JPS58221241A - Smelting method in flash smelting furnace using coke breeze - Google Patents

Abstract

PURPOSE:To lower the grade of copper in discharged slag and the cost of fuel by simultaneously charging a copper concentrate and coke breeze or a mixture of coke breeze with pulverized coal into a flash smelting furnace together with heavy oil and smelting the concentrate. CONSTITUTION:Coke breeze or a mixture of coke breeze with pulverized coal is charged into a shaft section through a concentrate burner together with prepared ore, flue ash and heavy oil. The ore is melted by the metallurgical reaction of the charged materials and heat of combustion of the fuel, and the molten ore flows into a settler section, where it is separated into matte as an under layer and slag as an upper layer by the difference in specific gravity. The slag contains magnetite formed by the metallurgical reaction, yet the magnetite is reduced by the reaction with the unburned coke covering the surface of the slag, so the grade of copper in the slag is lowered. At this time, the slag is preferably fluidized or agitated by putting an electrode or blowing gas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in copper pyrometallurgical smelting and more specifically self-smelting smelting.

There are various copper smelting methods depending on the properties and components of the raw material ore, but they can be roughly divided into two types: pyrometallurgical smelting and hydrometallurgical smelting. The pyrometallurgical method is mainly used to process copper sulfide ores, and consists of steps such as preliminary treatment, smelting, steelmaking, blister refining, and electrolysis. Pack copper concentrate.

Processes such as drying and roasting are performed, and blast furnaces, reverberatory furnaces,
It is charged into a flash-melting furnace, heated and melted, and separated into matte, whose main component is copper sulfide, and slag, whose main components are iron and silicic acid. The matte is further processed in a converter and separated into blister copper and converter slag, and the blister copper is further cast into an anode mold in a refining furnace and sent to an electrolytic process where the anode is electrolyzed to become electrolytic copper. Among the pyrometallurgical methods mentioned above, so-called flash furnace smelting (flash furnace smelting) involves smelting blast ore in a flash furnace.
Flash smelting method) has been widely used in recent years. This method smelts sulfide concentrates such as copper and nickel using the oxidation heat of iron sulfide in the ore, so it requires less fuel and is more expensive than other smelting methods that use blast furnaces, reverberatory furnaces, etc. It has been widely adopted because of its advantages such as thermal efficiency, non-pollution, easy operation management, and labor saving.

As mentioned above, although the flash smelting furnace smelting method has many advantages, the copper content of the slag discharged from the flash furnace settling section is higher than that of other blast furnaces, reverberatory furnaces, etc. One drawback is that a separate processing step is required to recover the silver inside.

The reason why the flash smelting method produces higher copper content in the slag than other smelting methods is that the metallurgical reaction is rapid in the flash smelting furnace.
Because it is an oxidizing atmosphere, overoxidation of iron progresses, resulting in magnetite)
This is because a large amount of (Feas4) is produced, the melting point and viscosity of the slag increase, and there is a large amount of physical copper contamination. The methods to reduce the generation of magnetite are as follows: 1) Increasing the silicic acid grade in the slag11)
Lowering the oxygen partial pressure in the furnace 1) I) Lowering the copper grade in the produced matte or raising the operating temperature can be considered, but 1) will increase the amount of solvent (flux) and reduce the overall Although the amount of slag increases and the copper grade decreases, the loss as a pure copper content does not decrease much (-).Also, in I+, the flash furnace itself is characterized by rapid metallurgical reactions,
It is difficult to intentionally control the oxygen partial pressure in the furnace only locally, and in 111) the amount of matte increases.

Conventionally, no effective method has been found because it has a negative impact on the post-treatment process and also increases the amount of fuel, so usually a) after the slag is discharged from the flash furnace, it is transferred to a separately installed smelter A method of reducing the copper content in the slag by leaving it at a raised temperature or adding iron sulfide, coal, and coke alone.b) After cooling the discharged slag, it is crushed and the Cu content is removed by flotation. Method of recovery C) An electrode is inserted into the settler part of the flash furnace, and this is called a flash furnace. )
Utilizing the reducing power of the electrode material and the heat generation and stirring caused by electricity,
Conventionally, methods have been adopted in which the copper quality in the slag is completely reduced.

