JPS5950132A - Method for operating flash smelting furnace for smelting copper - Google Patents

Abstract

PURPOSE:To enable the changeover of mineral oil to other fuel in a flash smelting furnace for smelting copper when a copper concentrate, etc. are charged into the furnace to produce matte and slag, by adding fine-grained coke and/or low- grade coal of a prescribed size to a prescribed position of the furnace as auxiliary fuel. CONSTITUTION:Fine-grained coke (precipitated coke breeze) and/or low-grade lump or fine coal of <=40mm. size is prepared. The solid fuel is added to a system for charging a copper concentrate, a flux, etc. on the upper stream side of a flash smelting furnace with respect to a copper concentrate dryer kiln and a flash transporter. The solid fuel is used as auxiliary fuel to maintain the operation temp. of the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides f! 3 This relates to technology for converting the fuel in the smelting flash smelting furnace from conventional mineral oil to solid carbonaceous fuel.□ The flash smelting furnace for copper smelting is charged with sulfurized copper concentrate (hereinafter referred to as copper concentrate) along with flux, etc. At the same time, air or oxygen-enriched air is blown in, and the reaction heat generated during oxidation is used as the main heat source to melt and oxidize the copper concentrate. This furnace produces slag, which is a molten material mainly composed of (matte) and silicate of iron oxide. At this time, the exhaust gas containing sulfur dioxide gas generated during the reaction is used as a raw material for producing concentrated sulfuric acid. Compared to other types of furnaces, flash furnaces utilize the heat of the oxidation reaction of concentrate,
It is widely used in Japan because of its low fuel consumption rate and good environmental management.

As mentioned above, flash furnaces use the heat of the oxidation reaction of raw materials as their heat source, but in the past they burned heavy oil to make up for the insufficient amount of M. However, in recent years, as the price of heavy oil has soared, fuel conversion measures using alternative fuels such as pulverized coal are being actively promoted.

Examples of alternative fuels used so far are (1) pulverized coal;
(2) Crushed old tires (old tire chips), (3
) Pulverized coal (-200 mesh is 80-90% or more), etc., but conventional examples of using these as fuel substitutes have many disadvantages as follows: (i) Substitution of heavy oil rate is low. When using powdered coal, the heavy oil substitution rate is 30%. When using pulverized coal, it is less than 80% in special flash-smelting furnaces that use electric heating, and less than 50% in other general flash-smelting furnaces.

(2) When using pulverized coal, the coal is dried and pulverized to produce fine powder, which requires pulverization equipment and is costly. Furthermore, the negative effect of deterioration of the working environment caused by the crushing is significant. When handling pulverized coal, including manufacturing and transporting it, special safety considerations must be taken to prevent explosions.

(3) Air flow transportation for introducing these alternative fuels, especially pulverized coal, into the furnace is carried out in a separate system from that of copper concentrate, which requires equipment and costs.

As described above, substantially all of the heavy oil in copper smelting flash smelting furnaces has not yet been replaced, and the replacement rate remains at an unsatisfactory value, and a considerable amount of incidental equipment and costs are required. This has little purpose as a substitute for heavy oil.

The inventors of the present invention have pursued the most rational, economical, and effective method of replacing heavy oil with respect to this theme, and as a result, have arrived at the following development.

(1) A method for operating a flash smelting furnace for copper smelting, characterized by charging granular coke into the flash furnace.

(2) Powder coke and/or lump powder low-quality coal with a size of 40 m or less are added to the copper concentrate/flux charging system upstream from the copper concentrate dryer gill and the pneumatic conveyor. A method for operating a flash smelting furnace for copper smelting, which is characterized by charging the flash furnace together with flux and the like.

(3) A method for operating a copper smelting flash smelting furnace characterized by replacing mineral oil at a ratio of over 80% by charging solid carbonaceous fuel into the flash smelting furnace equipped with high reflux reaction conditions. .

Further, by further advancing the above-described invention, the present inventors succeeded in regularly operating a flash-smelting furnace using only solid carbonaceous fuel 1) as an auxiliary fuel without using heavy oil.

The inventors are aware of the fact that 100% fuel conversion from heavy oil to solid coal-based fuel was achieved in a flash smelting furnace for smelting.
(There is no precedent.

Misfire 1! Regarding each requirement for renting IJ, please refer to 8-1 below.
! I will clarify.

(1) Solid carbonaceous fuels include various grades of coal, charcoal, and coke.

