A copper refining method using a bottom-blowing continuous refining furnace

Abstract

The present invention belongs to the technical field of bottom-blowing continuous copper refining, and specifically relates to a copper refining method using a bottom-blowing continuous refining furnace. The method comprises: continuously flowing hot matte into the bottom-blowing continuous refining furnace, simultaneously adding a slag-forming flux, and continuously refining to form a slag layer and a copper layer. The method also comprises: controlling the slag type of the bottom-blowing continuous refining furnace to be ferro-calcium slag, controlling the CaO / Fe ratio of the ferro-calcium slag by mass to 0.33-0.37, and controlling the ferroferric oxide content of the ferro-calcium slag by mass to 40%-55%. The refining method of the present invention results in a low copper content in the slag, reaching below 10.5%, and improves slag retention in the furnace lining, thereby extending the service life of the existing fully hot bottom-blowing continuous refining furnace by more than 50%.

Description

Technical Field

[0001] The invention belongs to the technical field of bottom blowing continuous blowing copper smelting, and in particular relates to a copper smelting method using a bottom blowing continuous blowing furnace. Background Art

[0002] Currently, bottom-blowing continuous converting furnaces primarily use ferrosilicon slag, but this has a short furnace lifespan, especially during fully hot continuous converting. It's difficult to protect the furnace lining by slag buildup (which effectively extends the furnace's lifespan and reduces the frequency of annual overhauls). Consequently, the furnace lifespan is often indirectly extended through short shutdowns and localized excavation and repairs. Furthermore, the bottom-blowing process also presents the difficult problem of high copper content in the slag and high copper content in the slag discharge.

[0003] Continuous blowing operations require timely slag discharge to ensure the normal sedimentation of metallic copper particles in the slag and minimize the amount of copper particles entering the slag bag with the slag. Currently, the optimal slag copper content is 12%-15%, and the slag discharge carries 280 tons of copper per 1,700 tons of slag. However, the bottom-blowing continuous blowing furnace has a short furnace life, especially in full-hot continuous blowing mode. Traditional bottom-blowing continuous blowing furnaces have a furnace life of less than 12 months in full-hot production mode.

[0004] In short, the bottom blowing process in the prior art cannot reduce the copper content in the slag and the copper output in the slag discharge while ensuring the service life of the furnace body. Summary of the Invention

[0005] The present invention aims to overcome the defects of the prior art bottom blowing converting process in that it is unable to achieve both furnace life and reduced slag copper content, thereby reducing the amount of copper in the slag discharge. A method for copper smelting in a bottom blowing continuous converting furnace is provided. The method results in a slag with a low copper content of less than 10.5%, and improves slag retention in the furnace lining, thereby extending the life of the existing fully hot bottom blowing continuous converting furnace by more than 50%.

[0006] To achieve the above-mentioned object, the present invention provides a copper smelting method in a bottom-blowing continuous blowing furnace, comprising: continuously flowing hot matte into the bottom-blowing continuous blowing furnace, simultaneously adding a slag-forming flux, and continuously blowing to form a slag layer and a copper layer, and further comprising: controlling the slag type of the bottom-blowing continuous blowing to be ferro-calcium slag, and controlling the CaO / Fe ratio by mass in the ferro-calcium slag to be 0.33-0.37, and controlling the mass content of ferroferric oxide in the ferro-calcium slag to be 40%-55%, preferably 45%-55%.

[0007] In some preferred embodiments of the present invention, the blowing method further comprises: controlling the mass content of calcium oxide in the ferro-calcium slag to 15%-17%, and / or the SiO2 content in the ferro-calcium slag to be lower than 2wt%.

[0008] In some preferred embodiments of the present invention, the blowing method further comprises:

[0009] When the mass content of calcium oxide in the ferrocalcium slag is less than 17%, the SiO2 content in the introduced raw material is controlled to be no more than 2wt% by mass, and the temperature of the ferrocalcium slag is controlled to be 1220-1235°C;

[0010] When the mass content of calcium oxide is between 17% and 19%, the SiO2 content in the introduced raw material is controlled to be no more than 3wt%, and the temperature of the iron-calcium slag is controlled to be between 1235°C and 1250°C;

[0011] When the mass content of calcium oxide is higher than 19%, the mass content of calcium oxide in the ferro-calcium slag is controlled to be 15%-17% by reducing the amount of slag-forming flux introduced and the reduction amount is 10%-25% of the theoretical mass amount of the slag-forming flux.

[0012] In some preferred embodiments of the present invention, the slag-forming flux is lime or limestone, and the limestone composition meets the following requirements: CaO ≥ 55% or CaCO3 ≥ 98% by mass, and the portion of the limestone with a particle size of 5 mm-15 mm is more than 90%, and the portion with a particle size of less than 5 mm does not exceed 10%.

[0013] In some preferred embodiments of the present invention, the blowing method further comprises: controlling the temperature of the copper layer to be 1220-1260°C, preferably 1230-1260°C, more preferably 1240-1260°C, and the temperature of the slag layer to be 1210-1245°C, preferably 1220-1245°C, more preferably 1220-1240°C by adjusting the flow rate of each gas introduced into the bottom blowing.

[0014] In some preferred embodiments of the present invention, the copper layer includes a matte layer and a crude copper layer.

