JPS61124538A - Method for evaluating performance of concentration burner for flash smelting furnace - Google Patents

Abstract

PURPOSE:To evaluate quantitatively and economically the performance of a concentration burner for a flash smelting furnace in a short period by using the partial pressure of oxygen in a melt as an index expressing a degree of progress of a metallurgical oxidation reaction at a high temp. in the furnace. CONSTITUTION:The partial pressure of oxygen in droplets of a melt dropping in the lower space of the shaft part of a flash smelting furnace and the partial pressure of oxygen in matte drawn out of a matte drawing hole in the settler part just below the shaft part are measured with oxygen probes each having a built-in oxygen concn. cell. These values are standardized on the basis of the partial pressure of oxygen at a fixed temp., and the ratio between the logarithms of the two standardized partial pressures of oxygen is calculated. The resulting value is used as a value for evaluating the performance of a concentrate burner.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves blowing concentrate and reaction air or oxygen-enriched air (hereinafter referred to as reaction gas) into a flash smelting furnace to cause a smelting reaction. Concerning a method for evaluating the performance of a concentrate burner.

[Conventional technology]

In a flash furnace, dry concentrate, such as copper concentrate, is blown in together with a reaction gas from a concentrate burner installed at the top of the reaction shaft, and the concentrate is instantly oxidized and melted, and valuable metals such as copper are used as scissors. Concentrate. In this case, it is important that the concentrate and the reaction gas are uniformly mixed so that a uniform oxidation reaction can proceed within a very short time as they fall through the reactor shaft. If the mixing condition is poor and unreacted and undissolved substances are generated locally, this may accumulate in the settler at the bottom of the reaction shaft and prevent the formation of drums.
This not only causes large fluctuations in the shear filling rate and quality of the drum, causing difficulties in operating the furnace, but also damages the bricks of the reaction shaft due to localized heating in areas where reactions occur in a concentrated manner. Furthermore, since the heat of the oxidation reaction of the concentrate cannot be fully utilized, the amount of auxiliary fuel used increases.

Here, the state of mixing of the concentrate with the reaction gas is largely controlled by the structure of the concentrate burner provided in the flash furnace and its operating conditions, that is, the performance of the concentrate burner.

Conventionally, to evaluate the performance of a concentrate burner, it was possible to determine what percentage of oxygen in the reaction gas contributed to the oxidation reaction of the concentrate by examining the mass balance of oxygen in the charge and output of the flash furnace. We have determined the oxygen efficiency that represents However, this method requires the evaluation of all oxides contained in the charge and the product, and there are many problems in terms of analysis technology, measurement errors, time and cost required for analysis, etc. It was difficult to ensure accuracy.

There is also a method of evaluating the performance of a concentrate burner using actual operational data such as the smoke ash generation rate and the difference between brood temperature and burst temperature.
It is difficult to draw correct conclusions from short-term operational data, and it is virtually impossible to maintain constant operating conditions such as fluctuations in raw material concentrate, making it impossible to make an absolute quantitative evaluation of burner performance. There was a point.

When the performance of the concentrate burner is sufficient during light-load operation with little concentrate charging, the minimum height required for reaction in the shaft can be determined by measuring the temperature distribution in the height direction within the shaft. It is possible to evaluate the performance of the concentrate burner by determining the temperature, but it is difficult to complete the measurement in a short time, and since the metallurgical reaction inside the shaft is a high-temperature oxidation reaction, it is possible to evaluate the required height of the shaft from only the temperature distribution. It is very dangerous to ask for something.

[Problem that the invention seeks to solve]

The present invention seeks to provide a method for determining the performance and placement height of a concentrate burner without waiting for long-term operating results as in the prior art.

[Means for solving problems]

The inventors selected the oxygen partial pressure in the solution as an index to express the progress of the high-temperature oxidation reaction inside the flash furnace, and in recent years this oxygen partial pressure has come to be used to measure the amount of oxygen in molten steel. Using an oxygen probe with a built-in oxygen concentration battery that uses stabilized zirconia as a solid electrolyte, measure the oxygen partial pressure in the solution in the shaft and settler parts, and correct this value to the oxygen partial pressure at a constant temperature (hereinafter referred to as This correction value is called the standardized oxygen partial pressure), and a detailed study of changes in the standardized oxygen partial pressure in the flash furnace revealed that the logarithm of the standardized oxygen partial pressure at the shaft outlet and the standardized oxygen partial pressure at the settler section We have discovered that the performance of a concentrate burner can be quantitatively evaluated by determining the ratio of pressure to logarithm.

