A method for efficient impurity removal during high-grade copper matte converter smelting

Abstract

This invention belongs to the field of copper smelting technology and relates to a method for efficiently removing impurities during high-grade copper matte converter blowing. Before the blowing process begins, high-grade copper matte is added to the converter all at once. The entire blowing process is divided into two stages according to the blowing steps. The first stage, from the start of oxygen blowing to the later stage of copper production, involves adding flux in batches, with slag skimming during the later stage. The second stage, from the later stage of copper production to the end of oxygen blowing, involves adding a deimpurifying agent in batches, resulting in crude copper. This method effectively solves the problem of difficult impurity element removal due to the short blowing time and small slag volume in the high-grade copper matte converter blowing process, achieving efficient removal of impurities such as lead, arsenic, antimony, and bismuth, resulting in significant economic and environmental benefits.

Description

Technical Field

[0001] This invention belongs to the field of copper smelting technology, and more specifically relates to a method for efficiently removing impurities during high-grade copper matte converter smelting. Background Technology

[0002] Currently, global copper production and consumption are growing steadily. With the continuous decline in copper concentrate grade and increasing environmental pressure, traditional smelting processes have gradually been phased out due to their shortcomings such as low production capacity, high energy consumption, significant environmental damage, and weak raw material adaptability. Oxygen-enriched smelting processes, characterized by high efficiency, energy saving, environmental protection, and strong raw material adaptability, have become an inevitable trend.

[0003] Copper matte, also known as copper matte, is mainly composed of Cu2S and FeS melt. Inevitably, the high-grade copper matte produced by the oxygen-enriched smelting process has a low iron content, which inevitably leads to a short blowing time and a small amount of slag in the subsequent blowing stage. This makes it difficult to remove impurities such as lead, arsenic, antimony, and bismuth. The impurity content in the crude copper is too high, and the copper content in the slag remains high, which causes great difficulties for subsequent smelting.

[0004] The current copper matte blowing process is theoretically divided into two main stages. The first stage is the slag-forming period, in which the FeS in the copper matte undergoes a strong oxidation reaction with the oxygen in the oxygen-enriched air blown in. The generated FeO then reacts with the added quartz flux to form ferroalloy slag (2FeO·SiO2). The slag is periodically discharged.

[0005] FeS + 1.5O₂ = FeO + SO₂

[0006] 2FeO + SiO2 = 2FeO·SiO2

[0007] The second stage is the copper-making period, during which the white matte continues to be smelted. The oxygen in the oxygen-enriched air blown in reacts with CuS to produce Cu2O and SO2. Cu2O then reacts with unreacted Cu2S to produce Cu and SO2.

[0008] Cu₂S + 1.5O₂ = Cu₂O + SO₂

[0009] 2Cu₂O + CuS = 6Cu + SO₂

[0010] This stage involves no flux or slag formation, and is characterized by the production of crude copper. During the blowing stage, the introduction of oxygen-enriched air results in vigorous agitation within the melt, creating favorable reaction kinetics. Current blowing technology primarily focuses on removing Fe and S, making its function relatively singular and ineffective in removing other impurities.

[0011] Due to the short blowing time in the high-grade copper matte converter blowing process, the amount of impurities such as lead, arsenic, antimony, and bismuth removed through the flue gas is reduced. The low iron content in the copper matte results in less blowing slag, and impurities cannot enter the slag for removal. Traditional blowing processes have low efficiency in removing impurities such as lead, arsenic, antimony, and bismuth.

[0012] Existing copper smelting technologies for removing impurities such as lead, arsenic, antimony, and bismuth mainly focus on the crude copper refining process, with little attention paid to impurity removal during the blowing process.

