JP2004527652A - Spouted bed apparatus for contacting objects with fluid - Google Patents

Abstract

A spouted bed electrochemical reactor 100 for treating a plurality of objects 114 with a fluid is described. This apparatus includes a tank 119 for bringing a plurality of objects 114 into contact with each other. The upward flow of the fluid such that the flow of fluid causes the object to flow upward from the moving layer 124 of the object to the release position, from which the object falls onto the distribution shield 123 and moves downward to the supply position. The directional flow and a portion of the object are confined within the conduit 116. Vessel 119 can be used to treat conductive objects, the fluid is an electrolyte, the electrodes are placed in contact with the moving bed, and the counter electrode 105 is spaced from the moving bed. Placed. This tank can be stationary or portable.

Description

【００４７】
サンプリングした１０個のクリップをＸ線回折によってニッケルおよび金の沈着厚さについて検出した。測定の結果、ニッケルの厚さ平均１２４．９マイクロインチ、標準偏差１８．０マイクロインチであった。測定の結果、金の厚さ平均３２．７マイクロインチ、標準偏差２．１マイクロインチであった。クリップのインタロックは観察されなかった。
【００４８】
実施例２
直径３ｍｍの平らなセンサディスクを、ドラフトパイプおよび粒子分配シールドを備えた直径７．５インチの噴流層チャンバをもつ携帯用メッキ装置を使用して電気メッキした。比較の手段として従来のバレルメッキ装置でもディスクを電気メッキした。下記のメッキ順序を両方の試験に用いた。

【００４９】
バレル内で電気メッキしたディスクは、バレル内の適切な陰極接触を維持するために、追加のメッキ媒体（金属ショット）を必要とした。媒体とメッキ済みの部品の体積比は、約３対１であった。部品およびメッキ媒体は、バレル内で、６Ｖ、１５Ａで６．３６時間、金電解液を使用してメッキされ、メッキ厚さは標準偏差１２．０マイクロインチで平均２２２．８マイクロインチに達した。
【００５０】
噴流層メッキ装置では、ディスクは、６Ｖ、５Ａで３．７時間メッキされ、メッキ厚さは標準偏差７．４マイクロインチで平均２２０．１マイクロインチに達した。噴流層装置は、バレルよりも４２％速く金属を付着させたばかりでなく、媒体を必要としないので、すべての金の付着が、媒体ではなく部品になされた。したがって、バレルで部品をメッキすると、噴流層装置でメッキするよりも、約５倍多くの金が必要とされた。
【００５１】
（電気採取の実施例）
本発明はまた、処理溶液、廃水、または採鉱の浸出水から価値ある金属を回収するための電気採取に、また汚染防止や廃水処理の手法として適している。化学薬品沈殿およびイオン交換など合金受軸（ｍｅｔａｌ−ｂｅａｒｉｎｇ）水の廃棄流の処理に対して現在用いられている技術では、金属を経済的に再生できる形にできない。毒物廃棄を減らし、利用可能な材料を再生する必要により、廃棄流内に溶けた金属の濃度を低減し、回収した金属の再生を可能にする技術の開発が必要となっている。
【００５２】
従来の電気採取システムの性能、コスト、および維持要件では、ある限られた適用分野に対してしか、経済的魅力がない。本発明は、この技術において著しい改良をした。設備コストを下げ、維持要件を減らし、性能を上げ、それによってより広範囲な適用分野で電気採取が可能になるからである。
【００５３】
電気採取の実際上の目的は、電気メッキとは、幾分異なる。電気メッキでは、付着の質および均一性が第一に重要であり、電流効率は、第二に重要である。電気採取では、電流効率および電流密度を最大にすることが第一の目的である。
【００５４】
本発明は、噴流層陰極として導電性媒体を用いて、電気採取に使用することができる。この媒体は、金属ショット、カットワイアショット、金属で被覆したガラス球、または、黒鉛または炭素の球または細粒（ｇｒａｎｕｌｅ）で構成することができる。球状媒体を使用すると、非常に浅いチャンバの底および分配シールドの角度（図５の角度ＡおよびＢ）を使用でき、しかも優れた層の動きを維持できるので、特に有利である。金属ショットおよび金属で被覆したガラス球を層の媒体として使用する場合、金属は、価値のある、容易に再生される形で回収される。
【００５５】
従来の電気採取では、平らな電極（陰極および陽極）が処理されるべき溶液に浸される。電極間に電位を加え、直流電流を溶液に通す。陰極では、電荷を与えられた金属イオンがその表面に拡散し、そこで陰極から電子を受け取り、金属状態に還元される。金属は、自由金属陽イオン（ｃａｔｉｏｎ）、または錯体金属陰イオン（ａｎｉｏｎ）、例えばシアン化物錯体として溶液中に存在することができる。金属イオンを陰極に運ぶ主な機構は、通常のフィックの拡散であり、電気的特性ではないことを留意されたい。
【００５６】
非常に低い電流密度では、陰極での還元レートは、電流密度（電極の単位面積当たりの電流）に比例する。しかし、より高い電流密度では、金属の還元レートが、金属イオンの陰極表面への拡散レートによって限定される。そのため、効果的に適用できる電流密度が実際上、限定される。限界電流密度は、定常状態拡散についてのフィックの第１の法則を使用し、拡散層における線形濃度変化についてのネルンストの仮定を用いて計算できる。拡散限定電流密度の方程式は、
ｉ_Ｌ＝−ＤｎＦＣ／ｄ
ただし、ｉ_Ｌ−限定電流密度
Ｄ−金属イオンの拡散係数
ｎ−金属イオンの負荷
Ｆ−ファラデーの数
Ｃ−金属イオンのバルク液体濃度
ｄ−ネルンストの拡散層の厚さ
とする。
【００５７】
ネルンストの金属イオン空乏層の厚さは、電極に隣接する溶液の攪拌の程度に依存する。静止溶液では、ネルンストの層の厚さは、約０．０５ｃｍである。攪拌した溶液では、その厚さは０．０１から０．００５ｃｍの間である。イオン空乏層を通る金属イオンの拡散レートは、層内の濃度勾配に線形比例する。陰極表面の金属濃度は、ゼロと推測できるので、濃度勾配は、ネルンストの層の厚さで分割したバルク金属イオン濃度になる。この２つのファクタで平らな陰極上の限界電流密度が制御される。
【００５８】
一例を挙げると、中程度に攪拌した１０００ｐｐｍのシアン化銀溶液から銀を回収するための限界電流は、約０．６Ａ／ｃｍである。しかし、電流効率は通常、だいたいこの値未満のオーダーの電流密度で落ちる。陰極での金属イオン濃度が減少するにつれて他の電極反応が優位になってくるからである。したがって、高い電流効率を維持するためには、付着レートを規制する、低い電流密度が必要である。
【００５９】
多孔性の、または固体物体の充填層からなる陰極では、状況は全く異なる。その表面積は、形状的に平らな電極に相当する電極の表面積よりもかなり大きく、その電流密度は、陰極の表面の特徴によって変わる。最高電流密度は、表面上の尖点で生じ、最低電流密度は凹みで生じる。さらに、イオンの拡散は、均一な厚さの層を通っては起こらない。増大した表面積により、電流密度が低減し、それによって電流効果が上がる。さらに、電極を構成する物体がもたらす細孔の平均半径が、ネルンストの層の厚さよりも小さく、溶液を細孔内に補充することができる場合、拡散通路は細孔の半径よりも短くなり、さらに高い電流効率および電流密度がもたらされる。
【００６０】
上記の分析は、細孔または充填層の陰極がもたらす電位性能の改善について指摘しているが、大抵の電解液が、電着した金属を化学的に再溶解（ｄｉｓｓｏｌｖｅ ｂａｃｋ）する可能性があることが、充填層および多孔性陰極の設計を面倒にしている。大抵の電解液は、構成成分の金属を再溶解できる。いくつか例を挙げると、シアン化カドミウム溶液、銅エッチング液、硝酸銅、硫酸銅、硫酸ニッケルがある。こうしたタイプの溶液から回収した純金属は、電着金属と再溶解金属では異なる。硫酸および硝酸など酸性溶液の再溶解レートは、ｐＨの関数であり、電気分解中のｐＨ制御によってある程度最小限に抑えることができる。
【００６１】
しかし、多孔性または充填層の陰極の表面積が非常に大きく、かつ液体−固体接触が強いと、かなりの金属の再溶解がもたらされる。陰極から電解液への電流の流れの大部分が陽極に最も近い電極表面に集中し、電流が、物体間の伝導を介して充填層陰極内を伝導することによって、これがさらに厄介になる。したがって、陰極層内の電流密度は、非常に低い。こうしたファクタのため、化学的溶解により、層内部からの金属の正味収支は損失になる。この現象により、上記のＨａｄｚｉｓｍａｊｌｏｖｉｃ他の使用したシステムの場合のように、層の投影表面積と体積の比が小さい場合、充填層陰極を使用する金属付着が著しく妨げられる。
【００６２】