However, measuring the oxygen partial pressure in the settler section is
As will be described later, it is necessary to insert an oxygen probe from the ceiling of the settler section, which makes measurement difficult, and this value can be substituted with the oxygen partial pressure of the mat extracted from the mat outlet directly below the shaft section. was constructed as follows.

That is, the present invention uses an oxygen probe with a built-in oxygen concentration battery to measure the partial pressure of oxygen in the melt droplets falling through the space below the shaft in a flash furnace, and to extract the oxygen from the mat outlet directly under the shaft of the settler section. Measure the oxygen partial pressure in the mat, find the standardized oxygen partial pressure from these values, find the ratio of the logarithm of the standardized oxygen partial pressure in the shaft and the standardized oxygen partial pressure in the mat, and refine this. This value is used to evaluate the performance of the ore burner.

The present invention will be explained in more detail below.

(b) Method for measuring oxygen partial pressure Oxides that exhibit virtually complete oxygen ion conduction under the conditions of smelting reactions in flash furnaces, such as stabilized zilfnia ZRO1M
An oxygen concentration battery (1) is constructed using go as a solid electrolyte.

pt/Pa (+)/zro +Mgo/po (n)
/pt (1) The electromotive force E of this oxygen concentration battery (1) can be expressed by the following equation (2).

However, R: Gas constant T: Absolute temperature 0K F: Faraday constant po2 (1): Oxygen partial pressure indicated by the reference electrode Po (11):
The reference electrode is not particularly limited as long as it exhibits a constant oxygen partial pressure at a constant temperature, but in copper smelting, Fe
-Fe0 is superior.

As is clear from equation (2), if the electromotive force E and temperature T of the oxygen-a dilute battery (1) can be measured, the oxygen partial pressure P indicated by the reference electrode can be measured.
o The value of (1) is known [for example, when the reference electrode is Fe-Fe0, RTln, P
o (1) --526800+ 129.6 T (J
-mol-')] Therefore, the oxygen partial pressure po (II) indicated by the measurement electrode can be determined.

(b) Standardization method for oxygen partial pressure Since the oxygen partial pressure measured by an oxygen concentration cell changes depending on the temperature, even if you try to estimate the progress of the reaction by the oxygen partial pressure at each measurement location in the flash furnace, it will be difficult to estimate the progress of the reaction at each measurement point. Since the temperature at different locations generally differs, the obtained oxygen partial pressure is adjusted to a certain temperature (for example, 1200°C in copper smelting).
It is necessary to standardize the oxygen partial pressure to the oxygen partial pressure at 1250 t:', 1250 t:', etc.).The standard method for this standardization is generally to evaluate from the redox reaction equation established between the compound components that make up the reaction system. In the present invention, since a large amount of iron is included in the constituent elements of ``N'' and ``I'', it is best to consider the following reaction formula.

・SiFe0(1)-1-0(g)-2FeO(1)
(31 Standard free energy change ΔG of equation (3)
0(T) can be expressed as follows using Fed(no).

Therefore, in order to standardize the oxygen partial pressure PO□(T, ) at the measurement temperature T, to the oxygen partial pressure P02(T2) at the standard temperature T2, the activity αFed'
Assuming that +2 α remains constant without changing, the following equation (6) can be obtained from equation (5).

Therefore, if the oxygen partial pressure at the measurement temperature T1 is found, the reaction free energy ΔG0 in equation (3) is known, so by substituting these values into equation (6), the oxygen partial pressure Po( r) can be obtained.

[Measurement experiment example]

In the present invention, at what points in the shaft section and settler section of the flash furnace should the oxygen partial pressure be measured? To investigate, we attempted to measure the oxygen partial pressure at various locations within the shaft and settler section. The longitudinal cross-sectional view and plan view of the furnace in FIG. 1 show the locations where the oxygen partial pressure is measured.

