JP3910143B2 - Spouted bed apparatus for contacting an object with a fluid - Google Patents

Description

【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 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 present invention is particularly applicable to electroplating of small parts that are difficult to plate by conventional means. The present invention relates to wastewater treatment, electrowinning, electrochemical synthesis, anodic electrochemical smoothing, anodizing, electrophoretic polymer coating, physical coating. It is also applied to the field, and is also used in general fields where the spouted bed is applied.
[0002]
(Background of the Invention)
Barrel plating, which rolls objects in a perforated horizontal rotating drum, is a common method for electroplating small parts. Exemplary techniques are disclosed in US Pat. No. 4,822,468 to Kanehiro and US Pat. No. 4,769,117 to Shino et al. Many micro components cannot be efficiently plated in the barrel due to poor contact with the current feeder or dirt inside the drum. Because of these problems, it is often necessary to add plating media (usually some kind of smooth metal shot) to the barrel to improve cathode contact and component movement. By using the medium, this medium is also plated, so that the time and current required for plating is significantly increased, thus increasing the plating cost per part. In addition, many small parts are fragile and can be interlocked so that they can break when rotated with heavy media. Therefore, these parts cannot be successfully plated in the barrel.
[0003]
Greigo US Pat. No. 5,487,824 is a specially designed integration for electroplating microparts using a horizontal acceleration rotating drum to maintain the motion of the part fill layer during electroplating. A mold 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 fluidized particles, uneven potential and particle separation effects. Furthermore, due to metal deposition, it is difficult to maintain fluidization of the entire bed when the particle size, and possibly the concentration, changes. The potential benefits of fluidized bed techniques are unlikely to be realized in an actual electro-deposition system.
[0005]
A typical spouted bed consists of a cylindrical tank with a conical bottom. This tank contains a layer of particles forming a spouted bed. The fluid is introduced as a jet into the spouted bed at the bottom of the cone. The fluid jet forms a “jet” that penetrates the layer of particles contained in the spouted bed and entrains the particles and moves the particles and fluid upward. The particles are released from the fluid flow in a region above the particle layer and fall to the top of the annular layer moving downward. The “pumping action” produced by the jet causes the particles to circulate through the tank in a toroidal fashion, upward in the jet and downward in the annular moving bed. A “draft pipe” can be incorporated into the vessel to assist in fluid transport of the particles. This draft pipe consists of a tube fixed in accordance with the position of the jet just aligned with the liquid jet. This draft pipe allows the transport of particles over a wider range of fluid velocities while slowing the dispersion of the liquid jet and stabilizing the fluid flow.
[0006]
Scott U.S. Pat. No. 4,272,333 describes a moving bed electrode (MBE) in which conductive particles move vertically down in the packing layer between two electrodes and the anode is shielded by a membrane. Disclose use. Since it is necessary to use a membrane to shield the anode, the mechanical friction of the moving layer of particles can damage the membrane in a short period of time, which makes it less attractive for practical application of this configuration example. Absent. Furthermore, metal deposition on the film can be a troublesome problem.
[0007]
Hadzismajlovic et al., Published by Hydrometallurgy, Vol. 22, p393-401 (1989), and Levin, US Pat. No. 1,789,443, includes a jet with an anode suspended above the surface of the spouted bed. The use of a layered cathode is disclosed. While this configuration can save the hassle of using a membrane to shield the electrodes, this configuration has several operational problems. Many electrolytes have poor electrical conductivity, so it is advantageous to place the cathode and anode close together to reduce the voltage drop across the cell. This cannot be achieved with these prior art systems. This is because the jet collides with the anode. In addition, the geometrically projected surface area of the spouted bed is very limited, impairing electrode performance.
[0008]
Conventional spouted beds also have a problem of particle recirculation, commonly referred to as “dead center” where a portion of the particle bed is stagnant. The dead point is usually present at the outer edge of the surface of the spouted bed and is caused by the jet not depositing particles around the spouted bed. As an attempt to solve this problem, a spouted bed with a very steep bottom cone angle is used. In all cases, the radius of the spouted bed is strictly limited to the distance that particles in the jet can be transported radially outward by the fluid flow.
[0009]
(Summary of Invention)
In the present invention, the distribution shield extends from near the upper edge of the draft pipe, radially outwardly downward, above the outer edge of the surface of the packed bed moving downward, toward the side wall of the tank, or beyond. It is used to transport 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. The object is released from the jet and deposited on the upper surface of the distribution shield. The object then moves 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, the stagnant area around the spouted bed is completely removed. Furthermore, the distribution shield makes it possible to form a spouted bed with a very large diameter with a moderate fluid flow. This is because it is no longer necessary to dynamically transport the object around the spouted bed via the fluid flow. Furthermore, if a distribution shield is used, it is possible to use a spouted bed having a large bottom cone angle and a large diameter and a shallow diameter. In this type of layer, the movement of the object is not directed downward, but is directed radially inward. This type of spouted bed is particularly advantageous for circulating fragile objects where objects can be crushed and broken by the weight of the deep layer, with a large projected area and a shallow depth layer desirable. It is particularly useful for spouted layers of conductive or partially conductive parts used as performance electrodes.
[0011]
A portable electroplating apparatus incorporating a pump and bath defining a spouted bed electrolysis reaction chamber is also provided by the present invention. This portable electroplating bath can be manually transported from the processing tank to a processing tank, an automatic plating system, or a hoist. The spouted bed tank is mounted on a platform with a pump that provides the necessary 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 to the spouted bed chamber can be regulated. In addition, it is desirable that the spouted bed tank can be easily detached from the portable device, and that the internal components can be easily detached from the tank for easy access to the inside of the tank.