この問題は、投影面積と体積の比が大きい、図５の本発明の実施形態のような薄く浅い層を使用することで改善される。分配シールドの使用により、液体の流量を増すことなく、噴流層の直径を大きくすることが可能になる。さらに、浅い傾斜を伴った円錐形の底を使用して、層の体積を増やすことなく、層の投影表面積を効果的に大きくすることができる。浅い底、ドラフトパイプ、および分配シールドを備えた噴流層を使用する場合、物体は、従来の噴流層内でのように下向きではなく、層の中心に向かって半径方向内向きに移動する。
【００６３】
部品、部片、または他の物体の装入を、１つ、２つまたは３つの物体の厚さをもつ層が、チャンバの底に沿って内向きに移動するように、維持できる。この構成では、液体−固体接触は、従来の噴流層よりも大幅に減少している。上記のＳｃｏｔｔの開示したシステムのような従来の噴流層と同様に液体が層中を通らず、移動層電極の外側を流れるためである。さらに、層が浅い場合、ほとんどの物体が電解液からの電流を受けるが、対照的により深い層では、層の表面にあるほんのわずかの物体しか電解液からの電流を受けない。この２つの効果は、回収された金属を化学的に溶解する可能性のある溶液から金属を電気分解により回収するために、特に有利である。
【００６４】
下記の実施例により、電気採取の適用例における噴流層陰極の使用について説明する。
【００６５】
実施例３
図８は、噴流層反応装置内の噴流層陰極について、電流効率を電流密度の関数として示す。この実験は、１ガロン（約４リットル）当たりＫ（ＡｇＣＮ）_２を３４．１ｇ、ＫＣＮを４２．５ｇ含むシアン化銀溶液を使用して行った。この図に示すように、噴流層陰極は、直径３ｍｍの球体または直径６ｍｍの球体を含み、攪拌しない平面電極、ならびに機械的に攪拌したセル内の平面電極よりも、はるかに高い電流密度でかなり良好な性能を示した。これは、同量の消費電気エネルギーでより大量の金属をより高いレートで取り出せることを意味する。
【００６６】
噴流層陰極の回収レートが大幅に上がったことを強調するため、噴流層内の３ｍｍの球体と攪拌した溶液に露出した平面電極を比較すべく、図８のデータを、陰極材料の単位面積当たりのシアン化銀溶液からの銀の回収レートの、電流密度に対する関係として図９に示す。金属回収レートは、電流効率と電流密度および銀（４．０２４ｇ／Ａ−ｈｒ）の電気化学当量との乗算によって計算される。図に示したように、噴流層は、平面電極の６倍の速さで金属を回収した。
【００６７】
実施例４
銅を、金属被覆した直径２ｍｍのガラス製の球体を５００ｍｌ含む陰極を使用する噴流層反応装置内のｐＨ１．９の硫酸銅溶液から回収した。一実験を、ドラフトパイプおよび粒子デフレクタを備え、分配シールドは備えていない、直径７．５インチのチャンバ内で、７．５アンペアで行った。第２の実験を、ドラフトパイプ、粒子デフレクタ、および分配シールドを備えた直径１２インチのチャンバで行った。図１０は、７．５インチのチャンバでは銅濃度の減少がほとんどなかったが、１２インチのチャンバでは急速に銅が回収されたことを示す。これは、分配シールドのない深い噴流層ではなく、分配シールドを備えた浅い噴流層を使用する場合、再エッチング（ｂａｃｋ ｅｔｃｈｉｎｇ）が減少するからである。
【００６８】
当業者は、本開示を知れば、本発明の構成部品および要素に対し、その機能に大きく影響することなく、様々な修正が可能であることを理解されたい。例えば、上記の特定の槽の構成を噴流層の技術とともに大幅に変えることができ、方形のチャンバを画定する４つの側壁、および槽の入口に向かって下向きに傾斜する単一の方形の底壁または層の入口に向かって下向きに細くなっている向かい合った方形の底壁など、円筒形でない形にすることができる。
【００６９】
同様に、陽極と陰極の位置を逆にして、外側の層を電解的に除去させることによって、金属物体を磨くことができる。さらに、再循環する物体を金属ではなく化学成分で被覆するために、開示された装置を、化学被覆成分と組み合わせたガス状流体とともに使用することができる。これによって、参照により特許の全内容を本明細書に合体する、１９９３年１０月１９日発行のＬｉｔｔｍａｎ他の米国特許第５，２５４，１６８号に開示された装置で一般に代表されるタイプの噴流層被覆装置が供給される。したがって、好ましい実施例について、例をあげて示しかつ詳細に説明したが、頭記の特許請求の範囲に規定された本発明の範囲から逸脱することなく、さらなる修正および実施例が可能である。
【図面の簡単な説明】
【図１】
本発明による携帯用噴流層電気化学反応槽、定置電解液タンク、およびドッキングシステムの断面立面図である。
【図２】
両方の底壁および側壁の開口がメッシュで覆われ、給電面がチャンバの底の上方に取り付けられている、図１の携帯用噴流層電気化学反応槽の修正例の断面立面図である。
【図３】
本発明による内蔵型携帯用ユニットを設けるように変更を加えた噴流層メッキ装置の外部上面図である。
【図４】
図３の線４−４に沿って切断した図３の装置の断面立面図である。
【図５】
浅い円錐形の底、および部品除去口を備えた同心の管状部品トラップを有する、変更を加えた噴流層電気化学反応槽の断面図である。
【図６】
図１、図２および図５に示したタイプの反応装置に複合処理溶液を供給するための流体システムの概略図である。
【図７】
図１に示した本発明の詳細の拡大部分断面図である。
【図８】
攪拌を伴った平面電極および伴わない平面電極（ｐｌａｎｅ ｅｌｅｃｔｒｏｄｅ）の使用と比較して、３ｍｍおよび６ｍｍの球体を使用しての本発明の噴流層電気化学反応装置におけるシアン化物溶液からの銀の電解回収について、電流効率を電流密度の関数として示すグラフである。
【図９】
攪拌した溶液内での平面電極の使用と比較して、シアン化物溶液からの銀の回収レートを本発明の噴流層の電流密度の関数として示すグラフである。
【図１０】
直径７．５インチのより深い噴流層反応装置の使用と比較して、直径１２インチの本発明の浅い噴流層反応装置を使用したｐＨ１．９の硫酸銅からの金属回収について、銅濃度を時間の関数として示すグラフである。[0001]
(Field of the Invention)
The present invention relates to the use of spouted beds of particles, pieces, parts and other small objects for processing in liquid or gaseous fluids. The invention applies in particular to the electroplating of small parts which are difficult to plate with conventional means. The present invention is directed to wastewater treatment, electrowinning, electrochemical synthesis, anodic electrochemical smoothing of the anode, anodizing, electrophoretic polymer coating, physical coating. It is also applied to the field, and also to the general field where spouted beds are applied.
[0002]
(Background of the Invention)
Barrel plating, which rolls objects in a perforated horizontal rotating drum, is a common method of electroplating small parts. Representative techniques are disclosed in U.S. Patent No. 4,822,468 to Kanehiro and U.S. Patent No. 4,769,117 to Shino et al. Many tiny parts cannot be plated efficiently in the barrel due to poor contact with the current feeder or contamination inside the drum. Because of these issues, it is often necessary to add plating media (typically some smooth metal shot) to the barrel to improve cathode contact and component movement. The use of the media also increases the plating time and current, and therefore the plating cost per part, since the media is also plated. In addition, many small parts are fragile and can interlock, so that they can break when rotated with heavy media. Therefore, these parts cannot be successfully plated in the barrel.
[0003]
Greigo U.S. Pat. No. 5,487,824 discloses a specially designed integration for electroplating microparts using a horizontal accelerating rotating drum to maintain the motion of a packed bed of parts during electroplating. A type electroplating system is disclosed.
