Method for producing blister copper from copper concentrate

Abstract

To provide technology directed to, firstly, improvement of an operation method of matte oxidation refining and, secondly, improvement of a copper concentrate oxidation smelting furnace.SOLUTION: A method for oxidation refining of matte. A copper concentrate oxidation smelting furnace.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present technology relates to a method for producing blister copper from copper concentrate.

[0002] This technology relates to an improvement in the matte oxidation refining operation method and an improvement in a copper concentrate oxidation smelting furnace. [Background technology]

[0003] In conventional matte oxidation refining, copper concentrate is oxidized and refined to produce matte consisting of Cu2S and FeS, and the matte is then oxidized and refined in a PS converter to produce blister copper.

[0004] In current copper smelting, an essential process is to oxidize copper concentrate and separate it into matte and slag. Summary of the Invention [Problem to be solved by the invention]

[0005] This technology relates to a method for producing blister copper from copper concentrate, and firstly, to improving the operating method of matte oxidation refining.

[0006] This technology relates to a method for producing blister copper from copper concentrate, and secondly, to improving a copper concentrate oxidation smelting furnace. [Means for solving the problem]

[0007] The present technology includes, for example, the inventions described in the following sections.

[0008] [1] Improvement of matte oxidation refining operation method Section 1. In the matte oxidation refining furnace, The copper production process is divided into the early stage, in which Cu2S is oxidized, and the later stage, in which commercial scrap containing Fe is added to molten copper from which S has been removed, and the copper is melted and oxidized. If necessary, in the early stage of copper production, copper scrap not containing Fe is charged and oxygen is blown into the matte to melt it, and if the heat source is insufficient, S2 is further added to melt the copper scrap, The point at which the oxidation of Cu2S is complete and the [S] in the blister copper reaches approximately 0.04 wt% is determined. After that, in the later stages of copper production, commercial scrap containing iron was charged, The total amount of Fe contained in the city scrap and the total amount of residual Fe (FeS and mixed Fe) present in the mat are summed up and expressed as the total number of moles of FeO. FeO mol% is defined as total number of FeO moles ÷ (total number of FeO moles + number of added CaO moles) × 100. Addition of CaO mol%=40mol%~10mol% so that FeO mol%=60mol%~90mol%. The copper slag is formed in the later stage of copper production. Matte oxidation refining method.

[0009] Section 2. In forming slag to absorb Fe2O3 generated by oxidation of Fe in the latter stage of coppermaking, CaO is added to form slag with a composition of FeO mol% = 60 mol% to 90 mol%, added CaO mol% = 40 mol% to 10 mol%, preferably FeO mol% = 65 mol% to 80 mol%, added CaO mol% = 35 mol% to 20 mol%, more preferably FeO mol% = 68 mol% to 75 mol%, added CaO mol% = 32 mol% to 25 mol%, and since the melting point of the slag rises when it is oxidized from an FeO-CaO system to an Fe2O3-CaO system, the operating temperature in the latter stage of coppermaking is increased to above approximately 1,330°C so that the slag maintains sufficient fluidity. Item 2. The method for oxidative refining matte according to Item 1.

[0010] Hereinafter, FeO-CaO and Fe2O3-CaO slags will be referred to as calcium ferrite and abbreviated as "CF." Furthermore, CF with a melting point of less than 1,330°C will be referred to as "low-melting-point CF."

[0011] Section 3. By adding an appropriate amount of Na2O to the CF slag in the later stage of copper production, the melting point of the slag in the later stage of copper production can be lowered, thereby lowering the operating temperature to the desired temperature range. Item 2. The method for oxidative refining matte according to Item 1.

[0012] Section 4. low-melting-point CF, FeO mol%=60 mol% to 90 mol% (preferably, FeO mol%=65 mol% to 80 mol%, more preferably, FeO mol%=68 mol% to 75 mol%, and most preferably, FeO mol%=70 mol%)-CaO mol%=40 mol% to 10 mol% (preferably, CaO mol%=35 mol% to 20 mol%, more preferably, CaO mol%=32 mol% to 25 mol%, and most preferably, CaO mol%=30 mol%), remaining after recovering CuO contained in the slag as Cu (blister copper) from the slag in the later stage of copper production in the matte oxidation refining method according to item 1 above by a gas soft reduction method, Alternatively, the low-melting CF with added Na2O can be solidified and crushed to be used as a hot metal dephosphorization agent. Method for treating post-copper-making slag.

[0013] Section 5. low-melting-point CF remaining after recovering Cu (blister copper) from the slag in the later stage of copper production in the method for oxidative refining of matte according to item 1 by a gas soft reduction method, FeO mol%=60 mol% to 90 mol% (preferably, FeO mol%=65 mol% to 80 mol%, more preferably, FeO mol%=68 mol% to 75 mol%, and most preferably, FeO mol%=70 mol%)-CaO mol%=40 mol% to 10 mol% (preferably, CaO mol%=35 mol% to 20 mol%, more preferably, CaO mol%=32 mol% to 25 mol%, and most preferably, CaO mol%=30 mol%); Alternatively, oxygen is blown onto the low-melting-point CF to which NaO has been added to oxidize FeO to FeO while dissolving CaO to a concentration of 32 mol% to 54 mol%, preferably 36 mol% to 50 mol%, thereby producing a low-melting-point CF with a high CaO concentration. A method for treating slag in the later stages of copper production.

[0014] Section 6. The method for dissolving CaO while oxidizing FeO in the low-melting-point CF to Fe2O3 is characterized in that a mixed gas of (oxygen + natural gas) is used as an oxygen-excess flame, and CaO powder is placed on the flame and sprayed onto the low-melting-point CF, thereby producing the low-melting-point CF with a high CaO concentration and a low melting point. Item 6. The method for treating slag in the later stages of copper production according to Item 5.

[0015] [2] Improvement of copper concentrate oxidation smelting furnace Section 7. In an oxidation smelting furnace for copper concentrate, The refractory surface that comes into contact with the slag generated during the smelting process is covered with stainless steel plates or heat-resistant steel plates, which extends the life of the refractory in the slag line. Oxidation smelting furnace for copper concentrate.

[0016] Section 8. In an oxidation smelting furnace for copper concentrate, a matte storage tank for storing matte that flows out of the smelting furnace through a matte outlet provided in the matte layer of the smelting furnace; The mat storage tank is structured so that the mat overflows and flows out through a mat outflow trough to the next process. The system is characterized by the ability to maintain a constant height of the matte top surface in the smelting furnace by using the siphon principle. Oxidation smelting furnace for copper concentrate.

[0017] Section 9. A stainless steel plate or a heat-resistant steel plate is installed in the horizontal area of ​​the settler through which a mixed gas of SO2 and N2 generated in the furnace of an oxidation smelting furnace for copper concentrate flows, CuS in the liquid phase in the mixed gas is deposited on the surface of the stainless steel plate or heat-resistant steel plate, The feature of this process is that the subsequent copper concentrate fine particles are removed by adhering them to the liquid phase CuS. Oxidation smelting furnace for copper concentrate.