[0012]
In the practice of the present invention, the conductive components are electroplated while circulating in a liquid spouted layer, where the liquid is an electrolyte containing metal ions. This component forms a moving packed layer that is maintained under cathodic current by being in contact with the feed surface. As current passes through the component, metal deposits from the electrolyte onto the component while the component circulates in the device. Usually, the parts are held in a non-conductive cylindrical tank with a conical bottom, but other shaped tanks can be used. The vessel can be made of a non-conductive plastic material, such as polypropylene.
[0013]
The electrolyte is introduced into the bath as a jet from the bottom of the cone into the layer of parts 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 as a moving packed bed of the part. Thus, the action brought about by this liquid jet first circulates the parts in the tank, first radially outwardly in the jet and then radially inwardly in the packed bed. The cathode connection with the filling layer is made via a metal contact or a power supply surface mounted inside the conical part or inserted from above into the filling layer. If the surface of the part to be plated is completely conductive, the power supply surface can be sized smaller than the particle layer. If the part is partially conductive by having non-conductive elements, as in the case of surface mount electronic components, electrical contact is made with the conductive part of the part while it is moving in the moving layer. In order to ensure this, it is desirable to use a feed surface with a much larger surface area. For example, most of the surface of the bottom conical portion can be lined with a conductive material and used as a power feeding surface. The counter electrode (anode) can be mounted above the moving packed bed in the spouted bed chamber, or can be placed outside the bath that defines the spouted bed chamber.
[0014]
The present invention also uses a power supply surface with a bumpy surface or other textured surface to facilitate movement of the object during electrodeposition and to prevent the object from sticking to the power supply surface. You can also. Bumps that are approximately the same size as the component are particularly useful because they prevent square objects from being pushed into each other or “tiled” as they slide over the feed surface. Further, the bumped or other textured power supply surface reduces the contact area between the object and the power supply surface, thereby reducing the possibility of the object fusing to the power supply surface during electroplating.
[0015]
It is preferred to incorporate a “draft pipe” in the vessel to assist in transporting the parts by liquid. This draft pipe is composed of a tube fixed in accordance with the position of the jet just above the liquid jet. This draft pipe delays the dispersion of the liquid jet and allows particle transport at a wider range of liquid velocities.
[0016]
Furthermore, it is preferable to use a component deflector arranged above the draft pipe. This component deflector is a conical point located above the jet, or a flat disc, or a concave surface facing downward. This deflector prevents the parts in the jet from exiting the chamber and deflects the part trajectory to the side wall of the vessel. The deflector also prevents the jet of entrained parts from colliding with ceiling components in the chamber. The presence of a draft pipe enhances the jet flow, so it is particularly advantageous to use a component deflector in combination with the draft pipe.
[0017]
It is also preferred to use a distribution shield. This distribution shield is conical and can extend from near the upper edge of the draft pipe above the outer edge of the inclined bottom wall of the vessel. This shield helps distribute the part to the outer edge of the spouted bed by preventing the part from falling near the center of the reaction chamber. Rather, these parts move along the top of the surface of the shield and deposit on the outer edge of the moving layer of the part.
[0018]
In the present invention, the counter electrode, usually the anode, can be placed 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, i.e. an electrode outside the spouted bed, can be used. In the case of an external counter electrode, the counter electrode is disposed proximate to a spouted bed bath that is at least partially immersed in the electrolyte. In order to allow current to pass through the electrolyte from the external counter electrode to the moving packed bed of the object entering the spouted bed tank, the openings are immersed in the side wall and / or the jet It is provided on the bottom wall of the layer tank. The bath opening in the liquid can be covered with a mesh, cloth or membrane to allow current to pass and prevent the loss of objects from the spouted bed bath. These openings also serve as a means for the electrolyte to enter and exit the spouted bed tank.
[0019]
Usually, in an electroplating application 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 applications of stationary electroplating and electrowinning, an insoluble internal anode is desirable.
[0020]
The present invention can also be practiced using a square 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 injected into the reaction chamber via a pump and there is no problem with this arrangement during operation. However, if the operation of the device is interrupted, parts from the layer can fall into the pump outlet due to gravity and actually contaminate the pump. Therefore, a means for holding the component in the tank is provided. One approach is to incorporate a screen at the jet inlet that does not allow the parts to pass. When using a screen, it is preferable to filter the fluid upstream of the screen to prevent contamination. An alternative is to use a solid “trap” configuration. This may be a simple “U” shaped pipe on the inlet conduit or may consist of two concentric pipes that reverse the direction of liquid flow. In either case, the part is captured by the density difference compared to the electrolyte. An access port can be incorporated into the trap to conveniently remove the part from the spouted bed chamber.
[0022]
The present invention also introduces various cleaning, plating, and rinsing solutions sequentially from separate holding tanks and circulates in the reaction chamber for an appropriate amount of time, after which the solution reservoir, control valve, control system, and It is also contemplated that the spouted bed can be used in a stationary configuration that is removed from the spouted bed through a manifold pipe system connected to a pump.
[0023]
The invention, its assembly and operation will be further understood from the following description of preferred embodiments of the invention, given 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 the liquid flow of the electrolytic solution to the spouted bed chamber 1, and further functions as a counter electrode for an object that is outside the chamber 1 and contained in the chamber 1. The stationary electrode 8 is provided. When the object is electroplated, the electrode 8 functions as an anode. The included objects may be the same as the object 124 of FIG. 5, but these objects are omitted from FIG. 1 for the sake of clarity. Tank 40 may be one of a series of processing tanks through which portable spouted bed chamber 1 is carried during electroplating in which processing solutions such as cleaning, plating and rinsing solutions are circulated in chamber 1 in turn. it can. Alternatively, as shown in FIG. 6, the chamber 1 (or the chamber 1 ′ in FIG. 2) can be fixed to the tank 40, and the processing solutions from a plurality of processing tanks can be sequentially passed through the tank 40.