[0004]
U.S. Pat. No. 3,1124,098 to Backhurst et al. And U.S. Pat. No. 3,703,446 to Haycock et al. Disclose fluidized bed cathodes. While fluidized beds have excellent liquid-solid contact, fluidized bed cathodes suffer from poor electrical contact between the fluidized particles, non-uniform potential and particle separation effects. Further, it is difficult to maintain fluidization of the entire bed if the size and possibly concentration of the particles change due to metal deposition. The potential benefits provided by the fluidized bed approach are unlikely to be realized in a practical electrodeposition system.
[0005]
A typical spouted bed consists of a cylindrical vessel with a conical bottom. This vessel contains a bed of particles forming a spouted bed. Fluid is introduced into the spouted bed at the bottom of the cone as a jet. The fluid jet penetrates a layer of particles contained in the spouted bed tank, entrains the particles and forms a "jet" that moves the particles and fluid upward. The particles are released from the fluid flow in an area above the layer of particles and fall to the top of the downwardly moving annular layer. The "pumping action" provided by the jet causes the particles to circulate through the vessel in a toroidal manner upward in the jet and downward in the annular moving bed. "Draft pipes" can be incorporated into the vessel to aid fluid transport of the particles. The draft pipe consists of a tube that is fixed just above the liquid jet and aligned with the jet aligned therewith. The draft pipe slows the dispersion of the liquid jet and stabilizes the flow of the fluid while allowing the transport of particles at a wider range of fluid velocities.
[0006]
US Pat. No. 4,272,333 to Scott describes a moving layer electrode (MBE) in which conductive particles move vertically down a packed layer between two electrodes and the anode is shielded by a membrane. Disclose use. The actual application of this configuration is less attractive because the membrane must be used to shield the anode, which can damage the membrane in a short time due to mechanical friction of the moving layer of particles. Absent. Furthermore, metal deposition on the film can be a troublesome problem.
[0007]
Hadzismajlovic et al., Published in Hydrometallurgy, Vol. 22, p. 393-401 (1989), and Levin, U.S. Pat. No. 1,789,443, describe a jet with an anode suspended above the surface of the spouted bed. It discloses the use of a layer cathode. Although this configuration can save the hassle of using a membrane to shield the electrodes, there are some operational problems with this configuration. Because many electrolytes have poor conductivity, it is advantageous to have the cathode and anode in close proximity to reduce the voltage drop in the cell. This cannot be achieved with these prior art systems. This is because the jet impinges on the anode. In addition, the geometrically projected surface area of the spouted bed is very limited, compromising electrode performance.
[0008]
Conventional spouted beds also have the problem of particle recirculation, commonly referred to as the "dead center" where a portion of the particle bed stagnates. Dead centers are usually located at the outer edge of the surface of the spouted bed and are due to the spout not depositing particles around the spouted bed. One attempt to solve this problem uses a spouted bed with a very steep bottom cone angle. In all cases, the radius of the spouted bed is strictly limited to the distance that particles in the spout can be transported radially outward by the fluid flow.
[0009]
(Summary of the Invention)
In the present invention, a solid cone is provided in which the distribution shield extends from near the upper edge of the draft pipe, radially downward and outwardly, to the side wall of the vessel above or beyond the outer edge of the surface of the packed bed moving downward. It is used to convey parts, pieces, particles, or other small objects to the outer edge of the spouted bed by preventing the object from falling near the center of the surface of the spouted bed. Objects are released from the jet and settle on the upper surface of the distribution shield. The object then travels along the top surface of the distribution shield and deposits at or beyond the outer edge of the surface of the moving layer.
[0010]
By using a distribution shield, stagnant areas around the spouted bed are completely eliminated. In addition, the distribution shield allows for the formation of very large spouted beds with moderate fluid flow. It is no longer necessary to transport objects dynamically around the spouted bed via the fluid flow. Furthermore, the use of a distribution shield allows the use of a shallow spouted bed with a large cone angle at the bottom and a large diameter. In this type of layer, the movement of the object is not directed downward but radially inward. This type of spouted bed is particularly advantageous for circulating fragile objects, where objects can be crushed and destroyed by the weight of the deep layers, where a large projected area and a shallow layer of depth are desirable, It is particularly useful for spouted beds of conductive or partially conductive components used as performance electrodes.
[0011]
A portable electroplating apparatus incorporating a pump and a bath defining a spouted bed electrolytic reaction chamber is also provided herein. This portable electroplating tank can be manually transported from the processing tank to a processing tank, an automatic plating system, or a hoist. The spouted bed is mounted on a platform with a pump that provides the required electrolyte flow to the spouted bed chamber. It is advantageous to incorporate a liquid bypass circuit and a regulating valve so that the flow of liquid into the spouted bed chamber can be regulated. It is also desirable that the spouted bed tank be easily removable from the portable device, and that the internal components be easily removable from the tank in order to facilitate access to the interior of the tank.
[0012]
In the practice of the present invention, conductive components are electroplated while the liquid circulates in a liquid spouted bed, which is an electrolyte containing metal ions. This component forms a moving packed layer that is maintained under cathodic current by making contact with the power supply surface. Metal passes from the electrolyte onto the component as the current passes through the component while the component circulates through the device. Typically, the components are held in a non-conductive cylindrical vessel with a conical bottom, although other shaped vessels can be used. The bath can be made of a non-conductive plastic material, for example, polypropylene.
[0013]
The electrolyte is introduced as a jet into the bath from the bottom of the cone into the layer of the component to be plated. The liquid jet entrains the part and the part is released from the liquid flow in an area above the moving bed and then moves radially inward downward as a moving packed bed of parts. Thus, the action provided by this liquid jet causes the parts to circulate in the vessel first radially outwardly upward in the jet and then downwardly radially inward in the packed bed. The cathodic connection to the filling layer is made via metal contacts or power supply surfaces mounted inside the cone or inserted from above into the filling layer. If the surface of the component to be plated is completely conductive, the power supply surface can be smaller in size than the particle layer. If the component is partially conductive by having non-conductive elements, electrical contact with the conductive portion of the component is made while the component is moving in the moving layer, as is the case with surface mounted electronic components. It is desirable to use a feeding surface with a much larger surface area to ensure that For example, most of the surface of the bottom conical portion can be lined with a conductive material and used as a power supply surface. The counter electrode (anode) can be mounted above the moving packed bed in the spouted bed chamber or can be located outside the vessel that defines the spouted bed chamber.
[0014]
The present invention also uses a power supply surface with a bump-like surface or other textured surface to facilitate movement of the object during electrodeposition and prevent the object from adhering to the power supply surface. You can also. Bumps about the same size as the part are particularly useful because they prevent rectangular objects from being pushed together or "tiled" as they slide over the feed plane. In addition, a bumpy or other textured surface of the power supply surface reduces the contact area between the object and the power supply surface, thereby reducing the likelihood of the object fusing to the power supply surface during electroplating.
[0015]
It is preferred to incorporate a "draft pipe" in the tank to assist in transporting the parts by liquid. The draft pipe consists of a tube fixed just above the liquid jet and aligned with the jet aligned therewith. This draft pipe slows the dispersion of the liquid jet and allows transport of particles at a wider range of liquid velocities.
[0016]
Furthermore, it is preferable to use a component deflector arranged above the draft pipe. The part deflector is a conical point or a flat disk or a downwardly concave surface located above the jet. The deflector prevents parts in the jet from exiting the chamber and deflects the trajectory of the parts to the side wall of the vessel. The deflector also prevents the jet of entrained parts from impinging on ceiling components in the chamber. It is particularly advantageous to use a component deflector in combination with a draft pipe, since the presence of the draft pipe enhances the flow of the jet.
[0017]
It is also preferred to use a distribution shield. The distribution shield may be conical and extend from near the upper edge of the draft pipe above the outer edge of the inclined bottom wall of the vessel. The shield helps distribute the components to the outer edges of the spouted bed by preventing the components from falling near the center of the reaction chamber. Rather, these components move along the top of the surface of the shield and deposit on the outer edges of the moving layers of the components.
[0018]
In the present invention, the counter electrode, usually the anode, can be located inside the spouted bed tank above the moving packed bed of parts and below the distribution shield or above the particle deflector. Alternatively, an external counter electrode, ie, an electrode external to the spouted bed, may be used. In the case of an external counter electrode, the counter electrode is located in close proximity to a spouted bed bath at least partially immersed in the electrolyte. Openings are provided in the soaked portion of the sidewall and / or in the spout to allow current to pass through the electrolyte from the external counter electrode to the moving packed bed of objects contained in the spouted bed vessel. It is provided on the bottom wall of the layer tank. The opening of the tank in the liquid can be covered with a mesh, cloth or membrane to allow the passage of current and prevent loss of objects from the spouted bed tank. These openings also serve as a means for electrolyte to enter and leave the spouted bed.
