior art] In a flash-smelting furnace, dry concentrate, such as copper concentrate, is blown together with reaction air or oxygen-enriched air from a concentrate burner installed at the top of a reaction shaft, and the concentrate is instantaneously blown into the furnace. Melts with oxidation and concentrates valuable metals such as copper. In this case, it is important that the concentrate and the reaction air or oxygen-enriched air are uniformly mixed so that a uniform oxidation reaction proceeds within a very short period of time as they fall through the reaction shaft. If this mixing condition is poor and unreacted or undissolved substances are generated locally, they may accumulate in the settler at the bottom of the reaction shaft and prevent the production of 〓, cause large fluctuations in 〓 temperature and quality, or cause dust. This not only causes difficulties in operating the reactor due to the increased amount of scattering outside the reactor, but also causes local heating in areas where reactions occur in a concentrated manner, resulting in damage to the bricks of the reaction shaft. In order to obtain such uniform mixing and reaction conditions, it is necessary to maintain the flow rate of the reaction gas blown into the concentrate falling from the concentrate chute at 80 m/sec or more. In other words, in order to increase the efficiency of the reaction between the concentrate and the oxygen being blown and shorten the reaction time, it is necessary to form a stable flame in the concentrate burner cone at the outlet of the concentrate chute and concentrate the concentrate in the flame. It is necessary to disperse the oxygen uniformly and to increase the rate of oxygen supply into the flame so that the oxygen can be supplied in a short time. If a stable flame is not formed at the exit of the concentrate chute, the time required for the reaction between the concentrate and oxygen to complete will be longer, so the height of the shaft should be increased in order to increase the residence time in the shaft part due to the furnace design. This leads to increased heat dissipation. However, even if a flame is formed, if the concentration of concentrate in the flame is poor, the concentrate dispersed outside the flame will hardly be combusted in the shaft section and will be scattered as dust to the waste heat boiler, causing dust troubles. Cause. On the other hand, if the concentrate dispersion in the flame is not uniform, the flame temperature will drop in areas where concentrate is excessively concentrated, and the supply of oxygen necessary for that area will not be able to keep up, causing the temperature in that area to drop even further. Some concentrates do not completely melt in the shaft section and fall into the settler section, becoming unburned and unmelted deposits, and some concentrates with small particle sizes become dust and scatter to the waste heat boiler, where they self-dissolve. This will cause trouble in the furnace boarding work and in the operation of the waste heat boiler. Furthermore, even if a stable flame is formed and the concentration and uniform distribution of the concentrate in the flame is good, if the supply of oxygen to the flame is insufficient, the concentrate will not burn sufficiently in the flame. , causing a phenomenon in which unburned materials remain. Conventional flash furnace concentrate burners are unsatisfactory in this respect. That is, FIG. 3 is a cross-sectional view showing a conventional concentrate burner, in which the lower part of the concentrate burner main body 1 has a ventilate-shaped constriction part 2, and below that, a burner cone 3 with a widened base is formed. . A tubular concentrate chute 4 is installed vertically in the center of the concentrate burner body 1 so that its tip protrudes slightly below the ventilate-shaped constriction part 2, and the fuel is passed through the center of the concentrate chute 4. burner 5
has its tip opened near the outlet of the burner cone 3. A dispersion cone 6 for dispersing falling concentrate is provided in a portion of the burner cone 3 below the outlet of the concentrate chute 4 of the fuel burner 5. The reaction air supplied through the blast pipe 7 passes through the ventilated constriction 2 around the concentrate chute 4.
