JP3846288B2

JP3846288B2 - Operation method of copper smelting furnace

Info

Publication number: JP3846288B2
Application number: JP2001361532A
Authority: JP
Inventors: 康夫尾島; 康裕近藤; 一哲川中
Original assignee: Sumitomo Metal Mining Co Ltd
Current assignee: Sumitomo Metal Mining Co Ltd
Priority date: 2001-11-27
Filing date: 2001-11-27
Publication date: 2006-11-15
Anticipated expiration: 2021-11-27
Also published as: JP2003160819A

Description

【０００１】
【発明の属する技術分野】
本発明は銅の乾式製錬法に関し、特に硫化銅精鉱あるいは硫化銅精鉱から得られたマットを連続的に酸化溶融製錬して粗銅を得る方法に関する。
【０００２】
【従来の技術】
銅の溶融製錬は、硫化銅精鉱を酸化溶融し、鉱石中のＦｅの一部を酸化しスラグとして除去すると共に、Ｓの一部をＳＯ₂とし、銅をＦｅＳとＣｕ₂Ｓの混合物であるマットとして濃縮する工程、ついで得られたマットをさらに酸化して鉄をスラグとして除去し粗銅を得る転炉工程とからなる。転炉工程は、鉄をほとんど含まない白カワ（Ｃｕ₂Ｓ）を得る工程（造カン期）、この白カワをさらに酸化して粗銅を得る造銅工程（造銅期）から成る。転炉で生成した粗銅は、さらに残る硫黄と酸素の除去のため、精製炉で酸化され、次いで還元される。粗銅の硫黄品位が０．１０％以下であれば、ほとんど酸化をすることなく還元によって硫黄と酸素の除去が行われる。なお、マットを得るための溶錬炉としては一般的に自溶炉が用いられ、転炉工程では通常横型転炉や縦型転炉が用いられる。
【０００３】
ところで、上記溶錬炉ではマット中の銅品位（マットグレード、ＭＧ）が通常７０質量％以下のマットが製造され、マットはバッチ式の転炉で白カワとされ、ついで粗銅とされる。最近ではプラント全体の生産性を高めるために、バッチ式の転炉工程を連続化したプロセスが実用化されている。
【０００４】
転炉工程を連続化した場合には炉内を最適な酸化度で維持することが重要となる。酸化度が低くなりすぎると産出する粗銅中の硫黄品位は１％を越え、精製工程での酸化時間が長くなり、生産性の低下を招く。逆に酸化度が高くなりすぎると、粗銅中の硫黄品位は低下するが、スラグに酸化溶解する銅が増加するため、スラグ量が増加してハンドリングコストの上昇や、収率の低下による経済損失の増大を招く。
【０００５】
従来、こうした問題を避けるために産出物を定期的にサンプリングし、スラグ中の銅品位や粗銅中の硫黄品位を分析して、その値をもとに操業条件を調整するのが一般的である。しかし、スラグの分析は、例えば簡易的な蛍光Ｘ線分析であっても、サンプル採取から冷却、粉砕、測定といった各作業が必要となり、測定結果が出るまで１サンプルで３０分近くかかる。また、スラグを間欠のタッピングで排出するタイプの炉では、タッピングする時期までサンプル採取が出来ないという問題がある。転炉工程を連続化したときには上記サンプリングし、分析してその結果により操業条件を調整することは実質的に有効な手段とはならなくなる。
【０００６】
また、粗銅中の硫黄の分析は、例えばＬＥＣＯ社製の硫黄分析装置などを用いれば比較的迅速に分析が可能となるものの、粗銅中に許容される硫黄濃度は０．０４〜１．２％程度と籔囲が狭く、迅速な対応には難がある。例えば、結果的に粗銅中の硫黄濃度が上記上下限値に近い場合には、炉内のいずれかでＣｕ２ＯあるいはＣｕ２Ｓがスラグおよび粗銅の別相として偏在している場合があり、この場合、こうした別相の量が未知となるため、この別相を消失させるために必要な条件変更指針を定量的に立てることが困難となる。さらに、粗銅を間欠のタッピングで排出するタイプの炉では、スラグの分析と同様にタッピングサイクルまでサンプル採取が出来ないという問題がある。
【０００７】