[0018] Section 10. The stainless steel plate or heat-resistant steel plate according to the above item 9 is prepared in two types, One of the stainless steel plates or heat-resistant steel plates is hung from the ceiling, and is installed so as to be in close contact with the ceiling, with a gap between the lower end and the slag surface through which the mixed gas can flow. The stainless steel plate or heat-resistant steel plate is then placed so that its lower end is immersed in the slag layer and its upper end has a gap through which the mixed gas can flow. The mixed gas flow is characterized by being made to alternately generate downward flows and upward flows. A flow path control device for the mixed gas.

[0019] Section 11. In order to make the mixed gas described in Item 9 flow along the surface of the stainless steel plate or heat-resistant steel plate, The cross-sectional shape of the initial stainless steel plate or heat-resistant steel plate is tapered so that the upper part is thick and the lower part is thin, The second cross-sectional shape of the stainless steel plate or heat-resistant steel plate is characterized by being tapered so that the lower part is thick and the upper part is thin. A flow path control device for the mixed gas.

[0020] Section 12. Item 9. The method is characterized in that by adhering protrusions made of stainless steel or heat-resistant steel to both sides of the first stainless steel plate or heat-resistant steel plate described above, the probability that liquid-phase CuS in the mixed gas will come into contact with the stainless steel plate or heat-resistant steel plate is increased. An apparatus for removing copper concentrate fine particles from the mixed gas.

[0021] Section 13. In an oxidation smelting furnace for copper concentrate, Molten pig iron is supplied to the lower region of the reaction shaft of the concentrate burner as a reducing agent for Fe3O4 using a ceramic tube whose surface is coated with a stainless steel plate or a heat-resistant steel plate; The molten pig iron is atomized and supplied by ejecting CO, H2, or hydrocarbon gas at high speed from the tip of the ceramic tube. Oxidation smelting furnace for copper concentrate.

[0022] Section 14. In an oxidation smelting furnace for copper concentrate, A reducing gas storage tank made of stainless steel, heat-resistant steel plate, or refractory material is installed at the bottom of the reaction shaft, inside the matte layer in the area where Fe3O4 falls; The reducing gas reservoir tank is provided with a gas outlet through which CO gas, H2, hydrocarbon gas, or a mixture thereof is supplied as a reducing agent for Fe3O4 in the form of bubbles, similar to a Jacuzzi bath, thereby reducing Fe3O4 to FeO. Oxidation smelting furnace for copper concentrate.

[0023] Section 15. In an oxidation smelting furnace for copper concentrate, The amount of oxygen supplied to the concentrate burner is the theoretical amount of oxygen. Oxidation smelting furnace for copper concentrate. [Effects of the Invention]

[0024] First, this technology can improve the operating method of matte oxidation refining.

[0025] Secondly, this technology can improve the copper concentrate oxidation smelting furnace. [Brief explanation of the drawings]

[0026] [Figure 1] Figure 1 shows the FeO-CaO phase diagram in the improvement of the matte oxidation refining operation method. [Figure 2] Figure 2 shows the Fe2O3-CaO phase diagram in the improvement of the matte oxidation refining operation method [1]. [Figure 3] Figure 3 shows an example of a Laval nozzle for adding CaO in the improvement of the matte oxidation refining operation method [1]. [Figure 4] Figure 4 shows the schematic diagram of the flash furnace in the improvement of the copper concentrate oxidation smelting furnace [2]. [Figure 5] FIG. 5 shows the FeO-SiO2 phase diagram in the improvement of the copper concentrate oxidation smelting furnace [2]. [Figure 6] FIG. 6 shows the layout of dust adsorption plates in the settler section in the improvement of the copper concentrate oxidation smelting furnace [2]. [Figure 7] FIG. 7 is a schematic diagram of a flash furnace burner in the improvement of a copper concentrate oxidation smelting furnace [2]. [Figure 8] FIG. 8 is a diagram showing a reducing gas injection device into a flash smelting furnace in the improvement of a copper concentrate oxidation smelting furnace [2]. DETAILED DESCRIPTION OF THE INVENTION [Example]

[0027] The present disclosure will be specifically described below with reference to examples.

[0028] However, the present disclosure is not limited to these examples.

[0029] In this specification, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits (i.e., "greater than or equal to, less than or equal to").

[0030] [1] Improvement of matte oxidation refining operation method First, the present technology relates to an improvement in the operating method of matte oxidation refining.

[0031] In the conventional method, copper concentrate is oxidized and smelted to produce matte consisting of Cu2S and FeS, and the matte is then oxidized and refined in a PS converter to produce blister copper.

[0032] The matte contains 60 wt% to 65 wt% Cu (by mass), with the remainder being FeS. If the matte were composed only of CuS, the Cu concentration in the matte would be approximately 80 wt%, so a considerable amount of FeS remains in the matte currently produced.

[0033] Therefore, current PS (Peirce-Smith) converter operation is divided into two stages: the kanji "kan" (the character "kan" is written with the "thread" radical replaced with the "gold" radical) stage, in which FeS is removed, and the copper-making stage, in which S is removed from Cu2S to produce Cu.

[0034] During the smelting stage, oxygen-enriched air is blown into the matte to preferentially oxidize the FeS, removing it as FeO and leaving a Cu2S-enriched phase called shirokawa (white slate) with a Cu concentration of approximately 75 wt%. When the Cu2S is 100 wt%, the Cu concentration is approximately 80 wt%, so a small amount of FeS remains. The FeO generated during the smelting stage is removed as fayalite by adding silica sand. This is similar to flash smelting, which oxidizes copper concentrate. However, unlike flash slag, smelting stage slag oxidizes the FeS in the matte to a high degree, easily producing Fe3O4, resulting in a high Cu content of 3 to 5 wt%.

[0035] Therefore, in order to recover Cu, the slag produced during the smelting stage is returned in a molten state to the oxidation smelting furnace for copper concentrate (for example, a flash smelting furnace), or it is slowly cooled to precipitate a CuS-enriched phase, which is then crushed and beneficiated, and only the CuS-enriched phase is returned to the oxidation smelting furnace for copper concentrate to recover Cu.

[0036] Therefore, copper scrap containing Fe must be melted during the smelting stage. Also, since the heat source during the smelting stage is the heat generated by the oxidation of FeS with the Fe in the copper scrap, high-purity copper scrap can be used as a coolant for melting, as there is an abundant heat source.

[0037] During the copper production stage, oxygen-enriched air is blown into a Cu2S-enriched layer called white smelting to separate the Cu2S into Cu and SO2, producing Cu known as blister copper. Here, Cu2S and blister copper (Cu) form two liquid phases, but because separation is difficult, oxygen blowing is continued until the S content in the molten copper reaches about 0.04 wt% (mass%).

[0038] Therefore, a large amount of Cu2O (melting point: 1,235°C) is generated. High-purity copper scrap melts during the copper-making stage, but the heat source during this stage is only the heat from the oxidation of Cu2S, so there is a limit to the heat source and therefore to the use of copper scrap. Slag is not formed during the copper-making stage.

[0039] This technology involves the process of producing blister copper by oxidatively refining matte consisting of Cu2S and FeS obtained by oxidatively refining copper concentrate.

[0040] Next, the principle of this technology will be described, and specific means will be explained while clarifying the differences from conventional methods.