[0015] In some preferred embodiments of the present invention, the position where the hot matte is fed into the furnace and the position where the slag-forming flux is added are both on the same end side of the bottom-blowing continuous converting furnace, and the same end side is on a different side from the copper discharge port and slag discharge port of the bottom-blowing continuous converting furnace.

[0016] In some preferred embodiments of the present invention, the continuous blowing is full-hot blowing, and the oxygen concentration in each bottom blowing gas is controlled to be lower than 28 wt %.

[0017] In some preferred embodiments of the present invention, the grade of the hot copper matte is controlled to be 72%-76%.

[0018] In some preferred embodiments of the present invention, the blowing method further comprises a step of treating the high silicon content of the ferro-calcium slag:

[0019] When the silicon content of the ferro-calcium slag is between 2wt% and 6w%, the cold copper matte added as the external silicon supplement is temporarily delayed to enter the furnace, and the hot copper matte is used to form a slag storage layer. After the material liquid level reaches the slag discharge requirement, the oxygen blowing pipe is used to assist in the slag discharge, and the slag is discharged until the furnace condition returns to normal;

[0020] When the silicon content of the ferrocalcium slag is greater than 6w%, borax is added from the gauge port or auxiliary material feed port of the bottom-blowing continuous blowing furnace to discharge the slag. The amount of borax added is controlled to be 5%-10% of the slag amount by mass.

[0021] In some preferred embodiments of the present invention, the blowing method further comprises a treatment step for coking:

[0022] When coking occurs at the mouth of a bottom-blowing continuous converting furnace, the furnace temperature is raised by 10-15°C to ensure it does not exceed 1260°C, and the temperature at the mouth is controlled above 1230°C. The particle size of the introduced slag-forming flux is controlled to ensure that, by mass, the fraction with a particle size of 5mm-15mm accounts for more than 90%. The raw cold copper matte is also controlled to contain no silicon-containing materials.

[0023] When coke grows at the gauge port of the bottom-blowing continuous blowing furnace, coke and pig iron need to be added, and the content of ferroferric oxide in the ferrocalcium slag is controlled. When the mass content of ferroferric oxide in the ferrocalcium slag is controlled to be greater than 55%, the total amount of pig iron and coke added is 0.14%-0.25% of the total mass of ferroferric oxide in the ferrocalcium slag in the furnace; when the mass content of ferroferric oxide in the ferrocalcium slag is controlled to be 40%-55%, the total amount of pig iron and coke added is 0.1%-0.14% of the total mass of ferroferric oxide in the ferrocalcium slag in the furnace.

[0024] In some preferred embodiments of the present invention, the blowing method further comprises at least one of the following steps for treating the high lead content in the blister copper:

[0025] (1) When the lead content of the crude copper in the copper layer exceeds 0.25 wt%, the grade of the raw hot matte or cold matte is controlled at 74 wt%-76 wt%;

[0026] (2) Control the iron-calcium slag from being oxidized and the lead content of the crude copper to be below 0.25wt%;

[0027] (3) After continuous blowing, refining is carried out in an anode furnace. During the refining, quartz is added to the anode furnace after casting is completed, and the amount of quartz is 0.07%-0.11% of the mass of the crude copper loaded in the anode furnace to form slag. Stable PbSiO4 is generated through reaction and discharged by skimming. The lead content in the obtained anode plate is stably controlled to be below 0.12wt%.

[0028] Beneficial effects:

[0029] The inventors of the present invention have found that ferrocalcium slag has good fluidity, which is conducive to the sedimentation of copper particles and the reduction of the copper content in the slag. However, the good fluidity of ferrocalcium slag can also cause the problem of scouring the furnace lining, affecting the slag hanging on the furnace lining and thus affecting the service life of the furnace body; while slag with poor fluidity is conducive to the slag hanging on the furnace lining, but the slag contains a large amount of copper; therefore, how to solve the technical problem of not being able to take into account the high copper content in the slag, the amount of copper in the slag discharge, and the service life of the furnace body is a difficulty in this field.

[0030] In this regard, the inventors conducted further research, taking into account factors such as slag flux consumption, slag copper content, slag discharge, and furnace lining protection, and found that through the above technical solution, in a bottom-blowing continuous refining process using hot matte as raw material (or as the main raw material), especially when the slag type is controlled to be ferro-calcium slag, specifically increasing the CaO / Fe ratio in the ferro-calcium slag to the above-mentioned suitable range is beneficial to reducing the activity of Fe3O4 in the slag, appropriately reducing the slag viscosity, and having slag type advantages such as good fluidity. Gas in the slag layer can be smoothly discharged, and copper particles in the slag can be quickly settled, thereby reducing the amount of copper inclusions, ensuring a low slag copper content index and the amount of copper in the slag discharge; at the same time, it fundamentally avoids the problem of large amounts of copper in the slag discharge, and is significantly superior to the ferro-silicon slag type commonly used in the prior art. The present invention also cooperates with controlling the appropriate amount of Fe3O4 in the ferro-calcium slag to facilitate the sedimentation of copper particles, while effectively slagging the furnace lining and effectively protecting the lining, effectively extending the service life of the bottom-blowing continuous refining furnace, and reducing the consumption of slag flux. Under the same conditions, if the CaO / Fe ratio is too high, slag-forming flux consumption is high, effective furnace slagging is impossible, the slag is highly scourable, and the lining cannot be protected, thus failing to guarantee the service life of the furnace lining. If the CaO / Fe ratio is too low, saturation precipitation is more likely to occur under the same temperature control, the bottom-blowing oxygen lance frequently clogs, and coking in the furnace is severe, seriously affecting normal continuous blowing operations. Under the same conditions, if the Fe3O4 content is kept low, refractory slagging is difficult. If the Fe3O4 content in the slag is high, the slag has poor fluidity and is sticky. The copper particles in the slag cannot quickly settle and aggregate, resulting in a high copper content in the slag and significant copper loss.