It is configured to be blown into the concentrate falling through the concentrate chute 4 from the concentrate chute 4 . However, the oxygen concentration in the air is relatively low (21~
40vol%) and the air blowing temperature is about 500℃, the tip of the fuel burner 5, which is the ignition source, is located near the outlet of the burner cone 3, and the inside of the burner cone 3 is heated. It was impossible to form a flame at the outlet of the concentrate chute 4 because the ore particles could not be heated to their ignition temperature. Recently, oxygen-enriched air has been used to increase the throughput of concentrates and reduce energy costs. Since oxygen-enriched air is sent from the pipe 7, depending on the amount of concentrate charged and the oxygen enrichment ratio, the flow rate of the reaction gas flowing through the ventilate-shaped constriction part 2 will be adjusted to the desired value by the volume reduction of nitrogen. below 80m/sec,
Uniform mixing of the concentrate and the reaction gas may not be possible in some cases. In order to solve this problem, the inventors filed Utility Model Application No. 124820/1983. In this invention, a repositionable flow rate adjusting cone is provided on the outer periphery near the lower end of the concentrate chute 4 so as to adjust the flow rate of the reaction gas in the ventilated constriction section 2 of the conventional concentrate burner. However, with this device, it was not possible to form a flame at the outlet of the concentrate chute 4 for the reasons mentioned above. On the other hand, a method of directly introducing highly pure oxygen for oxygen enrichment into the concentrate chute 4 is also considered. In this case, a part of the high concentration oxygen is preferentially used for the combustion of heavy oil, which is the auxiliary fuel, so the flame temperature of the heavy oil becomes much higher than when normal air is used. Since these are pre-mixed, less ignition energy is required and a flame can be generated within the burner cone 3. However, the flame is not stable and the concentrate that has left the concentrate chute 4 spreads into the burner cone 3, so semi-molten concentrate adheres to the inside of the burner cone 3, making it difficult to continue stable operation. In addition, in order to supply high concentration oxygen into the concentrate chute 4, the flow rate of the reaction gas supplied from around the concentrate chute 4 in the ventilate-like constriction part 2 is reduced, and the supply of oxygen into the flame is reduced. It was not possible to keep up with the combustion speed and maintain the combustion state up to the shaft section, and unburnt and unmelted materials were observed to accumulate in the settler section. [Problems to be Solved by the Invention] The present invention solves the above-mentioned problems by forming a stable flame at the tip of the concentrate chute, concentrating the concentrate in the flame, and distributing it uniformly. A method for operating a flash smelting furnace that increases the efficiency of the reaction between concentrate and oxygen and shortens the reaction completion time by ensuring that the rate of oxygen supply into the flame does not impede the combustion reaction of the concentrate. and to provide a concentrate burner therefor. [Means for Solving the Problems] In order to achieve this object, the present invention comprises an operating method and a structure of a concentrate burner as described in the claims. To explain the structure of the concentrate burner of the present invention with reference to an embodiment thereof, as shown in FIG. A tube 8 is provided, and an opening area adjustment spacer 9 is provided in the center of the outlet of the oxygen blowing tube 8 to narrow the opening area, and a guide vane 10 is provided at the opening at an appropriate angle with respect to the axial direction of the oxygen blowing tube 8. It is provided. FIG. 2 is a sectional view of the outlet of the oxygen blowing pipe 8, and the blowing speed of the oxygen blowing port is preferably 30 m/sec or more and 80 m/sec or less, and the guide vane 10 is relative to the axial direction of the oxygen blowing pipe 8. The appropriate inclination angle is 20 to 70 degrees, and the number of guide vanes 10 is 5 to 15. The flow rate adjusting cone 11 is fixed to a plurality of hanging rods 12 passing through the upper surface of the concentrate burner main body 1, and is suspended from the upper surface of the concentrate burner main body 1 near the ventilate-shaped constriction portion 2. By changing its fixing position, the length of the hanging rod 12 extending into the concentrate burner body 1 can be changed, and the position of the flow rate adjusting cone 11 can be moved up or down along the outer surface of the concentrate chute 4. It is now possible to shift it. The flow rate adjusting cone 11 is formed in the shape of a truncated cone with its lower side expanding upward, and its taper angle β is preferably equal to or slightly smaller than the taper angle γ of the inner surface of the concentrate burner body 1. . Further, the stopper 13 may be a nut, and a screw may be provided on the hanging rod 12 and screwed into this, or a method may be used in which a number of small holes are provided in the hanging rod 12 and a pin is inserted into the small hole at an appropriate position. . [Function] The structure of the concentrate burner of the present invention is as described above, and when operating a flash furnace using this concentrate burner, part or all of the high concentration oxygen used is transferred to the concentrate burner body. If oxygen is supplied from the oxygen blowing pipe 8 of 1, the oxygen will flow through the guide vane 10 provided at its tip.