以上の理由により、転炉を連続化した場合、条件変更を行うタイミングを取るのが経験と熟練度に依存することとなり、結果として操業の変動を招き、スラグ中の銅品位や粗銅中の硫黄品位の増加を招いていた。
【０００８】
【発明が解決しようとする課題】
本発明は、上記状況に鑑みて成したものであり、硫化銅精鉱あるいはマットを連続的に酸化して粗銅を得る上で、発生スラグ量、スラグヘの銅ロス量を少なくし、硫黄品位の低い粗銅を安定的に得ることを可能とする操業方法の提供を課題とする。
【０００９】
【課題を解決するための手段】
上記課題を解決する、本発明は、硫化銅精鉱を処理して生成されたマットを連続的に処理して粗銅を得る方法において、炉内溶体の酸化度を測定しつつ主としてマット装入量と、酸化反応用気体供給量と、スラグの還元用還元剤量との少なくともいずれか一つを調整することを特徴とする。即ち、本発明では、マットを連続的に処理して粗銅を得る方法において、炉内溶体の酸化度を測定しつつ主としてマット装入量と、酸化反応用気体供給量と、スラグの還元用還元剤量との少なくともいずれか一つを調整し、酸化度を一定に保つことを特徴とする銅製錬炉の操業方法である。
【００１０】
また、炉内溶体の酸化度が目標酸化度よりずれた場合にずれ量を補正するために炉内に吹き込むマット装入量、酸化反応用気体供給量、スラグの還元用還元剤量の少なくともいずれか一つの量を、ｌｏｇＰｏ₂ と粗銅中の硫黄品位との関係を利用して求め、得た値を用いて制御する。また、炉内の酸化度を測定するために、Ｐｏ₂センサーを使用し、所望の一定温度で得られた値を補正して用いる。
【００１１】
【発明の実施の形態】
本発明者らは上記課題を解決するために、固化したマットを酸化し、スラグと粗銅を生成する検討試験を行い、検討試験中の溶体の酸素分圧とスラグ中の銅品位および粗銅中の硫黄品位の関係について調査した。この際、溶体の酸素分圧の測定は市販のＰｏ₂センサー（ヘレウス・エレクトロナイト株式会社製Ｊ−ＨＹＯＰＦＰ１２００−６００）を用い、基準温度を１５４３Ｋとした。検討試験の結果として得た溶体の酸素分圧とスラグ中銅品位、粗銅中硫黄品位の関係を図１に示した。
【００１２】
この図１から、例えば粗銅中の硫黄品位を０．１％に制御したい場合、溶体のＰｏ₂を１０^-5（ａｔｍ）程度に制御する必要があることが分かる。この場合、仮に測定される酸素分圧が１０^-5（ａｔｍ）よりも高い場合、供給する酸素量を減少するか、還元剤を増加する必要があり、逆に測定される酸素分圧が１０^-5（ａｔｍ）よりも低い場合には、供給する酸素量を増加するか、還元剤を減少することが必要となる。なお、増加減する酸素の量は、生成する粗銅やスラグの重量を考慮して定量的に決定することが可能である。
【００１３】
【実施例】
次に実施例を用いて本発明をさらに説明する。
（実施例１）
内径１．５ｍ、高さ３．５ｍの反応塔と、内径１．５ｍ、長さ５．２ｍのセトラー部を有する小型自熔炉を用い４日間の連続試験を行った。試験は、マットと粉珪石と粉石灰（いずれも２００μｍ以下に粉砕したもの）を所定の比率で調合し、乾燥したもの（以下乾鉱）を反応塔天井に設けた精鉱バーナーから酸素３０％の酸素富化空気と共に反応塔内に吹き込み、スラグと粗銅を得るものである。また、試験中およそ２時間毎に消耗型のＰｏ₂センサーをセトラー部上方に設けた測定孔より溶体中に挿入し溶体の酸素分圧を測定した。
【００１４】
試験では粗銅中の硫黄品位を０．１５％以下で、かつスラグ中の銅品位を２５％以下で維持することを目標とした。この目標を達成するために試験中の溶体の酸素分圧をｌｏｇＰｏ₂＝−５．０前後で管理することとした。測定値がこの値から外れた場合に増減する酸素供給量の指標を決定するため、試験の計画バランスを目標の産出粗銅中の硫黄品位を０．１％、ｌｏｇＰｏ₂＝−５．５で産出が予想される粗銅中の硫黄品位を図１より０．１５％、１ｏｇＰｏ₂＝−４．５で産出が予想される粗銅中の硫黄品位を図１より０．０７％として３ケースで計算した。結果を表１に示す。表１からｌｏｇＰｏ₂が±０．５ずれた場合に±７Ｎｍ³／ｈのガス量の補正が必要となることがわかる。これにガス中の酸素濃度３０ｖｏ１％と試験炉内の溶体が入れ替わるのに必要な時間である８ｈに対する溶体の酸素分圧の測定間隔２ｈを加味して、酸素供給量の補正式として下記の式１を作成した。試験ではこの式を用いて供給するガス量の調整をおよそ２時間毎１回実施した。
【００１５】
【表１】

