【０００１】
【発明の属する技術分野】
本発明は、銅電解液からの銅の回収方法及び浄液方法に関するものであり、より詳しく述べるならば、銅電解精製における循環電解液中の不純物の堆積を防止するために電解液の一部を抜き出して、Ａｓ，Ｓｂ，Ｂｉ等の不純物を除去して回収するとともに銅を回収し、浄液された銅電解液を再循環する方法に関するものである。
【０００２】
【従来の技術】
銅電解では原料であるアノードに砒素、アンチモン、ビスマス等の不純物が含まれており、これらの不純物は電解液に移行し蓄積する。電解液中でこれらの不純物の濃度が高くなるとカソードを汚染し製品の純度を損なう。そのため不純物を電解液から逐次除去を行わなければならない。さらに、上記した不純物の他に電解液に含まれる銅も浄液処理により回収される。
【０００３】
不純物の除去方法は基本的には電解採取法及び硫化法で行われている。
電解採取法は、例えば、図１に示すように３段階の電解採取を行い、一段目の電解採取により回収された電着銅は外販され、二段目の電解採取により回収された電着銅は溶錬工程に繰返し、三段目では不純物を電析させスラッジ（泥）状の化合物として電析させた後ろ過により分離して回収する。
【０００４】
硫化水素を吹き込み硫化物として回収する方法（硫化法）は先ず電解採取により電解採取中の銅（Ｃｕ）を除去し、その後硫化水素を吹き込み、液中の不純物を硫化物として析出させる。
【０００５】
ところで、電解採取法には以下の問題がある。
（イ）三段目の電解採取後回収されるスラッジ性状は供給する電解液の組成の影響を受け、例えば銅濃度が高い場合は銅粉や銅粒が発生し、泥性状が定まらないのでろ過工程の自動化が困難である。
（ロ）電解途中での銅の除去効果が測定できず、後液中の不純物濃度を制御ができない。
（ハ）有害なアルシンガス（ＡｓＨ３）が発生する危険がある。
【０００６】
硫化法には以下の問題がある。
液中に含まれる銅（Ｃｕ）が不純物より先に硫化されるので、硫化前液中の銅濃度が高い場合は反応に必要とする硫化水素と発生する硫化物が増える。そのため一般に事前に電解採取により銅濃度を下げるが、電流効率の変動により電解後液中の銅濃度が安定しない。
上記方法は次のように具体化されている。
【０００７】
（１）特許文献１に記載の方法：硫化法であって、この方法の概略を図２に示した。即ち、脱銅電解を行った電解後液の一部に水硫化ソーダを添加し、発生した硫化水素ガスを他方の電解後液に吹き込む。なお、脱銅電解に代えて加熱濃縮を行うこともできる。
【０００８】
（２）特許文献２に記載の方法：（１）の方法では、水硫化ソーダを添加した一方の分割電解液からニッケルや鉄などの不純物を除去する際に、液中の硫酸濃度が高く、また処理量も多いために多量の中和剤を必要とするので、この欠点を改良する方法であって、その方法の概略を図３に示した。この骨子は、銅を硫化銅とし除去した後のろ液を加熱濃縮することにより、硫酸ニッケルの分離除去を先立って行い、その後水硫化ソーダを添加するところにある。即ち、硫化銅の沈殿、硫酸ニッケルの沈殿及び不純物の除去の三工程からなる。
【０００９】
（３）加熱濃縮後電解採取を行う方法（図４参照）：銅電液を加熱濃縮して溶解度差を利用して銅を硫酸銅として分離除去し、次いで電解採取を行い不純物をスラッジとして分離除去する方法。
【００１０】
【特許文献１】
特許第２９６０８７６号公報
【００１１】
【特許文献２】
特許第３１５１１８２号公報
【００１２】
【発明が解決しようとする課題】
前掲（３）の方法には次のような問題がある。（イ）硫酸銅濃度を高くして加熱濃縮するので、僅かな温度降下でも硫酸銅が結晶化し、配管の閉塞を生じる。（ロ）硫酸銅回収のための冷却するが、次の硫化工程で、硫化物のろ過性を向上するために再昇温するのでエネルギー消費が大きい。（ハ）硫酸銅回収時にニッケル濃度も下がるために、後の脱ニッケル工程での効率が低下する。（ニ）冷却後電解液中に１０ｇ／Ｌ以下の銅が残留する。これをそのまま電解採取すると不純物と共析するので、これを避けるためには硫化回収が必要となり、硫化コストが嵩む。
【００１３】
【課題を解決するための手段】
本発明に係る銅電解液からの銅の回収方法は、銅電解精製における循環電解液中の不純物の堆積を防止するために電解液の一部を抜き出して浄液するとともに銅を回収した後、再循環する銅電解液からの銅の回収方法において、抜き出した電解液に電解採取を施して銅の一部を電気銅として回収し、銅を回収した電解液を加熱濃縮し、次いで冷却して硫酸銅を分離回収し、好ましくは、その後硫酸銅を分離回収した電解液に電解採取を施すことを特徴とする。
