Hideo Hosoda*, Katsuyoshi Shimokawa*, Yoshie Takahashi**, Yutaka Yoshida***, Masami Tsunekawa**** and Toshimasa Hirama*

* Hokkaido National Industrial Research Insitute
** Sanyu Plant Service Co., Ltd.
*** Muroran Institute of Technology
**** Hokkaido University

+ Correspondence should be addressed to Hideo Hosoda:
(2-17 Tsukisamu-higashi, Toyohira-ku, Sapporo 062 Japan)

Abstract

Although scallops are one of the major products of the fishery industry around Hokkaido island, the treatment of waste scallop shells has been becoming an important subject from the environmental point of view because of a limitation of the space for reclamation and the bad smell they emit. Utilization of the shells in industries as a calcium source is the most desirable means for solving the above problems. In the present paper, calcination of scallop shell to produce quick lime was examined using an experimental fluidized bed reactor having a 0.16m inner diameter. Sieving the crushed shell to a maximum size of 3mm brought about a smooth fluidization state and steady operation of the calciner. For the products withdrawn from the bottom of the fluidized bed calciner, a high calcination ratio has attained as high as over 99% at a calcination temperature of 850*C[Celsius degeree] and a mean residence time in the calciner of 80 minutes. Reactivity and performance of sulfur dioxide absorption of the quick lime from the shell were measured and the results were compared with those values for quick lime from limestone. Excellent performance of sulfur dioxide adsorption was found for the quick lime from the shell, and this is obviously caused by a bigger mean size of the pores formed by calcination.

Key words: scallop shell, waste material, fluidized bed calcination, quick lime, sulfur dioxide absorption