[0041] The feature of this technology is that CF slag generated in PS converters is used as a dephosphorization agent for hot metal in the steel industry.

[0042] Hot metal dephosphorization agent is a low-melting-point CF that uses CaO, which has a melting point of 2,613°C, as a CaO-FeO or CaO-Fe2O3 system and becomes liquid at approximately 1,300°C or below, the hot metal dephosphorization temperature. Japan's future crude steel production is expected to reach 100 million tons per year, and the required amount of hot metal dephosphorization agent will also be commensurate with this. Therefore, it is necessary to appropriately control the amount of slag generated in PS converters.

[0043] In light of this background, in this technology, it is preferable to oxidize FeS to the white iron level in the stage of producing matte from copper concentrate (e.g., in a flash furnace).Flash furnace slag containing SiO2 is not suitable as a hot metal dephosphorization agent, but it has a variety of other uses and can be used as a secondary material in various steel refining processes.

[0044] As mentioned above, the PS converter of this technology does not have the conventional copper-making period, but only the copper-making period. Therefore, to avoid confusion with the oxidation refining period of white smelting, which is currently called the copper-making period, this technology uses separate names for the early period in which Cu2S is oxidized (hereinafter referred to as the early copper-making period) and the later period in which Fe is oxidized and removed (hereinafter referred to as the later copper-making period).

[0045] Since this technology only involves the oxidation refining of white iron, there is no need to use a PS converter with a rotating mechanism. Although it is possible to use a fixed furnace for continuous refining, we will explain this technology assuming the use of a PS converter from the perspective of making effective use of existing facilities.

[0046] The role of the PS converter in this technology is twofold: one is to separate Cu2S into Cu and SO2 to produce Cu, known as blister copper, and the other is to melt copper scrap.

[0047] Copper scrap can be broadly divided into two types: commercial scrap containing Fe, and high-purity copper scrap such as copper wire scrap and electrode scrap. A typical example of scrap containing a lot of Fe is shredder dust, which contains approximately 50 wt% Fe. The heat sources for oxidation refining of white copper are the heat of oxidation of Fe and the heat of oxidation of Cu2S. Copper scrap containing Fe has a sufficient heat source from the heat of oxidation of Fe, but a heat source is required to melt high-purity copper scrap.

[0048] Therefore, copper scrap containing Fe is used in the later stage of copper production to form a CaO-Fe2O3 slag and remove the iron. The heat source in the early stage of copper production is mainly the oxidation heat of Cu2S, with only a small amount of FeS remaining in the matte added, so there is little thermal margin. On the other hand, the heat source in the later stage of copper production is the oxidation heat of Fe contained in commercial scrap, so the thermal margin depends on the amount of commercial scrap used.

[0049] In the current copper-making stage using PS converters, it is necessary to thoroughly reduce the amount of Fe in the target blister copper, so oxygen is blown in until the iron in the slag becomes Fe2O3. Therefore, PS converter slag is either Fe2O3-SiO2 or Fe2O3-CaO. Most current PS converters use Fe2O3-SiO2 slag, which contains approximately 3-5 wt% Cu as Cu2O. However, the C smelting furnace slag used in the Mitsubishi Continuous Copper Smelting Process is CaO-Fe2O3 and is said to contain approximately 15.5 wt% Cu. Next, we will discuss the key points to consider when forming the slag using this technology.

[0050] In this technology, the slag equivalent to the copper-making slag of current PS converters is Fe2O3-CaO-based, and judging from the track record of the Mitsubishi Continuous Copper Smelting Process, the Cu content is likely to be 15 wt% or more, which is not a problem. In this technology, the Cu2O contained in the Fe2O3-CaO-based slag is subjected to gas soft reduction using CO, H2, and a mixture thereof while in the molten slag state, and recovered as Cu.

[0051] Soft reduction (law) Oxygen is blown onto the slag to convert all sulfides and metal particles in the slag into oxides. Metal oxides in the slag that are more easily reduced than FeO are then reduced. Soft reduction is a weak reduction method that uses a reducing agent of a quantity and quality that is incapable of reducing FeO, leaving the FeO in the slag. In soft reduction, if the amount of oxygen to be reduced is excessive, it is preferable to perform a preliminary reduction using hydrocarbon gas, iron powder, or pig iron particles to control the amount of oxygen to be reduced to an appropriate level.

[0052] There are two types of soft reduction: gas soft reduction, which uses a reducing gas as a reducing agent, and a method using Fe in a molten Cu-Fe alloy. In the gas soft reduction method, CO, H, or a mixture thereof is preferably used as the reducing gas to reduce oxides of valuable metals in the molten slag, such as Cu, Mo, and Sn, which are then absorbed into molten Cu, which is supplied separately. In the method using Fe in a molten Cu-Fe alloy as a reducing agent, valuable metals in the recovered molten slag, such as Cu, Mo, and Sn, are absorbed into the molten Cu-Fe alloy, necessitating a step of preferentially oxidizing and separating the Fe from the molten Cu-Fe alloy.

[0053] During this soft reduction, FeO in the FeO-CaO slag is also reduced and converted to an FeO-CaO slag. Therefore, the melting point of the reduced FeO-CaO slag is important. As can be seen from Figure 1, by using a FeO mol% of 60 mol% to 90 mol% (preferably, FeO mol% of 65 mol% to 80 mol%, more preferably, FeO mol% of 68 mol% to 75 mol%, and most preferably, FeO mol% of 70 mol%) and CaO mol% of 40 mol% to 10 mol% (preferably, CaO mol% of 35 mol% to 20 mol%, more preferably, CaO mol% of 32 mol% to 25 mol%, and most preferably, CaO mol% of 30 mol%), the melting point of the FeO-CaO slag can be lowered to approximately 1,410 K, or 1,137°C.

[0054] Therefore, at the transition to the later stage of copper production, CaO is added to form slag to absorb the generated Fe2O3. As mentioned above, the composition of this slag must be determined taking into account the melting point of the FeO-CaO slag after soft reduction.

[0055] In the slag formed based on the above concept, FeO is oxidized to Fe2O3 during the refining process, but the number of Fe moles and CaO moles do not change. Since the only thing that changes is the O that bonds with Fe, the melting point of the slag during and after refining can be calculated based on the CaO mol% mentioned above in Figure 2.

[0056] For example, slag with a composition of FeO mol% = 70 mol% - CaO mol% = 30 mol% has a composition of CaO mol% = 30 mol% in Figure 2, so Fe2O3 mol% = 70 mol%, and its melting point is 1,620°K ≒ 1,347°C. Therefore, the refining temperature in the later stages of copper production in the PS converter must be raised to over 1,350°C.

[0057] Therefore, in actual operation, the amount of Fe obtained by adding the total amount of Fe present in the furnace in the early stage of coppermaking to the total amount of Fe charged in the later stage of coppermaking is determined and expressed in moles, and since the number of moles of Fe = the number of moles of FeO, it is sufficient to add CaO in an amount such that FeO mol% = 60 mol% to 90 mol% (preferably, FeO mol% = 65 mol% to 80 mol%, more preferably, FeO mol% = 68 mol% to 75 mol%, and most preferably, FeO mol% = 70 mol%) - CaO mol% = 40 mol% to 10 mol% (preferably, CaO mol% = 35 mol% to 20 mol%, more preferably, CaO mol% = 32 mol% to 25 mol%, and most preferably, CaO mol% = 30 mol%).