さらに、本発明に係る銅電解液の浄液方法は、銅電解精製における循環電解液中の不純物の堆積を防止するために電解液の一部を抜き出して浄液した後、再循環する銅電解液の浄液方法において、抜き出した電解液に電解採取を施して銅の一部を電気銅として回収し、銅を回収した電解液を加熱濃縮し、次いで冷却して硫酸銅を分離回収し、硫酸銅を分離回収した電解液ろ液に銅の電解採取及び硫化処理を順次施すことにより、ヒ素、アンチモン及びビスマスなどの不純物をスラッジとして銅電解液から分離することを特徴とする。
以下、本発明の方法を図５を参照して詳しく説明する。
【００１４】
本発明に係る方法では、まず電解採取により電解液中の銅の一部を外販可能な電気銅として回収する。電解採取は２段階で行うが、その条件は、一般的なものであってよく、例えば電流密度を１８０〜２６０Ａ／ｄｍ２とすることができ、電解液中のＣｕ濃度は通常一段目で３５〜４０ｇ／Ｌ 程度、ニ段目で２５〜３０ｇ／Ｌまでに低下する。一段目で回収された電着銅はこのまま外販することができる。この電解採取は、（ａ）加熱濃縮する前に電解液中の銅濃度を下げることにより、配管の閉塞を回避することができ、（ｂ）加熱濃縮工程での加熱エネルギーを削減し、（Ｃ）電解採取のための加熱が必要ではなく、さらに（ｄ）ニッケル濃度の低下がないので後工程でのニッケル回収効率を高く保つことができるなどの利点をもたらす。
【００１５】
次に加熱濃縮と冷却及びろ過により銅電解液中の銅を硫酸銅の粗結晶として回収する。ここで、加熱は８０℃以上沸点以下の温度で、電解液の一部を蒸発させ、濃縮された硫酸銅が、溶解度の差により次の冷却工程で、晶出する濃度となるように濃縮する。その後電解液を冷却する。この結果得られる粗結晶の硫酸銅は銅電解の元工程に繰返すことができる。これら一連の処理後銅電解液中の銅イオン濃度は通常２０〜３０ｇ／Ｌとなる。この加熱濃縮により銅濃度は最初の電解液と同程度になっており、電解液量は半分程度に激減している。
【００１６】
さらに、２回目の電解採取により銅を回収し、同時に不純物除去のための前処理として電解液中の銅濃度を下げる。後者の不純物目的のための電解採取では、不純物であるヒ素、アンチモン及びビスマスの除去は目的とせずに、次の工程で硫化水素や硫化物の発生が少なくなる程度に、例えば５〜１０ｇ／Ｌに銅濃度を下げることを目的とする。第２回目の電解採取により得られる電気銅は第１回目のものより品質が劣るので外販には適していない。
【００１７】
上記した第二回目の電解採取の電解後液にはＡｓが６〜１２ｇ／Ｌ， Ｓｂが０．５〜１ ｇ／Ｌ、 Ｂｉが０．３〜０．８ｇ／Ｌ， Ｎｉが２５〜４０ｇ／Ｌ含まれる。これらのヒ素、アンチモン及びビスマスなどの不純物を、硫化水素ガス、水硫化ソーダなどを使用する硫化処理によりスラッジとして除去する。硫化後ろ過を行い、硫化物を分離回収される。
【００１８】
本発明の実施形態としては、図６に示すように、上記した基本的工程（図中＊を付す）に、処理後液循環、冷却による硫化ニッケルの分離回収、及び硫化水素製造工程を付加することが好ましい。
即ち、処理後液の循環については、▲１▼第１回目の電解採取の後液の一部を銅電解工程に繰り返す；▲２▼硫化後のろ液の一部を銅電解工程に繰り返す；▲３▼硫化ニッケル回収工程の冷凍後液の一部を銅の電解工程に繰り返す。
【００１９】
また、硫化後のろ液の一部からニッケルを回収するものである。硫化後液を冷却し結晶を晶出させ遠心分離を施した後乾燥を行い粗Ｎｉを回収する。
【００２０】
さらに、硫化のための硫化水素は電解液を利用して製造することができる。即ち、硫酸、水及び電解液を混合してＳＯ４濃度を３００〜６００ｇ／Ｌ程度に調整する。次に、得られた希硫酸液に水硫化ソーダを添加して硫化水素を発生させる。その後液に電解液を加え再び硫酸濃度を高めかつ液中の銅と反応させることにより、硫化水素を除去する。処理液を貯液槽に溜め、中和した後排水処理を行う。
【００２１】
【作用】
本発明においては、脱銅電解（電解採取）と加熱・濃縮・冷却を順次行うことにより銅を回収するために、配管の閉塞を避けることができる。また上記の方法により銅濃度を調整するため、図１又は図２にフローを図解した電解採取により銅濃度調整する方法よりも、不純物除去前の銅濃度が安定する。また、本発明の電解採取は脱銅目的で行っており、不純物の除去は硫化により行っているので、アルシンガス発生は起こらない。
以下、実施例により本発明をより詳しく説明する。
【００２２】
【実施例】
実施例１