[0031] The present invention combines ferro-calcium slag type control with bottom-blowing continuous converting furnace type, and controls the amount of ferroferric oxide and the CaO / Fe ratio in the ferro-calcium slag within the aforementioned appropriate ranges. This allows the copper content of the bottom-blowing continuous converting furnace slag to be stably controlled below 10.5 wt%, effectively controlling the phenomenon of large amounts of copper in the slag discharge. This significantly outperforms other bottom-blowing converting processes and can extend the life of existing fully hot bottom-blowing continuous converting furnaces by more than 50%. This contributes to the economical and efficient production of copper smelters and effectively saves costs. Conventional bottom-blowing continuous converting processes using ferro-silicon slag generally produce ferro-calcium slag with a copper content of between 12% and 15%, with the copper content in the slag discharge always exceeding 15%. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a diagram of the furnace lining of Example 1;

[0034] Figure 2 This is a diagram of the furnace lining of Example 2;

[0035] Figure 3 This is a comparison chart of the change of ferrosoferric oxide content when the CaO content in the slag is not less than 13% and less than 15%;

[0036] Figure 4 This is a comparison chart of the change of ferrosoferric oxide content when the slag contains 15%-17% CaO;

[0037] Figure 5 This is a comparison chart of the change of ferrosoferric oxide content when the CaO content in the slag is higher than 17% and not higher than 20%;

[0038] Figure 6 This is a comparison chart of the change of ferrosoferric oxide content when the slag contains SiO2 less than 2%;

[0039] Figure 7 This is a comparison chart of copper content changes when the slag contains SiO2 < 2%;

[0040] Figure 8 This is a comparison chart of the changes in copper content when the slag contains SiO2 less than 2%. DETAILED DESCRIPTION

[0041] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Among them, the terms "optional" and "optional" all mean that they may be included or not (or may be present or not).

[0042] In this invention, the copper content of the slag is the value obtained by sampling and testing during slag discharge. The copper content of the slag discharge refers to the copper content at the bottom of the slag ladle. Copper metal particles entrained in the molten slag in the slag ladle will settle to the bottom of the slag ladle and accumulate, forming the so-called bottom copper. The bottom copper is the weight of the copper lumps that condense at the bottom of the slag ladle after slow cooling and pouring. The proportion of copper content in the slag discharge is generally expressed as the ratio of bottom copper to slag discharge volume.

[0043] In the present invention, unless otherwise specified, all terms are measured by mass. For example, the grade of the material is measured by mass, and the copper content of the slag is measured by mass.

[0044] The present invention provides a copper smelting method using a bottom-blowing continuous blowing furnace, comprising: continuously flowing hot matte into the bottom-blowing continuous blowing furnace, simultaneously adding a slag-forming flux, and continuously blowing to form a slag layer and a copper layer; and further comprising: controlling the slag type of the bottom-blowing continuous blowing to be ferro-calcium slag, controlling the CaO / Fe ratio by mass in the ferro-calcium slag to be between 0.33 and 0.37, and controlling the mass content of ferroferric oxide in the ferro-calcium slag to be between 40% and 55%, preferably between 45% and 55%.

[0045] The above CaO / Fe is the mass ratio of calcium oxide in the ferro-calcium slag to the total amount of iron in the ferro-calcium slag. In addition to ferroferric oxide, the iron-containing substances in the ferro-calcium slag also include iron compounds such as ferrous oxide and ferric oxide.

[0046] It is understood that in a bottom-blowing continuous converting furnace, bottom blowing involves blowing gas from the bottom to the copper layer, where oxygen is transferred from the copper layer to the slag layer. This differs from other processes, such as top-blowing, which directly blows the slag layer, where oxygen is transferred from the slag layer to the copper layer. This results in a higher oxygen potential in the slag layer and a higher Fe3O4 content.

[0047] It should be noted that the copper layer described in the present invention includes a matte layer and a crude copper layer.