[0058] Next, the copper-making slag is subjected to gas soft reduction treatment using CO, H2, and their mixtures to recover Cu from Cu2O, but Fe3O4 is generated in some areas during the reduction process. However, the temperature of the surrounding Fe2O3-CaO slag before the soft reduction treatment exceeds 1,350°C, and the melting point of the slag after reduction, which has a FeO mol% of 60 mol% to 90 mol% (preferably, FeO mol% of 65 mol% to 80 mol%, more preferably, FeO mol% of 68 mol% to 75 mol%, and most preferably, FeO mol% of 70 mol%) and CaO mol% of 40 mol% to 10 mol% (preferably, CaO mol% of 35 mol% to 20 mol%, more preferably, CaO mol% of 32 mol% to 25 mol%, and most preferably, CaO mol% of 30 mol%), exceeds 1,127°C. Therefore, it is possible to avoid the phenomenon in which the viscosity of the entire slag increases due to Fe3O4 generated in some regions, causing the gas soft reduction to stop.

[0059] Next, if the temperature of the PS converter in the latter stage of copper production is too high (approximately over 1,350°C), it is possible to lower the melting point by adding flux. Candidates for such flux include Na2O, SiO2, and halogen compounds (CaF2, cryolite), but because the slag in the latter stage of copper production is used as a dephosphorizing agent for hot metal in the steel industry, SiO2 and halogen compounds are not recommended.

[0060] SiO2 reacts with CaO in the dephosphorization agent to form 2CaO·SiO2, resulting in CaO loss. Halogen element compounds are subject to strict limits on their use due to strict standards for fluorine ion elution from discarded steel slag, and the melting point lowering effect cannot be expected.

[0061] Although Na2O is expensive, it has strong dephosphorization ability, and therefore, in terms of the balance between cost, dephosphorization effect, and melting point lowering effect, the use of Na2O is preferred. The addition of Na2O can lower the melting point of a mixture of Fe2O3 mol%=60 mol% to 90 mol% (preferably, Fe2O3 mol%=65 mol% to 80 mol%, more preferably, Fe2O3 mol%=68 mol% to 75 mol%, and most preferably, Fe2O3 mol%=70 mol%) and CaO mol%=40 mol% to 10 mol% (preferably, CaO mol%=35 mol% to 20 mol%, more preferably, CaO mol%=32 mol% to 25 mol%, and most preferably, CaO mol%=30 mol%) to about 1100°C.

[0062] Next, a method for producing a hot metal dephosphorization agent for the steel industry from the late copper-making slag will be described.

[0063] The current dephosphorization method in the steel industry uses solid CaO, which poses various issues such as the reaction efficiency of CaO, but if molten CaO can be obtained at the dephosphorization treatment temperature, a revolutionary improvement can be expected.The low temperature for hot metal dephosphorization is about 1,300°C, so if the melting point of the dephosphorization agent is below about 1,250°C, it will be sufficiently effective.

[0064] The slag after gas soft reduction with CO, H, or a mixture thereof, having FeO mol%=60 mol% to 90 mol% (preferably, FeO mol%=65 mol% to 80 mol%, more preferably, FeO mol%=68 mol% to 75 mol%, and most preferably, FeO mol%=70 mol%) and CaO mol%=40 mol% to 10 mol% (preferably, CaO mol%=35 mol% to 20 mol%, more preferably, CaO mol%=32 mol% to 25 mol%, and most preferably, CaO mol%=30 mol%), may be cooled as it is and used as a hot metal dephosphorization agent.

[0065] In the case of hot metal dephosphorization, oxygen gas is blown in to oxidize the [P] in the hot metal to form (P2O5). If molten CaO is present at this time, it becomes the dephosphorization product (CaO·P2O5), and dephosphorization is further enhanced. The melting point of (CaO·P2O5) is approximately 1,000°C. If molten Na2O is also present at this time, it becomes the dephosphorization product (Na2O·P2O5), and dephosphorization is even more effective.

[0066] Next, if it is desired to increase the CaO content in order to reduce the amount of hot metal dephosphorization agent used, oxygen can be blown onto the low-melting-point CF shown in

[0068] to oxidize FeO to Fe2O3 while adding CaO, thereby producing Fe2O3-CaO with a melting point of 1,250°C or less. From Figure 2, it is clear that the composition of high-CaO content CF can range from Fe2O3 mol% = 50 mol% - CaO mol% = 50 mol% to Fe2O3 mol% = 63 mol% - CaO mol% = 37 mol%.

[0067] Next, the equipment for producing the high CaO content CF will be described.

[0068] The vessel used is a highly insulated vessel lined with stainless steel plate or heat-resistant steel plate. The low-melting-point CF after Cu recovery (FeO=60 mol% to 90 mol% (preferably, FeO=65 mol% to 80 mol%, more preferably, FeO=68 mol% to 75 mol%, and most preferably, FeO=70 mol%)-CaO=40 mol% to 10 mol% (preferably, CaO=35 mol% to 20 mol%, more preferably, CaO=32 mol% to 25 mol%, and most preferably, CaO=30 mol%)) is placed in the vessel. An oxygen-natural gas flame formed by a Laval nozzle as shown in FIG. 3 is irradiated onto the low-melting-point CF. CaO powder is added to the flame irradiation location. A KR (Kanbara Reactor) agitator with agitating blades made of stainless steel or heat-resistant steel is installed downstream of the flame irradiation location to homogenize the slag composition.

[0069] The various stainless steel sheets listed in JIS G0203 (2009) can be used, including stainless steel, austenitic stainless steel, ferritic stainless steel, austenitic-ferritic stainless steel, precipitation hardened stainless steel, low-carbon stainless steel, stabilized stainless steel, free-cutting stainless steel, and painted stainless steel.

[0070] The heat-resistant steel plate may be any of the various heat-resistant steel plates listed in JIS G0203 (2009), such as heat-resistant steel, martensitic heat-resistant steel, ferritic heat-resistant steel, austenitic heat-resistant steel, and precipitation-hardened heat-resistant steel.

[0071] When a stainless steel plate or a heat-resistant steel plate is used, SUS308 is preferably used.

[0072] The temperature of the low-melting point CF is 1,300°C or higher, and FeO = 70 mol% is oxidized to FeO 1.5During the exothermic reaction, the CaO powder is added while being heated with a high-temperature flame, which changes the CF to 70 mol%. CaO is easily dissolved. Continuous processing is possible by allowing the CF to overflow from the rear of the KR (Kanbara Reactor) agitator.

[0073] The actual operation of this technology will be summarized below.

[0074] Matte of white iron level is charged into the PS converter, and the early stage of copper production begins.

[0075] Here, oxygen is blown in to oxidize the Cu2S, and no slag is produced. The remaining FeS is oxidized to solid Fe2O3, which floats on the surface of the molten blister copper. High-purity copper scrap is used, but copper scrap containing Fe is not.