Ｃｕ濃度が５０ｇ／Ｌ，Ａｓ濃度が５ｇ／Ｌ、Ｂｉ濃度が０．３ｇ／Ｌ，Ｓｂ濃度が０．５ｇ／Ｌの銅電解液１００ｍ３を、電流密度が２５０Ａ／ｄｍ２の条件で電解採取して電気銅を得た。 この銅は通常の電気銅ベースの品位であった。該銅の品位は、Ａｓ＜５ｐｐｍ，Ｓｂ＜４ｐｐｍ，Ｂｉ＜２ｐｐｍであり、ＪＩＳ規格を満足する物であった。前記電解採取により後液中のＣｕ濃度を２５ｇ／Ｌまで下げたが，Ａｓ濃度は５ｇ／Ｌ， Ｂｉ濃度は０．３ｇ／Ｌ，Ｓｂ濃度は０．５ｇ／Ｌで変化しなかった。
この電解採取後液を沸点直下まで加熱して液量が５０ｍ３となるまで濃縮した。濃縮液はＣｕ濃度が５０ｇ／Ｌ，Ａｓ濃度が１０ｇ／Ｌとなった。濃縮液を３０℃まで冷却し、次いでろ過して粗結晶５ｔを得た。ろ液中のＣｕ濃度は２５ｇ／Ｌ，Ａｓ濃度が１０ｇ／Ｌ、Ｂｉ濃度が０．６ｇ／Ｌ，Ｓｂ濃度が１．０ｇ／Ｌとなった。ろ液に最初の電解採取と同じ条件で電解採取を施して、電解液中のＣｕ濃度を８ｇ／Ｌまで下げた。Ａｓ濃度は１０ｇ／Ｌ、Ｂｉ濃度は０．６ｇ／Ｌ，Ｓｂ濃度は１．０ｇ／Ｌで変わらなかった。電解採取後液に硫化水素を吹き込み、その後ろ過を行って硫化物沈殿物を分離した。硫化物は金属換算でＣｕ０．４０ｔ，Ａｓ０．４５ｔ，Ｂｉ０．０３ｔ，Ｓｂ０．０５ｔであった。不純物を除去した後の後液中の Ｃｕ濃度は０ｇ／Ｌ，Ａｓ濃度は１ｇ／Ｌ， Ｂｉ濃度は０ｇ／Ｌ，Ｓｂ濃度は０ｇ／Ｌであった。
【００２３】
比較例１
Ｃｕ濃度が５０ｇ／Ｌ，Ａｓ濃度が５ｇ／Ｌ、Ｂｉ濃度が０．３ｇ／Ｌ，Ｓｂ濃度が０．５ｇ／Ｌの銅電解液１００ｍ３を沸点直下まで加熱して液量が５０ｍ３となるまで濃縮した。濃縮液はＣｕ濃度が１００ｇ／Ｌ，Ａｓ濃度が１０ｇ／Ｌ、Ｂｉ濃度が０．６ｇ／Ｌ，Ｓｂ濃度が１．０ｇ／Ｌとなった。濃縮液を３０℃まで冷却し、次いでろ過して粗結晶１８ｔを得た。すなわち、粗結晶の量は実施例１の３．６倍と多量である。ろ液中のＣｕ濃度は１０ｇ／Ｌ，Ａｓ濃度が１０ｇ／Ｌ、Ｂｉ濃度が０．５ｇ／Ｌ，Ｓｂ濃度が０．８ｇ／Ｌとなった。ろ液に最初の電解採取と同じ条件で電解採取を施し、ろ過を行ってスラッジを分離した。硫化物は金属換算でＣｕ０．４５ｔ，Ａｓ０．４ｔ，Ｂｉ ０．０２５ｔ，Ｓｂ０．０４ｔであった。不純物をスラッジとして除去した後の後液中のＣｕ濃度は１ｇ／Ｌ，Ａｓ濃度は２ｇ／Ｌ， Ｂｉ濃度がは０ｇ／Ｌ，Ｓｂ濃度は０ｇ／Ｌであった。したがって、不純物除去効率は実施例１より劣っていた。
【００２４】
【発明の効果】
本発明によると、
（１）加熱濃縮前に電解採取して、銅を液中から除くため硫酸銅による配管の閉塞がない、
（２）銅を予め液中から除いているため生成する硫酸銅の量が少なく、硫酸銅を再溶解するエネルギー量が少なくて済み省エネルギー化となる、
（３）銅の除去が電解によるため硫酸銅を得るための冷却及びその後の液の昇温が不要に成り、省エネルギー化となる、
（４）電解法により銅を除去するためＮｉ等の不純物が銅と挙動を異にするため不純物を効率よく除去できる、
（５）電解採取を後工程においても採用するため硫化処理により銅を除くよりも硫化によるコストがかからない、
等の回収効率、加熱エネルギー消費及び銅などの有価金属回収などの全ての面で従来法よりも優れた成果が得られる。
【図面の簡単な説明】
【図１】従来技術に係る電解採取法のフローチャートである。
【図２】特許第２９６０８７６号公報の方法のフローチャートである。
【図３】特許第３１５１１８２号公報の方法のフローチャートである。
【図４】従来技術に係る加熱濃縮工程前置電解採取法のフローチャートである。
【図５】本発明方法の基本工程を示すフローチャートである。
【図６】本発明の実施形態の処理工程を示すフローチャートである。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for recovering copper from a copper electrolyte and a method for purifying the copper, and more specifically, a part of the electrolyte in order to prevent the accumulation of impurities in the circulating electrolyte in copper electrolytic refining. And a method for removing and recovering impurities such as As, Sb, Bi and the like, recovering copper, and recirculating the purified copper electrolyte.
[0002]
[Prior art]
