JP2002030350A - Method for producing coarse zinc oxide / lead sintered ingot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stably producing a crude zinc oxide / lead sintered ingot that is hard to soften or melt in a blast furnace without reducing the productivity of the sintered ingot. SOLUTION: In the method for producing a crude zinc oxide / lead sintered mass from a raw material for producing a crude zinc oxide / lead containing a zinc / lead raw material, a calcium oxide raw material and a silicon dioxide raw material, the amount of CaO in the calcium oxide raw material is increased. Is the amount of PbO corresponding to the amount of lead in the lead material and the amount of CaO in the calcium material.
And a zinc / lead raw material, a calcium oxide raw material, and a silicon dioxide raw material so as to be 40 to 50 mol% based on the total amount of SiO2 in the silicon dioxide raw material, and the crude zinc oxide / lead raw material. And a carbonaceous solid fuel with an upper limit of 1.0% by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a crude zinc oxide / lead sintered ingot, and more particularly to a method for preparing a raw material for producing a crude zinc oxide / lead ingot.

[0002]

2. Description of the Related Art A dry zinc / lead smelting method for simultaneously smelting zinc and lead, that is, a blast furnace method will be described. In the blast furnace method, first, raw materials including a zinc / lead raw material, a calcium oxide raw material, and a silicon dioxide raw material are prepared. The prepared ingredients are
Thereafter, they are mixed and granulated to obtain a raw material for producing a coarse zinc oxide / lead sintered mass (hereinafter, this raw material is referred to as a firing raw material). The firing raw material is charged into a sintering machine typified by a Dwyroid type sintering machine, undergoes oxidative roasting in a sintering machine at about 1200 to 1300 ° C., and the sintering reaction proceeds. In this way, a crude zinc oxide / lead fired product is produced. During firing, sulfides are burnt by oxidative roasting to generate a gas containing SO2, and this gas is suctioned and collected to produce sulfuric acid.

[0003] The burned material of crude zinc oxide and lead is crushed by a crusher, and a lump having a size of about 50 mm or more is sieved to a smaller lump to obtain a sintered lump of coarse zinc oxide and lead (hereinafter referred to as coarse zinc oxide and lead). The sinter mass is simply charged to the blast furnace together with coke as a sinter mass. Since the crushed material having a size of less than about 50 mm is not suitable for charging the blast furnace, the crushed material is repeatedly returned to the compounding step. Here, the percentage of the lumps (on the sieve) with respect to the whole baked material is called a sintering lumpy rate, and the higher the sintering lumpy rate, the higher the productivity in the firing step. In order to improve the sintering lump rate, it is necessary to obtain a fired product having high strength as is clear from the above.

[0004] In the blast furnace, about 1 ton from a tuyere provided in the lower part of the furnace.
A hot air of 000 ° C. is sent to reduce zinc oxide to zinc and lead oxide to lead by the coke. The zinc produced by the reduction is sent to the lead splash condenser from the upper part of the blast furnace together with the exhaust gas as metal vapor, and is recovered as zinc metal. In addition, lead generated by the reduction accumulates in the furnace bottom of the blast furnace, is periodically extracted with the slag to the front floor, is separated by a specific gravity difference in the front floor, and is recovered as lead metal.

[0005] When reducing a sintered ingot in a blast furnace, the high-temperature strength of the sintered ingot is important. Relatively low temperature (about 12
When the sintering mass softens or melts in the upper part of the blast furnace held at a temperature of less than or equal to 00 ° C, the gap between the sintering masses is blocked and the passage of hot air is hindered, and the reduction reaction of the crude zinc oxide is sufficient. This is because the amount of zinc dissolved in the generated slag increases, and the productivity deteriorates.