[0025]
The spouted bed chamber 1 consists of a cylindrical tank 2 with a conical bottom 11 and a removable top 12. The tank 2 is made of a non-conductive material such as polyethylene. As shown by the liquid surface S, the spouted bed chamber 1 is partially immersed in the electrolytic solution contained in the tank 40. The electrolyte is injected into the chamber 1 by an external pump 34 through a ball flow regulating valve 32, a socketed fitting 30, and an inlet pipe 18 fitted with a mesh screen 17. . The pump 34 is connected in a closed loop, complete with a tank 40, a tank outlet fitting 38, a 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 coupling 30 as shown in FIG. The inlet pipe is connected to the spouted bed tank 2 via a socketed receptacle 19. Pin 15 is used to hold inlet pipe 18 in socketed receptacle 19. The mesh screen 17 is attached to the edge of the inlet pipe 18 and holds the treated object in the tank 2 when the flow of liquid in the tank is interrupted. The pin 15 and the inlet pipe 18 and the mesh 17 attached thereto can be easily removed, and the object can 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 that entrains parts or objects supplied from below the draft pipe 4. A liquid jet involving an object (not shown) moves through the draft pipe 4 and impinges on a deflector 6 having a downwardly concave surface 7. The deflector 6 directs the entrained object downward in the radial direction, thereby releasing the object from the liquid jet. The released object is deposited on the top surface of the distribution shield 20, moves downward radially outward, slides down from the outer edge of the shield 20, and sits on the upper side of the clamping ring 28 around the upper edge of the chamber bottom 11. It deposits on the surface and moves radially inward downward towards the gap between the upper edge of the inlet pipe 18 and the lower edge of the draft pipe 4 in the moving packed bed.
[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 detachable assembly that can be easily removed by lifting the chamber top 12 from the spouted bed tank 2, thereby the tank 2. Will be able to access the inside. A small hole (not shown) can be provided in the top portion of the draft pipe adjacent to the shield to allow cathode gas from below the shield to be discharged into a moving liquid stream in the draft pipe.
[0029]
Electrical contact with the moving layer of the object is made by a conical feed surface 16 that is electrically conductive and lines the bottom wall 11 of the conical tank. As shown in more detail in the enlarged view of FIG. 7, the power supply surface 16 penetrates the bottom wall 11 of the chamber and includes a power supply surface block 25 having a cylindrical socket for receiving the lower portion of the plunger 10 and the coil spring 9. It is connected to the external power supply by a cathode connection comprising a conductive cylindrical plunger 10 that is in sliding contact. The spring element 9 is placed under the plunger 10 and provides an elastic pressure to maintain positive electrical contact between the upper surface of the plunger 10 and the lower surface of the feeding surface 16. The power supply surface 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 device by contact with a countersunk head bolt (not shown). The countersunk head bolt penetrates the bottom wall 11 and is screwed into the insulating metal connection block 25, thereby fixing the block to the bottom wall.
[0030]
The feed 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 fouling on the outer edge of the feed surface 16. Alternatively, the feed surface 16 can 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 bump-shaped, and uneven or other textures can be added to make it easier for the object to slide 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 feeding surface 16. The gap G is preferably about 0.2-1.0 mm and should 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. By providing the gap, the current density in this region is reduced, and the deposited metal is prevented from growing in a nodule shape at the intersection of the lower edge of the ring 28 and the upper surface of the power supply surface 16. This is particularly beneficial when electroplating partially conductive components, such as surface mount components. Without gaps, the nodular growth of deposited metal in this region can prevent part recirculation.
[0032]
If the plated parts tend to fuse to the upper part of the power supply surface, the clamping ring 28 can be extended further downward to cover most of the power supply surface 16 and help keep the particles moving. Sometimes beneficial. By further insulating the upper portion of the power supply surface 16 by extending the clamping ring 28 downward, a larger downward pressure is generated on the component in contact with the lower portion of the power supply surface, and the movement of the component is maintained. The The optimum width of the clamping ring 28 can be determined in several trial operations and depends on the shape of the part to be plated, the amount of insertion and the plating electrolyte. On the other hand, when the width of the tightening ring 28 is increased, the effective surface area of the power supply surface is reduced, so that the voltage is increased when partially conductive parts are plated. It is therefore desirable to use a clamping ring that is as narrow as possible while maintaining sufficient movement of the parts.
[0033]
In the embodiment shown in the figure 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, The counter electrode 8 attached to the adjacent stationary tank 40 is connected to the positive terminal of the power supply device and functions as an anode. Current is conducted from the anode to the moving object through one or more openings 26 in the side wall of the vessel 2, which are porous to hold the object in the vessel while passing liquid. Covered with mesh, cloth, or membrane. Accordingly, 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, a series of processing tanks can each be provided with pump means and docking means. An automatic means for detecting the presence of a reaction tank in each processing tank can be provided, and this can be used to automatically switch on the pump acting on the tank. The detection means may be a physical contact switch (not shown) in the tank, or a magnet 73 attached to the magnetic Hall effect detector 72 outside the tank and the reaction vessel inlet pipe 18 shown in FIG. This detection means can also include a relay module 74 corresponding to the input from the detector 72 to control the AC power supply 76 for operating the pump 43. In the embodiment of FIGS. 3 and 4, the detector 72 can be placed under the lip 71 near the position of the rail 70 and the corresponding magnet 73 attached to the rail. Instead of such physical or magnetic detection means, optical detectors or other means that can be effectively implemented to serve this purpose can also 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 is automatically activated when the reaction vessel is present and not activated when the tank is empty. It is.
