Abstract
A study on the recovery of yttrium was conducted using the phosphor sludges generated in the recycling process of obsolete CRTs. Yttrium was leached by HCl and $HNO _3$. The leaching efficiency of yttrium was extensively investigated in terms of acid concentration, leaching temperature and time, and pulp density. Yttrium and lead was recovered from leaching solutions also by precipitation method. The leaching behavior of yttrium was similar in both acids. The leaching efficiency of yttrium for both acids increased with time at the conditions of 3.0M, $90^{\circ}C$, and 280 g/L of pulp density. After 40 minutes, it was saturated to 93% and 90% for HCl and HNO$_3$respectively. Yttrium was recovered from leaching acid solution by the addition of $H_2$$C_2$$O_4$while lead was removed as $PbSO_4$by $Na_2$ $SO_4$.
폐CRT의 재활용 공정에서 Panel 유리에 도포 된 형광체의 제거 시 발생하는 슬러지로부터 Y를 회수하는 연구를 수행하였다. HCI및 $HNO_3$을 사용하여 Y를 침출하였으며 산 농도, 침출온도, 침출시간, 광액농도가 침출율에 미치는 영향을 조사하였다. 또한 침출액으로부터 Y와 Pb를 침전 법으로 회수하는 실험을 행하였다 슬러지로부터 HCl 및 $HNO_3$에 의한 Y의 침출거동은 유사한 경향을 나타내었다. 광액농도를 280 g/L로 하여 $90^{\circ}C$에서 3.0M HCl및$ HNO_3$로 침출 하였을 때 시간에 따라 Y의 침출율은 증가하다가 40분 이상에서는 각각 93%, 90%로 일정한 침출율을 나타내었다. 침출액에 $H_2$$C_2$$O_4$를 첨가하여 Y를 회수하였으며 Pb는 $Na_2$$SO_4$를 가하여 $PbSO4$로 제거하였다.