[0019]
Usually, in electroplating applications where the spouted bed is transported between a plurality of processing tanks, a soluble external anode made of the same metal as the metal dissolved in the electrolyte is desirable. On the other hand, in an application example of stationary electroplating and in electric sampling, an insoluble internal anode is desirable.
[0020]
The invention can also be practiced using a rectangular tank with an inclined bottom. In this case, the distribution shield is an inclined flat plate or plates, and the draft pipe and the inlet pipe can be tubular or rectangular.
[0021]
The electrolyte is pumped into the reaction chamber via a pump and during operation this arrangement is not a problem. However, if the operation of the device is interrupted, parts from the bed may fall by gravity into the outlet of the pump, actually soiling the pump. Therefore, means are provided for holding the components in the bath. One approach is to incorporate a screen that does not allow parts to pass through at the jet inlet. If a screen is used, it is preferable to filter the fluid upstream of the screen to prevent fouling. An alternative is to utilize a solid "trap" configuration. This may be a simple "U" shaped pipe on the inlet conduit, or it may consist of two concentric pipes that reverse the direction of liquid flow. In both cases, the component is caught by the density difference compared to the electrolyte. An access port can be incorporated into the trap to conveniently remove parts from the spouted bed chamber.
[0022]
The present invention also provides that various cleaning, plating, and rinsing solutions are introduced sequentially from separate holding tanks and circulated in the reaction chamber for an appropriate amount of time, after which the solution sump, control valve, control system, and It is also contemplated that the spouted bed can be used in a stationary configuration for removal from the spouted bed via a manifold pipe system connected to a pump.
[0023]
The invention, its assembly, and operation will be better understood from the following description of a preferred embodiment of the invention, which is illustrated by way of example in the accompanying drawings.
[0024]
(Detailed description of preferred embodiments)
Turning now to a more detailed description of the accompanying drawings, FIG. 1 shows a detailed cross-sectional view of a portable spouted bed reaction chamber or reactor 1 removably disposed within a stationary processing tank 40. The stationary processing tank 40 includes a pump system for supplying a liquid flow of the electrolytic solution to the spouted bed chamber 1, and further functions as a counter electrode for an object outside the chamber 1 and contained in the chamber 1. , A stationary electrode 8. When the object is electroplated, the electrode 8 functions as an anode. The included objects may be the same as the objects 124 in FIG. 5, but these objects have been omitted from FIG. 1 for clarity. The tank 40 may be one of a series of processing tanks in which the portable spouted bed chamber 1 is transported during electroplating, in which processing solutions such as cleaning, plating and rinsing solutions are sequentially circulated in the chamber 1. it can. Alternatively, as shown in FIG. 6, the chamber 1 (or the chamber 1 ′ in FIG. 2) may be fixed to the tank 40, and the processing solutions from the plurality of processing tanks may be sequentially passed through the tank 40.
[0025]
The spouted bed chamber 1 consists of a cylindrical vessel 2 with a conical bottom 11 and a removable top 12. The tank 2 is made of a non-conductive material such as polyethylene. The spouted bed chamber 1 is partially immersed in the electrolyte contained in the tank 40, as indicated by the liquid surface S. The electrolyte is injected into the chamber 1 by an external pump 34 via a ball flow regulating valve 32, a socketed fitting 30, and an inlet pipe 18 fitted with a mesh screen 17. . Pump 34 is connected in a closed loop completed with tank 40, tank outlet fitting 38, liquid strainer 36 and associated piping.
[0026]
The portable spouted bed chamber 1 can be detachably connected to the tank 40 by inserting the inlet pipe 18 into the socket connection 30, as shown in FIG. This inlet pipe is connected to the spouted bed tank 2 through a socket type receptacle (socketed receptacle) 19. Pin 15 is used to hold inlet pipe 18 in socketed receptacle 19. A mesh screen 17 is attached to the edge of the inlet pipe 18 and holds the treated objects in the tank 2 if the flow of liquid in the tank is interrupted. The pin 15 and the inlet pipe 18 and the mesh 17 attached thereto are easily removed, allowing the object to be removed from the bottom of the tank 2 of the spouted bed chamber 1.
[0027]
The liquid enters the tank 2 via the inlet pipe 18 and forms a jet entraining parts or objects supplied from below the draft pipe 4. The liquid jet entraining the object (not shown) travels through the draft pipe 4 and impinges on a deflector 6 having a downwardly concave surface 7. The deflector 6 directs the entangled object radially outward and downward, thereby releasing the object from the liquid jet. The released objects settle on the top surface of the distribution shield 20, move radially outward and down, slide down from the outer edge of the shield 20, above the clamping ring 28 around the upper edge of the bottom 11 of the chamber. It deposits on the surface and moves radially inward downwards in the moving packed bed towards the gap between the upper edge of the inlet pipe 18 and the lower edge of the draft pipe 4.
[0028]
The distribution shield 20 is attached to the top 12 of the chamber via a vertical support 22. The chamber top 12, support 22, distribution shield 20, deflector 6, and draft pipe 4 form a removable assembly that can be easily removed by lifting the chamber top 12 from the spouted bed tank 2, whereby the tank 2 Will be able to access the inside of the A small hole (not shown) can be provided in the top portion of the draft pipe adjacent to the shield to discharge cathode gas from under the shield into the moving liquid stream in the draft pipe.
[0029]
Electrical contact with the moving layer of the object is made by means of a conical power supply surface 16 which is electrically conductive and lines the bottom wall 11 of the conical tank. The power supply surface 16 extends through the bottom wall 11 of the chamber and has a lower part of the plunger 10 and a power supply surface block 25 having a cylindrical socket for receiving the coil spring 9, as shown in more detail in the enlarged view of FIG. It is connected to an external power supply by a cathode connection including a conductive cylindrical plunger 10 in sliding contact. The spring element 9 is placed under the plunger 10 and provides a resilient pressure to maintain a positive electrical contact between the upper surface of the plunger 10 and the lower surface of the feed surface 16. The feed plane block 25 is insulated by the polymer layer or coating 13 and is connected to the cathode connector 23 by an insulated conductor 27. Alternatively, the power supply surface 16 can be connected to an external power supply by contact with a countersunk bolt (not shown). The countersunk bolt penetrates the bottom wall 11 and is screwed into the insulated metal connection block 25, thereby securing the block to the bottom wall.
[0030]
The power supply surface 16 may be a conical metal sheet made of an electrically insulating material and held in place by a clamping ring 28 that prevents treated objects from staining the outer edges of the power supply surface 16. Alternatively, the power supply surface 16 may be provided with a metal layer coating or deposited on the bottom wall 11. The upper (outer) surface of the power supply surface 16 can be bumped and textured or otherwise textured to make it easier for objects to slip on it.
[0031]
FIG. 7 also shows a gap G that can be provided between the bottom surface of the clamping ring 28 and the upper surface of the power supply surface 16. The gap G is preferably about 0.2-1.0 mm and must be smaller than the part to be plated. The gap G dissipates high current density regions that tend to form at the insulated edges of the conductor through which current flows in the electrolyte. Providing the gap reduces the current density in this region and prevents the deposited metal from growing nodularly at the intersection of the lower edge of the ring 28 and the upper surface of the feed surface 16. This is particularly useful when electroplating partially conductive components, such as surface mount components. If no gap is provided, nodular growth of the deposited metal in this area can hinder recirculation of the part.
[0032]
If the plated part tends to fuse to the upper portion of the feed surface, the clamping ring 28 may be extended further down to cover most of the feed surface 16 and to help keep particles moving. Sometimes, it is beneficial. Extending the clamping ring 28 downwards further insulates the upper portion of the power supply surface 16 thereby creating greater downward pressure on components in contact with the lower portion of the power supply surface and maintaining component movement. You. The optimum width of the clamping ring 28 can be determined in several trials and depends on the shape of the component to be plated, the amount of insertion and the plating electrolyte. On the other hand, if the width of the tightening ring 28 is increased, the effective surface area of the power supply surface is reduced, so that when plating a partially conductive component, the voltage is increased. Therefore, it is desirable to use the narrowest possible tightening ring while maintaining sufficient movement of the parts.