[0048] The inventors further discovered that the calcium oxide content can directly affect the change of the ferroferric oxide content in the slag. The higher the calcium oxide content, the higher the solubility of ferroferric oxide. The inventors collected the Fe3O4 content in the slag at different CaO control intervals from April to September, as shown in the figure. Figure 3 and Figure 4 、 Figure 5 As shown, according to the data comparison, it can be seen that when the calcium oxide content is Figure 3 In the range of , the Fe3O4 content is mostly above 50wt%; when the calcium oxide content is increased to Figure 4 When the calcium oxide content is in the range of 15%-17%, the Fe3O4 content can be almost evenly distributed in the range of 40wt%-60wt%, which is adjustable. This adjustability can simultaneously ensure the process indicators such as slag copper content and the normal slag hanging of refractory materials in the furnace; and when the calcium oxide content is in the range of Figure 5The Fe3O4 content fluctuates greatly and has a large dispersion when the SiO2 content in the ferrocalcium slag is less than 2wt%. It can also be seen that when the SiO2 content in the ferrocalcium slag is less than 2wt%, the Fe3O4 content is more concentrated, which is more conducive to regulation. The inventors further discovered that the silicon dioxide content and the calcium oxide content can synergistically and directly affect the change of the ferroferric oxide content in the slag. The inventors collected data on the Fe3O4 content in the slag at different CaO control intervals from March to November when the SiO2 content in the ferrocalcium slag was less than 2wt%. Figure 6 As shown in the data, a comparison of the data shows that as the calcium oxide content increases, the ferrosoferric oxide content generally decreases. Therefore, in some preferred embodiments of the present invention, the blowing method further includes: controlling the calcium oxide content in the ferrocalcium slag to 15%-17% by weight, and / or controlling the SiO2 content in the ferrocalcium slag to less than 2% by weight.

[0049] The inventors further studied and found that when the SiO2 content in the iron-calcium slag is less than 2wt%, the distribution of Cu at different CaO / Fe contents, which is the key feature of the present invention, during the period of March to September is as follows: Figure 7-Figure 8 As shown, it can be seen that when the CaO / Fe ratio of the present invention is controlled at 0.33-0.37, the data with a Cu content of less than 10% accounts for a high proportion, and when the CaO / Fe ratio is lower than 0.33 or when the CaO / Fe ratio is higher than 0.37, the data with a Cu content of less than 10% accounts for a low proportion. Therefore, the present invention controls the CaO / Fe ratio by mass in the ferro-calcium slag to be 0.33-0.37, which is beneficial to the sedimentation of copper particles, thereby reducing the inclusion of copper.

[0050] In some preferred embodiments of the present invention, the blowing method further comprises:

[0051] When the mass content of calcium oxide in the ferrocalcium slag is less than 17%, the SiO2 content in the introduced raw material is controlled to be no more than 2wt% by mass, and the temperature of the ferrocalcium slag is controlled to be 1220-1235°C;

[0052] When the mass content of calcium oxide is between 17% and 19%, the SiO2 content in the introduced raw material is controlled to be no more than 3wt%, and the temperature of the iron-calcium slag is controlled to be between 1235°C and 1250°C;

[0053] When the mass content of calcium oxide is higher than 19%, the mass content of calcium oxide in the ferro-calcium slag is controlled to be 15%-17% by reducing the amount of slag-forming flux introduced and the reduction amount is 10%-25% of the theoretical mass amount of the slag-forming flux. In this preferred embodiment, when the calcium oxide content is lower than 17% and the silicon content in the slag is low and does not exceed 2wt%, the overall slag melting point is low, and the temperature of the ferro-calcium slag is controlled to be close to the lower limit of the slag layer temperature range; when the mass content of calcium oxide is between 17% and 19% and the silicon content is too high, the melting point of the ternary ferro-silicon-calcium slag is particularly high, and it is necessary to appropriately increase the temperature to ensure the fluidity of the slag; when the silicon oxide content is too high, it is necessary to adjust the amount of slag-forming flux, and it is preferred to add additional substances such as borax to improve the fluidity of the sticky slag.

[0054] It should be pointed out that the silicon content is mainly controlled by controlling the silicon content of the material entering the furnace, and the slag temperature is mainly controlled by the oxygen concentration of the gas supply.

[0055] In some preferred embodiments of the present invention, the grade of the hot matte is controlled to be 72%-76%. Within this range, it can be adjusted in real time according to the matching conditions of the smelting furnace and the bottom blowing continuous converting furnace to avoid prolonged overoxidation in the bottom blowing continuous converting furnace.

[0056] In some preferred embodiments of the present invention, the slag-forming flux is lime or limestone. The limestone composition satisfies the following requirements: CaO ≥ 55% or CaCO₃ ≥ 98% by mass, with at least 90% of the limestone having a particle size of 5 mm to 15 mm and no more than 10% having a particle size less than 5 mm. This preferred solution achieves a suitable particle size, ensuring a high furnace loading rate and preventing excessive amounts of small particles from being carried away by the flue gas and unable to enter the furnace for proper slag formation. Furthermore, the amount of slag-forming flux carried away by the flue dust is reduced, facilitating the effective addition of the slag-forming flux and ensuring proper slag formation.

[0057] In the art, bottom-blowing continuous converting furnaces are bottom-blown by introducing gases, including compressed air, nitrogen, and oxygen. Oxygen is supplied via an oxygen lance. Nitrogen is introduced to protect the lance and reduce the total oxygen concentration of the three gases. Temperature adjustment can be achieved by controlling the nitrogen and oxygen feed rates to vary the oxygen concentration during the blow process.

