Characteristics tests for recovery of rare metals from real sea with adsorbents

Katakai, Akio; Kasai, Noboru; Tamada, Masao; Hasegawa, Shin; Seko, Noriaki; Kawabata, Yukiya*; Onuma, Kenji*; Takeda, Hayato*; Sugo, Takanobu

JAERI-Tech 2002-040, 79 Pages, 2002/03

JAERI-Tech-2002-040.pdf:8.62MB

The present report dealt with experimental methods of adsorbents synthesis, recovery, elution, analysis in experimental equipment for recovery of rare metals from seawater to evaluate performance of the adsorbent synthesized by radiation-induced graft-polymerization. In the adsorbent synthesis, monomers of acrylonitrile and methacryl acid were continuously co-grafted into polymer nonwoven fabric irradiated with electron beam. The grafted nonwoven fabric was amidoximated and treated with alkaline solution in batch processing. The obtained adsorbent fabrics which were cut into 116 sheets of the square, 160 mm 290 mm, were alternatively stacked with spacers to make an adsorbent cassette. In recovery process, a large-sized cage packing 144 pieces of the adsorbent cassette was dipped into sea in the depth of 20 m by using an experimental marine equipment. In the case of a small-sized cage, there are 36 adsorbent cassettes in it. In elution step, first, marine animals which were adhered on the adsorbent cassette were washed out immediately after the adsorbent cassettes were recovered from sea. From every 72 adsorbent cassettes packed into elution unit, second, alkaline and rare metals were fractionally eluted by changing acid concentration in fractional elution equipment. The eluted metals were adsorbed onto a commercial chelate resin to transport them to purificatory factory. Concentrations of metals in eluent and waste solution were analyzed with inducticely coupled plasma atomic emission and mass spectrometry (ICP-AES and ICP-MS). The rare metal distribution in the adsorbent was evaluated by using the same analytical methods.