In copper electrolysis, the anode, which is a raw material, contains impurities such as arsenic, antimony, and bismuth, and these impurities migrate to and accumulate in the electrolytic solution. High concentrations of these impurities in the electrolyte will contaminate the cathode and impair product purity. Therefore, impurities must be sequentially removed from the electrolyte. Further, in addition to the impurities described above, copper contained in the electrolytic solution is also recovered by the cleaning solution treatment.
[0003]
The method of removing impurities is basically performed by an electrowinning method and a sulfidation method.
In the electrowinning method, for example, as shown in FIG. 1, three stages of electrowinning are performed, and the electrodeposited copper recovered by the first-stage electrowinning is sold outside, and the electro-deposited copper recovered by the second-stage electrowinning Is repeated in the smelting process, and in the third step, impurities are electrodeposited and deposited as a sludge (mud) -like compound, and then separated and recovered by filtration.
[0004]
In the method of injecting hydrogen sulfide and recovering it as sulfide (sulfidation method), first, copper (Cu) during electrowinning is removed by electrowinning, and then hydrogen sulfide is blown in to precipitate impurities in the liquid as sulfide.
[0005]
By the way, the electrowinning method has the following problems.
(B) The properties of the sludge collected after the third stage of electrowinning are affected by the composition of the supplied electrolyte. For example, when the copper concentration is high, copper powder and copper particles are generated, and the mudiness is not determined, so filtration is performed. It is difficult to automate the process.
(B) The effect of removing copper during electrolysis cannot be measured, and the impurity concentration in the post-solution cannot be controlled.
(C) There is a risk that harmful arsine gas (AsH 3 ) is generated.