[0058] In the prior art, the smelting temperature is generally controlled at a relatively low temperature during the blowing process. This temperature can not only ensure the degree of reaction and melt fluidity, but also avoid the furnace process safety brought about by high-temperature control. High-temperature operation is prone to bring risks such as low furnace refractory life and furnace burn-through. In this regard, in some preferred embodiments of the present invention, the blowing method further includes: controlling the copper layer temperature to 1220-1260°C, preferably 1230-1260°C, more preferably 1240-1260°C, and the slag layer temperature to 1210-1245°C, preferably 1220-1245°C, more preferably 1220-1240°C, by adjusting the flow rate of each gas introduced into the bottom blowing. In the preferred embodiment of the present invention, higher copper layer and slag layer temperatures are adopted, which can be adapted to the iron-calcium slag type, which is more conducive to sufficient reaction and slag formation, and avoids the situation where the iron-calcium slag melting point and temperature are too low, resulting in poor fluidity of the slag type and inability to fully react and slag formation.

[0059] The continuous blowing process of the present invention may or may not involve the introduction of cold matte as a raw material. When cold matte is not introduced as a raw material, the process is fully hot-blowing. Cold matte may be added during full hot-blowing to serve as an external silicon source to reduce intermediate metal inventory. Cold matte is discharged from the smelting furnace during bottom blowing maintenance. In some preferred embodiments of the present invention, the continuous blowing process is fully hot-blowing (i.e., hot matte accounts for 100% of the raw material, i.e., no cold matte is introduced as a raw material), and the oxygen concentration in each gas introduced into the bottom blowing process is controlled to be less than 28 wt%.

[0060] In the art, full hot blowing is more difficult to extend the life of the furnace than non-full hot blowing, because the thermal balance is difficult to control and cannot meet the production requirements of a longer furnace period. The full hot blowing scheme of the present invention can reduce the heat release of blowing by controlling the grade of the hot matte entering the furnace to 72%-76%; and synergistically reduce the oxygen concentration in each incoming gas to below 28wt%, thereby maintaining thermal balance and significantly extending the life of the furnace.

[0061] The oxygen concentration in each gas introduced during bottom blowing is controlled to be lower than 28 wt %, which can be controlled by introducing nitrogen into the inner channel of the oxygen lance. This belongs to the prior art and will not be described in detail here.

[0062] In some preferred embodiments of the present invention, the hot matte is introduced into the furnace and the slag-forming flux is added at the same end of the bottom-blowing continuous converting furnace, which is located on a different side from the copper and slag discharge ports of the bottom-blowing continuous converting furnace. This preferred solution fully utilizes the existing oxygen lance distribution and moves the reaction zone forward, allowing the hot matte to come into contact with the slag-forming flux immediately after entering the furnace. This creates a larger reaction area within the furnace, enhances the contact reaction, maximizes the formation of a fluid ferro-calcium slag, and facilitates better separation of the copper slag.

[0063] During normal slag making of the present invention, the silicon content of the calcium iron slag is preferably less than 2 wt%. In some preferred embodiments of the present invention, the blowing method further comprises a step of treating the calcium iron slag with a high silicon content: slag removal is performed when the silicon content of the calcium iron slag is above 2 wt%.

[0064] The inventors further discovered that the silicon content of the ferro-calcium slag may be abnormal during the continuous blowing process. In this regard, preferably, the slag removal step includes: when the silicon content of the ferro-calcium slag is between 2wt% and 6w%, temporarily suspending the addition of cold copper matte as a supplementary silicon to the furnace, using hot copper matte to form a slag storage layer, and after the material liquid level reaches the slag removal requirement, using an oxygen lance to assist in removing sticky slag, and slag removal (e.g., after 30t to 60t of slag removal) until the furnace condition returns to normal; in this case, when the silicon content in the bottom-blowing continuous blowing furnace increases, as long as there is sufficient hot copper matte in the smelting furnace, the furnace can be added, and the amount of flux added during blowing is adjusted according to the estimated flow rate of hot copper matte entering the furnace in real time, slag is formed as quickly as possible, the silicon content of the slag is reduced, the slag fluidity is increased, and the high-silicon slag in the furnace is discharged as quickly as possible.

[0065] Preferably, the slag removal step includes adding borax from the gauge port or auxiliary material feed port of the bottom-blowing continuous converting furnace to remove the slag when the silicon content of the ferro-calcium slag exceeds 6% by weight. The amount of borax added is controlled to be 5%-10% of the slag volume by weight. After this treatment step, observing the subsequent changes in the silicon content and slag fluidity of the slag indicates that the furnace condition has returned to normal.

[0066] It should be noted that in this field, cold matte refers to the cold state of hot matte obtained by slow cooling and crushing. Cold matte is typically used as an effective reducing material after overoxidation in bottom-blowing continuous refining furnaces. Those skilled in the art may choose to add or not add cold matte to the hot matte feedstock.

[0067] The inventors further discovered that during the continuous blowing process, there may be a situation where coking in the furnace worsens. Coking is caused by low temperature, splashing, too many magnets, etc. Further research and analysis show that coking at the furnace mouth is caused by low temperature and splashing, and coking at the gauge port is caused by too many magnets. In this regard, in some preferred embodiments of the present invention, the blowing method also includes a treatment step for the coking situation: when coking occurs at the furnace mouth of the bottom-blowing continuous blowing furnace, the furnace temperature is increased by 10-15°C and the furnace temperature is ensured not to exceed 1260°C, and the temperature at the furnace mouth is controlled to be above 1230°C; the particle size of the introduced slag-forming flux is controlled to meet the following requirements: in terms of mass content, the portion with a particle size of 5mm-15mm is more than 90%; and the raw material cold copper matte is controlled to contain no silicon-containing materials. Among them, controlling the particle size of the slag-forming flux to meet the above conditions can prevent part of the limestone powder from falling directly into the outside of the original coke and failing to melt, thereby accelerating the growth of coke. The raw material cold copper matte is controlled to not contain silicon-containing materials. In the case of iron-calcium slag, if silicon-containing materials are mixed in, the melting point of the iron-silicon-calcium ternary slag will reach above 1300℃. Due to the increased melting point, it will not melt at normal operating temperature, so the precipitation of coking will be accelerated.