The height of the side wall of the shaft part 1 of the flash furnace is changed and the upper and lower Φ
Open measurement holes 2.3.4.5 in the shaft height direction and radial direction (1 m each from the furnace wall with a shaft radius of 3 m)
Changes in the standardized oxygen partial pressure at the 2 m center and 2 m from the center were determined. In addition, as for the oxygen partial pressure in the settler section 6, several locations are selected for each measurement among the lower contact area directly below the shaft section, the openings 8 to 12 downstream from it, and the warming ports 13 and 14. In addition to determining the change in the oxygen partial pressure in the horizontal direction, the change in the standardized oxygen partial pressure in the solution in the settler in the vertical direction was also investigated through the measurement hole 15 provided in the ceiling at the center of the settler.

Figure 1 shows the values of standardized oxygen partial pressure in the shaft part and each mat hole corresponding to the distance from the shaft part entrance,
Table 1 shows the results of different measurement positions within the shaft. FIG. 3 shows the normalized partial pressure of oxygen in the vertical direction in the solution in the settler section, measured through the measurement hole 15.

Table 1 From the results in Table 1, it can be seen that within the shaft portion, if the height is the same, there is almost no difference in the standardized oxygen partial pressure in the radial direction. However, if the impact of the melt droplets on the oxygen probe is insufficient, PO will be measured at a high level. Therefore, it is preferable to measure at a position where the spatial density of melt droplets is high, that is, directly below the burner cone of the concentrate burner (in the example in Table 1, at a position 2 m in the radial direction from the shaft furnace wall).

The graph in Figure 1 uses the top of the center of the shaft as its origin as the horizontal axis, draws a perpendicular line from there, and shows the distance of the line extending from the solution surface toward the downstream of the settler part. The marks indicate measurements taken at the same time.In the shaft part, the normalized oxygen partial pressure decreases as you go lower (towards the right in the figure), but in the settler part, it decreases from just below the shaft part. Regardless of the distance, the normalized oxygen partial pressure no longer changes much. Also, in Figure 2, the first
The changes in the oxygen concentration in the settler part in the depth direction were measured four times using measurement hole 15 in the figure.If the measurement time points were the same, the normalized oxygen partial pressure in the vertical direction in the solution in the settler part was almost the same. It shows that it never changes.

From the above results, it is considered that the smelting reaction is completed in the shaft part or the settler part directly below the shaft part, and the temperature at which the measurement area of oxygen partial pressure is standardized is 1250 C and 1250 C in the case shown in Figure 1. The one shown in Figure 2 is 1200
C, but the trends obtained do not change even if these standardized temperatures are changed.

Therefore, it is judged that the smaller the difference between the standardized oxygen partial pressures between the lower shaft part and the settler part, the better the performance of the concentrate burner is, or that there is a margin in performance, and these standardized oxygen partial pressures can be used to quantitatively evaluate the performance of the concentrate burner. and can be evaluated absolutely. When removing wrinkles from the mat removal lower part ~ 12 of the settler section, at the beginning of removal, the particles near the bottom of the settler that have accumulated around the removal opening are discharged, but gradually the needles closer to the warm surface flow toward the removal opening. It shows the tendency to Therefore, since the fracture at each tap hole in the latter stage of sampling shows almost the same value as the oxygen partial pressure in the settler at the mat opening position, it was sampled instead of directly measuring the oxygen partial pressure of the solution in the settler part of the furnace. Measuring the partial pressure of oxygen in the drum can be used as a substitute characteristic.

[Evaluation of burner performance]

For example, the oxygen partial pressure is measured from the measurement hole 5 in the shaft part in Figure 1, and the oxygen partial pressure of the drum is extracted from the drum extractor lower directly below the shaft part. and measure each standardized oxygen partial pressure as PO(R
/S) and PO(S/T).

Therefore, in the normal operation of copper smelting, the copper concentrate supplied from the concentrate burner contains repeated dust containing oxides, copper slag powder, and melt droplets falling down the shaft. The higher the wrinkle quality is, the higher the PO will be.The higher the wrinkle quality, the higher the PO should be.However, in reality, the PO should be higher as you go to the bottom of the shaft.
eS reduces higher oxides in dust and steel slag, and PO decreases as it goes toward the bottom of the shaft.

In such a case, the performance η of the concentrate burner is determined as follows.

The value of η can take a value of θ to 100, but the performance of the concentrate burner is better as the value of η is larger, and it has quantitative properties.In other words, in the graph of Figure 1, the upper part of the shaft on the horizontal axis The smaller the slope of the standardized oxygen partial pressure from the point to the settler section 18 directly below the shaft section, the better the performance.