[0006]
The sulfurization method has the following problems.
Since the copper (Cu) contained in the solution is sulfided before the impurities, when the concentration of copper in the solution before sulfide is high, the amount of hydrogen sulfide required for the reaction and sulfide generated increase. Therefore, the copper concentration is generally reduced by electrowinning beforehand, but the copper concentration in the post-electrolysis solution is not stable due to fluctuations in current efficiency.
The above method is embodied as follows.
[0007]
(1) Method described in Patent Document 1: Sulfidation method, which is schematically shown in FIG. That is, sodium hydrosulfide is added to a part of the post-electrolysis solution after the copper removal electrolysis, and the generated hydrogen sulfide gas is blown into the other post-electrolysis solution. In addition, heat concentration can also be performed instead of copper removal electrolysis.
[0008]
(2) Method described in Patent Document 2: In the method (1), when removing impurities such as nickel and iron from one of the divided electrolytes to which sodium bisulfide is added, the sulfuric acid concentration in the solution is high, Further, since a large amount of the treatment requires a large amount of the neutralizing agent, this method is a method for improving this disadvantage, and FIG. 3 schematically shows the method. The essence of this skeleton is that the filtrate after removing copper as copper sulfide is heated and concentrated to separate and remove nickel sulfate prior to addition of sodium hydrosulfide. That is, it comprises three steps of precipitation of copper sulfide, precipitation of nickel sulfate and removal of impurities.
[0009]
(3) Method of performing electrowinning after heating and concentration (see FIG. 4): Heating and concentrating a copper electrolytic solution to separate and remove copper as copper sulfate using the difference in solubility, then performing electrowinning to separate impurities as sludge How to remove.
[0010]
[Patent Document 1]
Japanese Patent No. 2960876
[Patent Document 2]
Japanese Patent No. 3151182
[Problems to be solved by the invention]
The method (3) has the following problems. (A) Since the concentration of copper sulfate is increased while heating and concentrating, copper sulfate is crystallized even with a slight temperature drop, and the piping is blocked. (B) Cooling for recovery of copper sulfate, but in the next sulfurization step, the temperature is raised again to improve the filtration of sulfides, so that energy consumption is large. (C) Since the nickel concentration also decreases during the recovery of copper sulfate, the efficiency in the subsequent nickel removal step decreases. (D) After cooling, 10 g / L or less of copper remains in the electrolytic solution. If this is electrolytically collected as it is, it co-deposits with impurities, so that it is necessary to recover sulfide to avoid this, and the cost of sulfide increases.
[0013]
[Means for Solving the Problems]
The method for recovering copper from the copper electrolytic solution according to the present invention, after extracting and purifying a part of the electrolytic solution and recovering copper in order to prevent the deposition of impurities in the circulating electrolytic solution in copper electrolytic refining, In the method of recovering copper from the recirculated copper electrolyte, the extracted electrolyte is subjected to electrolytic sampling to recover a part of copper as electrolytic copper, and the recovered electrolyte is heated and concentrated, and then cooled. It is characterized in that copper sulfate is separated and recovered, and preferably, the electrolytic solution from which copper sulfate is separated and recovered is subjected to electrolytic sampling.
Further, the method for purifying a copper electrolytic solution according to the present invention is characterized in that, in order to prevent the accumulation of impurities in the circulating electrolytic solution in copper electrolytic refining, a part of the electrolytic solution is extracted and purified, and then the copper electrolytic solution is recirculated. In the liquid purification method, the extracted electrolytic solution is subjected to electrolytic sampling to collect a part of copper as electrolytic copper, and the electrolytic solution in which copper is recovered is concentrated by heating, and then cooled to separate and collect copper sulfate. By subjecting the electrolyte filtrate from which copper sulfate has been separated and recovered to electrolytic copper sampling and sulfidation treatment in order, impurities such as arsenic, antimony and bismuth are separated as sludge from the copper electrolyte.
Hereinafter, the method of the present invention will be described in detail with reference to FIG.
[0014]
In the method according to the present invention, first, a part of copper in the electrolytic solution is recovered as electrolytic copper that can be sold by electrowinning. The electrowinning is performed in two stages, and the conditions may be general conditions, for example, the current density may be 180 to 260 A / dm 2, and the Cu concentration in the electrolytic solution is usually 35% in the first stage. To about 40 g / L, and to 25 to 30 g / L at the second stage. The electrodeposited copper recovered at the first stage can be sold as it is. In this electrolytic sampling, (a) by lowering the copper concentration in the electrolytic solution before heat concentration, it is possible to avoid clogging of the piping, (b) reduce the heating energy in the heat concentration step, and (C) There is an advantage that heating for electrowinning is not required, and that (d) the nickel concentration in the subsequent step can be kept high because there is no decrease in nickel concentration.