Therefore, it is necessary to obtain a sintered mass having high strength at high temperatures. However, conventionally, there has been a problem that when the high-temperature strength of the sintered ingot is increased, the sintered ingot ratio is reduced. More specifically,
Attempts to produce a high-strength sintered ingot at low temperatures, that is, to increase the sintering rate, decrease the high-temperature strength, and to produce a high-temperature-strength sintered ingot, decrease the low-temperature strength, i.e., sintering. There was a problem that the clotting rate was reduced.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems by providing a crude zinc oxide / lead sinter which is hard to be softened or melted in a blast furnace without reducing the sintering rate. An object of the present invention is to provide a method for stably producing a lump.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for producing a crude zinc oxide / lead sintered material containing a zinc / lead material, a calcium oxide material and a silicon dioxide material. In the method for producing a lump, the amount of CaO in the calcium oxide raw material is set to the sum of the amount of PbO corresponding to the amount of lead in the lead raw material, the amount of CaO in the calcium raw material, and the amount of SiO2 in the silicon dioxide raw material. 4 for
A raw material of zinc / lead, a raw material of calcium oxide and a raw material of silicon dioxide are prepared so as to be 0 to 50 mol%, and a carbonaceous solid fuel having an upper limit of 1.0% by weight based on the raw material for producing crude zinc oxide / lead. Is added.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors filed Japanese Patent Application No. 11-180131, filed in Japanese Patent Application No. 11-180131, and filed calcium calcium (Ca)
O), lead (Pb) in the zinc / lead raw material and silicon dioxide (SiO2) in the silicon dioxide raw material to CaO-PbO-S
It was presumed that an iO2-based composition was produced (hereinafter, CaO-
The PbO-SiO2 composition is referred to as CPS phase). In Japanese Patent Application No. 11-180131, this CaO-PbO-SiO
A method has been proposed in which the sinter lump ratio is improved by using a two-component low melting point composition. The method is CaO-PbO-Si
Since it was presumed that the O2-based low-melting composition worked as a binder for the fired product, the raw materials were mixed so as to lower the melting point of the composition and increase the amount of the composition relative to the fired product. The purpose is to improve the strength of the fired product and improve the sintering lump rate. However, it is clear that when the sintered ingot forms a low melting point composition in the blast furnace, the sintered ingot tends to soften or melt. Therefore, the present invention
By adjusting the method of mixing the raw materials to generate a high melting point CPS phase and improve the high temperature strength, the decrease in the sintering mass ratio due to the higher melting point of the CPS phase was confirmed by adding carbonaceous solid fuel to the firing raw material. Then, it is burned and prevented by raising the sintering temperature.

[0010] By the way, CaO-PbO produced in a crude zinc oxide / lead calcination product obtained by calcining a conventional calcination raw material.
The component range of the —SiO 2 composition is CaO—Pb in FIG.
In the melting point diagram of the O—SiO 2 composition, CaO: Pb
Each mole% of O: SiO2 is (40:25:35), (4
0:35:25), (30:45:25), (30: 3
5:35). The highest melting point in this range is 40 mol% CaO (40:
25:35) and (40:35:25), and its melting point can be read to be about 1500 ° C. from an isotherm existing almost parallel to the line. Therefore CP
In order to raise the melting point of the S phase from the conventional maximum temperature of 1500 ° C., it is necessary to increase the molar percentage of CaO from 40 molar%.

In order to increase the mol% of CaO, the amount of CaO in the calcined product is increased or PbO or SiO2 is decreased. For this purpose, it is necessary to adjust the method of mixing the raw materials. However, the total amount of Pb in the raw materials becomes PbO and becomes a fired product, and the entire amount of CaO and SiO2 also becomes a fired product. PbO amount corresponding to Ca
Ratio of CaO amount to total amount of O amount and SiO2 amount (hereinafter, this ratio is referred to as CaO mol% in firing raw material)
May be adjusted so as to be 40 mol% or more of the lead raw material, the calcium oxide raw material, and the silicon dioxide raw material.

