| 摘要 |
PROBLEM TO BE SOLVED: To reduce multivalent metal cation content of a dilute acid water solution by filtering the dilute acid water solution through finely crushed diatomaceous earth treated by an alkali metal silicate. SOLUTION: A multivalent metal cation such as of molybdenum is reduced from a dilute acid water solution by contacting the dilute acid water solution with a diatomaceous earth by providing an alkali metal silicate-treated finely crushed diatomaceous earth and filtering the dilute acid water solution through the diatomaceous earth. The particle size is characterized by a fine powder, but preferably the particle size is 1 to 50μm. The alkali metal is preferably sodium and potassium, and the alkali metal silicate water solution can be contained in about 1 to 30 wt.%/volume, preferably about 5 to 30 wt.%/volume, and more preferably about 8 to 20 wt.%/volume. This finely divided diatomaceous earth is used as a filter auxiliary of such liquid as beer, or the like.
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