[0015]
Next, the copper in the copper electrolyte is recovered as crude crystals of copper sulfate by heat concentration, cooling and filtration. Here, the heating is performed at a temperature of 80 ° C. or higher and a boiling point or lower to evaporate a part of the electrolytic solution and concentrate the concentrated copper sulfate to a concentration that crystallizes in the next cooling step due to a difference in solubility. . Thereafter, the electrolyte is cooled. The resulting crude crystalline copper sulfate can be repeated in the original step of copper electrolysis. After these series of treatments, the copper ion concentration in the copper electrolyte is usually 20 to 30 g / L. Due to this heat concentration, the copper concentration is almost equal to that of the first electrolytic solution, and the amount of the electrolytic solution is drastically reduced to about half.
[0016]
Further, copper is recovered by the second electrowinning, and at the same time, the copper concentration in the electrolytic solution is lowered as a pretreatment for removing impurities. In the latter electrowinning for the purpose of impurities, the removal of arsenic, antimony and bismuth as impurities is not intended, and the generation of hydrogen sulfide and sulfide is reduced in the next step, for example, 5 to 10 g / L. The purpose is to lower the copper concentration. The electrolytic copper obtained by the second electrowinning is inferior in quality to that of the first electrowinning and is not suitable for external sales.
[0017]
The electrolyzed solution of the second electrowinning described above contains 6 to 12 g / L of As, 0.5 to 1 g / L of Sb, 0.3 to 0.8 g / L of Bi, and 25 to 40 g of Ni. / L. These impurities such as arsenic, antimony and bismuth are removed as sludge by a sulfurizing treatment using hydrogen sulfide gas, sodium hydrogen sulfide or the like. After sulfuration, filtration is performed to separate and collect sulfide.
[0018]
As an embodiment of the present invention, as shown in FIG. 6, post-treatment liquid circulation, separation and recovery of nickel sulfide by cooling, and a hydrogen sulfide production step are added to the above-described basic steps (marked with * in the figure). Is preferred.
That is, regarding the circulation of the solution after the treatment, (1) a part of the solution after the first electrowinning is repeated in the copper electrolysis step; and (2) a part of the filtrate after the sulfurization is repeated in the copper electrolysis step; {Circle over (3)} A part of the liquid after freezing in the nickel sulfide recovery step is repeated in the copper electrolysis step.
[0019]
Further, nickel is recovered from a part of the filtrate after sulfidation. After the sulfidation, the liquid is cooled to crystallize the crystals, subjected to centrifugal separation, and then dried to collect crude Ni.
[0020]
Further, hydrogen sulfide for sulfurization can be produced using an electrolytic solution. That is, sulfuric acid, water and an electrolytic solution are mixed to adjust the SO 4 concentration to about 300 to 600 g / L. Next, sodium hydrogen sulfide is added to the diluted sulfuric acid solution to generate hydrogen sulfide. Thereafter, an electrolytic solution is added to the solution to increase the sulfuric acid concentration again and react with copper in the solution to remove hydrogen sulfide. The treatment liquid is stored in a storage tank, and after neutralization, drainage treatment is performed.
[0021]
[Action]
In the present invention, since copper is recovered by sequentially performing copper removal electrolysis (electrolysis sampling) and heating / concentration / cooling, clogging of the piping can be avoided. In addition, since the copper concentration is adjusted by the above method, the copper concentration before removing the impurities is more stable than the method of adjusting the copper concentration by electrolytic extraction illustrated in the flow chart of FIG. 1 or FIG. In addition, the electrowinning of the present invention is performed for the purpose of copper removal, and the removal of impurities is performed by sulfuration, so that no arsine gas is generated.
Hereinafter, the present invention will be described in more detail with reference to examples.
