Six leaching solutions, 1M ammonium acetate (pH7.0) , 0.1 M r. cetate buffer (pH5.0) 0.05 M EDTA (pH4.8) , 0.1 M chlorhydric acid (pH 1.0) , 3% hydrogen peroxide in 2.5% acetic acid (pH2.6) , 0.1 M ascorbic r. cid (pH2.4) were used.

• 试验中采用了6种提取溶剂:1M乙酸铵溶液(pH7.；0)；1