[0076] When the [S] (sulfur component) in the blister copper reaches approximately 0.04 wt% (mass%), the early coppermaking operation is terminated, and commercial scrap containing Fe is then charged. The amount of Fe charged into the furnace at this time is expressed in moles as the total Fe content, including the Fe content of FeS remaining in the white hull oxidized during the early coppermaking operation. Since the number of moles of Fe is equal to the number of moles of FeO, 60 mol% to 90 mol% of FeO (preferably, 65 mol% to 80 mol%, more preferably, 68 mol% to 75 mol%, and most preferably, 70 mol%) is set, and 40 mol% to 10 mol% of CaO (preferably, 35 mol% to 20 mol%, more preferably, 32 mol% to 25 mol%, and most preferably, 30 mol%) is added to correspond to the FeO mole%, and the later coppermaking operation begins. The end point of the later copper production stage may be determined by analyzing the Fe in the blister copper or by calculation from the Fe value charged.

[0077] The slag is removed at the end of the final copper-making stage. The ladle used to receive the final copper-making slag (Fe2O3 = 60 mol% to 90 mol% (preferably, Fe2O3 = 65 mol% to 80 mol%, more preferably, Fe2O3 = 68 mol% to 75 mol%, most preferably, Fe2O3 = 70 mol%) - CaO = 40 mol% to 10 mol% (preferably, CaO = 35 mol% to 20 mol%, more preferably, CaO = 32 mol% to 25 mol%, most preferably, 30 mol%)) is a highly insulated ladle lined with stainless steel plate or heat-resistant steel plate. The final copper-making slag is then reduced using a gas soft reduction furnace using CO, H2, and a mixture thereof to reduce the approximately 15 wt% of Cu2O dissolved in the slag, recovering Cu (blister copper). The remaining slag, which is the low-melting-point CF, is solidified and sold as a hot metal dephosphorization agent. Alternatively, the low-melting point CF is oxidized while dissolving CaO to produce high-concentration CaO low-melting point CF, which is then solidified and sold as a hot metal dephosphorization agent.

[0078] [2] Improvement of copper concentrate oxidation smelting furnace Secondly, the present technology relates to an improvement of a copper concentrate oxidation smelting furnace.

[0079] In current copper smelting, a process to oxidize copper concentrate and separate it into matte and slag is essential. The principle is that FeS in the copper concentrate reacts with oxygen to form FeO, which then reacts with SiO2 in the gangue to form fayalite (fayalite), which is separated as a low-melting-point slag.

[0080] Conventional copper concentrate oxidation smelting furnaces have the following problems: (1) Fe3O4 remains during the oxidation smelting process, (2) the slag has a high FeO content, which causes severe wear on the magnesia-chromium refractories used in the furnace's slag line, and (3) unreacted copper concentrate particles escape from the furnace together with a mixed gas of generated SO2 and residual N2 in the blown-in air. Hereinafter, the mixed gas of SO2 and N2 from a flash smelting furnace will be referred to as the mixed gas. We have developed a method to solve these problems, which will be described in detail below.

[0081] The detailed explanation will be given using the flash smelting furnace shown in Figure 4, which accounts for approximately 40% of copper concentrate oxidation smelting furnaces currently in operation, but the principles can also be applied to other methods.

[0082] Furthermore, by improving the equipment with this technology, the oxidation smelting process of the copper concentrate itself will be improved, resulting in significant improvements not only in the flash smelting furnace but also in the operation of the PS converter. The contents will be explained in detail step by step.

[0083] In a flash smelting furnace, copper concentrate and oxygen-enriched combustion air are blown into the furnace from a concentrate burner installed at the top of a section called the reaction shaft, which is 6 m high and 6 m in diameter, as shown in Figure 4. The concentrate burner is also called a flash smelting furnace burner. In the section called the reaction shaft of the burner shown in Figure 4, FeS in the copper concentrate is oxidized to FeO, and gangue, which is mainly composed of SiO2, is converted into fayalite (FeO-SiO2 system), which is then separated as slag with a low melting point and good fluidity.

[0084] As shown in the FeO-SiO2 phase diagram in Figure 5, the melting point of 2FeO·SiO2 is low at 1,205°C, making it highly fluid, and because FeO has high activity, it causes severe wear to the slag line of the magnesia-chromium refractory used in the furnace walls.

[0085] In actual operation, in order to reduce the activity of FeO in the slag and protect the slag line on the furnace wall, silica sand is added to make the slag rich in SiO2, and the melting point is increased within the range that allows for slag fluidity.

[0086] In addition, due to differences in the mineral phase of the copper concentrate, unreacted copper concentrate fine particles are generated, which escape from the furnace along with the mixed gas and accumulate in the waste heat recovery boiler installed downstream of the flash smelting furnace, requiring cleaning work approximately once a week. Furthermore, copper concentrate fine particles are also collected in the electrostatic precipitator installed downstream of the waste heat recovery boiler, requiring cleaning of the bag filter during major repairs once a year. These operations are performed manually, which imposes a significant workload. Thus, various issues remain with flash smelting furnaces.

[0087] Furnace wall protection method The first flash smelting furnace improvement technology is a furnace wall protection method characterized by covering the refractory surface of the slag line of the flash smelting furnace with stainless steel plate or heat-resistant steel plate to prevent the slag from coming into contact with the refractory.

[0088] Stainless steel sheets or heat-resistant steel sheets are extremely stable because oxidation reactions do not occur in low-oxygen conditions. Even if the FeO concentration is high, FeO and Fe do not react, so the stainless steel sheets or heat-resistant steel sheets do not react with the flash furnace slag. Furthermore, because the flash furnace atmosphere is the mixed gas, the stainless steel sheets or heat-resistant steel sheets are not oxidized. This technology eliminates the need to add silica sand to enrich the slag, allowing for a reduction in the amount of flash furnace slag.

[0089] For example, if one ton of copper concentrate contains 25 wt% Fe (mass%) and 9 wt% SiO2, the amount of FeO generated is 250 kg x 71.8 / 55.8 ≒ 322 kg ≒ 4.48 x 10 3 mol, SiO2 = 90 kg ≒ 1.5 × 10 3 mol. If this is a slag with FeO ≒ 75 mol and SiO2 = 25 mol, the melting point will be 1,185°C, and the activity of FeO will increase, but corrosion of the refractory caused by the slag is prevented by stainless steel plates or heat-resistant steel plates, so this is not a problem. Since SiO2 = 90 kg, the FeO absorbed by this will be 270 kg. Since the FeO generated = 322 kg, 52 kg will be surplus. The SiO2 that absorbs this will be = 14 kg. In other words, 14 kg of silica sand should be added.

[0090] If this were the current SiO2-rich operation, a slag of FeO ≒ 58 mol and SiO2 = 42 mol would be produced, so SiO2 = 90 kg would absorb 149 kg of FeO. Since FeO = 322 kg would be generated, 173 kg would be left over. This would be absorbed by SiO2 = 104 kg. In other words, 104 kg of silica sand would need to be added. Therefore, the amount of slag generated would increase by 90 kg.

[0091] That is, by covering the refractory surface of the slag line of a flash smelting furnace with stainless steel plates or heat-resistant steel plates, the amount of slag generated when processing 1 ton of copper concentrate can be reduced by 90 kg.