(2) Powdered coke refers to powder coke, granular coke, or a mixture of both, and includes various types of coke other than the lump coke normally used in steelmaking, but especially coke from coke ovens. It is desirable to use precipitated coke powder, which is coke mixed with powder particles that is a by-product during the cooling process when taking out coke. Table 1 shows the particle size distribution, components and calorific value of the precipitated coke powder. Furthermore, a flow sheet for producing coke powder is shown in Fig. 1.

As the powder coke, in addition to the above-mentioned precipitated coke powder, subsieve coke with about 10 days under sieve may be used alone or in combination.

(3) Lump-grain powder low-quality coal refers to coal other than sized high-grade coal, and lignite is a particular example.

The particle size distribution, components, and calorific value of Wang Po coal (produced in Lishu), which is the lignite used in the present invention, are shown in the first tatami mat.

Table 1: Particle size distribution, components, and calorific value of precipitated coke powder and Wanpo coal (4) Upstream of the copper concentrate dryer kiln and pneumatic conveyor means 1:

The charging system of copper self-melting smelting equipment in various places in Japan is roughly shown in Figure 2. In Figure 2, the dryer kiln is number 12 and the pneumatic transporter is number 14.15. The powdered coke may be added anywhere upstream of the dryer kiln 12, but as shown in Figure 2, the powdered coke hopper 3 is placed in parallel with the pot concentrate hopper 2. The method of adding copper concentrate, flux, etc. on the carrying conveyor 8 by installing and continuously extracting it is advantageous in that the charging system O:q can be shared by all subsequent charging systems. , is the most desirable aspect.

(5) A flash-smelting furnace equipped with high-speed reaction conditions can be used even when granular coke, lump granular powder, and low-quality coal are charged without any 4t:f treatment such as pulverization, or when solids of any type are charged. This refers to a flash smelting furnace that has OHI conditions for high-speed reaction that are sufficient to burn it without any problems even when carbonaceous fuel is charged in large quantities with a mineral oil substitution rate of over 80%. (1) Use oxygen or oxygen-enriched air as the oxidation gas to be blown into the flash furnace. (ii) Preheat the oxidation gas to be blown into the flash furnace. (i)
ii) It is possible to charge substances that accelerate the combustion rate of solid carbonaceous fuel (catalyst materials, combustion improvers, etc.) into the furnace shaft together with the oxidation reaction gas, together with the charge, or alone. The most effective aspect is to use the air or oxygen-enriched air blown into the flash furnace as high-temperature hot air of 650°C or higher, preferably 900 to 1000°C.

Each invention of the present application will be specifically explained below.

Regarding the first invention (Claim 1), (1)
It has been thought that coke cannot be used for high-speed combustion because it has a low volatile content and a high ignition point. A flash-smelting furnace was also said to be a furnace in which the reaction must be completed while the charge is descending within the shaft. Therefore, in the past, GJI et al.'s fine powder E1 combustion t9 was briefly considered as a substitute for mineral oil combustion in flash furnaces. However, the present inventors have discovered that granular coke can be sufficiently used as an auxiliary heat source for flash-smelting furnaces as long as the in-furnace reaction rate is high to a certain extent, and that by charging granular coke, Powdered coke will remain on the hot water surface of the furnace settler, but if the furnace condition fT= and the amount of pulverized coke charged are controlled so that the amount of stagnation does not tend to increase, I hope he can continue his stable performance. Of course, if a large amount of mineral oil is forcibly replaced by granular coke under conditions where the reaction rate in the furnace is low, phenomena such as the development of a heap in the furnace and difficulty in tapping will occur, but the temperature at various parts in the furnace and the humidity of the exhaust gas It has been found that by gradually increasing the substitution rate while monitoring the matte temperature, slag temperature, etc.1, it is possible to replace mineral oil with pulverized coke to the extent that is permissible in the high yield adapted to the furnace. Furthermore, compared to conventional mineral oil combustion, the slag filling Jy and matte temperature do not pose a problem for tapping even at gfj7 low point (this seems to be due to a decrease in the amount of magnetite in the furnace). Even if the coke floats along the settler surface, there is almost no dredging of red #1 coke,
It was confirmed that a sufficiently high thermal efficiency could be maintained.

In the present invention, the most desirable embodiment is to add coke mixed with powder at a predetermined mixing ratio at the most upstream part of the fn concentrate/flux charging system to the flash furnace. It is transported and dried together with the ore and flux, and charged into the flash furnace through the concentrate burner U7 at the top of the furnace. Feeding and loading (this also includes the case of blowing into the furnace via Wfi or using a -V burner).