式１
酸素供給増減量(Nm³/h)＝-(1ogPo2-(-5.0))×1.4×30÷100×2÷8
試験期間中の酸素分圧の測定値と式１により調整して供給したガス量を表２に示した。
【００１６】
【表２】

また、試験期間中、約４時間毎にスラグ層の一部と粗銅層の一部をタッピングし、スラグサンプルはＩＣＰで粗銅サンプルはＬＥＣＯ社製の硫黄分析装置で定量分析を行った。産出した粗銅とスラグの分析値を表３に示す。この結果より、炉内の酸化度を定期的に測定し、供給する酸素量を調整することで、粗銅中の硫黄品位０．１５％以下を保ちつつ、スラグ中の銅品位を２５％以下に抑えられたことがわかる。
【００１７】
【表３】

【００１８】
（比較例）
溶体の酸素分圧を測定しないで、産出した粗銅とスラグの分析値に応じて供給するガス量を調整した以外は実施例と同じ方法で粗銅とスラグを得る試験を４日間実施した。スラグ中の銅の分析値から産出物組成を目標の値に近づけるための酸素供給量の補正式をマスバランスより求め、下記の式（２）を作成した。試験では１日毎にスラグの分析を実施し、この式を用いて供給するガス量の調整をおよそ２４時間毎に実施した。
【００１９】
式２
酸素供給増減量(Nm³/h)＝−（スラグ中の銅品位−18）×1.4×30÷100
試験期間中の産出した粗銅とスラグの分析値と式２により調整して供給したガス量を表４に示す。産出物品位の変動は大きく、粗銅中の硫黄品位は最高で１％、スラグ中の銅品位も３１％以上まで上昇した。
【００２０】
【表４】