[0092] Technology for recovering unreacted copper concentrate fine particles The second new technology is a technology for recovering the unreacted copper concentrate fine particles that flow out of the furnace together with the mixed gas. Here, we focused on the fact that the mixed gas temperature is approximately 1,250°C to 1,300°C, and that the copper concentrate fine particles contained in the mixed gas are mainly Cu2S, which has a melting point of 1,100°C.

[0093] The Cu2S melts and becomes liquid, and along with solid gangue, it travels through the mixed gas flow and passes through the settler shown in Figure 4. These copper concentrate fine particles collide with each other in the uptake shaft, and the larger particles fall into the slag layer. However, a significant amount of copper concentrate fine particles still escapes into the exhaust gas pipe, causing the problems mentioned above. There is also the problem of them adhering to the furnace walls in the uptake section.

[0094] In addition, since a slag discharge port is provided near the uptake shaft, there is a risk that copper concentrate particles that fall into the slag will flow out of the furnace together with the slag without settling or separating into the matte layer.

[0095] This technology involves placing a stainless steel plate or a heat-resistant steel plate in the horizontal region of the settler, causing the liquid phase Cu2S in the mixed gas to adhere to the surface of the stainless steel plate or the heat-resistant steel plate, and subsequently causing copper concentrate fine particles to adhere to the liquid phase Cu2S and remove it from the mixed gas.

[0096] Two types of stainless steel or heat-resistant steel plates are prepared. The first stainless steel or heat-resistant steel plate is suspended from the ceiling, with a gap between its bottom end and the slag surface for the mixed sludge to flow through, and is placed in close contact with the ceiling. The second plate is placed so that its bottom end is immersed in the slag layer and its top end is placed so that a gap for the mixed gas to flow through is left. In this way, the mixed gas flow path is controlled so that the mixed gas alternates between downward and upward flows.

[0097] Next, preferably, the cross-sectional shape of the first stainless steel plate or heat-resistant steel plate is tapered so that it is thick at the top and thin at the bottom, so that the mixed gas flows along the surface of the stainless steel plate or heat-resistant steel plate. The cross-sectional shape of the second stainless steel plate or heat-resistant steel plate is tapered so that it is thick at the bottom and thin at the top. In this way, both the downward flow and the upward flow flow along the surface of the first stainless steel plate or heat-resistant steel plate. By alternately installing these two plates as a set, downward flow and upward flow are repeatedly generated.

[0098] Next, protrusions made of stainless steel or heat-resistant steel are attached to the surface of the stainless steel or heat-resistant steel plate to generate turbulence. This increases the probability that the liquid CuS will come into contact with the stainless steel or heat-resistant steel plate. Hereinafter, the combination of the above two types of stainless steel or heat-resistant steel plates will be referred to as a dust adsorption disk.

[0099] 6 shows V-shaped grooves (hereinafter referred to as V-grooves) carved at intervals into the surface of the stainless steel plate or heat-resistant steel plate, and a wide vertical groove is carved at the apex of the V, allowing the deposits to accumulate and flow down. Multiple V-grooves may be provided at the same height in the horizontal direction. A wide vertical groove is carved at the apex of each V, allowing the deposits to accumulate and flow down.

[0100] Next, protrusions that generate turbulence are attached to the convex portions between the V-shaped grooves. Because the protrusions are designed to generate turbulence, there are no particular restrictions on their shape. This creates a situation similar to that observed when raw rubber is harvested from rubber trees. A cover is then installed between the bottom of the vertical groove and the slag layer to block the mixed gas, preventing the falling deposits from being blown away by the mixed gas flow.

[0101] Figure 6 shows the installation diagram of the dust suction cup in the settler section.

[0102] Fe 3 O 4 Technology to reduce FeO The third new technology is characterized by adding atomized molten pig iron, which has reducing power for Fe3O4 and generates little gas, to the lowest region of the reaction shaft of the flash smelting furnace burner shown in Figure 7, and reducing the appropriate amount of falling Fe3O4 to FeO.

[0103] Reducing gases include CO and H2, but CO and H2 are suitable as gases that reduce Fe3O4 to FeO in the copper smelting temperature range but do not reduce FeO to Fe.

[0104] Below, we will explain the mechanism by which Fe3O4 is generated during oxidation smelting of copper concentrate and its harmful effects, and discuss the importance of eliminating Fe3O4 using this technology.

[0105] When copper concentrate is oxidized, thermodynamic principles dictate that FeS will turn into Fe3O4 in the initial stage when the oxygen concentration is high. The FeO that is subsequently produced reacts with the surrounding SiO2 to form slag.

[0106] When oxidizing copper concentrate, it is difficult to separate the oxidation of ZnS and FeS from the viewpoint of the free energy of oxide formation. Therefore, in the oxidation refining of copper concentrate, the amount of oxygen required to oxidize FeS plus 3 / 2 moles of oxygen per mole of ZnS is required. If the amount of ZnS is ignored, there will not be enough oxygen to oxidize FeS, resulting in more FeS remaining than the calculated amount.

[0107] The reaction formula for FeS is FeS + 3 / 2 × O2 = FeO + SO2, so the theoretical amount of oxygen required to oxidize FeS is 3 / 2 moles of the number of moles of FeS contained in the copper concentrate, and it is preferable to add 3 / 2 moles of the number of moles of ZnS contained in the copper concentrate to this amount.

[0108] Here, Cu in copper concentrate is CuS, and when heated to 220°C or higher, a decomposition reaction occurs: 2CuS = CuS + 1 / 2S. Furthermore, since the melting point of S is 115.2°C and the boiling point is 444.6°C, S vaporizes and escapes from the copper concentrate when heated to 444.6°C or higher. Therefore, when copper concentrate is roasted to 444.6°C or higher, the theoretical oxygen amount does not need to take into account the CuS contained in the copper concentrate.

[0109] However, because CuS is present in copper concentrate that has only been dried normally, oxidation treatment of the copper concentrate requires the addition of oxygen to oxidize S, as shown by the equation 2CuS ⇒ CuS + 1 / 2S, i.e., S + O = SO, i.e., 1 / 2 mol of oxygen in Cumol number. Hereinafter, the theoretical oxygen amount is defined as (3 / 2 mol of FeS moles contained in the copper concentrate + 3 / 2 mol of ZnS moles) when the copper concentrate has been roasted at 444.6°C or higher, and (3 / 2 mol of FeS moles contained in the copper concentrate + 3 / 2 mol of ZnS moles + 1 / 2 mol of Cumol number contained in the copper concentrate) when the copper concentrate has only been dried at temperatures below 444.6°C.

[0110] In actual operation, the reaction does not proceed as expected. If the amount of oxygen is too high, the amount of Fe3O4 produced increases, and the amount of remaining FeS decreases. As a result, there is not enough FeS to react with Fe3O4, and the amount of remaining Fe3O4 increases.