[0035]
FIG. 2 shows that the opening 31 is provided in the bottom wall of the tank, and that these openings are covered with a plastic mesh 33 in order 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 shown with the same number followed by a prime symbol ('). Cathodic contact is made through a moving layer of parts and a conductive rod 35, which has an insulating sleeve 37 and is attached to the chamber sidewall and electrical connector via bolts 39. This conductive rod is covered or covered with an insulating sleeve 37 except for the exposed tip in contact with the moving layer of the part. The circulation of parts in the apparatus of FIG. 2 is similar to that of the apparatus of FIG. The opening 31 covered with a mesh 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 greatly reduced.
[0036]
The opening 31 in the bottom wall of the chamber also improves solution drainage from the chamber 2 'after the cleaning, electroplating and rinsing processes. On the other hand, the apparatus of FIG. 1 has a much larger power supply surface area than the apparatus of FIG. Thus, the apparatus of FIG. 1 is more suitable for electroplating partially conductive parts, such as surface mount electronic components, and the apparatus of FIG. 2 is more suitable for electroplating metal parts or metal 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 below the shield to be exhausted into the moving liquid stream in the draft pipe.
[0037]
FIG. 3 shows a top view of the portable plating apparatus 41 having the spouted bed reaction tank 50 detachably placed in the processing tank 87 containing the processing solution L. This device is designed to be transported from tank to tank in order to circulate the processing solution, such as cleaning solution, rinsing solution, plating solution, etc. in the tank 50 in order, so that it is similar to a plating barrel or plating rack. Can be used.
[0038]
4 is a cross-sectional view of device 41 taken along line 4-4 of 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 the side rails 70, 70. The side rail rests on the side wall lip 71 of each processing tank 87, and handles 86, 86. The apparatus includes transversal platforms 52 and 54 connecting the side rails 70, 70. The submersible head centrifugal pump 88 is attached to the base 54. The inlet of the pump is attached to the liquid strainer 95 via an elbow 94. The pump outlet 96 is connected to a plastic T-joint 97 through a short segment of plastic pipe.
[0039]
The inlet pipe 98 of the spouted bed 50 is detachably coupled to the T-shaped joint 97. The third opening of the T-shaped 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 the solution circulating in the spouted bed tank 50 can be adjusted by using the bypass valve 90. The spouted bed tank 50 is open to the atmosphere and has an opening 56 covered with a mesh in the lower chamber side wall. The solution is returned to the processing tank through openings 56 covered with mesh.
[0040]
An electrical connection (cathode) by a negative direct current to an object circulating in the tank 50 is made through the side wall of the tank 50 via an electrical connector 48. The counter electrode or anode 44 is mounted in the processing tank 87 close to 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. The current passes between the anode 44 and the circulating object contained in the tank 50 through the opening 56 of 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. The 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 held in place by a screwed tightening ring 110. Liquid enters the annulus formed by concentric pipes 112 and 113 via threaded pipe 108. Parts 113, 112, 111, 110, and 109 form an object trap that holds the object 114 of the conductive layer 124 in the chamber when the flow of liquid in the chamber is interrupted. This trap can also be used to remove the coated object from the chamber by removing the cap 109 from the access port 111. The liquid enters the chamber via the inlet pipe 113 and forms a jet that entrains the object 114 when the object is sent through the gap 115 below the draft pipe 116.
[0042]
The liquid jet moves along with the entrained object through the draft pipe and collides with the deflector 101. The deflector 101 directs the entrained object outward and releases the object from the liquid jet. The released object falls onto the distribution shield 123, moves radially outward, deposits on the outer edge of the bottom wall 106, and radiates downward toward the draft pipe 116 and gap 115 in the moving packed bed 124. Move inward direction. The distribution shield 123 is attached to the chamber via a support 118 that rests 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 °, most preferably for a round object. 20 ° to 50 °, and 35 ° to 60 ° for non-round objects.
[0043]
Electrical contact with the layer 124 is made by countersunk bolts 107 that penetrate the bottom wall 106 of the chamber and contact the 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 a bolt 103 passing through the connector strip 104 and the side wall of the layer 119. The bottom surface of the distribution shield 123 is inclined radially outwardly upward so that the released gas is easily trapped under the shield and easily exits the chamber. A deflector ring 117 mounted around the draft pipe 116 prevents the object from colliding with the counter electrode 105. The liquid exits the spouted bed chamber via a threaded pipe fitting 122 having an inlet opening 121 and attached to the conical cover 120. The cover 120 seals the spouted bed tank 119 through the O-shaped ring 102. The conical cover facilitates complete removal of the gas 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. The solution for the electroplating process includes a cleaning agent, an acid, a plating solution, and a rinsing solution that are sequentially placed in tanks T1 to T6. The object to be plated is charged into the spouted bed tank 100. The solutions from tanks T1 to T6 are then delivered separately to the spouted bed reactor reactor 100 via the inlet tube 138, solenoid valve 142, inlet manifold 146, and pump 136. The solution exits spouted bed reactor 100 through outlet tube 144, outlet manifold 147 and solenoid valve 140.
[0045]
During the electroplating process, the inlet and outlet solenoid valves to one processing tank are opened and the pump operates to circulate the solution to and from the processing tank in a closed loop. Each tank can be circulated in turn to perform the electroplating process. Solenoid valves 140 and 142, power supply, control panel 132, and pump 136 can be manually actuated 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 because only one set of inlet and outlet solenoid valves connected to process 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) spouted bed chamber with a draft pipe and particle distribution shield is used to electroplate a 2 mm long, 0.7 mm diameter stamped copper connector clip did. These clips are very light and tend to interlock when rotated with the media and therefore cannot be easily electroplated in the barrel. Approximately 20,000 clips of 50 ml were charged into the spouted bed chamber. This is the minimum charge for a device of this size. The apparatus is manually transported between processing tanks and follows the following processing sequence.