The concentrate is supplied into the concentrate chute as a swirling flow at high speed, and as the concentrate and high concentration oxygen are mixed uniformly and sufficiently, the ignition energy is small, and the concentrate leaving the concentrate chute 4 is fed into the burner. A flame can be formed immediately within the cone 3.
In addition, some or all of the high concentration oxygen is concentrated in the concentrate chute 4.
Since the oxygen is supplied from the oxygen blowing pipe 8 inside the air blowing pipe 7
The amount of air or oxygen-enriched air supplied from the concentrate chute 4 can be reduced compared to when only air is used as the oxygen-containing gas, and the flow rate of the reaction gas supplied to the ventilate section 2 around the concentrate chute 4 can be reduced. 80m/
sec or less, the position of the flow rate adjusting cone 11 on the outer periphery of the concentrate chute 4 is adjusted to narrow the gap through which the gas is blown from the blast pipe 7 to the ventilated constriction part 2, and the flow rate of the reaction gas is adjusted to 80 to 240 m/sec. sec
By doing so, oxygen is sufficiently supplied into the flame generated in the burner cone 3, and the reaction between the concentrate and oxygen is completed in a very short time, and the self-smelting method of the present invention The purpose of the furnace operating method can be achieved. Ventilation-shaped constriction section 2 around the concentrate chute 4
The reason for keeping the flow rate of the reaction gas supplied to the area between 80 and 240 m/sec is as mentioned above when the flow rate is 80 m/sec or less, but when it is over 240 m/sec, the flow resistance of the gas in this area increases. This is undesirable because not only does the power consumption of the blower increase, but also the concentratedly supplied concentrate is dispersed outside the flame, and the amount of unburned concentrate that is scattered toward the waste heat boiler increases. In addition, the supplied high concentration oxygen is generally supplied to the concentrate chute 4, but when the amount of high concentration oxygen used increases and the pressure drop becomes too large if the entire amount is supplied to the concentrate chute 4, When the focus of the shaft section rises and deposits on the furnace wall of the shaft section become partially thin, and it is desired to change the position of the focus, it is necessary to mix a portion of the high concentration oxygen with the reaction air. [Example] Examples will be described below. Example 1 A flash-smelting furnace equipped with four concentrate burners according to the present invention as shown in FIG. The processing amount of copper concentrate is 55t/H, 5700m ³ /H of oxygen enriched with 90% oxygen purity is used from concentrate chute 4 at 3200m ³ /H, and mixed with the blast air for 2500m ³ /H. It was operated. At this time, the flow velocity of the ventilated constriction section 2 of the oxygen-enriched air was 92 m/s, which was 80 m/s.
m/S, especially the flow rate adjustment cone 1.
Using No. 1, no operation was required to increase the flow velocity in the ventilate-like constriction section. In this operation, a flame was formed in the burner cone 3, and no unburned ore was observed to accumulate in the settler section. The results are shown in Table 1. Examples 2 to 4 Using the same concentrate burner as in Example 1, the processing amount of copper concentrate was 40, 50, and 60 t/H, respectively, and the amount of oxygen used for enrichment was 4600 to 6000 m ³ /H. From Shoot 4
3,200 to 3,000 m ³ /H was blown, and the rest was used by mixing it into the air blowing. In Example 2, the flow velocity of the ventilated constriction part 2 is 80 m/s or less without using the flow velocity adjustment cone 11, so the flow velocity of the ventilated constriction part 2 is adjusted to 150 m/s using the flow velocity regulation cone.
In addition, in Examples 3 and 4, the flow velocity in this part was further increased to 210 m/S, and as a result, in both cases, flame was formed in the burner cone 3, and the flow velocity in the settler part was increased. No accumulation of combustion ore was observed. Example 5 The same concentrate burner as in Example 1 was used, the processing amount of copper concentrate was 35 t/H, and the amount of enriched oxygen used was 3600 m ³ /
The entire amount of H is blown into the concentrate chute 4, and the flow rate of the air through the ventilated constriction part is adjusted by the flow rate adjustment cone 11.