Further, as for the pulverulent coke, although the production flow sheet in FIG. 1 does not show S and the most preferable example is 1-coke (sedimented powder) T', FH is not limited to this only.

Second invention (q' Jr.
) Regarding (1) Powdered coke and/or lumpy low-quality coal with a voice of 40 or less should be added to the charging system for concentrates, fluxes, etc. upstream of the dryer kiln and pneumatic conveyor. You can enter.

-4 These solid coals become pulverized coal and endanger the concentrate/flux river dryer kiln and pneumatic transport equipment. It can be passed to temperature tCL, °C.

(2) Coke powder and/or size 40? By adding low-quality coal to the charging system such as 11σ concentrate and 7 ranks upstream of the dryer kiln and pneumatic conveyor, there will be a large number of mixed cheatons before entering the furnace. When it enters the furnace, it is in a completely mixed state with sulfide, which is a sulfide that burns well in the furnace, and when charged alone, it burns quickly and weighs the solid carbonaceous fuel quickly into the furnace. It is thought that internal combustion became possible. In the case of the example described later, a stream of high-temperature hot air is added to the above conditions to further speed up the reaction. It is also thought that it has an auxiliary combustion effect that promotes the combustion of t1· or a catalytic effect that promotes the reaction.

Regarding the third invention (Claim 3), (1)
In a flash furnace equipped with fast reaction conditions, solid carbonaceous fuel can achieve a heavy oil substitution rate of over 80% regardless of its quality and regardless of whether it is fired exclusively or co-fired (with concentrate). Among these, in the case of the Ryoichi fA flash-smelting furnace, the reaction rate is especially high, so it was possible to achieve a replacement rate that was substantially sufficient to eliminate the need for in-furnace combustion of heavy oil.

Of course, the best method is to add coke granules to the concentrate/flux charging system from the beginning in terms of cost, reaction, and workability.

Specific examples of the present invention will be described below.

FIG. 2 shows the flow up to charging copper concentrate and solid carbonaceous fuel together into a flash furnace. As the formulation hopper n1,
A copper concentrate hopper 2, a hopper 3 for granular coke as a representative of solid carbonaceous fuel, and a flux hopper 4 are arranged side by side, and each is brought in from an appropriate source. For example, granular coke is carried into the hopper 3 from a granular coke iron table 5 by a packet crane MK. A cutting device 6 such as a constant feed conveyor is provided below each hopper, and raw material is cut out from each hopper in a predetermined radius.

The cut raw material components are sent to a receiving bin 10 by a carrying conveyor 8. Conveying equipment such as a chute or a vibrating conveyor may be used instead of the carrying conveyor. From the receiving bin, the feedstock is introduced into the dryer kiln 12 and pneumatically transported by the cage mill 14 through the conduit 15. By mixing the solid carbonaceous fuel with the copper concentrate or the like at a stage upstream of pneumatic transport, a very uniformly mixed charge mixture is produced. The pneumatically transported mixture is supplied to a heating bin 20 via a chamber 16 and a group of cyclones 18. From the bottom of the head bin 20, the charge is passed through the flash furnace concentrate burner 22, for example by means of a Buehler conveyor.

Collected dust from the cyclone via the dryer Cottrell is also charged. The flash-smelting furnace 30 is a well-known borrowed type equipped with a shaft 31, a ceratra 32, and an uptake 33, and is also equipped with hot air blowing means (not shown).

In this way, the copper concentrate at a predetermined flashing ratio in the flash furnace,
t, one-body carbonaceous fuel, flux, etc. are charged in a very uniformly mixed state, and they react very efficiently and effectively by the hot air in the δ furnace, and the required calorific value is be done.

In the flash-smelting furnace, the oxidation reaction using high-temperature hot air, which was previously developed by the applicant, is carried out. This means that in a conventional flash furnace, the humidity of the blown air or acid-purple enriched air is 35%.
By maintaining the copper production capacity at 650°C or higher, preferably 900 to 10°C, the copper production capacity was successfully increased from 0 to 650°C. It is also suitable for the use of 100% solid carbon as a fuel conversion measure. It was found that there was no High-temperature hot air is, for example, iron or ferroalloy IH! It can be easily obtained by using a regenerative hot-blast furnace that uses B gas mainly composed of CO generated from a smelting furnace.