1. Immersion cleaning agent 5 minutes
2. Cathode cleaning agent 5 minutes 6V, 6A
3. Water rinse 3 minutes
4). Hydrochloric acid (50%) activator 5 minutes
5. Water rinse 5 minutes
6). Cyanide immersion 3 minutes
7). Copper cyanide plating 5 minutes 6V, 8A
8). 1 minute scoop and rinse
9. Water rinse 3 minutes
10. Sulfuric acid (5%) 5 minutes
11. Water rinse 3 minutes
12 Nickel sulfamate plating 20 minutes 6V, 8A
13. Water rinse 3 minutes
14 Sulfuric acid (5%) 5 minutes
15. Water rinse 3 minutes
16. Hard gold plating 25 minutes 6V, 6A
17. 3 minutes for scooping and rinsing
18. Water rinse 3 minutes
19. Hot pure water rinse 3 minutes
[0047]
Ten sampled clips were detected for nickel and gold deposition thickness by X-ray diffraction. As a result of measurement, the nickel thickness averaged 124.9 microinches and the standard deviation was 18.0 microinches. As a result of the measurement, the gold thickness averaged 32.7 microinches and the standard deviation was 2.1 microinches. No clip interlocks were observed.
[0048]
Example 2
A 3 mm diameter flat sensor disk was electroplated using a portable plating apparatus with a 7.5 inch diameter spouted bed chamber equipped with a draft pipe and particle distribution shield. As a means for comparison, the disk was electroplated with a conventional barrel plating apparatus. The following plating sequence was used for both tests.

[0049]
The disc electroplated in the barrel required additional plating media (metal shot) to maintain proper cathode contact in the barrel. The volume ratio of media to plated parts was about 3: 1. The parts and plating media were plated in a barrel using gold electrolyte at 6V, 15A for 6.36 hours, and the plating thickness reached an average of 222.8 microinches with a standard deviation of 12.0 microinches. .
[0050]
In the spouted layer plating apparatus, the disc was plated at 6V, 5A for 3.7 hours, and the plating thickness reached an average of 220.1 microinches with a standard deviation of 7.4 microinches. The spouted bed apparatus not only deposited the metal 42% faster than the barrel, but also required no media, so all gold deposition was done on the part, not the media. Therefore, plating parts with a barrel required about 5 times more gold than plating with a spouted bed apparatus.
[0051]
(Example of electricity collection)
The present invention is also suitable for electrical extraction to recover valuable metals from treatment solutions, wastewater, or mining leachate, and as a pollution control and wastewater treatment technique. Techniques currently used for the treatment of waste streams of metal-bearing water, such as chemical precipitation and ion exchange, cannot make the metal economically recyclable. Due to the need to reduce poison disposal and recycle available materials, there is a need to develop technologies that reduce the concentration of dissolved metal in the waste stream and allow the recovered metal to be regenerated.
[0052]
The performance, cost, and maintenance requirements of conventional electricity harvesting systems are economically attractive only for certain limited applications. The present invention has made significant improvements in this technology. This is because equipment costs are reduced, maintenance requirements are reduced and performance is increased, thereby enabling electricity harvesting in a wider range of applications.
[0053]
The practical purpose of electrowinning is somewhat different from electroplating. In electroplating, the quality and uniformity of deposition is first important, and current efficiency is second important. In electrical sampling, the primary objective is to maximize current efficiency and current density.
[0054]
The present invention can be used for electrowinning using a conductive medium as the spouted bed cathode. The medium can be composed 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 very shallow chamber bottom and distribution shield angles (angles A and B in FIG. 5) can be used and excellent layer motion can be maintained. When metal shots and metal-coated glass spheres are used as the layer media, the metal is recovered in a valuable and 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. Note that the main mechanism for carrying 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 metal reduction rate is limited by the diffusion rate of metal ions to the cathode surface. This effectively limits the current density that can be effectively applied. The limiting current density can be calculated using Fick's first law for steady state diffusion and using Nernst assumptions for linear concentration changes in the diffusion layer. The equation for diffusion limited current density is
i _L = -DnFC / d
However, i _L -Limited current density
D-Diffusion coefficient of metal ions
n-metal ion loading
Number of F-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 static solution, the Nernst layer thickness is about 0.05 cm. For stirred solutions, the 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 assumed to be zero, the concentration gradient becomes the bulk metal ion concentration divided by the thickness of the Nernst layer. These two factors control the limiting current density on a 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 more 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]
The situation is quite different for a cathode which consists of a porous or solid object packing layer. Its surface area is considerably larger than the surface area of the electrode, which corresponds to a geometrically 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 dents. Furthermore, ion diffusion does not occur through uniform thickness layers. The increased surface area reduces the current density and thereby increases the current effect. Furthermore, when the average radius of the pores brought by the objects that make up the electrode is smaller than the thickness of the Nernst layer and the solution can be replenished into the pores, the diffusion path becomes shorter than the radius of the pores Higher current efficiency and current density are provided.
[0060]
Although the above analysis points to the improvement in potential performance provided by the pores or packed bed cathodes, most electrolytes may chemically dissolve the electrodeposited metal. This complicates the design of the packed bed and the porous cathode. Most electrolytes can redissolve the constituent metals. Some examples include cadmium cyanide solutions, copper etchants, copper nitrate, copper sulfate, and nickel sulfate. Pure metals recovered from these types of solutions differ between electrodeposited and remelted metals. The redissolution rate of acidic solutions such as sulfuric acid and nitric acid is a function of pH and can be minimized to some extent by pH control during electrolysis.
