低品位アルミニウムドロスの減容化，無害化および再資源化を指向した湿式処理プロセスの開発

<p>For the purpose of volume reduction and detoxification of the low-grade aluminum dross (abbreviated as L-dross) with low content of metallic Al, the leaching behavior of two kinds of L-dross was investigated using 2 mol/dm³ H₂SO₄ and 2 mol/dm³ NaOH with or without heating operation. Ettringite with an anion removal ability was synthesized from the L-dross leachate generated after the volume reduction and detoxification treatment. A series of wet treatment process composed of L-dross leaching and ettringite synthesis was tried to develop in this study.</p><p>In the case of leaching with 2 mol/dm³ H₂SO₄, the Al³⁺ concentration in leachate and leaching percentage are increasing with an increase in leaching temperature in the order of 85°C > 50°C > Room temperature. On the other hand, the effect of heating on L-dross leaching using 2 mol/dm³ NaOH is not remarkable. In terms of volume reduction, it is found that the H₂SO₄ leaching with heating is effective and the residual ratio shows approximately 50 mass%.</p><p>According to the detoxification due to the dissolution of metallic Al and the hydrolysis of AlN, the heating effect appears to both leachates. The NaOH solution is found to be more valid than the H₂SO₄ for the acceleration of Al dissolution and AlN decomposition. Ettringite was synthesized easily from both leachates treated with 2 mol/dm³ H₂SO₄ and 2 mol/dm³ NaOH, by adding Ca(OH)₂ and CaSO₄ · 2H₂O. It is considered that the wet treatment process suggested in this study makes contribution to the volume reduction and detoxification of the L-dross and the synthesis of ettringite using the L-dross leachate.</p>