[0022]
【Example】
Example 1
Electrolysis of 100 m 3 of a copper electrolyte having a Cu concentration of 50 g / L, an As concentration of 5 g / L, a Bi concentration of 0.3 g / L, and a Sb concentration of 0.5 g / L under the conditions of a current density of 250 A / dm 2. The sample was collected to obtain electrolytic copper. This copper was of normal electrolytic copper base quality. The grade of the copper was As <5 ppm, Sb <4 ppm, Bi <2 ppm, and satisfied the JIS standard. The concentration of Cu in the post-solution was reduced to 25 g / L by the above-mentioned electrowinning, but the As concentration was 5 g / L, the Bi concentration was 0.3 g / L, and the Sb concentration was 0.5 g / L, and did not change.
After the electrowinning, the liquid was heated to just below the boiling point and concentrated until the liquid volume became 50 m 3 . The concentrate had a Cu concentration of 50 g / L and an As concentration of 10 g / L. The concentrate was cooled to 30 ° C. and then filtered to obtain 5t of crude crystals. The concentration of Cu in the filtrate was 25 g / L, the concentration of As was 10 g / L, the concentration of Bi was 0.6 g / L, and the concentration of Sb was 1.0 g / L. The filtrate was subjected to electrowinning under the same conditions as the first electrowinning to reduce the Cu concentration in the electrolyte to 8 g / L. The As concentration was 10 g / L, the Bi concentration was 0.6 g / L, and the Sb concentration was 1.0 g / L. Hydrogen sulfide was blown into the solution after the electrowinning, followed by filtration to separate a sulfide precipitate. The sulfides were Cu 0.40 t, As 0.45 t, Bi 0.03 t, and Sb 0.05 t in terms of metal. After removing the impurities, the Cu concentration in the post-solution was 0 g / L, the As concentration was 1 g / L, the Bi concentration was 0 g / L, and the Sb concentration was 0 g / L.
[0023]
Comparative Example 1
100 m 3 of a copper electrolyte having a Cu concentration of 50 g / L, an As concentration of 5 g / L, a Bi concentration of 0.3 g / L, and a Sb concentration of 0.5 g / L was heated to just below the boiling point to reduce the liquid volume to 50 m 3 . The solution was concentrated until complete. The concentrated solution had a Cu concentration of 100 g / L, an As concentration of 10 g / L, a Bi concentration of 0.6 g / L, and an Sb concentration of 1.0 g / L. The concentrate was cooled to 30 ° C. and then filtered to obtain 18t of crude crystals. That is, the amount of the coarse crystals is as large as 3.6 times that of the first embodiment. The concentration of Cu in the filtrate was 10 g / L, the concentration of As was 10 g / L, the concentration of Bi was 0.5 g / L, and the concentration of Sb was 0.8 g / L. The filtrate was subjected to electrowinning under the same conditions as for the first electrowinning, followed by filtration to separate sludge. The sulfides were Cu 0.45 t, As 0.4 t, Bi 0.025 t, and Sb 0.04 t in terms of metal. After removing impurities as sludge, the Cu concentration in the post-solution was 1 g / L, the As concentration was 2 g / L, the Bi concentration was 0 g / L, and the Sb concentration was 0 g / L. Therefore, the impurity removal efficiency was inferior to Example 1.
[0024]
【The invention's effect】
According to the present invention,
(1) Electrolytic sampling before heating and concentration to remove copper from the liquid so that there is no blockage of piping due to copper sulfate.
(2) Since copper is previously removed from the liquid, the amount of copper sulfate generated is small, and the amount of energy for re-dissolving copper sulfate is small and energy saving is achieved.
(3) Since copper is removed by electrolysis, cooling for obtaining copper sulfate and subsequent temperature rise of the liquid are not required, and energy is saved.
(4) Since impurities such as Ni behave differently from copper because copper is removed by an electrolytic method, impurities can be efficiently removed.
(5) Since the electrowinning is adopted also in the post-process, the cost due to sulfidation is lower than removing copper by the sulfidation treatment.
In all aspects, such as the recovery efficiency, heating energy consumption, and the recovery of valuable metals such as copper, excellent results can be obtained as compared with the conventional method.
[Brief description of the drawings]
FIG. 1 is a flowchart of an electrowinning method according to a conventional technique.
FIG. 2 is a flowchart of a method disclosed in Japanese Patent No. 2960876.
FIG. 3 is a flowchart of a method disclosed in Japanese Patent No. 3151182.
FIG. 4 is a flowchart of a conventional electrowinning method prior to a heat concentration step.
FIG. 5 is a flowchart showing the basic steps of the method of the present invention.
FIG. 6 is a flowchart illustrating processing steps according to the embodiment of the present invention.