[0061]
However, the very large surface area of the porous or packed bed cathode and the strong liquid-solid contact result in significant metal remelting. This is further exacerbated 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 the current is conducted in the packed bed cathode through 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 metal from within the layer. This phenomenon significantly hinders metal deposition using a packed bed cathode when the ratio of projected surface area to volume of the layer is small, as in the system used by Hadzismajlovic et al.
[0062]
This problem is remedied by using thin and shallow layers, such as the embodiment of the present invention of FIG. 5, with a large projected area to volume ratio. The use of a distribution shield makes it possible to increase the diameter of the spouted bed without increasing the liquid flow rate. Furthermore, the conical bottom with shallow slope can be used to effectively increase the projected surface area of the layer without increasing the layer volume. When using a spouted bed with a shallow bottom, a draft pipe, and a distribution shield, the object moves radially inward toward the center of the layer, rather than down as in a conventional spouted bed.
[0063]
The loading of parts, pieces, or other objects can be maintained such that a layer with one, two or three object thicknesses moves inward along the bottom of the chamber. In this configuration, liquid-solid contact is greatly reduced over conventional spouted beds. This is because the liquid does not pass through the layer as in the conventional spouted bed as in the system disclosed by Scott, and flows outside the moving bed electrode. In addition, when the layer is shallow, most objects receive current from the electrolyte, whereas in a deeper layer, 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 can chemically dissolve the recovered metals.
[0064]
The following examples illustrate the use of spouted bed cathodes in electrical sampling applications.
[0065]
Example 3
FIG. 8 shows the current efficiency as a function of current density for the spouted bed cathode in the spouted bed reactor. In this experiment, K (AgCN) per gallon (about 4 liters) ₂ Was performed using a silver cyanide solution containing 34.1 g and 42.5 g of KCN. As shown in this figure, the spouted bed cathode contains 3 mm diameter spheres or 6 mm diameter spheres, which are considerably higher at a much higher current density than the unstirred planar electrodes and the planar electrodes in the mechanically stirred cells It showed good performance. This means that a greater amount of metal can be removed at a higher rate with the same amount of consumed electrical energy.
[0066]
To emphasize that the recovery rate of the spouted bed cathode was significantly increased, the data of FIG. 8 per unit area of cathode material was compared to compare the 3 mm sphere in the spouted bed with the planar electrode exposed to the stirred solution. FIG. 9 shows the relationship between the silver recovery rate from the silver cyanide solution and the current density. The metal recovery rate is calculated by multiplying the current efficiency by the current density and the electrochemical equivalent of silver (4.024 g / A-hr). As shown in the figure, the spouted bed recovered metal at 6 times the speed of the planar electrode.
[0067]
Example 4
Copper was recovered from the copper sulfate solution at pH 1.9 in a spouted bed reactor using a cathode containing 500 ml of metal-coated glass spheres with a diameter of 2 mm. One experiment was conducted at 7.5 amps in a 7.5 inch diameter chamber with a draft pipe and particle deflector, but no distribution shield. A second experiment was conducted in a 12 inch diameter chamber equipped with a draft pipe, particle deflector, and distribution shield. FIG. 10 shows that there was little decrease in copper concentration in the 7.5 inch chamber, but copper was rapidly recovered 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 recognize that various modifications can be made to the components and elements of the present invention without significantly affecting its function, given the present disclosure. For example, the particular vessel 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 downward toward the vessel inlet Or it can be non-cylindrical, such as an opposing square bottom wall that tapers down towards the entrance of the bed.
[0069]
Similarly, metal objects can be polished by reversing the positions of the anode and cathode and electrolytically removing the outer layer. Further, the disclosed apparatus can be used with a gaseous fluid in combination with a chemical coating component to coat a recirculating object with a chemical component rather than a metal. This is a type of jet generally represented by the apparatus disclosed in Littman et al., US Pat. No. 5,254,168, issued Oct. 19, 1993, which is incorporated herein by reference in its entirety. A layer coating apparatus is supplied. Accordingly, while the preferred embodiment has been shown and described in detail by way of example, 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 sectional elevation view of a portable spouted bed electrochemical reaction tank, a stationary electrolyte tank, and a docking system according to the present invention.
2 is a cross-sectional elevation of a modification of the portable spouted bed electrochemical reactor of FIG. 1 with both bottom wall and side wall openings covered with a mesh and the feed surface is mounted above the bottom of the chamber. FIG.
FIG. 3 is an external top view of a spouted layer plating apparatus modified to provide a built-in portable unit according to the present invention.
4 is a cross-sectional elevation view of the apparatus of FIG. 3 taken along line 4-4 of FIG.
FIG. 5 is a cross-sectional view of a modified spouted bed electrochemical reactor having a shallow conical bottom and a concentric tubular part trap with a part removal port.
6 is a schematic diagram of a fluid system for supplying a combined treatment solution to a reactor of the type shown in FIGS. 1, 2 and 5. FIG.
7 is an enlarged partial cross-sectional view of the details of the present invention shown in FIG.
FIG. 8 from the cyanide solution in the spouted bed electrochemical reactor of the present invention using 3 mm and 6 mm spheres compared to the use of planar electrodes with and without agitation. 2 is a graph showing current efficiency as a function of current density for electrolytic recovery of silver.
FIG. 9 is a graph showing the rate of silver recovery from a cyanide solution as a function of the current density of the spouted bed of the present invention compared to the use of a planar electrode in a stirred solution.
FIG. 10 shows metal recovery from pH 1.9 copper sulfate using a 12 inch diameter shallow spouted bed reactor of the present invention as compared to the use of a deeper 7.5 inch diameter spouted bed reactor. 3 is a graph showing copper concentration as a function of time.