However, when the molar percentage of CaO in the sintering raw material is increased as compared with the conventional case, the sinter lump ratio decreases as described above. To prevent this, a carbonaceous solid fuel is added with the upper limit of 1.0% by weight based on the firing raw material. Then, during firing, the carbonaceous solid fuel burns and the sintering temperature rises.
This is because when the temperature rises, sintering of the firing raw material is promoted, and a fired material having high strength is obtained, and the sintered mass ratio is improved. The carbonaceous solid fuel is, for example, pulverized coal or pulverized coke. The amount to be added is a maximum of 1.0% by weight based on the firing raw material.
It is. This is because the sintering temperature further rises if more is added, but the rate of increase of the sintering temperature with respect to the added amount decreases.

[0013] The addition of a carbonaceous solid fuel with an upper limit of 1.0% by weight based on the calcined raw material can improve the sintered lump ratio to the conventional sintered lump ratio because of the CaO mole fraction in the calcined raw material. % Is up to about 50%. This CaO50
The term “mol%” corresponds to a line in which the melting point of the CPS phase is 1800 ° C. in the melting point diagram of the CaO—PbO—SiO 2 composition shown in FIG. That is, when the melting point of the CPS phase exceeds 1800 ° C., the high-temperature strength is improved, but the sintering lump ratio is lower than before, which is not preferable.

Hereinafter, the present invention will be described with reference to examples.

[0015]

EXAMPLES [Examples and Conventional Examples, Comparative Examples] Fifteen kinds of firing raw materials shown in Table 1 were prepared by combining zinc / lead raw materials, calcium oxide raw materials, silicon dioxide raw materials, and the like. The weight of each prepared raw material is 50 kg.
Here, Formulations 1 to 4 are conventional formulation examples. Formulation 5,
Nos. 8 and 11 are prepared so that Ca mol% in the raw material for firing becomes 40 to 50 mol%. Formulas 6 and 7 are examples in which 0.5% and 1.0% by weight of coke were added to the material of Formula 5, respectively, and Formulas 9 and 10 were 0.5 and 1.0% of coke to the material of Formula 8, respectively. Formulations 12 and 13 are examples in which 0.5% and 1.0% by weight of coke were added to the raw material of Formulation 11, respectively. As a result, in the preparation 14, the Ca mole% in the firing raw material was 50%.
%, And Formulation 15 was prepared by adding 1.0% by weight of coke to Formulation 14.

[0016]

[Table 1]

These fifteen kinds of blended raw materials were mixed and granulated to obtain a raw material for firing, and the raw material was charged into a small sintering machine for testing to obtain a raw zinc oxide / lead fired product. C generated in the fired product
Table 2 shows the chemical composition of the PS phase. The chemical composition of the CPS phase was applied to the melting point diagram of the CaO—PbO—SiO 2 composition shown in FIG.
Shown in

[0018]

[Table 2]

From Table 2, it can be seen that the CPs of Formulations 1-4, which are conventional examples,
The melting point of the S phase was 1500 ° C. or less. Formulations 5 to 13 are those in which Ca mol% in the firing raw material is 40 to 50 mol%.
590 to 1780 ° C, and was in the range of 1500 to 1800 ° C. Formulations 14 and 15 were prepared by further increasing the Ca mole% in the raw material for firing to 54 mole%, and the melting point was further higher at 1880 ° C.

Next, the high-temperature strength of the fifteen kinds of baked products prepared so that the melting points of these CPS phases were different was measured as follows. (High temperature strength measurement method) The fired product is a clenched fist-shaped mass,
Lumps were arbitrarily taken out of the fifteen kinds of fired products, and cubes of 20 mm square were cut out of them to obtain test pieces. The test piece is placed in a heating furnace, and is pressed from above the test piece with a pressing plate having a load of 500 g. The pressure plate is provided with a displacement measuring mechanism, and when the test piece is softened by heating and compressed by the load of the pressure plate, the displacement amount is measured.

Then, the temperature of the furnace is increased at a predetermined speed while measuring the displacement of the test piece. Therefore, in order to determine the high-temperature strength, it is important to know at what temperature in the present case the softening starts and what kind of softening curve is drawn thereafter. However, in this case, the heating temperature when the predetermined amount of displacement is reached is simply used as a measure of the high-temperature strength. There is no criterion that the predetermined amount of displacement must be large, so that it was set to 1 mm. That is, the temperature at the point of displacement of 1 mm was used as a substitute for the high-temperature strength.