In order to solve the above-mentioned problems in flash smelting furnace smelting, the present inventors conducted tests in actual operation based on theoretical considerations, and as a result, carried out high matte quality operation in a flash smelting furnace of the flash furnace type. The inventors have completed the present invention by discovering that if coke powder or coke powder and pulverized coal are used together with blown heavy oil together with copper concentrate, the copper quality in the slag can be reduced.

The present invention also lowers fuel costs in today's world where energy costs are rising.

An object of the present invention is to provide a method for reducing the copper content in discharged slag and reducing fuel costs in a flash furnace smelting method.

The gist of the present invention is a flash smelting furnace smelting method characterized in that coke powder or coke powder and pulverized coal are simultaneously injected into a flash smelting furnace together with heavy oil and smelted.

Further details of the present invention will be explained based on the drawings. 1st
The figure is a process explanatory diagram showing the process of the flash furnace smelting method.
FIG. 2 is a process explanatory diagram showing an embodiment to which the present invention is applied.

Regarding the process of the flash furnace smelting method, for example, an example of the autocumbu method will be explained with reference to Fig. 1. Various copper concentrates are processed in advance by a method such as or bedding, taking into account the specific gravity of copper and sulfur and other impurities. #) P1 is combined to form a blended ore, and to the blended ore is added a solvent such as silicate ore that has been crushed in advance to an appropriate particle size using a pulverizer. Since these charges contain moisture, they are dried to a moisture content of 1% or less to almost 0% using a flash dryer using hot air or a rotary kiln, and then placed in a furnace top charging bin (not shown). Once stored. In addition, the smoke ash collected from the drying process of the mixed ore and the smoke ash from the flash-melting furnace exhaust gas treatment process are also stored in a top-of-the-furnace smoke ash charging bin (not shown).

These mixed ores and smoke ash are extracted from each charging bin using a chain conveyor, etc., and are heated to about 500℃ using a heat exchanger or hot blast stove using steam recovered from a boiler.
Together with hot air and heavy oil, it is ejected into the shaft of the furnace via the concentrate burner at the top of the flash furnace. Copper concentrate is heated here by oxidation heat of iron, sulfur, etc. and combustion heat of heavy oil,
The temperature reaches a high temperature of 0° C. or more, and a metallurgical reaction occurs while the charge momentarily falls into the shaft, melting and accumulating in the Ceratra. #'i in part of setra.

High R due to heavy oil burner! Separate into mat and slag while maintaining A and utilizing the difference in specific gravity. That is, the mat with a large specific gravity is separated into the lower part, and the small slag is separated into the upper part. The matte is transported to the next process, a converter, using a ladle, and the slag is taken out to an smelting furnace to reduce the copper content, and is reduced by adding fK heating steel, iron sulfide, coke, etc. After reducing the copper content in the slag, it is granulated. On the other hand, the combustion exhaust gas at about 1,600°C passes through the uptake section, collects dust using a boiler, cyclone, Cottrell, etc., and collects smoke ash, which is then repeatedly charged to the top of the furnace. Exhaust gas is sent to a sulfuric acid plant. In the converter, the iron and sulfur in the matte are removed through the steps of can making and steelmaking to produce blister copper.The blister copper is then refined in a refining furnace and cast into a blister copper anode suitable for the electrolytic process. do. The above is an overview of the pyrometallurgical smelting method using a flash furnace.

Next, the present invention will be explained based on FIG. As shown in FIG. 2, the difference from FIG. 1 is that the present invention is applied to a flash melting furnace of the electric furnace type, which does not have a smelting furnace but has an electrode in the ceratra section.

