JP2682636B2 - Operating method of flash smelting furnace - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for operating a flash furnace for producing a mat, which is a smelting intermediate of copper, from a copper sulfide concentrate.

[Conventional technology]

There is a flash smelting furnace called a flash smelting furnace, which is one of the smelting furnaces made from sulfide concentrate. This flash furnace is equipped with a reactor with a concentrate burner at the top, one end connected with the lower end of the reactor, a settler provided with slag holes and mat holes on its side, and the other end of the settler. The smelting process is basically as follows.

First, powdered concentrate, flux, auxiliary fuel and the like are blown into a reaction tower from a concentrate burner together with a reaction gas such as preheated air. In the reactor, the combustible components sulfur and iron in the powder concentrate react with the reaction gas and are stored in the settler section. In the settler section, the solution is 2F due to the difference in specific gravity.
It is separated into a slag containing eO.SiO ₂ as a main component and a matte which is a mixture of Cu ₂ S and FeS. Then, the slag is discharged from the slag hole to the outside of the flash furnace, and the mat is intermittently extracted from the mat hole in response to the request of the converter in the next step. Normally, in the operation in this process, in the case of slag, the ratio of iron grade and silicon dioxide grade in slag (hereinafter Fe / SiO ₂₎ for suppressing erosion of bricks in the furnace by slag and facilitating extraction ) Is 1.1 to 1.3, and the slag temperature is 1220 to 1250 ° C. In the case of mats, the concentration of the concentrate is adjusted so that the mat quality and mat temperature are suitable for the operation of the converter in the next process. And adjusting the amount of auxiliary fuel. In the present specification, quality means a weight ratio.

[Problems to be solved by the invention]

By the way, conventionally, silicate ore is used as the flux, but there are some silicate ores containing noble metals and some not containing them, and normally gold-containing silicate ores containing noble metals are preferentially used. There is. This is because the precious metal in the gold-containing silicate ore is easily concentrated in the mat, so that the precious metal can be efficiently recovered. Therefore, in order to increase the amount of precious metal recovered, a high treatment capacity for silicate ore is required, but in this respect, the conventional operating method of a flash smelting furnace cannot be said to be sufficient.

That is, the conventional flash smelting furnace operating method is, as described above, slag quality, slag temperature, mat quality, in order to adjust the mat temperature to be within a predetermined range, the composition of the concentrate to be used is determined and The processing amount is uniquely decided,
There is a problem that it is not possible to arbitrarily increase the amount of silicate ore.

An object of the present invention is to solve this problem and provide a method for operating a flash smelting furnace capable of increasing the throughput of silicate ore.

[Means and actions for solving the problem]

As a result of various studies by the present inventors, by adjusting the CaO grade and the slag temperature in the slag, without increasing the erodibility of the slag to the bricks in the furnace, and without losing the fluidity of silicate ore The inventors have found that it is possible to increase the amount of processing, and have reached the present invention. That is, the present invention, by adding and mixing limestone and quicklime tower to the concentrate or the like to be supplied to the concentrate burner, to adjust the CaO grade in the slag, by adjusting the slag temperature according to the CaO grade silicate A method for operating a flash smelting furnace characterized by increasing the amount of ore processed. The present invention will be described below based on representative test examples and examples.

(1) Erosion property The erosion property of slag to bricks is one of the important operational control items. Therefore, in the present invention, the inner diameter of the reactor brick is 1.5 m, and the height from the settler surface to the reactor ceiling is 3.5 m.
At the settler, a small-sized flash furnace with a brick inner diameter of 1.5 m and a length of 5.2 m was used, and the CaO content in the slag was changed by changing the mix of the concentrate blown into the reactor from the concentrate burner.
By adjusting the grade and Fe / SiO ₂ , three types of slag shown in Table 1 were obtained, and an erosion test was carried out by the rotary furnace method using this slag and the maguro-type electroformed brick used in the actual furnace. . The rotary furnace method is a heavy oil combustion burner provided at one end of the burner, and an apparatus comprising an iron or stainless steel cell whose inner wall is lined with a test brick,
In use, after charging a predetermined amount of slag inside the cell, while rotating the cell, heat and melt the slag with a heavy oil combustion burner, and measure the amount of eroded bricks by holding at a predetermined temperature for a predetermined time To do. Table 2 shows the amount of erosion of the magcro-type electroformed brick when the number of revolutions was 6 rpm and 3Hr was held at 1620 to 1680 ° C. by using the value measured in the thickness direction of the brick. From this result, it can be seen that there is no difference in erodibility between A corresponding to conventional slag and other slags.

(2) Liquidity of slag Liquidity of slag is also one of the important control items in actual operation, and the liquidity of slag is judged every time it is discharged from the slag hole, and it is used as a guideline for operation. The method for determining the fluidity of the slag at this time is to observe the fluid state of the slag discharged to the outside of the furnace and to give a score of 0 to 5 points (hereinafter, referred to as Karami point). It is judged as slag.

The fluidity of the slag was determined by this determination method also in the tests and examples that were the basis of the present invention. The test was conducted using the above-mentioned small-scale flash furnace, and the CaO grade and Fe / SiO ₂ in the slag were adjusted by changing the ratio of the concentrate, silicate ore and limestone blown into the reactor from the concentrate burner, and assisted. The slag temperature was adjusted by changing the amount of fuel. The results are shown in FIGS.