[0013] Therefore, how to provide a method for efficiently removing impurities in high-grade copper matte converter smelting, and how to efficiently remove impurity elements such as lead, arsenic, antimony, and bismuth during the high-grade copper matte converter smelting process, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0014] In view of this, the present invention provides a method for efficiently removing impurities in high-grade copper matte converter smelting. By adopting a two-stage smelting method for high-grade copper matte, it effectively solves the problems of difficulty in removing impurities such as lead, arsenic, antimony, and bismuth caused by the small amount of slag in the high-grade copper matte smelting stage, high impurity content in crude copper, and persistently high copper content in slag. It fills the difficulties and gaps in the existing technology where impurities such as lead, arsenic, antimony, and bismuth cannot be effectively removed in the high-grade copper matte smelting process.

[0015] To achieve the above objectives, the present invention adopts the following technical solution:

[0016] A method for efficiently removing impurities during high-grade copper matte converter smelting includes the following steps:

[0017] (1) Add all the high-grade matte into the converter and prepare to start the smelting process;

[0018] (2) First stage: from the start of oxygen blowing to the later stage of copper making, flux is added in 3-8 batches, and slag is removed in the later stage of copper making;

[0019] (3) Second stage: from the later stage of copper making to the end of oxygen blowing, the impurity removal agent is added in 2-4 batches. After the oxygen blowing is completed, crude copper is obtained.

[0020] Furthermore, the high-grade copper matte mentioned in step (1) is high-grade copper matte with a grade of 65%-78%.

[0021] Furthermore, the total amount of flux added in step (2) is 5%-8% of the mass of matte.

[0022] Furthermore, the time interval between each batch of flux added in step (2) is 20-60 minutes.

[0023] Furthermore, the flux mentioned in step (2) includes one or more of silicon dioxide and calcium oxide.

[0024] It is worth noting here that the number of batches of flux added is determined according to the iron content in the slag. Slag removal is carried out when the iron content in the slag no longer increases or when the copper content in the furnace reaches 85-90% before slag removal.

[0025] The beneficial effects of the above-mentioned further scheme are: the slag removal operation in the later stage of copper production can reduce the adverse effects of impurity removal agent loss and reduced impurity removal capacity caused by the reaction between flux and impurity removal agent, thereby reducing production costs.

[0026] Furthermore, the total amount of the impurity removal agent added in step (3) is 3%-5% of the mass of copper matte.

[0027] Furthermore, the time interval between each batch of adding the impurity remover in step (3) is 15-30 minutes.

[0028] Furthermore, the impurity removal agent mentioned in step (3) includes one or more of sodium carbonate, calcium carbonate, and phosphorus pentoxide.

[0029] It is worth noting here that the impurity remover reacts with impurities such as lead, arsenic, antimony, and bismuth in copper matte. It is added in 3-5 times the amount required for the reaction, in 2-4 batches. When the lead content in the copper matte is high, phosphorus pentoxide is the primary impurity remover; when the arsenic and antimony content is high, sodium carbonate and calcium carbonate are the primary impurity removers. The reactions involved include:

[0030] As2O5+3Na2CO3=2Na3AsO4+3CO2;

[0031] As2O5+3CaCO3=Ca3(AsO4)2+3CO2;

[0032] As₂O₅ + 3CaO = Ca₃(AsO₄)₂;

[0033] Sb2O5+3Na2CO3=2Na3SbO4+3CO2;

[0034] Sb2O5+3CaCO3=Ca3(SbO4)2+3CO2;

[0035] Sb₂O₅ + 3CaO = Ca₃(SbO₄)₂;

[0036] Bi₂O₃ + Na₂CO₃ = 2NaBiO₂ + CO₂;

[0037] Bi2O3+CaCO3=Ca(BiO2)2+CO2;

[0038] Bi₂O₃ + CaO = Ca(BiO₂)₂;

[0039] P2O5 + 3PbO = Pb3(PO4)2.

[0040] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. This invention adds high-grade copper matte all at once before the smelting process begins, which optimizes the production process, saves manpower and resources, and further reduces production costs compared to the current smelting process that adds copper matte in batches.