[0111] On the other hand, in fayalite slag, Fe3O4 has low solubility, so if Fe3O4 remains without reacting with FeS, it will remain in the solid phase. The presence of solid Fe3O4 in the slag increases the viscosity of the slag, causing matte droplets to accumulate at the bottom of the slag layer and be mechanically captured before being discarded as granulated slag. As a result, 0.7 wt% to 1.0 wt% of Cu remaining in the slag becomes copper loss. Furthermore, if solid Fe3O4 is present in the matte, it will accumulate and grow on the refractory surfaces of the hearth and furnace walls, causing operational difficulties.

[0112] Thus, solid phase Fe3O4 is harmful in copper smelting, and it is desirable to completely eliminate it. However, because the time it takes for copper concentrate to react in the reaction shaft is short, about one second, oxidation is controlled with great care, but it has not been possible to completely eliminate the residual Fe3O4.

[0113] In actual operation, the amount of residual Fe3O4 is controlled to a minimum, resulting in an appropriate amount of FeS remaining in the matte. As an indicator of this, the Cu concentration in the matte is controlled to 55-65 wt%. In PS converters, which refine matte to produce blister copper, operation is divided into two stages: the smelting stage, in which the FeS in the matte is preferentially removed, and the copper-making stage, in which silica sand is added to remove the FeS as fayalite. The remaining Cu2S is then oxidized to produce blister copper.

[0114] Because the copper-making slag from the PS converter has a high Cu2O content, after cooling it is beneficiated to recover the Cu-rich fraction, which is then returned to the flash furnace to recover the Cu. The remaining tailings are discarded along with the flash furnace slag. As a result, the generation of Fe3O4 in the flash furnace complicates the copper smelting process and results in significant copper loss.

[0115] In this technology, (1) Controlling the amount of oxygen injected into the flash furnace burner close to the theoretical oxygen amount and allowing the amount of Fe3O4 to remain in the lower region of the reaction shaft; (2) adding a molten pig iron mist to the lower region of the reaction shaft to forcibly reduce the amount of FeO; (3) Furthermore, the remaining Fe3O4 is almost entirely converted to FeO by the reducing gas ejected from the inside of the matte layer. It is characterized by:

[0116] The theoretical oxygen amount used in this technology is intended to minimize FeS in the matte. (1) The total amount of gas generated in a flash furnace is limited by the capacity of the gas treatment equipment in the flash furnace system. Therefore, there is a limit to the amount of reducing gas required to reduce the generated Fe3O4. Currently, the amount of oxygen blown into the flash furnace burner is controlled to minimize the generated Fe3O4. (2) As a result, the amount of FeS in the matte is determined.

[0117] In this technology, the theoretical oxygen amount that makes the FeS content in the matte zero in the flash smelting furnace is used, but this simply means that the amount of oxygen currently used in the PS converter manufacturing stage (the kanji character for "soft" is written with the "thread" radical replaced with the "metal" radical) is used in the flash smelting furnace, and the total amount of oxygen used remains unchanged.

[0118] Here, we will discuss the ease of reducing Fe3O4 at copper smelting temperatures around 1,250°C.

[0119] When FeO and Fe3O4 are dissolved in molten slag at 1,250°C, increasing the amount of Fe3O4 increases the viscosity of the slag. Therefore, if Fe powder is added in an amount such that Fe3O4 + Fe = 4FeO and the slag is stirred with a stainless steel rod, the Fe3O4 disappears in a short time and becomes FeO, lowering the viscosity of the slag and increasing its fluidity. Experiments have confirmed that Fe3O4 is extremely easily reduced. At temperatures above 1,250°C, when CO gas comes into contact with Fe3O4, Fe3O4 becomes FeO, generating CO2.

[0120] Next, a method for creating a reducing atmosphere for Fe3O4 in the region below the reaction shaft of the flash furnace burner will be described.

[0121] The reducing agents for reducing Fe3O4 include iron powder, pig iron, hydrocarbon gas, CO gas, and H2, but there are two effective methods for reducing Fe3O4.

[0122] One method involves adding atomized molten pig iron as a pre-reducing agent to the lower region of the reaction shaft. A ceramic tube coated with a stainless steel or heat-resistant steel plate is used to atomize molten pig iron in an amount sufficient to leave a moderate amount of Fe3O4. The molten pig iron is carbon-saturated pig iron, containing approximately 4.32 wt% C and having a melting point of approximately 1145°C. The reduction of Fe3O4 produces mostly FeO and some CO2. This method reduces excess Fe3O4 to FeO while reducing the total amount of gas generated in the flash furnace.

[0123] The second method is to supply CO gas, H2, or hydrocarbon gas from inside the matte layer to the area below the reaction shaft where the Fe3O4 particles fall. A gas reservoir tank made of stainless steel plate, heat-resistant steel plate, or refractory material with a gas outlet is installed inside the matte, and CO gas, H2, hydrocarbon gas, or a mixture of these gases is pumped into the tank, releasing reducing gas bubbles like a Jacuzzi bath. The gas-based reduction reaction has the advantage that the reducing gas adheres to the Fe3O4, preventing the Fe3O4, which has a higher density than the matte, from settling into the matte while converting it to FeO.

[0124] By these two methods, Fe3O4 is almost completely reduced to FeO.

[0125] CO can be purchased, but by implementing this series of technologies, external purchases will become unnecessary.

[0126] If the above operation is carried out, unlike the current situation, the FeS content in the matte in the flash smelting furnace can be oxidized to almost zero, so the operation of the PS converter will be limited to the copper-making phase, omitting the smelting phase, and the PS converter will become surplus. By utilizing the surplus PS converter, the amount of copper scrap used can be increased. All commercial scrap containing Fe will be processed in the PS converter during the copper-making phase.

[0127] The copper-making stage of a PS converter is divided into an early stage in which Cu2S is oxidized and a later stage in which copper scrap containing Fe is melted. In the early copper-making stage, copper scrap containing no Fe is melted. If the heat source is insufficient, S2 can be added to create a heat source. In the early copper-making stage, the amount of S is high, so adding CaO would result in CaO loss due to CaS, so slag is not produced. However, if the S content decreases, CaO can be added to form a CaO-Fe2O3 slag.

[0128] All commercial scrap containing Fe is melted in the later stage of copper production. As described in

[0057] , CaO is added to form a CaO-Fe2O3 slag in the later stage of copper production. There is no limit to the amount of commercial scrap containing Fe that can be processed in the later stage of copper production, as long as the operating temperature of the PS converter is raised to approximately 1,350°C and a CaO-Fe2O3 slag is formed.

[0129] Furthermore, by making the slag in the later stages of copper production a CaO-Na2O-Fe2O3 system to lower its melting point and lowering the operating temperature of the PS converter to below 1,200°C, it is possible to prevent erosion of refractories and increase the amount of Fe-containing commercial scrap that can be processed.

[0130] In this way, by using CaO-Na2O-Fe2O3-based slag, the melting point of the slag can be lowered, and the operating temperature can be lowered, thereby preventing erosion of converter refractories caused by the slag and reducing energy loss.