Fig. 1 shows the relationship between Fe / SiO ₂ and slag temperature and karami point when limestone is not added. Figs. ₂ and 3 show CaO grade in slag of limestone of 3 to 6 wt. % and 6-13 illustrates the relationship between the Fe / SiO ₂ and slag temperature and Karami point when added to a wt%. From these results, the required slag temperature decreases as the CaO quality increases, that is, if the slag temperature is kept constant and the CaO quality is increased while maintaining constant fluidity, Fe / SiO ₂ It turns out that it can be lowered.

(3) Amount of slag generated Since an increase in the amount of slag generated will reduce the actual yield of copper and precious metals, it is necessary to suppress the amount of slag generated as much as possible. A decrease in Fe / SiO _{2 in} the slag and an increase in CaO grade lead to an increase in the amount of slag generated.Therefore, how much Fe / SiO ₂ and CaO grade should be adopted depends on the required silicate ore treatment. It should be decided in consideration of an increase in capacity and a decrease in actual yield due to the amount of slag generated. When treating gold-containing silicate ore in a flash smelting furnace, the limiting values for this combination are Fe / SiO ₂ = 0.8 and CaO grade 13%.

(4) Optimum range CaO in slag that can increase silicate ore treatment capacity from the test results of (1) and (2) above and the limiting conditions of (3)
The relationship between the grade and Fe / SiO ₂ and the required slag temperature determined by these is shown below.

When the CaO grade in the slag is less than 3 wt% Y ≧ 1449.7-199.3X−0.4X ^{2 When} the CaO grade in the slag is 3 to 6 wt% Y ≧ 2390.7−2426.6X + 1250.8X ² The CaO grade in the slag is In the case of 6 to 13% by weight Y ≧ 2540.1−2850.3X + 1500.1X ² where Y is the slag temperature (unit: ° C) and X is Fe / S.
iO ₂ , each formula is CaO grade, and good fluidity is ensured by keeping the slag temperature above the calculated value on the right side obtained by the value of X arbitrarily selected within the range of 0.8 to 1.0. It shows that you can do it. Note that the slag temperature is preferably 1350 ° C or lower in consideration of the erosion property of bricks in order to operate stably for a long period of time.

〔Example〕

A small flash furnace in which copper concentrate, silicate ore shown in Table 3 and limestone crushed to 200 μm or less are mixed as shown in Table 4, and the resulting ore is used for the test. Was blown into the reactor from a concentrate burner and melted to obtain slag and mat. At this time, the slag in the settler was operated for 4 days while adjusting the amount of auxiliary fuel so that the slag had a Karami point of 3. The results of this operation are shown in Table 5. From Table 5, it is possible to decrease Fe / SiO ₂ by increasing the CaO addition amount and increasing the CaO grade in the slag, that is, to increase the silicate ore treatment amount, and to lower the slag content than in the case of no addition. It can be seen that the same fluidity can be obtained at temperature.

〔The invention's effect〕

As described above, according to the method of the present invention, it is possible to increase the processing capacity of silicate ore without impairing the fluidity of slag, and without increasing the erosion of slag on bricks. Become.

[Brief description of the drawings]

Fig. 1 shows the relationship between Fe / SiO ₂ , slag temperature, and karami point when limestone is not added, and Figs. 2 and 3 show that the limestone content of CaO is 3 when limestone is the source of CaO. ~ 6%
And when added to a 6-13%, it illustrates the relationship between the Fe / SiO ₂ and slag temperature and Karami point.

Claims (3)

(57) [Claims] 1. A reaction tower provided with a concentrate burner, one end of which is connected to the lower end of the reaction tower, and a settler provided with a slag hole and a mat hole on its side surface, and the other end of the settler. In the operating method of a flash smelting furnace that is basically composed of a flue gas and uses copper sulfide concentrate as a raw material, when the calcium oxide grade in the slag is less than 3% by weight, Y is taken as the slag temperature (unit: ° C. ), Where X is the ratio of iron grade to silicon dioxide grade (Fe / SiO ₂ ), the slag temperature is adjusted within the temperature range determined by the following formula, and X = 0.8 to 1.0.
A method of operating a flash smelting furnace characterized by operating in the range of Y≥1449.7-199.3X-0.4X ² 2. A reaction tower provided with a concentrate burner, one end of which is connected to the lower end of the reaction tower, and a settler provided with a slag hole and a matt hole on its side surface, and the other end of the settler. In a method of operating a flash smelting furnace that is basically composed of a flue gas and uses copper sulfide concentrate as a raw material, Y is slag when the calcium oxide grade in the slag is 3% by weight or more and less than 6% by weight. When the temperature (unit: ° C) and X is the ratio of iron grade to silicon dioxide grade (Fe / SiO ₂ ), the slag temperature is adjusted within the temperature range obtained by the following formula, and X = 0.8 to 1.0. A method of operating a flash smelting furnace characterized by operating in the range of Y ≧ 2390.7−2426.6X + 1250.8X ² 3. A reaction tower provided with a concentrate burner, one end of which is connected to the lower end of the reaction tower, a settler provided with a slag hole and a matt hole on its side surface, and the other end of the settler. In a method of operating a flash smelting furnace that is basically composed of a flue gas and uses copper sulfide concentrate as a raw material, Y is slag when the calcium oxide grade in the slag is 6% by weight or more and less than 13% by weight. When the temperature (unit: ° C) and X is the ratio of iron grade to silicon dioxide grade (Fe / SiO ₂ ), the slag temperature is adjusted within the temperature range obtained by the following formula, and X = 0.8 to 1.0. A method of operating a flash smelting furnace characterized by operating in the range of Y ≧ 2540.1−2850.3X + 1500.1X ²