[0033]
In the embodiment shown for coating the object with the metal component of the electrolyte, the electrode in contact with the moving layer of the object is connected to the negative terminal of the power supply, functions as a cathode, and is connected to the tank 2. The counter electrode 8 attached to the adjacent stationary tank 40 is connected to the positive terminal of the power supply and functions as an anode. Electric current is conducted from the anode to the moving object through one or more openings 26 in the side walls of the vessel 2, which are porous to hold the object in the vessel during the passage of liquid. Covered with mesh, cloth, or membrane. Therefore, the liquid is discharged from the tank 2 through the mesh opening 26.
[0034]
To implement the embodiment of FIG. 1 and the embodiments of FIGS. 2-4, each of the series of processing tanks can be provided with pump means and docking means. An automatic means for detecting the presence of a reaction tank in each processing tank is provided, which can be used to automatically switch on a pump working on the tank. The detection means may be a physical contact switch (not shown) in the tank, or a magnetic Hall effect detector 72 outside the tank and a magnet 73 attached to the reactor inlet pipe 18 as shown in FIG. The detecting means may include a relay module 74 corresponding to an input from the detector 72 to control an AC power supply 76 for operating the pump 43. In the embodiment of FIGS. 3 and 4, the detector 72 can be located below the lip 71 near the location of the rail 70 and the corresponding magnet 73 mounted on the rail. Instead of such physical or magnetic detection means, optical detectors or other means which can be effectively implemented for this purpose can be used. Accordingly, it is an object of the present invention to ensure that the pump for each tank used with the embodiment of FIGS. 1-4 will automatically operate when a reaction tank is present and will not operate when the tank is empty. It is.
[0035]
FIG. 2 shows a view except that openings 31 are provided in the bottom wall of the tank and these openings are covered with a plastic mesh 33 to hold components (not shown) circulating in the tank 2 ′. 1 shows a spouted bed electrochemical reactor 1 'similar to that shown in FIG. Components that are essentially the same as in FIG. 1 are indicated with the same numbers followed by a prime ('). Cathode contact is made with the moving layer of the component through a conductive rod 35, which has an insulating sleeve 37 and is attached via bolts 39 to the chamber sidewalls and electrical connectors. The conductive rod is covered or covered with an insulating sleeve 37 except for the exposed end in contact with the moving layer of the component. The circulation of parts in the apparatus of FIG. 2 is similar to that of the apparatus of FIG. The mesh-covered opening 31 in the bottom wall of the chamber provides a larger direct current path between the moving layer of the cathode component and the external anode 8 'than the device of FIG. As a result, the voltage during electroplating is significantly reduced.
[0036]
Openings 31 in the bottom wall of the chamber also improve solution draining from the chamber vessel 2 'after cleaning, electroplating and rinsing processes. On the other hand, the device of FIG. 1 has a much larger surface area of the power supply surface than the device of FIG. Thus, the device of FIG. 1 is more suitable for electroplating partially conductive components, such as surface mount electronic components, and the device of FIG. 2 is more suitable for electroplating metal components or components. ing. A small hole 43 can be provided in the top portion of the draft pipe 4 'adjacent to the shield 20' to allow any cathode gas from beneath the shield to be evacuated to the moving liquid stream in the draft pipe.
[0037]
FIG. 3 shows a top view of a portable plating apparatus 41 having a spouted bed reaction tank 50 removably placed in a processing tank 87 containing a processing solution L. The apparatus is designed to be transportable from tank to tank in order to circulate processing solutions, such as cleaning, rinsing, and plating solutions, sequentially in tank 50, so that it is similar to a plating barrel or plating rack. Can be used.
[0038]
FIG. 4 is a cross-sectional view of the device 41 taken along line 4-4 in FIG. The lower part of the apparatus is immersed below the surface S of the processing solution L, and the entire apparatus is supported by side rails 70, 70, which rest on the side wall lip 71 of each processing tank 87 and handle 86, 86 is provided. The device comprises transversal platforms 52 and 54 connecting the side rails 70,70. The submersible head centrifugal pump 88 is attached to the table 54. The inlet of the pump is attached to a liquid strainer 95 via an elbow 94. The pump outlet 96 is connected to a plastic tee 97 via a short segment of plastic pipe.
[0039]
The inlet pipe 98 of the spouted bed 50 is detachably connected to a T-shaped joint 97. The third opening of the T-joint 97 is attached to the bypass ball valve 90 via a plastic pipe, an elbow 99, and a plastic pipe 60. The outlet of the ball valve 90 returns the solution to the processing tank 87 via the plastic pipe and elbow segments shown in FIGS. The amount of solution circulating in the spouted bed tank 50 can be adjusted by using a bypass valve 90. Spouted bed tank 50 is open to the atmosphere and has an opening 56 covered with mesh in the lower chamber side wall. The solution is returned to the processing tank via an opening 56 covered with a mesh.
[0040]
Electrical connection (cathode) by negative direct current to the objects circulating in the tank 50 is made through the side wall of the tank 50 via the electrical connector 48. The counter electrode or anode 44 is mounted in a processing tank 87 near the tank 50 by a conductive connector 43 carried by a conductive support rod 42 connected to the positive terminal of the DC power supply. Electric current passes between the anode 44 and the circulating body contained in the tank 50 via the opening 56 in the tank 50. The internal components of the tank 50 are the same as those shown in the tank 2 of FIG.
[0041]
FIG. 5 shows a spouted bed electrochemical reactor 100 with a tank 119 containing a draft pipe 116, an object deflector 101, and a distribution shield 123. The vessel 119 is cylindrical and has a conical bottom 106 and a conical top 120. Electrolyte is injected into the layer chamber through an object trap consisting of an inner inlet pipe 113 and a concentric outer pipe 112. The outer pipe 112 has a threaded access port 111. The access port 111 is sealed by a cap 109 which is held in place by a screw tightening ring 110. Liquid enters the annulus formed by concentric pipes 112 and 113 via threaded pipe 108. The parts 113, 112, 111, 110 and 109 form an object trap and hold the object 114 of the conductive layer 124 in the chamber when the flow of liquid in the chamber is interrupted. The trap can also be used to remove a coated object from the chamber by removing the cap 109 from the access port 111. The liquid enters the chamber via inlet pipe 113 and forms a jet that entrains the object 114 as the object is sent through gap 115 below draft pipe 116.
[0042]
The liquid jet moves along with the entrained object through the draft pipe and impinges on the deflector 101. The deflector 101 directs the entrained object outward and releases the object from the liquid jet. The released objects fall onto the distribution shield 123, move radially outward, settle on the outer edge of the bottom wall 106, and radiate downward toward the draft pipe 116 and the gap 115 in the moving packed bed 124. Move in the direction. The distribution shield 123 is attached to the chamber via a support 118 resting on the bottom wall 106 of the chamber. The angle A from the horizon to the bottom wall 106 and the angle B from the horizon to the upper surface of the distribution shield 123 are preferably 10 ° to 70 °, more preferably 20 ° to 60 °, and most preferably for round objects. 20 ° to 50 °, and 35 ° to 60 ° for non-round objects.
[0043]
Electrical contact with layer 124 is made by countersunk bolt 107 which penetrates bottom wall 106 of the chamber and contacts moving layer 124 of the object. The counter electrode 105 is disposed below the particle distribution shield 123 and is connected to an external power supply (not shown) via the connector strip 104 and the bolt 103 penetrating the side wall of the layer 119. The bottom surface of the distribution shield 123 is sloped upward and radially outward so that the released gas easily exits the chamber without being trapped under the shield. A deflector ring 117 mounted around the draft pipe 116 prevents objects from colliding with the counter electrode 105. Liquid exits the spouted bed chamber via a threaded pipe fitting 122 having an inlet opening 121 and attached to a conical cover 120. The cover 120 seals the spouted bed tank 119 via the O-shaped ring 102. The conical cover facilitates complete removal of gases released during electrolysis.
[0044]
FIG. 6 shows a schematic diagram of an electroplating fluid system incorporating the type 100 stationary spouted bed electrochemical reactor of FIG. Reactor 100 is connected to stationary power supply and control panel 132 via electrical cables 134 and 135. Solutions for the electroplating process include a cleaning agent, an acid, a plating solution, and a rinsing solution that are sequentially placed in tanks T1 through T6. The object to be plated is charged into the spouted bed tank 100. The solutions from tanks T1 to T6 are then separately delivered to spouted bed reactor 100 via inlet pipe 138, solenoid valve 142, inlet manifold 146, and pump 136. The solution exits spouted bed reactor 100 via outlet tube 144, outlet manifold 147, and solenoid valve 140.