[0068] When coking occurs at the furnace mouth of a bottom-blowing continuous converting furnace, the converting method of the present invention may further include: melting the coking at the furnace mouth at a normal production position to prevent deterioration and growth; and raising the local temperature by pushing coke into the furnace mouth.

[0069] In some preferred embodiments of the present invention, the blowing method further includes a step to address coking: When coke builds up at the gauge port of the bottom-blowing continuous blowing furnace, coke and pig iron are added, and the ferroferric oxide content in the ferro-calcium slag is controlled. This helps improve the overoxidative atmosphere in the precipitation zone (near the coke formation). This is primarily achieved through the addition of reducing substances and control of the blowing endpoint, resulting in a blister copper grade of 98.5%-99.2%.

[0070] Preferably, when coke grows at the gauge port of the bottom-blowing continuous blowing furnace, coke and pig iron need to be added, and the content of ferroferric oxide in the ferrocalcium slag is controlled. When the mass content of ferroferric oxide in the ferrocalcium slag is controlled to be greater than 55%, the total amount of pig iron and coke added is 0.14%-0.25% of the total mass of ferroferric oxide in the ferrocalcium slag in the furnace; when the mass content of ferroferric oxide in the ferrocalcium slag is controlled to be 40%-55%, the total amount of pig iron and coke added is 0.1%-0.14% of the total mass of ferroferric oxide in the ferrocalcium slag in the furnace.

[0071] The inventors have further discovered that due to the relatively poor lead removal capability of the ferro-calcium slag type, the lead content of the blister copper obtained by continuous blowing may increase. Therefore, in some preferred embodiments of the present invention, the blowing method further includes at least one of the following steps to address the high lead content of the blister copper:

[0072] (1) When the lead content of the crude copper in the copper layer exceeds 0.25 wt%, the grade of the raw material hot matte or cold matte is controlled at 74 wt%-76 wt%; in terms of the ingredients, the lead content of the mixed ore is avoided to be too high;

[0073] (2) Control the iron-calcium slag from oxidation and control the lead content of crude copper to below 0.25wt%. In this case, the furnace will not be oxidized. The iron-calcium slag will not be oxidized, and the surface of the slag sample will be smooth, and there will be no large and obvious bubbles in the slag layer.

[0074] (3) After continuous blowing, the anode furnace is used for refining. During the refining, quartz is added to the anode furnace after the casting is completed, and the amount of quartz is 0.07%-0.11% of the mass of the crude copper loaded in the anode furnace to form slag. Stable PbSiO4 is generated through reaction, and the slag is discharged by skimming. The lead content in the resulting anode plate is stably controlled to be below 0.12wt%. Among them, the addition of quartz to form slag will cause Pb to be discharged with the slag, and the content is reduced. In this preferred embodiment, after regulation, the lead content of the anode plate can be stably controlled to be below 0.12%, which is more conducive to ensuring that the anode copper composition meets the standard. It can be understood that the above measures work together. If one measure is effective, the others may not be implemented.

[0075] The embodiments of the present invention are described in detail below, which are exemplary and only used to explain the present invention, and are not to be construed as limiting the present invention.

[0076] Example 1

[0077] A copper converting method using a bottom-blowing continuous converting furnace is as follows:

[0078] The hot matte from the smelting process is continuously fed into the bottom-blowing continuous converting furnace. The hot matte contains 3.5% Fe and has a grade of 75.3%. The raw material flow rate during normal converting is 0.4 t / min, ensuring that the hot matte tends to be continuous, stable, and has small fluctuations. A slag-forming flux is also added. Furthermore, the raw hot matte and slag-forming flux (limestone) are fed from the end position of the bottom-blowing continuous converting furnace used for converting. This end position is at the ends of the bottom-blowing continuous converting furnace where the copper and slag discharge ports are located. This allows for immediate slag formation, and the slag type is ferro-calcium slag. This embodiment is fully hot-state converting, without the introduction of raw cold matte, and the oxygen concentration in each bottom-blowing gas is controlled to be less than 28 wt%.

[0079] The real-time addition amount is calculated based on the real-time matte grade and matte flow rate.

[0080] Calculation example:

[0081] Assuming the iron content of matte is 3.5% and the matte flow rate is 0.4t / min (i.e. 24t / h); the iron content of matte per hour is: 24t×0.035=0.84t;

[0082] Set CaO / Fe=0.35; m(CaO)=0.35×m(Fe)=0.35×0.84t=0.294t;

[0083] The amount of limestone CaCO3 added to the metering belt = 0.294×100 / 56 = 0.525t.