[0042] 2. The present invention adopts a two-stage impurity removal process in the blowing stage, which improves the removal rate of impurities such as lead, arsenic, antimony, and bismuth in the blowing stage, enabling the blowing stage to have a high-efficiency impurity removal capability, and effectively alleviating the excessive pressure of removing impurities such as lead, arsenic, antimony, and bismuth in the crude copper refining stage caused by oxygen-enriched smelting.

[0043] 3. In this invention, flux and impurity remover are added sequentially during the blowing stage to remove impurities. By utilizing the excellent reaction conditions provided by the blowing stage, the amount of flux and impurity remover added is reduced, further reducing production costs and making it more suitable for industrial production.

[0044] 4. After the blowing process is completed, there is no need to remove the slag. Impurities such as lead, arsenic, antimony, and bismuth react with the impurity removal agent to form slag. The slag and crude copper are separated into layers, and the content of impurity elements in the crude copper decreases. Since the slag contains a certain amount of crude copper, the crude copper and slag enter the next production step together in this invention. This does not reduce the direct copper recovery rate, does not increase equipment, does not increase energy consumption, and the slag can be utilized in the next step. Attached Figure Description

[0045] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0046] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] Hot matte, after testing, mainly contains: Cu 70.5wt.%, Pb 1.314wt.%, As 0.205wt.%, Sb 0.102wt.%, and Bi 0.025wt.%. It is added to the converter for blowing. The first stage is from the start of oxygen blowing to the later stage of copper making, about 180 minutes. Flux silica is added in 4 batches, with the amount of silica added being 6% of the mass of matte. The first and second batches each have 2% of the mass of matte added, and the third and fourth batches each have 1% of the mass of matte added. The batches are spaced 45 minutes apart. 40 minutes after the fourth batch of flux is added, the iron content in the slag is tested. When the iron content no longer increases, the slag is skimmed off.

[0050] The second stage, from the late stage of copper production to the end of oxygen blowing, lasts approximately 60 minutes. Two batches of impurity-removing agents, phosphorus pentoxide and sodium carbonate, are added. In the first batch, phosphorus pentoxide is added at 3% of the mass of the copper matte, and sodium carbonate at 0.5% of the mass of the copper matte. In the second batch, phosphorus pentoxide is added at 2% of the mass of the copper matte, with a 30-minute interval between batches. The blowing process ends 30 minutes after the second batch of impurity-removing agents is added, yielding crude copper.

[0051] Tests revealed that the crude copper mainly consisted of Cu 98.7 wt.%, Pb 0.126 wt.%, As 0.0225 wt.%, Sb 0.0236 wt.%, and Bi 0.012 wt.%.

[0052] Example 2

[0053] Hot matte, after testing, mainly contains: Cu 71.2wt.%, Pb 1.42wt.%, As 0.236wt.%, Sb 0.164wt.%, and Bi 0.021wt.%. It is added to the converter for blowing. The first stage is from the start of oxygen blowing to the later stage of copper making, about 180 minutes. Flux calcium oxide is added in 5 batches, with the amount of calcium oxide added being 8% of the mass of matte. The first, second, and third batches are each 2% of the mass of matte, and the fourth and fifth batches are each 1% of the mass of matte. The batches are spaced 36 minutes apart. 32 minutes after the fourth batch of flux is added, the iron content in the slag is tested. When the iron content no longer increases, the slag is skimmed off.

[0054] The second stage, from the late stage of copper production to the end of oxygen blowing, lasts about 60 minutes. Sodium carbonate, a deimpurifying agent, is added in three batches, with a total addition amount of 5% of the mass of matte. The first and second batches each contain 2% of the mass of matte, and the third batch contains 1% of the mass of matte. The blowing process ends 20 minutes after the third batch is added, yielding crude copper.

[0055] Tests revealed that the crude copper mainly consisted of Cu 98.6 wt.%, Pb 0.133 wt.%, As 0.0105 wt.%, Sb 0.013 wt.%, and Bi 0.010 wt.%.