[0045]
During the electroplating process, the inlet and outlet solenoid valves to one of the processing tanks are opened, and the pump operates to circulate the solution to and from the processing tank in a closed loop. Each tank can be cycled in turn to perform the electroplating process. Solenoid valves 140 and 142, power supply, control panel 132, and pump 136 can be manually activated by switch 139 or can be controlled by a computer. At the end of the plating process, the plated object is removed from the bath 100 and the process is repeated. Instead of separate solenoid valves 140 and 142, a remotely operated, multi-port rotary selector valve is used, since only one set of inlet and outlet solenoid valves connected to processing tanks T1 to T6 will be open at all times. You can also.
[0046]
(Example of electroplating)
Example 1
A portable plating apparatus with a 7.5 inch (19 cm) diameter spouted bed chamber with a draft pipe and a particle distribution shield is used to electroplate a 2 mm long, 0.7 mm diameter stamped copper connector clip. did. These clips cannot be easily electroplated in the barrel because they are very light and tend to interlock when rotated with the media. About 20,000 50 ml clips were charged to the spouted bed chamber. This is the minimum charge for a device of this size. The apparatus is transported between the processing tanks by hand and follows the following processing sequence.

[0047]
Ten sampled clips were detected for nickel and gold deposition thickness by X-ray diffraction. As a result of the measurement, the average thickness of the nickel was 124.9 micro inches and the standard deviation was 18.0 micro inches. As a result of the measurement, the average thickness of the gold was 32.7 micro inches and the standard deviation was 2.1 micro inches. No clip interlock was observed.
[0048]
Example 2
A 3 mm diameter flat sensor disk was electroplated using a portable plating apparatus having a 7.5 inch diameter spouted bed chamber with a draft pipe and a particle distribution shield. As a means of comparison, the disk was also electroplated with a conventional barrel plating apparatus. The following plating sequence was used for both tests.

[0049]
Electroplated disks in the barrel required additional plating media (metal shots) to maintain proper cathode contact in the barrel. The volume ratio of media to plated parts was about 3: 1. Parts and plating media were plated in a barrel at 6V, 15A for 6.36 hours using a gold electrolyte and the plating thickness reached an average of 222.8 microinches with a standard deviation of 12.0 microinches. .
[0050]
In the spouted bed plating apparatus, the disks were plated at 6V, 5A for 3.7 hours and the plating thickness averaged 220.1 microinches with a standard deviation of 7.4 microinches. The spouted bed apparatus not only deposited metal 42% faster than the barrel, but also required no media, so all gold deposition was done on the parts, not the media. Thus, plating parts in a barrel required about five times more gold than plating in a spouted bed apparatus.
[0051]
(Example of electric sampling)
The present invention is also suitable for electrowinning to recover valuable metals from treatment solutions, wastewater, or mining leachate, as well as pollution control and wastewater treatment techniques. Techniques currently used for treating waste streams of metal-bearing water, such as chemical precipitation and ion exchange, do not allow metals to be economically regenerated. The need to reduce toxic waste and regenerate available materials requires the development of technologies that reduce the concentration of dissolved metals in the waste stream and enable the recovery of recovered metals.
[0052]
The performance, cost, and maintenance requirements of conventional electric harvesting systems are economically attractive for only a limited set of applications. The present invention has made significant improvements in this technology. It lowers equipment costs, reduces maintenance requirements, and increases performance, thereby allowing for electrical harvesting in a wider range of applications.
[0053]
The practical purpose of electrowinning is somewhat different from electroplating. In electroplating, adhesion quality and uniformity are of primary importance, and current efficiency is of secondary importance. In electrowinning, maximizing current efficiency and current density is a primary objective.
[0054]
The invention can be used for electrowinning, using a conductive medium as the spouted bed cathode. The medium can be comprised of metal shots, cut wire shots, glass spheres coated with metal, or graphite or carbon spheres or granules. The use of spherical media is particularly advantageous because it allows the use of very shallow chamber bottoms and distribution shield angles (angles A and B in FIG. 5) while maintaining excellent layer movement. When metal shots and glass spheres coated with metal are used as the medium of the layer, the metal is recovered in a valuable, easily regenerated form.
[0055]
In conventional electrowinning, flat electrodes (cathode and anode) are immersed in the solution to be treated. A potential is applied between the electrodes and a direct current is passed through the solution. At the cathode, charged metal ions diffuse to the surface where they receive electrons from the cathode and are reduced to the metallic state. The metal can be present in solution as a free metal cation, or a complex metal anion, such as a cyanide complex. It should be noted that the main mechanism for transporting metal ions to the cathode is normal fick diffusion, not electrical properties.
[0056]
At very low current densities, the reduction rate at the cathode is proportional to the current density (current per unit area of the electrode). However, at higher current densities, the rate of metal reduction is limited by the rate of diffusion of metal ions to the cathode surface. This effectively limits the current density that can be applied effectively. The limiting current density can be calculated using Fick's first law for steady-state diffusion and using Nernst's assumption for linear concentration changes in the diffusion layer. The equation for the diffusion limited current density is
i _L = -DnFC / d
Where i _L -Limited current density
D-Diffusion coefficient of metal ion
Load of n-metal ions
F-number of Faraday
C-Bulk liquid concentration of metal ions
d-Nernst diffusion layer thickness
And
[0057]
The thickness of the Nernst metal ion depletion layer depends on the degree of stirring of the solution adjacent to the electrode. In a static solution, the thickness of the Nernst layer is about 0.05 cm. For a stirred solution, its thickness is between 0.01 and 0.005 cm. The diffusion rate of metal ions through the ion depletion layer is linearly proportional to the concentration gradient in the layer. Since the metal concentration on the cathode surface can be estimated to be zero, the concentration gradient is the bulk metal ion concentration divided by the thickness of the Nernst layer. These two factors control the limiting current density on the flat cathode.
[0058]
As an example, the limiting current for recovering silver from a moderately stirred 1000 ppm silver cyanide solution is about 0.6 A / cm. However, current efficiency usually drops at current densities on the order of less than this value. This is because other electrode reactions become dominant as the metal ion concentration at the cathode decreases. Therefore, to maintain high current efficiency, a low current density that regulates the deposition rate is required.
[0059]
With a cathode consisting of a porous or packed layer of solid objects, the situation is quite different. Its surface area is much larger than the surface area of an electrode corresponding to a topographically flat electrode, and its current density depends on the surface characteristics of the cathode. The highest current density occurs at the cusps on the surface and the lowest current density occurs at the depression. In addition, diffusion of ions does not occur through layers of uniform thickness. The increased surface area reduces the current density, thereby increasing the current effect. Furthermore, if the average radius of the pores provided by the objects making up the electrode is smaller than the thickness of the layer of Nernst and the solution can be refilled in the pores, the diffusion path will be shorter than the radius of the pores, Higher current efficiency and current density are provided.
[0060]
Although the above analysis points to the improved potential performance provided by the cathode of the pores or the packed bed, most electrolytes can chemically dissolve the electrodeposited metal. This complicates the design of packed layers and porous cathodes. Most electrolytes can redissolve the constituent metals. Cadmium cyanide solution, copper etchant, copper nitrate, copper sulfate, nickel sulfate to name a few. Pure metal recovered from these types of solutions is different for electrodeposited and remelted metals. The re-dissolution rate of acidic solutions, such as sulfuric and nitric acids, is a function of pH and can be minimized to some extent by pH control during electrolysis.
[0061]
However, very large porous or packed layer cathode surface areas and strong liquid-solid contact can result in considerable metal redissolution. This is further complicated by the fact that the majority of the current flow from the cathode to the electrolyte is concentrated on the electrode surface closest to the anode, and that the current conducts through the packed bed cathode via conduction between objects. Therefore, the current density in the cathode layer is very low. Because of these factors, chemical dissolution results in a loss of the net balance of the metal from inside the layer. This phenomenon, as in the system of Hadzismajlovic et al. Described above, significantly prevents metal deposition using a packed bed cathode when the ratio of projected surface area to volume of the layer is small.
[0062]
This problem is ameliorated by using a thin, shallow layer, such as the embodiment of the invention of FIG. 5, where the ratio of projected area to volume is large. The use of a distribution shield allows the spouted bed diameter to be increased without increasing the liquid flow rate. Further, the conical bottom with a shallow slope can be used to effectively increase the projected surface area of the layer without increasing the volume of the layer. When using a spouted bed with a shallow bottom, a draft pipe, and a distribution shield, the objects move radially inward toward the center of the bed rather than downward as in a conventional spouted bed.