A feature of the present invention is that coke breeze or coke breeze and pulverized coal are injected into the shaft via a concentrate burner together with the above-mentioned conventional method of mixed ore, smoke ash, and heavy oil, and it cannot be applied to conventional processes. The equipment can be used as is, with the exception of equipment related to coke breeze and pulverized coal. How to use pulverized coke and pulverized coal in the shaft part is as follows:
It may be used by installing a dedicated burner in the flash furnace shaft, or it may be added to a fixed amount continuously or intermittently during transportation of the mixed ore.

On the other hand, as coke powder, dried various commonly used coke powder can be used. Due to its properties, it is advantageous to use coke that is in powder form and has a low ash content and a high volatile content. Generally, coke with an ash content of 12% or less and a volatile content of 0.5% or more is used, but preferably ash content is 2.0%. The following coke has a volatile content of 6 points or more. In addition, the finer the grains 18'', the more the use of heavy oil can be reduced. However, although the use of ultrafine coke improves the replacement rate of single heavy oil,
Since the reduction rate of magnetite, which is one of the features of the present invention, may decrease and the monthly grinding cost will increase, the grinding particle size of coke and pulverized coal should be 16 to 325 mesh.
It is preferable that the particle size distribution falls within the range of 7.

The coke powder containing these coke powder and pulverized coal is uniformly distributed in the furnace from the furnace top concentrate burner or via a separate burner dedicated to coke powder and coke powder containing pulverized coal, and is partially combusted. (The unburned coke powder falls down the shaft.

Cover the surface of the solution in the furnace. In particular, it is preferable that the charged coke powder uniformly covers the entire surface of the melt in the Ceratra after entering the seven-layer treatment. In this way, the ore becomes a solution due to the metallurgical reaction of the charge and the combustion heat of the fuel, and flows into the seratra section, where it is separated into two layers, the lower layer of matte and the upper layer of slag, due to the difference in specific gravity. The upper layer of slag contains magnetite produced by metallurgical reactions, and this magnetite reacts with the unburned coke powder covered on the surface of the slag, reducing the magnetite and reducing the copper grade in the slag. decreases. At this time, it is preferable to fluidize and stir the slag in order to promote the interfacial reaction, and this purpose can be achieved in particular by charging electrodes, blowing gas, etc., as in a self-electric furnace.

The decrease in magnetite in the slag may be caused by replacing heavy oil with coke breeze, but could it be due to a sudden metallurgical reaction in the flash furnace shaft? Coke can be used to the extent that it does not inhibit. The preferred amount is 60 to 50 inches of heavy oil. In addition, the object of the present invention can be achieved not only by using coke powder alone, but also by using ordinary pulverized coal together with coke powder to adjust the ash content and volatile content of coke powder, as described above. I can do it.

In the flash-smelting furnace smelting method using coke breeze or coke breeze and pulverized coal of the present invention, the amount of coke breeze or coke breeze and pulverized coal used can replace 50% or more of heavy oil, so that the magnetite in the slag can be reduced by the conventional method. , the copper loss carried away by the slag was reduced by 15% from 6% or more to less than 4.5cm.
It has become possible to reduce the amount by more than 100%. In addition, by causing a combustion reaction of coke powder and pulverized coal in the Ceratra section,
Instead of burning heavy oil using a heavy oil burner, which was conventionally used in the Ceratra, it is now possible to elute matte and slag in the Ceratra using only electric agitation using electrodes, significantly reducing the fuel cost for the entire flash-smelting furnace. Construction savings were made.

Also, the exhaust gas temperature #, that is, the uptake inlet temperature is 12
The temperature was lowered by about 50°C compared to 50 to 1600°C, which had the effect of reducing troubles caused by smoke ash in the uptake section and boiler section.

The matte and exhaust gas from Ceratra are treated in the same manner as in the past, and the slag is used as granulated slag for cement and other uses without the need for a separate furnace.

The present invention will be described below based on embodiments of the present invention in comparison with conventional methods.

(Example) Both the present invention and the conventional method use a flash furnace type flash furnace, and the sizes thereof are as follows.