[0056] Comparative Example 1

[0057] Hot matte was added in batches, containing 72.46 wt.% Cu, 1.337 wt.% Pb, 0.301 wt.% As, 0.103 wt.% Sb, and 0.012 wt.% Bi. After adding 0.3 tons of flux silica to an empty furnace, the first batch of 51.8 tons of matte was added. 35 minutes after the start of smelting, slag was skimmed off and a second batch of 20.12 tons of matte was added. Ten minutes later, 0.3 tons of flux silica were added. Thirty-five minutes later, another 0.3 tons of flux silica were added. Twenty minutes later, slag was skimmed off and a third batch of 19.02 tons of hot matte was added. Forty minutes later, another 0.3 tons of flux silica were added. Subsequently, 0.4 tons of flux silica were added at the 25th, 55th, and 75th minutes. Slag skimming and smelting were completed 20 minutes after the last batch of flux silica was added.

[0058] Tests revealed that the main components of the crude copper were Cu 98.501 wt.%, Pb 0.344 wt.%, As 0.227 wt.%, Sb 0.094 wt.%, and Bi 0.014 wt.%.

[0059] Comparative Example 2

[0060] Hot matte, after testing, mainly contains: Cu 71.6 wt.%, Pb 1.253 wt.%, As 0.425 wt.%, Sb 0.112%, and Bi 0.025 wt.%. It is added to a converter for refining. The first stage, from the start of oxygen blowing to the later stages of copper production, lasts approximately 180 minutes. Flux silica is added in four batches, with a 45-minute interval between batches. 40 minutes after the fourth batch of flux is added, the iron-silicon ratio in the slag is measured to be 1.8 and no longer increasing; slag removal is then performed. The second stage involves continuing refining for 60 minutes after slag removal, after which the refining process is completed.

[0061] Tests revealed that the crude copper mainly consisted of Cu 98.7 wt.%, Pb 0.401 wt.%, As 0.269 wt.%, Sb 0.103 wt.%, and Bi 0.012 wt.%.

[0062] Comparative Example 1 is crude copper obtained by existing smelting process, and Comparative Example 2 is crude copper prepared according to the technical solution of the present invention without adding impurity removal agent.

[0063] The compositional analysis of the crude copper showed that the removal rates of impurities such as Pb, As, Sb, and Bi obtained by the method of this invention were significantly higher than those of comparative examples 1-2. This indicates that the method of this invention enables efficient impurity removal during the blowing stage, solving the problem of difficulty in removing impurities such as lead, arsenic, antimony, and bismuth during the blowing process of high-grade matte due to oxygen-enriched smelting. This method allows the production of crude copper that meets or exceeds industry standards.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0065] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for efficiently removing impurities during high-grade copper matte converter smelting, characterized in that, Includes the following steps: (1) Add all the high-grade matte to the converter and prepare to start the smelting process; (2) First stage: from the start of oxygen blowing to the later stage of copper making, flux is added in 3-8 batches, and slag is removed in the later stage of copper making; (3) Second stage: from the later stage of copper making to the end of oxygen blowing, the impurity removal agent is added in 2-4 batches. After the oxygen blowing is completed, crude copper is obtained. In step (1), the high-grade copper matte is copper matte with a grade of 65%-78%; In step (2), the total amount of flux added is 5%-8% of the mass of matte; The time interval between each batch of flux added in step (2) is 20-60 minutes; The flux in step (2) includes silicon dioxide and / or calcium oxide; The total amount of the impurity removal agent added in step (3) is 3%-5% of the mass of copper matte; The impurity removal agent in step (3) includes one or more of sodium carbonate, calcium carbonate, and phosphorus pentoxide.

2. The method according to claim 1, characterized in that, Before slag removal in step (2), the copper content in the furnace reaches 85-90%.

3. The method according to claim 1, characterized in that, The time interval between each batch of adding the impurity remover in step (3) is 15-30 minutes.

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