【００２１】
【発明の効果】
本発明によれば、サンプル採取から分析までに要する作業が不要となり、またタッピングによりスラグあるいは粗銅を排出するタイプの炉では、タッピングサイクルを待たずに酸化度を既知とすることが可能である。そのため、早期の微調整による修正が可能である。また炉内の酸化度とスラグ中の酸素分圧と粗銅中の酸素分圧は高範囲で比例関係となるため、測定値に応じて定量的な修正操作が可能となる。これらの利点によって粗銅中の硫黄品位やスラグ中の銅品位を安定化させることが可能である。また、精製工程およびスラグ処理工程の負荷が少ないプロセスが可能となる。
【図面の簡単な説明】
【図１】検討試験の結果として得た溶体の酸素分圧とスラグ中銅品位、粗銅中硫黄品位の関係を示した図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a copper smelting method, and more particularly to a method for obtaining crude copper by continuously oxidizing and smelting a copper sulfide concentrate or a mat obtained from a copper sulfide concentrate.
[0002]
[Prior art]
In the melting and smelting of copper, copper sulfide concentrate is oxidized and melted, part of Fe in the ore is oxidized and removed as slag, part of S is SO _2, and copper is a mixture of FeS and Cu ₂ S. A step of concentrating as a mat, and a converter step of further oxidizing the obtained mat to remove iron as slag to obtain crude copper. The converter process consists of a step of obtaining white copper (Cu ₂ S) containing almost no iron (Cu ₂ S) and a copper making step (copper making phase) of further oxidizing the white river to obtain crude copper. The crude copper produced in the converter is oxidized in a refining furnace and then reduced in order to remove remaining sulfur and oxygen. If the sulfur grade of crude copper is 0.10% or less, sulfur and oxygen are removed by reduction with little oxidation. Note that a flash furnace is generally used as a smelting furnace for obtaining a mat, and a horizontal converter or a vertical converter is usually used in a converter process.
[0003]
By the way, in the above smelting furnace, a mat having a copper grade (mat grade, MG) of 70% by mass or less is generally manufactured, and the mat is made into white leather in a batch type converter and then made into crude copper. Recently, in order to increase the productivity of the entire plant, a process in which batch-type converter processes are continuous has been put into practical use.
[0004]
When the converter process is continued, it is important to maintain the inside of the furnace with an optimum degree of oxidation. If the degree of oxidation becomes too low, the sulfur grade in the crude copper produced will exceed 1%, and the oxidation time in the refining process will become longer, leading to a decrease in productivity. Conversely, if the degree of oxidation becomes too high, the sulfur grade in the crude copper will decrease, but the amount of copper dissolved and oxidized in the slag will increase, so the amount of slag will increase and handling costs will increase, and economic losses due to lower yields will result. Increase.
[0005]
Conventionally, in order to avoid such problems, it is common to periodically sample the output, analyze the copper grade in the slag and the sulfur grade in the crude copper, and adjust the operating conditions based on that value. . However, even if slag analysis is simple fluorescent X-ray analysis, for example, each operation such as sampling, cooling, crushing, and measurement is required, and it takes about 30 minutes for one sample to obtain a measurement result. In addition, in a furnace that discharges slag by intermittent tapping, there is a problem that samples cannot be collected until the tapping time. When the converter process is made continuous, the above sampling, analysis, and adjustment of the operation conditions based on the result will not be an effective means.
[0006]
Moreover, although analysis of sulfur in crude copper can be performed relatively quickly using, for example, a sulfur analyzer manufactured by LECO, the sulfur concentration allowed in crude copper is 0.04 to 1.2%. The degree and range are narrow, and it is difficult to respond quickly. For example, as a result, when the sulfur concentration in the crude copper is close to the above upper and lower limit values, Cu2O or Cu2S may be unevenly distributed as a separate phase of slag and crude copper in any of the furnaces. Since the amount of the different phase is unknown, it is difficult to quantitatively establish a condition change guideline necessary for eliminating the different phase. Furthermore, in a furnace that discharges crude copper by intermittent tapping, there is a problem that samples cannot be collected until the tapping cycle, as in the case of slag analysis.
[0007]