It was operated at a speed of 120 m/s. As a result, flame was formed in the burner cone 3, and no accumulation of unburned ore was observed in the settler section. Comparative Example 1 In a flash smelting furnace equipped with four conventional concentrate burners as shown in Figure 3, 55 t/H of copper concentrate and 5500 m ³ /H of oxygen enriched with 90% oxygen purity were mixed into the blast air. It was operated. At this time, the flow velocity of oxygen-enriched air through the ventilated constriction section 2 was 105 m/s, which exceeded the appropriate value of 80 m/s, but no flame formation was observed in the burner cone 3, and no flame formation was observed in the settler section. There was a deposit of unburned ore. Comparative Example 2 Concentrate burner 4 according to the invention as in Example 1
Copper concentrate 40t/H, oxygen purity 90 in a flash furnace equipped with a book
4400 m ³ /H of oxygen for oxygen enrichment of 3200 m ³ /H from the concentrate chute 4 was mixed into the blast air and 1200 m 3 /H of oxygen was mixed into the blast air.
The operation was performed using m ³ /H. At this time, the flow velocity of the oxygen-enriched ventilated air constriction section 2 was 67 m/s, which was outside the range of the operating method of the present invention, when the flow velocity adjustment cone 11 was not used and the flow velocity was left as it was. At this time, a flame was formed in the burner cone 3, but unburnt ore was deposited in the settler section. The results of Examples 2 to 5 and Comparative Examples 1 and 2 are also listed in Table 1.

【table】

〔Effect of the invention〕

As is clear from the results in Table 1, in Examples 1 to 5, which used the concentrate burner of the present invention and operated according to the method of the present invention, a flame was formed in the burner cone, No accumulation of unburned ore was observed in the settler section, indicating that oxygen and concentrate were mixed well in the concentrate chute according to the present invention. or the concentrate burner of the present invention was used, but the dust generation rate was significantly reduced compared to the dust generation rate in Comparative Examples 1 and 2 using an operating method outside the scope of the method of the present invention. I understand. Furthermore, as shown in Comparative Example 2, when the flow velocity of the ventilate-like constriction of the concentrate burner decreases, flame is formed in the burner cone at the tip of the concentrate burner, but
Due to insufficient supply of oxygen, the combustion state inside the burner cone could not be maintained up to the shaft section, and some concentrate was left unburned and deposited in the settler section.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the concentrate burner for flash smelting furnace of the present invention, Fig. 2 is a sectional view of the outlet of the oxygen blowing pipe 8 of Fig. 1, and Fig. 3 is a sectional view of a conventional concentrate burner. It is. DESCRIPTION OF SYMBOLS 1... Concentrate burner main body, 2... Ventilate-shaped constriction part, 3... Burner cone, 4... Concentrate chute, 5... Fuel burner, 6... Dispersion cone, 7... Blow pipe, 8... Oxygen blowing pipe, 9... Opening area adjustment spacer, 10... Guide vane, 11
...Flow rate adjustment cone, 12...Hanging rod, 13
……Fasteners.

Claims (1)

[Claims] 1. In a method of operating a flash smelting furnace in which a part of the reaction air is replaced with high concentration oxygen, part or all of the high concentration oxygen used is replaced in the concentrate chute of a concentrate burner. A method for operating a flash smelting furnace, characterized in that the flow rate of reaction gas is blown in as a swirling flow and supplied to a ventilate section around the outlet of a concentrate chute at a flow rate of 80 to 240 m/sec. 2 A tubular concentrate chute is located in the center of the burner body and extends to the ventilate-shaped constriction of the burner body, and the reaction gas is concentrated between the concentrate chute and the ventilate-shaped constriction. In a concentrate burner for a flash smelting furnace where ore is injected into the upper part of a reaction shaft, an oxygen blowing pipe is provided surrounding the fuel burner in the concentrate chute, and the oxygen blowing pipe is installed in the tip opening in the concentrate chute. A flash smelting furnace characterized in that a guide vane is provided to generate a swirling flow, and a flow rate adjusting cone is provided in contact with the outer periphery of the concentrate chute and near the ventilate part so as to be able to change its position along the longitudinal direction of the concentrate chute. Concentrate burner for use.