Claims (40)

An apparatus for contacting a plurality of objects with a fluid,
Downward from the sidewall toward the fluid inlet suitable for providing an upward flow of the fluid to cause the object to flow upwardly from a supply position adjacent to the inlet to a release position where the object is released from flow A tank having an inclined bottom wall;
A deflection member disposed near the release position to capture and release the upwardly flowing object from the fluid flow; and
A distribution shield mounted in the basin and having an upper surface inclined downward and extending away from near the release position toward the return position, wherein the released object falls onto the upper surface of the distribution shield And is moved downwardly from the release position to the return position so that the return position deposits the released object on the upper portion of the inclined bottom wall. Arranged above the upper part of the inclined bottom wall, the inclined bottom wall moving the moving layer of the deposited object downward from the upper part toward the supply position along the inclined bottom wall A distribution shield that is suitable for
A conduit mounted in the vessel and disposed above the fluid inlet to receive the upward flow of the object, confining the flow of the object from near the supply position at least near the distribution shield And a conduit suitable for allowing upward flow of the object to pass through an opening in the distribution shield.   The apparatus of claim 1, wherein the bottom wall is conical, substantially surrounded by the side wall, and an upper portion of the distribution shield is connected to an upper portion of the conduit.   An apparatus for coating the object with metal, wherein the fluid is an electrolyte containing the metal, the object is at least partially conductive, and the apparatus is further in contact with the moving layer. The apparatus of claim 1, comprising: an electrode disposed on the substrate; and a counter electrode spaced apart from the moving layer and adapted to contact the fluid.   4. The apparatus of claim 3, wherein the electrode comprises a sheet or layer of conductive material suitable for covering at least a portion of the bottom wall and contacting the moving layer.   The apparatus according to claim 4, wherein the conductive material is provided with a texture for facilitating movement of an object.   The bath is partially immersed in the electrolyte, and 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 between the object and the counter electrode; The apparatus of claim 3 having an opening immersed in an electrolyte to allow current flow.   The apparatus of claim 6, wherein the opening is covered with a porous mesh, cloth or membrane to hold the object in the bath.   The apparatus of claim 3, wherein the counter electrode is disposed under the distribution shield and comprises a device that prevents the object from being held on the upper surface of the counter electrode. The deflection member is caught on the way an object carried upward by the flow of the fluid, to deflect away from the counter electrode is attached to the lower than the counter-electrode, according to claim 8.   The apparatus of claim 3, wherein the distribution shield and the counter electrode are removably attached within the vessel and are removable to allow internal access into the vessel.   The tank includes a fluid outlet for discharging the fluid from the tank, and the apparatus further supplies a plurality of fluids from respective corresponding sources to the inlet of the tank, and each of the fluids. The apparatus according to claim 1, comprising a device for returning from the outlet to the corresponding source from which the fluid is supplied.   The said continuous supply apparatus is an apparatus of Claim 11 provided with the member which attaches | detaches the said tank continuously to each of the several container which is a supply source corresponding to one of the said fluids so that attachment or detachment is possible.   The continuous supply device includes a pump for transferring a fluid from a container to which the tank is attached to an inlet of the tank; a control valve for controlling a flow of fluid from the container to which the tank is attached to the inlet of the tank; The apparatus according to claim 12, further comprising a frame for supporting a tank, wherein the pump and the valve are portable units for moving between the plurality of containers.   A detection device for detecting the presence of the tank of each container, and a switch that automatically activates the pump in response to the detection device when the tank is present in a corresponding one of the containers. 14. The apparatus of claim 13, comprising.   The tank has a portable configuration with a joint for connecting the inlet to a conduit for supplying the fluid to the tank, and the mounting member continues the tank on each container. Each container is detachably supported, each container having a supply conduit, a pump for introducing fluid from the container into the supply conduit, and a valve for controlling the flow of fluid from the supply conduit to the tank inlet The apparatus of claim 12 comprising:   The apparatus of claim 15, further comprising: a detection device that detects the presence of the tank in each container; and a switch that automatically activates the pump in response to the detection device.   A supply conduit connected to the tank inlet, 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 tank inlet 12. The apparatus of claim 11, further comprising a control valve for controlling fluid flow in the bypass conduit to regulate fluid flow rate.   12. The apparatus of claim 11, wherein the fluid is a liquid, the vessel is open to the atmosphere, at least a portion of the vessel is immersed in the fluid, and the outlet comprises an opening in the immersed portion of the vessel. .   A plurality of containers each for containing a corresponding processing solution used for processing the object; a pump for circulating the processing solution; an inlet manifold for connecting the output of the pump to each container; and a corresponding solution From the outlet of the tank to the corresponding container, a remotely operable valve for simultaneously connecting the inlet manifold and the outlet manifold, respectively, to one of the containers, and the valve away from the position The apparatus according to claim 1, further comprising a control device for operation.   In order to prevent the object from being discharged through the tank inlet in the absence of fluid flow, a mesh screen disposed relative to the tank inlet; The apparatus of claim 1, further comprising a filter for filtering fluid.   The particle trap further comprising a particle trap that provides a channel that bends upstream of the vessel inlet to prevent the object from being discharged through the vessel inlet in the absence of the fluid flow. The device described in 1. 2. The deflecting member according to claim 1, wherein the deflecting member is mounted above the distribution shield and is disposed near the release position so as to catch the upward flowing object halfway and divert away from the fluid flow. Equipment.   23. The apparatus of claim 22, wherein the deflecting member has a recessed surface for capturing and deflecting the object halfway.   The apparatus of claim 1, wherein the bottom wall and the distribution shield are each inclined at an angle in a range of 20 ° to 50 ° from a horizontal line.   The fluid in the vessel is a mixture of liquid and gas, and the distribution shield is directed upward and away from the middle portion of the conduit to the side wall to prevent gas accumulation under the distribution shield. The apparatus of claim 1, wherein the apparatus has a lower surface that slopes toward it.   The fluid in the tank is a mixture of liquid and gas, and by providing a flow path for the gas from below to above the distribution shield, gas is prevented from accumulating under the distribution shield. The apparatus of claim 1, wherein a vent is provided. An apparatus that is immersed in an electrolyte fluid and electrolyzes a plurality of objects with an electrolyte fluid, wherein the objects are at least partially conductive,