[0063]
The loading of parts, pieces or other objects can be maintained such that a layer having one, two or three objects thickness moves inward along the bottom of the chamber. In this configuration, liquid-solid contact is significantly reduced compared to a conventional spouted bed. This is because the liquid does not pass through the layer but flows outside the moving layer electrode as in the conventional spouted bed as in the system disclosed by Scott above. Furthermore, when the layer is shallow, most objects receive current from the electrolyte, while in contrast, in deeper layers, only a few objects at the surface of the layer receive current from the electrolyte. These two effects are particularly advantageous for recovering metals by electrolysis from solutions that may chemically dissolve the recovered metals.
[0064]
The following example illustrates the use of a spouted bed cathode in an electric harvesting application.
[0065]
Example 3
FIG. 8 shows the current efficiency as a function of current density for a spouted bed cathode in a spouted bed reactor. This experiment is based on K (AgCN) per gallon (about 4 liters). ₂ And 32.5 g of KCN and 42.5 g of KCN. As shown in this figure, the spouted bed cathode comprises a 3 mm diameter sphere or a 6 mm diameter sphere, with much higher current densities than unstirred planar electrodes as well as planar electrodes in mechanically stirred cells. It showed good performance. This means that a greater amount of metal can be extracted at a higher rate with the same amount of electrical energy consumed.
[0066]
To emphasize that the spouted bed cathode recovery rate has increased significantly, the data in FIG. 8 was used to compare the 3 mm spheres in the spouted bed with the planar electrodes exposed to the agitated solution per unit area of cathode material. FIG. 9 shows the relationship between the recovery rate of silver from the silver cyanide solution and the current density. The metal recovery rate is calculated by multiplying the current efficiency with the current density and the electrochemical equivalent of silver (4.024 g / A-hr). As shown, the spouted bed recovered metal six times faster than the planar electrode.
[0067]
Example 4
Copper was recovered from a pH 1.9 copper sulphate solution in a spouted bed reactor using a cathode containing 500 ml of metal-coated 2 mm diameter glass spheres. One experiment was performed at 7.5 amps in a 7.5 inch diameter chamber with a draft pipe and particle deflector, and no distribution shield. A second experiment was performed in a 12 inch diameter chamber with a draft pipe, particle deflector, and distribution shield. FIG. 10 shows that there was little reduction in copper concentration in the 7.5 inch chamber, but copper was recovered rapidly in the 12 inch chamber. This is because back etching is reduced when using a shallow spouted bed with a distribution shield rather than a deep spouted bed without a distribution shield.
[0068]
Those skilled in the art will appreciate, given the present disclosure, that various modifications may be made to the components and elements of the present invention without significantly affecting its function. For example, the particular tank configuration described above can vary significantly with spouted bed technology, with four sidewalls defining a square chamber, and a single square bottom wall that slopes down toward the inlet of the tank. Alternatively, it may be non-cylindrical, such as opposed square bottom walls tapering downward toward the entrance of the layer.
[0069]
Similarly, metal objects can be polished by reversing the position of the anode and cathode and electrolytically removing the outer layers. Further, the disclosed apparatus can be used with a gaseous fluid in combination with a chemical coating component to coat the recirculating body with a chemical component rather than a metal. This provides a jet of the type generally represented by the apparatus disclosed in Littman et al., US Pat. No. 5,254,168, issued Oct. 19, 1993, the entire contents of which are hereby incorporated by reference. A layer coating device is provided. Thus, while the preferred embodiment has been illustrated and described in detail, further modifications and embodiments are possible without departing from the scope of the invention as defined in the appended claims.
[Brief description of the drawings]
FIG.
1 is a cross-sectional elevation view of a portable spouted bed electrochemical reactor, stationary electrolyte tank, and docking system according to the present invention.
FIG. 2
FIG. 2 is a cross-sectional elevation view of a modification of the portable spouted bed electrochemical reactor of FIG. 1 with both bottom and side wall openings covered by mesh and a feed surface mounted above the bottom of the chamber.
FIG. 3
FIG. 4 is an external top view of a spouted bed plating apparatus modified to provide a built-in portable unit according to the present invention.
FIG. 4
FIG. 4 is a cross-sectional elevation view of the device of FIG. 3 taken along line 4-4 of FIG.
FIG. 5
FIG. 3 is a cross-sectional view of a modified spouted bed electrochemical reactor having a concentric tubular component trap with a shallow conical bottom and a component removal port.
FIG. 6
FIG. 6 is a schematic diagram of a fluid system for supplying a complex processing solution to a reactor of the type shown in FIGS. 1, 2 and 5.
FIG. 7
FIG. 2 is an enlarged partial cross-sectional view of the details of the invention shown in FIG. 1.
FIG. 8
Electrolysis of silver from cyanide solution in spouted bed electrochemical reactors of the present invention using 3 mm and 6 mm spheres as compared to the use of planar electrodes with and without agitation 4 is a graph showing current efficiency as a function of current density for recovery.
FIG. 9
FIG. 4 is a graph showing the recovery rate of silver from a cyanide solution as a function of current density in a spouted bed of the present invention, as compared to using a planar electrode in a stirred solution.
FIG. 10
The copper concentration was measured over time for metal recovery from copper sulfate pH 1.9 using a 12 inch diameter shallow spouted bed reactor of the present invention compared to the use of a 7.5 inch diameter deeper spouted bed reactor. 5 is a graph shown as a function of.

Claims (40)

An apparatus for contacting a plurality of objects with a fluid,
At least 1 toward the fluid inlet configured to provide an upward flow of the fluid to cause the object to flow upward from a supply position adjacent the inlet to a release position where the object is released from the flow; A tank having at least one bottom wall inclined downward from two side walls;
A distribution shield having an upper surface mounted within said vessel, inclined downwardly and extending away from near said release position and toward a return position, wherein said released object falls onto an upper surface of said distribution shield. Moving upwardly away from the release position to the return position, wherein the return position deposits the released object on an upper portion of the inclined bottom wall. Disposed above an upper portion of the inclined bottom wall, the inclined bottom wall moving the layer of the deposited object downward from the upper portion along the inclined bottom wall toward the supply position. A distribution shield configured to;
A conduit mounted within the vessel and positioned above the fluid inlet to receive the upward flow of the object, confining the flow of the object from near the supply location at least near the distribution shield. A conduit extending upwardly and configured such that an upward flow of the object passes through an opening in the distribution shield. The apparatus of claim 1, wherein the bottom wall is conical, substantially surrounded by the sidewall, and an upper portion of the distribution shield is connected to an upper portion of the conduit. A device for coating the object with a metal, wherein the fluid is an electrolyte comprising the metal, the object is at least partially conductive, and the device further comprises contacting the moving layer. The apparatus of claim 1, comprising an electrode disposed on the moving bed and a counter electrode spaced from the moving bed and configured to contact the fluid. 4. The apparatus of claim 3, wherein the electrode comprises a sheet or layer of conductive material that covers at least a portion of the bottom wall and is configured to contact a moving layer of the object. 5. The device of claim 4, wherein the conductive material is textured to facilitate moving objects. The bath is partially immersed in the electrolyte, a counter electrode is disposed outside and adjacent to the bathed portion of the bath, and a side wall or bottom wall of the bath is provided between the object and the counter electrode. 4. The device of claim 3, wherein the device has at least one opening immersed in the electrolyte to allow current flow. The apparatus according to claim 6, wherein the opening is covered with a porous mesh, cloth or membrane to hold the object in a bath. 4. The apparatus of claim 3, wherein the counter electrode is located below the distribution shield and comprises means for preventing the object from being held on an upper surface of the counter electrode. 9. The apparatus of claim 8, further comprising a deflecting member mounted below the counter electrode to intercept an object carried upward by the fluid flow and deflect away from the counter electrode. 4. The apparatus of claim 3, wherein the distribution shield and the counter electrode are removably mounted within the vessel and are removable to allow internal access into the vessel. The tank further comprises a fluid outlet means for discharging the fluid from the tank, and the apparatus further comprises means for continuously supplying a plurality of fluids from a corresponding supply source to the inlet of the tank; Means for returning fluid from said outlet means to said corresponding supply source of fluid. 12. The apparatus of claim 11, wherein the continuous supply means comprises means for sequentially and removably attaching the vessel to each of a plurality of vessels, each supply source corresponding to one of the fluids. The continuous supply means includes a pump means for conveying a fluid from a container to which the tank is attached to an inlet of the tank, a control valve means for controlling a flow of fluid from the attached container to an inlet of the tank, and the tank. 13. The apparatus of claim 12, further comprising a supporting frame, wherein the pump means and the valve means are portable units for moving between the plurality of containers. Detecting means for detecting the presence of the tank in each of the containers, and a switch for automatically activating the pump means in response to the detecting means when the tank is present in a corresponding one of the containers. 