Table 2 shows the high-temperature strength thus measured, that is, the temperature (° C.) at the time of displacement of 1 mm. From Table 2,
The temperature at the time of 1 mm displacement of the formulas 1-4 as the conventional example is 112
9-1214 ° C. On the other hand, Ca
1 m for formulas 5 to 15 in which O mol% is 40 mol% or more
It can be seen that the temperature at the time of the displacement of m is 1292 ° C. or higher, which is higher than the conventional example.

Next, a description will be given of a method of measuring the sintered mass ratio, which is a guide to see how the productivity of the firing step has changed by increasing the CaO mole% in the firing raw material. (Measurement method of sintered mass ratio) The fired product cooled to room temperature is dropped from a height of 2.5 m onto a 10 mm-thick iron plate to be crushed, and the obtained crushed material is sieved with a 50 mm sieve. I do. Then, the percentage of the weight on the sieve with respect to the weight of the fired product dropped is calculated. This operation is further repeated twice, and the average value of the three calculated values is defined as the sintered mass ratio.

The sinter lump ratio thus measured is also shown in Table 2. As shown in Table 2, the ratios of the sintered lumps of Formulations 1 to 4 as conventional examples were 19.3 to 32.8%. On the other hand, in Formulations 5, 8, 11, and 14 in which the CaO mole% in the firing raw material was increased to 40 mole% or more, the sintering lump ratio was 5.6 to 14.5.
0%, lower than the conventional example.

Therefore, in order to improve the sintering lump ratio of the preparations 5, 8, 11, and 14, the coke is added in an amount of 0.5 to 1.0% by weight.
Formulations 6, 7, 9, 10, 12, 13, 1
5 Looking at these sintering lump rates from Table 2, Formulation 6 in which the CaO mole% in the firing raw material was 40 to 50 mole%,
7, 9, 10, 12, and 13 were 25.3 to 35.5%, indicating that the sintered mass ratio was improved to the level of the conventional example or more. These are examples in the present invention.

Another one is to reduce the CaO mole% in the firing material to 5%.
In Formula 15 where the content was increased to 0 mol% or more, coke was added to 1.
It can be seen that even if 0% is added, the sintered mass ratio is 13.5%, not reaching the value of the conventional example. From the above, the present invention in which CaO mol% in the sintering raw material is set to 40 to 50 mol% and coke is added in an amount of 1.0% by weight or less, the high temperature strength can be reduced without lowering the sintering mass ratio than before. It turns out that it is very effective as a means for improving.

[0027]

As is apparent from the above, according to the present invention, the sintering lump ratio is not reduced in the firing step.
Crude zinc oxide / lead sintered ingots that are difficult to soften or dissolve in the blast furnace can be stably manufactured.

[Brief description of the drawings]

FIG. 1 is a melting point diagram of a known CaO—PbO—SiO2 composition.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shuji Okada 17-5 Isouracho, Niihama-city, Ehime Prefecture F-term in Niihama Research Laboratory, Sumitomo Metal Mining Co., Ltd. 4K001 AA20 AA30 BA02 CA33 CA34 CA36 DA05 DA06 GA02 GA10

Claims (1)

[Claims] 1. A method for producing a raw zinc oxide / lead sintered mass from a raw material for producing a raw zinc oxide / lead containing a raw material of zinc / lead, a raw material of calcium oxide and a raw material of silicon dioxide, comprising the steps of: PbO amount corresponding to the amount of lead in the lead material and Ca in the calcium material
A zinc / lead raw material, a calcium oxide raw material, and a silicon dioxide raw material are prepared so as to be 40 to 50 mol% with respect to the total amount of O and SiO2 in the silicon dioxide raw material,
A method for producing a crude zinc oxide / lead sintered mass, comprising adding a carbonaceous solid fuel to the raw material for producing a crude zinc oxide / lead in an amount up to 1.0% by weight.