With the present invention, everything that was previously impossible has been achieved.
It was possible to achieve a substantial replacement of r. I) Granular coke and/or agglomerated powder and low-quality stone skin are
If processing is also a special charging setup (r2 must also be 2y and 6.!
4)'? It is charged into a flash furnace together with ore to produce a very good limb-flange formation reaction and maintain the required temperature.

This means that the solid carbonaceous fuel and ζ;1♀11 ore are directly
Mix uniformly under a mixing ratio of 650 ”C
The above high-temperature hot air could be achieved without any problems in the 4N furnace used in (1), and the present mortar melting furnace has an atmosphere [7] that extremely speeds up the reaction stage 1r5 by using high-temperature hot air. Because of this, it is a homogeneous charcoal zeta mixture with lump powder V1
(4: No special addition, no additional processing required,
The fact that it was able to burn completely smoothly and completely in the furnace itself was a rather luxurious effect. f','go)2 was carried out using coke powder.

Compared to the previous results shown in the far right column, there was virtually no change in the slag quality or the smelt quality, and stable operation of the flash furnace was ensured.

The present invention has been explained above, and the effects of the present invention can be summarized as follows: (1) Substantially all heavy oil can be replaced, reducing energy costs and coping with future energy situations. Successful.

(2) Pretreatment such as crushing of solid carbonaceous fuel is not required;
The need to provide a separate charging crotch (r'+If) for solid carbonaceous fuel can be eliminated.

(3) It is safer than pulverized coal and provides a sanitary working environment.

(4) The cost is low due to the use of precipitated coke powder.

(5) Precipitated coke powder has less volatile content than coal or petroleum, and requires less air and HP gas for combustion per unit calorific value.

(6) Is the flash furnace settler during operation? , some 21 on the 5th side
It is expected that carbonaceous fuel will float, but if the conditions are controlled to the extent that the floating amount does not increase, there will be no problem.
On the contrary, it has a reducing effect on the slag layer, and 1: Because it is in the slag phase! It is expected that this will have the effect of reducing the carbon content and f-ratio.

[Brief explanation of the drawing]

Is Figure 1 Shen 1? 70-sheet of the process of producing evening coke, and Figure KS2 is a schematic flowchart of the process of charging copper concentrate and solid carbonaceous fuel into a flash furnace under mixing. 1; :', 1.1 Gohon-': Group 2: M
mm hopper 3: Powdered coke hopper 4: 7 Lux honba 5: Powdered coke ridge 6: Cutting and weighing device 8: Search conveyor 10: Receiving bin 12: Dryer kiln 14: Cage mill 15: Air flow axial conduit 16: Booyamba 18:-Lee Ikron
22: Concentrate burner 30: Forehearth 31:
Shaft 32 Fake Settler 33:Uptape ゛□°゛Jllj person's name Motoi Kurauchi Butsuma
Aki Kurahashi, ``Coke''

Claims (1)

[Claims] 1) In a copper smelting flash-smelting furnace charged with concentrate, 7 lux and other charges to produce matte and slag, the furnace operation 9
A method for operating a copper smelting flash-smelting furnace characterized by charging granular coke as auxiliary fuel for temperature maintenance. 2) The method according to claim 1, wherein the coke powder is precipitated coke powder. 3) Powder coke and/or lump powder low quality coal of size 40w or less is added to the charging system for copper concentrate/flux etc. upstream from the copper concentrate dryer kiln and pneumatic transport machine to produce copper concentrate/flux etc. A method for operating a copper smelting flash smelting furnace characterized by charging the same into the flash smelting furnace. 4) The method according to claim 3, wherein the coke powder is precipitated coke powder, or the low quality coal is lignite. 5) Charge granular coke and/or lump powder low-quality coal of size 401 or less into a high-temperature M-smelting furnace in which air or oxygen-enriched air is preheated to 650°C or higher and blown into the furnace. 4. The method of claim 3, wherein substantially the entire amount of mineral oil is replaced by. 6) A method for operating a flash smelting furnace for copper smelting, characterized in that a solid carbonaceous fuel is charged into a flash smelting furnace equipped with fast reaction conditions, thereby replacing mineral oil in a proportion of more than 80%. 7) The method according to claim 6, wherein the flash-smelting furnace equipped with high-speed reaction conditions is a high-temperature hot air flash-smelting furnace in which air or oxygen-enriched air is preheated to 650° C. or higher and blown into the furnace. .