For the above reasons, when the converter is made continuous, the timing for changing the conditions depends on experience and skill, resulting in operational fluctuations, copper quality in slag and sulfur in crude copper. It has led to an increase in quality.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above situation. In obtaining crude copper by continuously oxidizing copper sulfide concentrate or mat, the amount of generated slag, the amount of copper loss in the slag is reduced, and the sulfur quality is reduced. It is an object to provide an operation method capable of stably obtaining low crude copper.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is a method for obtaining crude copper by continuously treating a mat produced by treating copper sulfide concentrate, and mainly measuring the amount of mat charged while measuring the degree of oxidation of the solution in the furnace. And at least one of an oxidation reaction gas supply amount and a reducing agent amount for reducing slag. That is, in the present invention, in the method of obtaining crude copper by continuously treating a mat, the amount of mat charging, the amount of gas supplied for oxidation reaction, and the reduction for reducing slag are measured while measuring the degree of oxidation of the solution in the furnace. It is a method for operating a copper smelting furnace characterized by adjusting at least one of the amount of the agent and keeping the degree of oxidation constant.
[0010]
In addition, when the oxidation degree of the solution in the furnace deviates from the target oxidation degree, at least one of the amount of mat charged, the amount of gas supplied for oxidation reaction, and the amount of reducing agent for reducing slag to correct the deviation amount One amount is determined by using the relationship between log Po ₂ and sulfur grade in the crude copper, and is controlled using the obtained value. Further, in order to measure the degree of oxidation in the furnace, a Po ₂ sensor is used, and a value obtained at a desired constant temperature is corrected and used.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In order to solve the above-mentioned problems, the present inventors conducted a study to oxidize the solidified mat and produce slag and crude copper. The oxygen partial pressure of the solution during the study test, the copper grade in the slag, and the crude copper The relationship between sulfur grades was investigated. At this time, the oxygen partial pressure of the solution was measured using a commercially available Po ₂ sensor (J-HYOPFP 1200-600 manufactured by Heraeus Electronite Co., Ltd.), and the reference temperature was set to 1543K. The relationship between the oxygen partial pressure of the solution obtained as a result of the examination test, the copper grade in slag, and the sulfur grade in crude copper is shown in FIG.
[0012]
From FIG. 1, it can be seen that, for example, when it is desired to control the sulfur grade in crude copper to 0.1%, it is necessary to control the Po ₂ of the solution to about 10 ⁻⁵ (atm). In this case, if the measured oxygen partial pressure is higher than 10 ⁻⁵ (atm), it is necessary to decrease the amount of oxygen supplied or increase the reducing agent. Conversely, the measured oxygen partial pressure is 10 If it is lower than ⁻⁵ (atm), it is necessary to increase the amount of oxygen supplied or reduce the reducing agent. Note that the amount of oxygen that increases and decreases can be quantitatively determined in consideration of the weight of the produced crude copper and slag.
[0013]
【Example】
Next, the present invention will be further described using examples.
Example 1
A four-day continuous test was conducted using a small self-melting furnace having a reaction tower having an inner diameter of 1.5 m and a height of 3.5 m and a settler portion having an inner diameter of 1.5 m and a length of 5.2 m. In the test, mat, powdered silica and powdered lime (all pulverized to 200 μm or less) were prepared at a predetermined ratio, and dried (hereinafter “dry ore”) from a concentrate burner provided on the reaction tower ceiling with 30% oxygen. It is blown into the reaction tower together with the oxygen-enriched air to obtain slag and crude copper. Further, during the test, a consumable Po ₂ sensor was inserted into the solution through a measurement hole provided above the settler portion, and the oxygen partial pressure of the solution was measured.
[0014]
The test aimed to maintain the sulfur grade in crude copper at 0.15% or less and the copper grade in slag at 25% or less. In order to achieve this goal, the oxygen partial pressure of the solution under test was controlled to be around log Po ₂ = −5.0. In order to determine the index of the oxygen supply amount that increases or decreases when the measured value deviates from this value, the planned balance of the test is 0.1% for the sulfur quality in the target produced crude copper, and log Po ₂ = −5.5. The sulfur grade in crude copper expected to be produced is 0.15% from Fig. 1 and the sulfur grade in crude copper expected to be produced at 1 og Po ₂ = -4.5 is 0.07% from Fig. 1 in 3 cases. Calculated. The results are shown in Table 1. From Table 1, it can be seen that when the log Po ₂ deviates by ± 0.5, a gas amount correction of ± 7 Nm ³ / h is necessary. In addition to this, the following equation is used as a correction formula for the oxygen supply amount, taking into account the measurement interval 2h of the oxygen partial pressure of the solution with respect to 8h, which is the time required for the solution in the test furnace to be replaced with the oxygen concentration 30vo1% in the gas. 1 was created. In the test, the amount of gas supplied was adjusted once every approximately 2 hours using this equation.
[0015]
[Table 1]

