Nippon Suisan Gakkaishi 77 (5), 871-875 (2011)

Development of efficient precipitator composed of baked shell

AKIHITO TERAI,1 FUSAICHI YAMAMOTO,2
TOMOTAKA OHASHI3 AND HARUHIKO TOYOHARA1*

1Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto 615-8086, 2YONDEN CONSULTANTS CO. INC., Takamatsu, Kagawa 761-0121, 3HydroWorks Co. Ltd., Koriyama, Fukusima 963-0207, Japan

With the aim of utilizing the oyster shells which are generally discarded in shell culture, we have developed an efficient precipitator to clarify muddy water from a baked oyster shell.

We examined the effect of baking temperature (200°C, 300°C, 400°C, 500°C, and 600°C) on the effect of precipitation and found that 400°C was the most effective baking temperature to produce a precipitator. The efficiency of precipitation was evaluated as the precipitation ability of the baked shell in muddy water containing kaolin. Precipitators made of shell baked at temperatures below 300°C were more efficient under slow stirring conditions, while those baked at temperatures above 500°C were more effective under fast stirring conditions. Precipitators made of shell baked at 400°C were effective under both stirring conditions. The specific surface area and grain size of the shell reduced with the increase in baking temperature. This is possibly because 400°C is a suitable baking temperature for both generating the small grain size that is effective for flock formation and realizing a large specific surface area necessary for the physical strength of the flock.


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