[0131] The slag formed in the later stages of copper production is a CaO-Fe2O3 or CaO-Na2O-Fe2O3 system, and is therefore expected to contain approximately 15 wt% or more of Cu2O. The CuO in the slag is recovered as Cu from the slag by gas soft reduction or soft reduction using a Cu-Fe alloy. The remaining CaO-FeO or CaO-Na2O-FeO slag is sold as a hot metal dephosphorization agent for the steel industry. At this time, the CaO-FeO or CaO-Na2O-FeO slag after Cu recovery can be reoxidized to form a CaO-Fe2O3 or CaO-Na2O-Fe2O3 slag, and the CaO content can be increased at the same time.

Claims

1. In the matte oxidation refining furnace, Cu 2 The copper production process is divided into the early stage, in which sulfur is oxidized, and the later stage, in which iron-containing commercial scrap is added to molten copper from which sulfur has been removed, and the copper is melted and oxidized. If necessary, in the early stage of copper production, copper scrap not containing Fe is charged and oxygen is blown into the matte to melt it. If the heat source is insufficient, S is further added. 2 to dissolve the copper scraps, Cu 2 The point at which the oxidation of S is complete and the [S] in the blister copper reaches approximately 0.04 wt% is determined. After that, in the later stages of copper production, commercial scrap containing iron was charged, The total amount of Fe contained in the municipal waste, the total amount of FeS remaining in the mat, and the total amount of Fe mixed in the mat layer are expressed in moles, and the total number of Fe moles is expressed as FeO moles. FeO mol% = the number of FeO mols ÷ (the number of FeO mols + the number of added CaO mols) × 100; The FeO mol% is set to 60 mol% to 90 mol%, and CaO mol% is added to supplement the FeO mol% to make it 100%, The copper slag is formed in the later stage of copper production. Matte oxidation refining method.

2. When slag is formed in the later stage of copper production and then oxidized, FeO is oxidized to Fe 2 O 3 changes to Fe 2 O 3 The operating temperature in the latter stage of coppermaking is raised to over 1,350°C so that the slag with a composition of 60-90 mol% CaO mol% = 40-10 mol% maintains sufficient fluidity. The method for oxidative refining matte according to claim 1.

3. The appropriate amount of Na is added to the slag in the later stage of copper production. 2 The addition of O lowers the operating temperature in the later stages of copper production to the desired temperature range. The method for oxidative refining matte according to claim 1.

4. The method for oxidative refining matte according to claim 1 further comprises recovering Cu (blister copper) from the slag in the later stage of copper production by gas soft reduction, and then adding low-melting point CF (FeO=60mol%-90mol%-CaO=40mol%-10mol%) or Na to the slag. 2 The low-melting-point CF with added O is solidified and crushed, and used as a hot metal dephosphorization agent. Method for treating post-copper-making slag.

5. The method for oxidative refining matte according to claim 1 further comprises recovering Cu (blister copper) from the slag in the later stage of copper production by gas soft reduction, and then adding low-melting point CF (FeO=60mol%-90mol%-CaO=40mol%-10mol%) or Na to the slag. 2 Oxygen was blown onto the low-melting-point CF to which O was added to convert FeO into Fe 2 O 3 While oxidizing the CF, CaO is dissolved to a concentration of 32 mol% to 54 mol%, preferably 36 mol% to 50 mol%, thereby producing a CF with a high CaO concentration and a low melting point. A method for treating slag in the later stages of copper production.

6. The FeO in the low-melting point CF was replaced with Fe 2 O 3 The method for dissolving CaO while oxidizing it is characterized by producing a high CaO concentration low-melting point CF with a low melting point by creating an oxygen-excess flame using a mixed gas (oxygen + natural gas), placing CaO powder on the flame, and spraying it onto the low-melting point CF. The method for treating slag in the later stages of copper production according to claim 5.

7. In an oxidation smelting furnace for copper concentrate, The refractory surface that comes into contact with the slag generated during the smelting process is covered with stainless steel plates or heat-resistant steel plates, which extends the life of the refractory in the slag line. Oxidation smelting furnace for copper concentrate.

8. In an oxidation smelting furnace for copper concentrate, a matte storage tank for storing matte that flows out of the smelting furnace through a matte outlet provided in the matte layer of the smelting furnace; The mat storage tank is structured so that the mat overflows and flows out through a mat outflow trough to the next process. The system is characterized by the ability to maintain a constant height of the matte top surface in the smelting furnace by using the siphon principle. Oxidation smelting furnace for copper concentrate.

9. SO generated inside the oxidation smelting furnace for copper concentrate 2 and N 2 A stainless steel plate or a heat-resistant steel plate is placed in the horizontal area of ​​the settler through which the mixed gas flows. Liquid phase Cu in the mixed gas 2 S is adhered to the surface of the stainless steel plate or heat-resistant steel plate, The liquid phase Cu 2 S is characterized by the subsequent adhesion and removal of copper concentrate fine particles. Oxidation smelting furnace for copper concentrate.

10. Two types of the stainless steel plate or heat-resistant steel plate according to claim 9 are prepared, One of the stainless steel plates or heat-resistant steel plates is hung from the ceiling, and is installed so as to be in close contact with the ceiling, with a gap between the lower end and the slag surface through which the mixed gas can flow. The stainless steel plate or heat-resistant steel plate is then placed so that its lower end is immersed in the slag layer and its upper end has a gap through which the mixed gas can flow. The mixed gas flow is characterized by being made to alternately generate downward flows and upward flows. A flow path control device for the mixed gas.

11. In order to make the mixed gas according to claim 9 flow along the surface of the stainless steel plate or heat-resistant steel plate, The cross-sectional shape of the initial stainless steel plate or heat-resistant steel plate is tapered so that the upper part is thick and the lower part is thin, The second cross-sectional shape of the stainless steel plate or heat-resistant steel plate is characterized by being tapered so that the lower part is thick and the upper part is thin. A flow path control device for the mixed gas.

12. By adhering protrusions made of stainless steel or heat-resistant steel to both sides of the first stainless steel plate or heat-resistant steel plate according to claim 9, liquid phase Cu in the mixed gas can be prevented. 2 S is characterized by increasing the probability of contact with the stainless steel plate or heat-resistant steel plate, An apparatus for removing copper concentrate fine particles from the mixed gas.

13. In an oxidation smelting furnace for copper concentrate, In the lower region of the reaction shaft of the concentrate burner, Fe 3 O 4 As a reducing agent for the molten pig iron, a ceramic tube whose surface is covered with a stainless steel plate or a heat-resistant steel plate is used to reduce CO, H 2 , hydrocarbon gas, or a mixture thereof is sprayed, atomized, and supplied. Oxidation smelting furnace for copper concentrate.

14. In an oxidation smelting furnace for copper concentrate, At the bottom of the reaction shaft, Fe 3 O 4 a reducing gas storage tank made of stainless steel plate, heat-resistant steel plate, or refractory material is installed inside the matte layer in the area where the reducing gas falls; Fe is discharged from a gas outlet provided in the reducing gas reservoir. 3 O 4 CO gas, H 2 , hydrocarbon gas, or a mixture of these gases is supplied as bubbles like in a Jacuzzi bath. 3 O 4 is reduced to FeO, Oxidation smelting furnace for copper concentrate.

15. In an oxidation smelting furnace for copper concentrate, The amount of oxygen supplied to the concentrate burner is the theoretical amount of oxygen. Oxidation smelting furnace for copper concentrate.

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