METHOD FOR DESALTING AND WASHING SEA SAND

PURPOSE:To uniformly and perfectly wash sea sand within a short time, by successively immerising the whole of a sand layer in a water layer with the flow- down of said water layer in such a state that all of upper, side and lower surface parts of sand in the downwardly flowing water layer are present in water. CONSTITUTION:Stock sand 3 is supplied on the net body 2 in a sand tank 1 so as to fill said tank 1 and waste finish washing water containing a small amount of salt obtained by the preceding finish washing in a waste finish washing water tank 5 is sent by a pump 4 to fill a water layer so as to cover the upper surface of the stock sand 3. Subsequently, a vacuum generator 9 is operated to perform preparatory washing and sand in the sand tank 1 is brought to a state wetted with water of which the salt is reduced. After preparatory washing, fresh water is sent from a fresh water pipe 15 to impart a fresh water filled layer by the same way as the aforementioned one and sucked under vacuum by the vacuum generator 9 to perform finish washing. Water entering the waste finish washing water tank 5 by finish washing is stored and used in the preparatory washing water of sea sand entering the sand tank 1 in the next time. Desalted sand after finish washing is discharged to the outside by inverting the sand tank 1 and the filling of stock seasand is performed again to perform desalting operation.