When calculating η, the value of PO of the shaft part Po (R/S
) is the lower part of the shaft part, and it is preferable to measure it at the upper part of the settler part than the joint with the ceiling brick, and the value of PO in the settler part PO The value for the lower part directly under the shaft is preferable, although the value for the lower part directly below the shaft can also be used.

A desirable value of η is 95 or more when the standardized oxygen partial pressure is measured at the lower part of the shaft and at the wrinkle outlet directly below the shaft.

Regarding absoluteness, the thermodynamic intensive variable logPo□(S/
'I'), it is considered that all thermodynamic and operational variables are standardized.

On the other hand, if the copper concentrate supplied from the concentrate burner does not contain high-grade oxidized fractions such as repeated dust or copper slag powder, Po
The value of increases toward the bottom of the shaft, so in such a case, η is determined as:

〔Example〕

Examples (explained below).

Example 1 The improved concentrate burner shown in Fig. 3 (a), using 4 <- burners at the top of the shaft, and the conventional concentrate burner with 31 shafts shown in Fig. 3 (b) A method for evaluating the performance of a concentrate burner when using the top part G will be explained.

The conventional concentrate burner shown in FIG. 3G) has a venturi-shaped constriction part 22 at the bottom of the concentrate scoop main body 21, and a constrictor cone 23 with a widened base is formed below the constriction part 22. ing. A tubular concentrate chute 24 is located in the center of the concentrate chute 21 and its lower end is connected to a venturi-shaped constriction part 22.
A heavy oil burner 25 is installed vertically so as to protrude further downward, and passes through the center of the concentrate chute 24.
The opening at the lower end of the heavy oil burner 25 is the burner cone 23
It is located near the exit. Burner cone 23 below the outlet at the lower end of concentrate chute 24 of heavy oil burner 25
There is a dispersion cone 2 on the outer periphery of the part that disperses the falling concentrate.
6 is provided. Reaction air supplied into the concentrate burner main body 21 through the blast pipe 27 flows through the concentrate chute 24.
It is configured to be blown into the concentrate falling through the concentrate chute 24 from the venturi-shaped throttle part 22 of the block.

The improved concentrate burner shown in Fig. 3(a) is shown in Fig. 1 et al.)
An oxygen blowing pipe 28 is provided surrounding the heavy oil burner 25 inside the conventional concentrate burner (concentrate shoe) 24,
The outlet part of the oxygen blowing pipe 28 is provided closer to the lower end than the center of the concentrate chute 24, and an opening area adjustment spacer 29 is provided in the center to narrow the opening area, and the opening part is set closer to the lower end than the center of the concentrate chute 24.
10 guide vanes 3 inclined at 45° with respect to the axial direction of 8
0 is set. The lower end surface of the dispersion cone 26 attached to the outer periphery of the lower end of the heavy oil burner 25 is connected to the lower end 3 of the concentrate chute 24.
It is a plane with substantially the same height as 2. The slope of the conical surface on the outer periphery of the concentrate dispersion cone 26 is parallel to a line connecting the inside of the lower end 32 of the concentrate chute 24 and the inside of the lower end of the burner cone 23 . A flow rate adjusting cone 33 is suspended from the outer periphery of the lower end of the concentrate chute 2Φ by a hanging rod 34 and is suspended by a stopper 35 so that its position can be adjusted up and down from the upper surface of the concentrate burner body 21. The outer surface of the lower half of the flow rate adjusting cone 33 is formed parallel to the inner surface of the concentrate burner body 21. Then, part or all of the high concentration oxygen is blown into the concentrate chute 2Φ through the oxygen blowing pipe 28 as a swirling flow, and the gas flow rate is set to 80 to 24
0 m/sec.

The operation using both concentrate burners was continued for about one month, and the average value of the operation results during that period is shown.

On the other hand, the evaluation of concentrate burners is the result obtained in a very short period of time when the respective operations are stable, but the oxygen partial pressure in the shaft part 1 is at a height of 8 from the top of the shaft part 1 to the warm temperature.
It is measured at a point 5.0 m below the top of m, and the oxygen partial pressure in the settler section 6- is 1, and it is 1 from the start of removing the drum taken out from the wrinkle removing lower directly below the shaft section 1.
The value of η was determined using the value measured after 0 minutes.