14. The apparatus of claim 13, further comprising: means. The vessel is portable for providing the fluid to the vessel with a fitting for connecting the inlet to a conduit, and the mounting means connects the vessel with the vessel on each vessel. And each of the vessels is configured to releasably support the vessel, wherein each of the vessels comprises a supply conduit, pump means for drawing fluid from the container into the supply conduit, and a valve for controlling the flow of fluid from the supply conduit to the inlet of the vessel. 13. The apparatus of claim 12, comprising means. Detecting means for detecting the presence of the tank in each of the containers, and a switch for automatically activating the pump means in response to the detecting means when the tank is present in a corresponding one of the containers. 16. The apparatus of claim 15, further comprising: means. A supply conduit connected to the inlet of the vessel, a bypass conduit connected to the supply conduit for recirculating at least a portion of the fluid in the supply conduit to a corresponding source, and arriving at the inlet of the vessel. 12. The apparatus of claim 11, further comprising a control valve for controlling a flow of fluid in the bypass conduit to regulate a flow rate of the fluid. The fluid is a liquid, the reservoir is open to the atmosphere, at least a portion of the reservoir is submerged in the fluid, and the outlet means comprises at least one opening in the submerged portion of the reservoir. An apparatus according to claim 1. A plurality of containers each for containing a corresponding processing solution used for processing the object, a pump means for circulating the processing solution, an inlet manifold for connecting the output of the pump means to each of the containers, An outlet manifold for returning the solution to be returned from the outlet of the vessel to the corresponding container, remotely operable valve means for simultaneously connecting the inlet manifold and the outlet manifold to one of the containers respectively, and the valve means therefrom. The apparatus of claim 1, further comprising control means for operating from a remote location. A mesh screen positioned against the inlet of the tank to prevent the object from being discharged through the inlet of the tank when there is no flow of the fluid; and a mesh screen upstream of the mesh screen. The apparatus of claim 1, further comprising a filter for filtering the fluid. 2. The apparatus according to claim 1, further comprising a particle trap providing a curved flow path upstream of the tank inlet to prevent the object from being discharged through the tank inlet in the absence of the fluid flow. An apparatus according to claim 1. The apparatus of claim 1, further comprising a deflecting member mounted above the distribution shield and positioned near the release position so as to intercept the upwardly flowing object and divert away from the fluid flow. . 23. The apparatus of claim 22, wherein the deflecting member has a concave surface for intercepting and deflecting the object. The apparatus of claim 1, wherein the bottom wall and the distribution shield are each inclined at an angle ranging from about 20 ° to about 50 ° from a horizontal. The fluid in the vessel is a mixture of a liquid and a gas, and the distribution shield is upwardly away from the middle portion of the conduit and on the side wall to prevent gas from accumulating under the distribution shield. The device of claim 1 having a lower surface that slopes toward it. The fluid in the vessel is a mixture of liquid and gas and providing a flow path for the gas from below to above the distribution shield to prevent gas from accumulating under the distribution shield 2. The device according to claim 1, further comprising degassing means. An apparatus immersed in an electrolyte fluid and electrolyzing a plurality of objects with the electrolyte fluid, wherein the objects are at least partially conductive.
At least one sloped downwardly from at least one side wall toward a fluid inlet configured to provide an upward flow of the fluid to cause the object to flow upward from a supply position adjacent the inlet to a release position. A tank having two bottom walls, wherein the object is released from the flow in a release position, the released objects are deposited on an upper portion of the bottom wall from a release position, and the bottom wall is a layer of the object. A tank configured to move downward along the bottom wall from the upper portion thereof toward the supply position,
An electrode arranged to contact the moving layer and a counter electrode arranged to contact the fluid,
Pump means for carrying the fluid from a container to the inlet of the vessel;
Control valve means for controlling the flow of fluid from the vessel to the inlet of the vessel;
An apparatus for providing a portable unit wherein said pump means and said valve means move between a plurality of containers, comprising a frame engaged with said container and supporting said tank on said container. A dispensing shield having an upper surface mounted within the vessel and having a downwardly sloping and extending away from near the release position and toward a return position above an upper portion of the sloping bottom wall; Object falls onto the upper surface of the distribution shield and moves downwardly thereabove to the return position, from which the object is deposited on an upper portion of the inclined bottom wall and the inclined 28. The apparatus of claim 27, further comprising a distribution shield moving downwardly along the configured bottom wall toward the supply location. Mounted in the vessel and positioned above the fluid inlet to receive the flow of the object, and extending upwardly to confine the flow of the object from near the supply location at least near the distribution shield; 29. The apparatus of claim 28, further comprising a conduit configured to cause an upward flow of an object to pass through an opening in the distribution shield. 29. The apparatus of claim 28, wherein the distribution shield and the counter electrode are removably mounted within the vessel and are removable to allow internal access to the vessel. 29. The apparatus of claim 28, further comprising a deflector mounted above the distribution shield and positioned near the release position to intercept the upwardly flowing object and divert away from the fluid flow. The bath is partially immersed in the electrolyte, a counter electrode is disposed outside and adjacent to the immersed portion of the bath, and a side wall or bottom wall of the bath is configured to allow current to flow between the object and the counter electrode. 29. The device of claim 28, having at least one opening immersed in an electrolyte to allow flow between the openings. 33. The device of claim 32, wherein the opening is covered with a porous mesh, cloth or membrane to hold the object in a bath. 29. The apparatus of claim 28, wherein the counter electrode is located below the distribution shield and comprises means for preventing the object from being held on an upper surface of the counter electrode. 35. The apparatus of claim 34, further comprising a deflecting member mounted below the counter electrode to intercept an object carried upward by the fluid flow and deflect away from the counter electrode. 28. The apparatus of claim 27, wherein the electrode comprises a sheet or layer of conductive material that covers a substantial portion of the bottom wall and is configured to contact a moving layer of the object. 37. The device of claim 36, wherein the conductive material is textured to facilitate movement of the object. And further comprising an insulating element made of a non-conductive material and positioned to overlap an upper portion of the sheet or layer, wherein the insulating element reduces a current density near a lower edge of the insulating element. 37. Apparatus according to claim 4 or claim 36, wherein a gap is provided between the upper part of the sheet or layer. An apparatus for contacting a fluid with a plurality of objects,
At least one of a fluid inlet configured to provide an upward flow of the fluid to cause the object to flow upward from a supply position adjacent the inlet to a release position where the object is released from the flow; A tank having at least one bottom wall inclined downward from the side wall;
A distribution shield having an upper surface mounted within said vessel, inclined downwardly and extending away from near said release position and toward a return position, wherein said released object falls onto an upper surface of said distribution shield. Moving upwardly away from the release position to the return position, wherein the return position deposits the released object on an upper portion of the inclined bottom wall. Disposed above an upper portion of the inclined bottom wall, the inclined bottom wall moving the layer of the deposited object downward from the upper portion along the inclined bottom wall toward the supply position. A distribution shield configured to;
An electrode disposed to contact the moving layer, and a counter electrode configured to contact the fluid, wherein the fluid is an electrolyte containing a metal for coating the object, Is at least partially conductive. An apparatus for contacting a fluid with a plurality of objects,
At least one sloped downwardly from at least one side wall toward a fluid inlet configured to provide an upward flow of the fluid to cause the object to flow upward from a supply position adjacent the inlet to a release position. A tank having two bottom walls,
A deflecting member disposed near the release position to catch the upwardly flowing object from the flow of the fluid on the way and release it,
A distribution shield having an upper surface mounted within said vessel, inclined downwardly and extending away from near said release position and toward a return position, wherein said released object falls onto an upper surface of said distribution shield. Moving downwardly away from the release position toward the return position, the return position depositing the released object on an upper portion of the inclined bottom wall. The inclined bottom wall is disposed above an upper portion of the inclined bottom wall, and the inclined bottom wall moves the layer of the deposited object downward from the upper portion along the inclined bottom wall toward the supply position. A distribution shield configured to move.

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