Formula 1
Oxygen supply increase / decrease (Nm ^{3 /} h) =-(1ogPo2-(-5.0)) × 1.4 × ³⁰ ÷ 100 × ² ÷ 8
Table 2 shows the measured value of the oxygen partial pressure during the test period and the amount of gas supplied after being adjusted according to Equation 1.
[0016]
[Table 2]

Further, during the test period, a part of the slag layer and a part of the crude copper layer were tapped about every 4 hours, and the slag sample was analyzed by ICP and the crude copper sample was quantitatively analyzed by a sulfur analyzer manufactured by LECO. Table 3 shows analytical values of the produced crude copper and slag. From this result, by periodically measuring the degree of oxidation in the furnace and adjusting the amount of oxygen to be supplied, the copper quality in the slag is reduced to 25% or less while maintaining the sulfur quality in the crude copper at 0.15% or less. You can see that it was suppressed.
[0017]
[Table 3]

[0018]
(Comparative example)
A test for obtaining crude copper and slag was carried out for 4 days in the same manner as in the examples except that the oxygen partial pressure of the solution was not measured and the amount of gas supplied was adjusted according to the analytical values of the produced crude copper and slag. From the analytical value of copper in the slag, a correction formula for the oxygen supply amount to bring the product composition close to the target value was obtained from mass balance, and the following formula (2) was created. In the test, slag analysis was performed every day, and the amount of gas supplied was adjusted approximately every 24 hours using this equation.
[0019]
Formula 2
Oxygen supply increase / decrease (Nm ³ / h) =-(Copper grade in slag-18) x 1.4 x 30/100
Table 4 shows the analytical values of the crude copper and slag produced during the test period and the amount of gas supplied after being adjusted according to Equation 2. The variation of the product grade was large, the sulfur grade in crude copper was up to 1%, and the copper grade in slag also rose to over 31%.
[0020]
[Table 4]

[0021]
【The invention's effect】
According to the present invention, the work required from sample collection to analysis becomes unnecessary, and in a furnace that discharges slag or crude copper by tapping, the oxidation degree can be made known without waiting for a tapping cycle. Therefore, correction by early fine adjustment is possible. In addition, since the oxidation degree in the furnace, the oxygen partial pressure in the slag, and the oxygen partial pressure in the crude copper are in a proportional relationship in a high range, a quantitative correction operation can be performed according to the measured value. With these advantages, it is possible to stabilize the sulfur grade in the crude copper and the copper grade in the slag. In addition, a process with less load on the refining process and the slag treatment process is possible.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the oxygen partial pressure of a solution obtained as a result of a study test, the copper grade in slag, and the sulfur grade in crude copper.

Claims

In the method of obtaining the crude copper by continuously treating the mat, at least any one of the amount of the mat charged, the amount of gas supplied for oxidation reaction, and the amount of reducing agent for reducing slag while measuring the degree of oxidation of the solution in the furnace If the oxidation degree of the solution in the furnace is kept constant and the oxidation degree of the solution in the furnace is deviated from the target oxidation degree, a mat device that is blown into the furnace to correct the amount of deviation is adjusted. At least one of the input amount, the gas supply amount for the oxidation reaction, and the reducing agent amount for reducing the slag is determined using the relationship between the log Po ₂ of the oxygen partial pressure of the solution in the furnace and the sulfur grade in the crude copper. A method for operating a copper smelting furnace, characterized in that control is performed using the obtained and obtained values .

The Po ₂ sensor is used to measure the degree of oxidation of the melt in the furnace, and the deviation amount is corrected using a value obtained at a desired constant temperature. How to operate a copper smelting furnace .