[0084] The purity of CaO is 55%, and the limestone has a particle size of 5mm-15mm of 95% and a particle size of less than 5mm of 5%; converted to a CaCO3 purity of 98.21%; 0.525 / 98.21% = 0.5345t;

[0085] Eliminating measurement deviations, the actual bonding of the slag-forming flux with the iron must also be considered, requiring an amplification factor. This means multiplying the calculated amount by a loss of 1.1-1.2. 0.5345 × 1.15 = 0.6147 t / h, which is the amount of slag-forming flux added.

[0086] Subsequent adjustments are made based on the actual slag calcium oxide test results, controlling the slag calcium oxide content to 15%-17%. By adjusting the flow rates of the various bottom-blowing gases, the slag temperature is maintained at 1230°C and the copper layer temperature at 1245°C. During normal slagging, the SiO2 content in the iron-calcium slag is less than 2wt%.

[0087] When the mass content of calcium oxide in the ferro-calcium slag is lower than 17%, the SiO2 content in the introduced raw material is controlled to be no more than 2wt% by mass, and the temperature of the ferro-calcium slag is controlled to be close to 1230° C. and between 1220° C. and 1235° C.; when the mass content of calcium oxide is between 17% and 19%, the SiO2 content in the introduced raw material is controlled to be no more than 3wt%, and the temperature of the ferro-calcium slag is controlled to be close to 1245° C. and between 1235 and 1250° C.; when the mass content of calcium oxide is higher than 19%, the mass content of calcium oxide in the ferro-calcium slag is controlled to be between 15% and 17% by adjusting the amount of slag-forming flux introduced to 80% of the theoretical mass amount of the slag-forming flux.

[0088] In this embodiment, the copper content of the slag obtained by slag discharge is 9.5%, the calcium oxide content is 16.5%, the ferroferric oxide content is 47%, and the copper content of the slag discharge is 12.5%. Figure 1 .

[0089] Example 2

[0090] The method of Example 1 was followed, except that the copper layer temperature was controlled at 1220° C. and the slag layer temperature was controlled at 1210° C. by adjusting the flow rate of each bottom blowing gas.

[0091] In this embodiment, the copper content of the slag obtained by slag discharge is 10.5%, the calcium oxide content is 15%, the ferrosoferric oxide content is 55%, and the copper content of the slag discharge is 13.4%. The slag adhesion of the furnace lining is good, similar to that of Example 1.

[0092] Comparative Example 1

[0093] The method of Example 1 was followed, except that, in parameter control, the amount of limestone added was controlled to 130% of the normal value (i.e., 0.6147 t / h) of Example 1, so that the slag contained 19.25% calcium oxide, 29.1% ferrosoferric oxide, and a CaO / Fe ratio of 0.48.

[0094] In this comparative example, the copper content of the slag obtained by slag discharge is 9.32%, the copper content of the slag discharge is 12%, and the slag temperature is 1250℃. Figure 2 , the furnace lining slag is poor.

[0095] Comparative Example 2

[0096] The method of Example 1 was followed, except that the amount of limestone added was controlled to 135% of the normal value of Example 1 (i.e., 0.6147 t / h), so that the CaO / Fe ratio in the slag was 0.57, the slag contained 21.87% calcium oxide, and the slag contained 28.96% ferrosoferric oxide.

[0097] In this comparative example, the copper content of the slag obtained by slag discharge was 9.85%, the copper content of the slag discharge was 12.3%, and the slag temperature was 1255°C. The furnace lining condition: the slag was falling off, the brick joints were obvious, and the furnace life could not be guaranteed.

[0098] Comparative Example 3

[0099] The method of Example 1 is followed, except that quartz is selected as the slag-making flux to make iron-silicon slag, not iron-calcium slag.

[0100] In this comparative example, the copper content of the slag obtained by slagging was 13.69%, the calcium oxide content was 0%, the silicon content was 26.36%, and the copper content in the slag was 14.6%. The slag temperature was 1225°C. The slag was relatively thin, estimated to be 1 / 4-1 / 3 the thickness of the ferro-calcium slag.

[0101] The above examples show that, compared to the comparative examples, the method of the present invention can achieve better process control indicators, with the copper content of the slag being as low as 10.5% or less. Moreover, the refractory material lining the furnace body can effectively prevent slag, thereby extending the furnace life. A comparison of Example 1 and Comparative Examples 1-2 shows that improper control of the ferrosoferric oxide content and CaO / Fe ratio can affect slag in the furnace; a comparison of Example 1 and Comparative Example 3 shows that the iron-calcium slag type solution of the present invention is conducive to achieving better technical effects.

[0102] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A copper converting method using a bottom-blowing continuous converting furnace, comprising: Hot matte is continuously flowed into a bottom-blowing continuous blowing furnace, and a slag-forming flux is added at the same time for continuous blowing to form a slag layer and a copper layer. The method is characterized in that the continuous blowing is fully hot blowing, and the oxygen concentration in each bottom-blowing gas is controlled to be lower than 28wt%. The slag-forming flux is limestone, and the limestone composition meets the following requirements: CaO ≥ 55% or CaCO3 ≥ 98% by mass, and the portion of the limestone with a particle size of 5mm-15mm is more than 90%, and the portion with a particle size of less than 5mm does not exceed 10%. The method also includes: controlling the slag type of the bottom-blowing continuous blowing to be ferro-calcium slag, and controlling the CaO / Fe ratio by mass in the ferro-calcium slag to be 0.33-0.37, the mass content of calcium oxide in the ferro-calcium slag to be 15%-17%, the SiO2 content in the ferro-calcium slag to be lower than 2wt%, and the mass content of ferroferric oxide in the ferro-calcium slag to be 45%-55%.

