JPH0515769B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a smelting method for oxidizing and smelting copper sulfide ore to obtain pine with a low iron content and close to so-called white glue. [Conventional technology] In conventional copper smelting, copper sulfide concentrate is oxidized and melted, part of the Fe in the ore is oxidized and removed as slag, and part of the S is converted into SO ₂ and converted into Cu ₂ S. FES
The matuto smelting stage is carried out in a smelting furnace where copper is concentrated as matuto, which is _a eutectic material of The process consists of a step of producing white glue to obtain blister copper, and a step of producing copper by further blowing this white glue to obtain blister copper.The steps of producing white glue and producing copper are usually carried out in a converter. Blast furnaces, reverberatory furnaces, and flash smelting furnaces are generally used as smelting furnaces in which pine smelting is carried out. Among these, blast furnaces and reverberatory furnaces use silicate ore and limestone as solvents to convert part of the iron into FeO- A SiO ₂ -CaO slag is formed, and in a flash furnace, silicate ore is used as a solvent to form an FeO-SiO ₂ slag and copper is concentrated and separated into matte containing about 40 to 60% Cu by weight. This pine is taken out from the smelting furnace and transferred to a converter, silicate ore is added as a solvent and oxidized blowing is performed to remove the iron content as FeO-SiO ₂ slag. It is refined into coarse copper. However, the iron silicate-based slag conventionally formed in these smelting furnace and converter processes is different from the case where FeO-SiO ₂ -CaO-based slag is formed using limestone in addition to silicate ore, and the case where slag is formed using silicate ore. using only ore
There are cases in which FeO-SiO ₂ -based slag is formed, but in particular, (1) in the case of blast furnaces and reverberatory furnaces in which FeO-SiO ₂ -CaO-based slag is formed, the Fe content is 35% by weight or less; Furthermore, even in the case of a flash smelting furnace that forms FeO-SiO ₂ system slag, Fe is about 40% by weight or less, which means that the ability to retain iron oxide is low and a large amount of slag is generated. (2) High viscosity of slag. (3) Due to the synergistic reasons of (1) and (2) above, the amount of copper lost to the slag increases. (4) Since the amount of trivalent iron dissolved is small, solid Fe ₃ O ₄ is likely to precipitate in the furnace,
It is easy to cause so-called magnetite trouble, where magnetite accumulates at the bottom of the furnace. (5) Since acidic SiO ₂ is used as the basis, the amount of oxides such as As and Sb dissolved in the slag is small, so the removal rate of As and Sb is low, and they tend to remain in blister copper. There were flaws. However, until now this iron silicate slag has been used as there was no other choice, so it is used once in the pine smelting stage and generally several times in the white glue production stage in the converter. In addition, slag is separated and discharged in stages, which not only complicates the copper smelting process, but also causes a large amount of heat loss, and requires environmentally inconvenient disposal of leaked gas during intermittent slag discharge. There were many profitable issues. The Mitsubishi Continuous Copper Manufacturing Process, which has been proposed in recent years and has been put into actual operation, uses three types of furnaces in series to obtain blister copper from copper ore all at once without transferring the solution, and it overcomes the problems of the conventional method. However, in the matuto smelting stage, silicate ore is used as a solvent to create iron silicate slag containing about 40% by weight of Fe and 31% by weight of SiO ₂ , so the copper grade of matuto is 65% by weight. I couldn't have hoped for more. This is because if the copper content of the pine exceeds this level, the precipitation of solid phase magnetite will become significant, making it difficult to continue actual operation. In this method, pine containing approximately 65% Cu by weight is continuously fed to a copper making furnace after separating the slag produced, and limestone is added to it as a solvent.
It is said that by forming Cu ₂ O-CaO-Fe ₃ O ₄ system slag, slag with high fluidity and relatively low copper content can be obtained in copper making furnaces where blister copper and slag coexist. Although it is
No. 5337), in reality, the slag of copper making furnaces is Cu16% by weight.
It is necessary to solidify the entire amount and repeat it in the pine smelting stage, resulting in a poor copper yield. There were problems such as the fact that impurities such as Sb were likely to be insufficient. [Object of the Invention] The present invention solves the above-mentioned drawbacks when smelting copper sulfide ore, and by producing calcium ferrite slag in the copper smelting process, copper sulfide ore can be made from copper sulfide ore with substantially less iron content. The aim is to obtain pine that is close to white glue. [Means for Solving the Problems] In order to achieve this object, the present invention uses CaO-based solvents such as limestone to remove most of the fraction in copper sulfide ore without using silicate ore as a solvent. Oxidation and smelting was carried out by adding an amount sufficient to oxidize and form calcium ferrite slag, and adding an amount of oxygen necessary to convert the copper content into matt with a low iron content, which was almost like white glue. It is something. As a result of various researches, the inventors and others have previously published their research titled "Phase Equilibrium Between Calcium Ferrite Slag, Matte, and Molten Copper" (Tohoku University Mineral Processing and Smelting Research Institute Bulletin Vol. 39, No. 2, 1982). December 115-122
According to the slag phase, ferrite slag and pine generally dissolve significantly into each other at the smelting temperature, and a large amount of copper sulfide dissolves in the slag phase.
It was thought that such a pine smelting method could not be adopted because the production of ferrite slag in the pine smelting process to obtain pine of about 10% by weight would result in a large loss of copper. However, as a result of various studies, the inventors have found that when producing the above-mentioned ferrite slag, if the copper quality of the pine is further increased, the mutual solubility decreases, and the coexisting slag becomes white and contains almost no iron. The present invention was achieved by discovering that the copper content in the converter slag is equal to or less than that in ordinary converter slag (about 3% Cu). In the process of the invention, copper sulfide ore, usually copper sulfide concentrate, is flashed into a furnace together with air, oxygen or oxygen-enriched air, or is blown into the melt through a nozzle, using silica as a solvent. No ore is used at all, and a lime-based solvent such as limestone is added to melt it. The amount of lime-based filler added is determined by the amount of iron contained in the copper sulfide ore, excluding about 5% by weight or less of Fe contained in the form of matte, which is converted into oxides to form calcium ferrite slag (FeO- A sufficient amount is required to form _{CaO (Fe2O3} -CaO), and the amount of CaO source is required to be approximately 0.24 to 0.80% by weight relative to the weight of Fe that will become the oxide. On the other hand, the oxygen required for the oxidation of iron to form slag, the oxidation of sulfur other than the sulfur necessary to form pine out of the sulfur content in the ore, and the oxidation of other impurities that turn into slag or volatilize are highly purified. oxygen,
It is necessary to introduce oxygen-enriched air or air into the furnace together with or separately from the ore, but at this time, the inside of the furnace is smelted due to heat of oxidation of iron, heat of combustion of sulfur, heat generated by slag formation, etc. It is preferable to supply an amount of oxygen that can maintain the temperature, or to extract a part of the SO ₂ gas discharged from the furnace in high concentration and make it possible to maintain the thermal balance of the furnace as an SO ₂ − O ₂ mixed gas. is preferred. However, if the amount of oxygen supplied by high-purity oxygen or oxygen-enriched air is insufficient, it will not be possible to maintain the furnace at the desired smelting temperature. It goes without saying that it is necessary to supply oxygen for this auxiliary fuel combustion. It is preferable that the content of SiO ₂ in the raw material copper sulfide ore is 3% by weight or less in order to keep the produced calcium ferrite slag as pure as possible. The pine produced by doing this is
The content is about 75% by weight of Cu, about 20% by weight of S, and about 5% by weight of Fe or less, and a calcium ferrite slag containing about 3% by weight of Cu is obtained as slag. Cu in slag can be recovered by solidifying and crushing the slag and flotation separation, or by reducing and smelting the slag while remaining in solution, and the amount of slag that is discarded can be reduced to 0.5% by weight or less of Cu. Mat concentrated to about 75% Cu by weight can be easily converted to blister copper by subsequent oxidative blowing. [Effects] The method of the present invention has the following advantages. (1) By generating calcium ferrite slag, the amount of slag in the smelting process can be reduced to 2/3 or less compared to conventional methods, and copper loss is reduced overall. (2) The viscosity of slag can be significantly lowered. (3) By generating calcium ferrite slag, it is possible to obtain high-quality pine with low iron content, close to white glue, all at once in terms of smelting statistics. (4) Since it is a basic slag, it easily dissolves acidic arsenic and antimony oxides, making it possible to lower the distribution rate of these impurities into the mat than before. (5) Problems caused by magnetite during the smelting process are less likely to occur. (6) Since the amount of slag produced is small, the energy saving effect is large. [Example] Examples will be described below. Example 1 30 g of molten matte and molten slag having the composition shown in Table 1 were placed in a magnesia crucible maintained at approximately 1300°C.
Prepare 43g of copper sulfide concentrate and CaO (98% or more pure CaO content) in a molten bath using a lance pipe to add 95%O ₂ -5%N ₂ (both % by volume) and the lance was injected without being immersed.

