Development of new metal recovery technology from wasted PCBs by supercritical water treatment and bioleaching

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K00604
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental conscious materials and recycle
• Research Institution: Akita Prefectural University
• Principal Investigator: Liang Ruilu 秋田県立大学, システム科学技術学部, 准教授 (10315624)
• Co-Investigator(Kenkyū-buntansha): 宮田 直幸 秋田県立大学, 生物資源科学部, 教授 (20285191)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: リサイクル / 超臨界水処理 / 廃電子基板 / バイオリーチング / 選択的粉砕 / 篩い分け選別 / 溶媒抽出

Outline of Final Research Achievements

In order to develop the recycling technology of valuable metals efficiently from wasted printed circuit boards (PCBs), we studied the application of supercritical water treatment, selective crushing, separation by sieving and bioleaching. Experimental results showed that supercritical water oxidation process was strong enough to decompose the plastic of PCBs, and the metal grade increased from about 18% to 30%. It was possible to selectively crush the glass fiber which became fragile after supercritical water processing by stirring crush or other milling methods. It was possible to recover more than 97% of copper and more than 85% of many other metals only by sieving the sample after crushing. In addition, bioleaching of the concentrate and metals recovery from leach liquor of concentrate were also investigated. The new recycling technology for metal recycling from PCBs by supercritical water processing was developed.

Free Research Field

リサイクル

Academic Significance and Societal Importance of the Research Achievements

廃電子基板の構造から、従来の粉砕法で金属と樹脂との単体分離度が低いため、主な金属以外のレアメタルはリサイクルされていない。超臨界水で処理した廃電子基板試料の金属の延性・展性およびガラス繊維を中心とした非金属の脆さを利用して、選択的粉砕法を用いて金属と非金属を完全に単体分離することができた。さらに粉砕とふるい分けのみの簡単な方法で高品位・高回収率の金属回収新技術を開発した。この技術により省エネルギーで含有量の少ないレアメタルの回収や、有機物を多く含む廃棄物からの金属リサイクルが期待される。