2. The blowing method according to claim 1, characterized in that: The blowing method further comprises: When the mass content of calcium oxide in the ferrocalcium slag is less than 17%, the SiO2 content in the introduced raw materials is controlled to be no more than 2wt% by mass, and the temperature of the ferrocalcium slag is controlled to be 1220-1235°C; When the mass content of calcium oxide is between 17% and 19%, the SiO2 content in the introduced raw materials is controlled to be no more than 3wt%, and the temperature of the iron-calcium slag is controlled to be between 1235°C and 1250°C; When the mass content of calcium oxide is higher than 19%, the mass content of calcium oxide in the iron-calcium slag is controlled to be 15%-17% by reducing the amount of slag-forming flux introduced and the reduction amount is 10%-25% of the theoretical mass amount of the slag-forming flux.

3. The blowing method according to claim 1, wherein: The blowing method further includes: controlling the temperature of the copper layer to be between 1220° C. and 1260° C., and the temperature of the slag layer to be between 1210° C. and 1245° C. by adjusting the flow rate of each bottom blowing gas.

4. The blowing method according to claim 3, characterized in that: The blowing method further includes: controlling the temperature of the copper layer to be between 1230° C. and 1260° C. and the temperature of the slag layer to be between 1210° C. and 1245° C. by adjusting the flow rate of each bottom blowing gas.

5. The blowing method according to claim 3, characterized in that: The blowing method further includes: controlling the temperature of the copper layer to be between 1220° C. and 1260° C. and the temperature of the slag layer to be between 1220° C. and 1245° C. by adjusting the flow rate of each bottom blowing gas.

6. The blowing method according to claim 1, characterized in that: The position for feeding the hot matte and the position for adding the slag-forming flux are both on the same end side of the bottom-blowing continuous converting furnace, and the same end side is on a different side from the copper discharge port and the slag discharge port of the bottom-blowing continuous converting furnace.

7. The blowing method according to claim 1, characterized in that: The grade of the hot copper matte is controlled to be 72%-76%.

8. The blowing method according to claim 7, characterized in that: The blowing method further includes a step of treating the high silicon content of the ferro-calcium slag: When the silicon content of the ferro-calcium slag is between 2wt% and 6wt%, the cold copper matte added as the external silicon supplement is temporarily delayed, and the hot copper matte is used to form a slag storage layer. After the material liquid level reaches the slag discharge requirement, the oxygen blowing pipe is used to assist in the slag discharge, and the slag is discharged until the furnace condition returns to normal; When the silicon content of the ferro-calcium slag is greater than 6wt%, borax is added from the gauge port or auxiliary material feed port of the bottom-blowing continuous blowing furnace to discharge the slag. The amount of borax added is controlled to be 5%-10% of the slag amount by mass.

9. The blowing method according to claim 8, characterized in that: The blowing method also includes a treatment step for coking: When coking occurs at the mouth of a bottom-blowing continuous converting furnace, the furnace temperature is raised by 10-15°C to ensure it does not exceed 1260°C, and the temperature at the mouth is controlled above 1230°C. The particle size of the introduced slag-forming flux is controlled to ensure that, by mass, the fraction with a particle size of 5mm-15mm accounts for more than 90%. The raw cold copper matte is also controlled to contain no silicon-containing materials. When coke grows at the gauge port of the bottom-blowing continuous blowing furnace, coke and pig iron need to be added, and the content of ferroferric oxide in the ferrocalcium slag should be controlled. When the mass content of ferroferric oxide in the ferrocalcium slag is controlled to be greater than 55%, the total amount of pig iron and coke input should be 0.14%-0.25% of the total mass of ferroferric oxide in the ferrocalcium slag in the furnace; when the mass content of ferroferric oxide in the ferrocalcium slag is controlled to be 45%-55%, the total amount of pig iron and coke input should be 0.1%-0.14% of the total mass of ferroferric oxide in the ferrocalcium slag in the furnace.

10. The blowing method according to claim 1 or 7, characterized in that: The blowing method further comprises at least one of the following steps for treating the high lead content in the blister copper: (1) When the lead content of the crude copper in the copper layer exceeds 0.25 wt%, the grade of the raw hot copper matte is controlled at 74 wt%-76 wt%; (2) Control the iron-calcium slag to prevent over-oxidation and control the lead content of crude copper to below 0.25wt%; (3) After continuous blowing, refining is carried out in an anode furnace. During the refining, quartz is added to the anode furnace after casting is completed, and the amount of quartz is 0.07%-0.11% of the mass of the crude copper loaded in the anode furnace to form slag. PbSiO4 is generated through reaction and discharged by skimming. The lead content in the obtained anode plate is stably controlled to be below 0.12wt%.

11. The blowing method according to claim 8, characterized in that: When the lead content of the crude copper in the copper layer exceeds 0.25wt%, the grade of the cold copper matte is controlled at 74wt%-76wt%.

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