The device is
(A) a container for the electrolyte fluid;
(B) a tank for electrolytically treating the object with the electrolyte fluid;
(C) a frame that engages with the container and supports the tank on the container so as to provide a portable unit that moves between a plurality of containers;
The tank
(A) a bottom wall inclined downward from the side wall toward a fluid inlet suitable for providing an upward flow of the fluid to cause the object to flow upward from a supply position adjacent to the inlet to a release position; The object is released from the flow in a release position, the object released from the release position is deposited on an upper portion of the bottom wall, and the bottom wall follows the moving layer of the object along the bottom wall. A bottom wall suitable for moving downward from the upper part of the lever toward the supply position;
(B) an electrode arranged to contact the moving layer of the object;
The container
(A) a pump that carries the fluid from a container to the inlet of the tank;
(B) a control valve for controlling the flow of fluid from the container to the inlet of the tank;
(C) having a counter electrode arranged to contact the fluid ;
The apparatus further comprising a deflection member disposed near the release position for capturing and releasing the upward flowing object from the fluid flow halfway .   A distribution shield mounted in the vessel and having an upper surface inclined downward and extending away from near the release position and above a top portion of the inclined bottom wall, the discharge shield being released. The object falls on the upper surface of the distribution shield and moves downwardly to the return position, from which the object is deposited on the upper portion of the inclined bottom wall, the inclination 28. The apparatus of claim 27, further comprising a distribution shield that moves downwardly along the bottom wall toward the supply position.   Mounted in the vessel and disposed above the fluid inlet to receive the flow of the object, extending upward to confine the flow of the object from near the supply position at least near the distribution shield, and 30. The apparatus of claim 28, further comprising a conduit suitable for 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 attached within the vessel and are removable from the vessel to allow access to the inside of the vessel. 29. The deflecting member according to claim 28, wherein the deflecting member is mounted above the distribution shield and is disposed near the release position so as to catch the upwardly flowing object and divert away from the fluid flow. apparatus.   The bath is partially immersed in the electrolyte, and a counter electrode is disposed outside and adjacent to the immersed portion of the bath, and the side wall or the bottom wall of the bath has a current flowing between the object and the counter electrode. 30. The apparatus of claim 28, having an opening immersed in an electrolyte to allow flow between the two.   33. The apparatus of claim 32, wherein the opening is covered with a porous mesh, cloth or membrane to hold the object in the bath.   29. The apparatus of claim 28, wherein the counter electrode is disposed under the distribution shield and comprises a device that prevents the object from being held on the upper surface of the counter electrode. The deflection member is caught on the way an object carried upward by the flow of the fluid, to deflect away from the counter electrode is attached to the lower than the counter-electrode, according to claim 34.   28. The apparatus of claim 27, wherein the electrode comprises a sheet or layer of conductive material suitable for covering a substantial portion of the bottom wall and contacting the moving layer.   37. The apparatus of claim 36, wherein the conductive material is textured to facilitate movement of an object.   Further comprising an insulating element made of a non-conductive material and suitable for overlapping the upper portion of the sheet or layer, and for reducing the current density near the lower edge of the insulating element; 37. An apparatus according to claim 4 or 36, wherein a gap is provided between an upper portion of the sheet or layer. A device for contacting a plurality of objects with a fluid,
Downward from the sidewalls toward a fluid inlet suitable for providing an upward flow of the fluid to cause the object to flow upwardly from a supply position adjacent to the inlet to a release position where the object is released from flow. A tank having an inclined bottom wall;
A deflection member disposed near the release position to capture and release the upwardly flowing object from the fluid flow; and
A distribution shield mounted in the basin and having an upper surface inclined downward and extending away from near the release position toward the return position, wherein the released object falls onto the upper surface of the distribution shield And is moved downwardly from the release position to the return position so that the return position deposits the released object on the upper portion of the inclined bottom wall. Arranged above the upper part of the inclined bottom wall, the inclined bottom wall moving the moving layer of the deposited object downward from the upper part toward the supply position along the inclined bottom wall A distribution shield that is suitable for
An electrolyte suitable for contacting the moving layer and a counter electrode suitable for contacting the fluid, wherein the fluid is an electrolyte containing a metal for coating the object, wherein the object is at least A device that is partially conductive. A device for contacting a plurality of objects with a fluid,
A tank having a bottom wall that slopes downward from the side wall toward a fluid inlet suitable for providing an upward flow of the fluid to cause the object to flow upwardly from a supply position adjacent to the inlet to a release position; ,
A deflection member disposed near the release position to capture and release the upwardly flowing object from the fluid flow; and
A distribution shield mounted in the basin and having an upper surface inclined downward and extending away from near the release position toward the return position, wherein the released object falls onto the upper surface of the distribution shield And is moved away from the release position toward the return position so that the return position deposits the released object on an upper portion of the inclined bottom wall. Arranged above the upper part of the inclined bottom wall, the inclined bottom wall moving the moving layer of the deposited object downward from the upper part toward the supply position along the inclined bottom wall A device comprising a distribution shield that is suitable for causing.

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