[Table] A double pipe is used for the injection lance pipe, and 37.5 g/min of copper sulfide concentrate and 3.9 g/min of CaO are supplied from the inner pipe.
Blow is carried out by flowing with N ₂ gas at 0.46/min, and O ₂ gas at 8.76/min from the outer tube at 31.0/min.
It was injected at a flow rate of m/sec. After continuing blowing under the above conditions for 40 minutes and stopping for 5 minutes, the slag and matte were cooled and solidified, and the weight and analytical quality of the slag and matte were determined, and the amount of each component was determined from the amount and quality of the matte and slag initially charged. Table 2 shows the results of calculating the amount of pine, the amount of slag produced by the reaction, and the quality thereof.

[Table] In this test, the dust generation rate was about 5% by weight. During this period, no troubles due to the formation of magnetite were observed. Comparative example 30g of molten matte with the same composition as Example 1 and Fe/
Example 45 g of molten slag mainly composed of FeO- _{Fe2O3 - SiO2} system with SiO2 _1.4 was prepared, and copper sulfide concentrate having the composition shown in Table 1 was added to the molten bath kept at 1300℃. Add the same amount as 1 and 97% purity as a solvent.
When SiO ₂ was injected at a rate of 7.6 g/min using the same gas, slag rose up after 5 minutes, and then the amount of the supply source decreased due to the formation of a high melting point substance mixed with matte and generated magnetite. It became impossible to inject these substances into the melt, and furthermore, these substances caused blockage of the lance pipe, making it impossible to continue the experiment.

Claims (1)

[Claims] 1. A sufficient amount of calcareous solvent to convert most of the iron in the ore into calcium ferrite slag without using silicate ore as a solvent for copper sulfide ore,
A method for smelting copper sulfide ore, which is characterized in that copper is oxidized and refined into pine with a low iron content and a sufficient amount of oxygen to form pine with a white color.