Shaft part ・・・・・・・・・ 6mφ×(height) 6
．． 9mm Seratra ・・・・・・・・・ Width 7. Om
x (height) + + X (length) 19.75m Uptake 2.5mφ Coke powder, which is a mixture of single coke powder and pulverized coal as shown below, was charged to the blended ore at a ratio of approximately 15 to 9 parts per ore at the time of bedding.

The particle size distribution and properties of pulverized coke and pulverized coal are as follows. In both the method of the present invention and the conventional method, 9 air is blown into hot air at 450°C and smelted from a concentrate burner at a rate of 48,000 m"/h. I did this.

Next, Table 1 shows the operating conditions and results for the method of the present invention, that is, when single coke powder and coke powder mixed with pulverized coal were used together with one oil, and when conventional heavy oil alone was used.

As is clear from Table 1, the amount of copper loss in the slag from the Ceratra section has increased from 0.58% to 90.48% compared to the conventional one, and the copper purity ratio of matte and slag has increased. 0.90%, 90.76% and 0
．． 74%, 16chi and 17% compared to 100 in the conventional method
The loss is reduced when the grade of magnetite in the slag is 6.8%, 4.1% and 4.2%, i.e. 2.
It is clear that this is due to the decrease of 7% and 2.6%,
The economic effects are enormous.

2) In addition, the fuel consumption rate is estimated to be 28,000 yen and 13,000 yen less than the amount of ore processed, but it is necessary to replace part of the heavy oil with coke and to lower the copper content in the slag. Due to the reduction in the electricity used for the electrodes and the elimination of the heavy oil used in the conventional Ceratra, it has become possible to save approximately 20 centimeters in fuel costs.

6) Also, the uptake part inlet temperature is 50% lower than that of the conventional method.
The temperature decreases in temperature, but this is because the surface of the melt is covered with unburned coke powder, which retains heat and improves heat conduction to the container. This has the effect of reducing troubles.

As described above, the method of the present invention not only reduces copper loss in slag, which is a problem with conventional flash furnace smelting methods, but also significantly reduces fuel costs in today's world where energy costs are rising. This is an extremely useful invention economically.

It goes without saying that the present invention is not limited to the dead weight furnace type flash smelting furnace, but can also be applied to other flash smelting furnace smelting methods.

[Brief explanation of the drawing]

FIG. 1 is a process explanatory diagram showing a flash smelting furnace smelting process, and FIG. 2 is a process explanatory diagram showing an embodiment example when the present invention is applied to a dead weight furnace type flash smelting furnace. Agent: Patent attorney Sanro Kimura (To) Figure 1: Illumination furnace - Chair: Amendment to procedure (voluntary) Attorney, Director General of the Agency, End of 1930, 91
'l 6r11, Indication of the case Patent application 1983-103522 2, Name of the invention Name of flash smelting furnace smelting method using coke powder Name (618) For Mitsui Mining & Mining Co., Ltd. - 114, Agent (Shipping) Showa year month "1) (1) 2 pages 1
Correct "many" in the second line to "many". (2) On page 8, line 12, "coke powder, pulverized coal" is corrected to "coke powder, pulverized coal." (3) Change “× (length)” on page 11, line 9 to “2.6
(Length) Correct as J. (4) On page 11, line 11, "the method of the present invention applied to a self-melting furnace" is corrected to "this embodiment applied to a self-melting furnace". (5) Correct "particle size distribution (mesh)" in the first line of page 12 to "particle size distribution (mesh %)". (6) Page 13, line 6 “16,000 Kail, J” to “10,000 K”
I corrected it with Jj. (7) The Difference column in Table 1 on page 14 is corrected as follows. A, (2) − (1) column 13 line “△10.3.J”
△10.9'', A, 〃 19th line ``△196''
to "△195", and (3) - (1) column 14 line "
△13” to “△10”, engineering, line 19 “△
18. IJ to "△1Z6", or more (2)

Claims (1)

[Claims] (1) A method of smelting copper concentrate, etc. in a flash furnace, characterized in that coke breeze or coke breeze and pulverized coal are injected together with heavy oil and smelted together with the copper concentrate. .