These results are shown in Table 2.

From the results shown in Table 2, it can be seen that the improved burner is superior to the conventional burner, and that the performance of the concentrate burner can be quantitatively evaluated using η.

Example 2 The improved concentrate burner shown in FIG. 3(a) was used, and high concentration oxygen was blown from the concentrate chute 24 to operate at a total oxygen concentration of 27%. At this time, the flow velocity of the air supplied to the venturi-shaped constriction section 22 around the outlet of the concentrate chute was 110 m/s.

Further, the performance evaluation value η of the concentrate burner was measured in the same manner as in Example 1 and was 97%.

Next, the amount of oxygen supplied from the concentrate chute 24 was increased to bring the oxygen concentration in the total blast to 38%, and the flow velocity of the air supplied to the venturi-shaped constriction section 22 around the concentrate chute outlet was 61 m/s. . At this time, the performance evaluation value η of the concentrate burner decreased to 94%. Therefore, the position of the flow rate regulating cone 33 provided at the lower part of the outside of the concentrate chute is lowered slightly to increase the venturi-shaped constriction part 22 around the concentrate chute outlet.
When the flow velocity of the air supplied to the tube was set to 110 m/s, the value of η measured again was as good as 97%.

These results are shown in Table 3.

Table 3 [Effects of the Invention] As is clear from the above explanation, according to the present invention, the performance of a concentrate burner for self-smelting can be evaluated quantitatively, quickly and economically, which makes it possible to evaluate the performance of a concentrate burner for self-smelting in a short time and economically. When replacing an ore burner with a newly set concentrate burner, it is possible to easily evaluate whether the burner has superior performance or not, and based on the evaluation results, it is possible to determine the enrichment method for enriched oxygen. It is possible to maintain concentrate burner performance at a high level by changing operating conditions such as maintaining the flow rate of air supplied to a part of the venturi around the outlet of the concentrate chute above a certain value, and If the concentrate burner has sufficient performance, the value measured at the position of the measurement point in the shaft at a position higher than the height near the shaft outlet can be applied to the calculation formula for η evaluation, and the value of 97% or more can be obtained. If a numerical value is obtained, it means that the metallurgical reaction within the shaft has essentially finished by then, which has the advantage of contributing to the design of a flash furnace with a short shaft height and low energy loss.

[Brief explanation of drawings]

Figure 1 shows the measurement position of the oxygen partial pressure in the flash furnace and the oxygen partial pressure measured at that measurement position in relation to the distance from the shaft entrance, and Figure 2 shows the depth direction of the settler part. Figure 3 (a) is a cross-sectional view of the improved concentrate burner used in the embodiment of the present invention, and Figure 3 (b) is a diagram showing changes in oxygen partial pressure. It is a sectional view of an ore burner. 1...Shaft part, 2.3.4.5.15...Measurement hole,
6...Settler part, -7,8,9,10X11.12-
fillip mouth, 13.14...Hime exit, 16...warm,
17... drum, 18... settler part directly below the shaft part, 2
]... Concentrate burner body, 22... Venturi-shaped throttle part, 23... Burner cone, 24... Concentrate chute, 25... ff1M burner, 2
6...Dispersion cone, 27...Blow pipe, 28...Oxygen blowing pipe, 29...Opening area adjustment spacer, 30...Guide vane, 31...Lower end surface, 32...Lower end, 33...Flow rate adjustment cone , 3÷...hanging rondo, 35...stopping metal fitting. Applicant: Sumitomo Metal Mining Co., Ltd. 1'' Fig. 1 □ Shaft entrance h゛ et al. distance Fig. 3 (α) 31 Lower end surface Fig. 3 (b)

Claims (1)

[Claims] (1) Using an oxygen probe with a built-in oxygen concentration battery, we measured the partial pressure of oxygen in the melt droplets falling through the space below the shaft in the flash furnace and extracted them from the mat outlet directly below the shaft in the settler part. After measuring the oxygen partial pressure in the matte and standardizing these values to the oxygen partial pressure at a constant temperature, find the ratio of the logarithm values of these two standardized oxygen partial pressures and use this as the evaluation value of the concentrate burner. A method for evaluating the performance of a refined steel burner for a flash smelting furnace.