| 摘要 |
From processing residues of scallop (Patinopecten yessoensis), cadmium is removed without separating the midgut gland and thus an organic fertilizer and an organic feed are produced. To the processing residues of scallop including the midgut gland in which cadmium has been accumulated at a high concentration, a small amount of an aqueous citric acid solution is added and the mixture is heated to 55 to 65°C. Thus, the thin midgut gland membrane is broken and the internal solution thereof containing cadmium is eluted. From the liquid mixture comprising solid matters and the internal solution of the midgut gland thus eluted, the solid matters are separated. As the aqueous citric acid solution, a solution prepared by mixing at least 9 wt%, relative to the processing residues, of water with 1.8 to 3.3 wt%, relative to the total weight of the processing residues and water, of citric acid is used. The cadmium content of the solid matters can be further reduced by adding water to the solid matters having been separated and then heating the mixture to 55 to 65°C to thereby washing off cadmium remaining in the solid matters. |
