Method of extracting salts from brine using gravitational force

摘要

Concentrated salt brine is extracted from a dilute salt brine solution by vaporizing the solution at reduced vacuum pressure created by a gravitational force. A column 1 contains a piston 4 which forms a chamber 2 at the top. The piston may be held in place by an external restraint 3. The chamber is filled with dilute salt brine and the restraints are released. Gravitational force causes the piston to sink down the column, reducing the pressure in the chamber which vaporizes the desalinated liquid leaving the salts suspended in a concentrated brine 7. This brine is drawn off once the piston is fully deployed through a valve arrangement in the piston plate 8 and hence the weight of liquid is reduced. At this point the negative pressure in the chamber exerts a negative force on the piston causing it to rise. The pressure in the chamber will increase and condense the desalinated vapour back to liquid which can be drawn off from the chamber once the piston has returned to its starting position. Alternatively, the desalinated vapour could be drawn off directly which would cause the piston to rise.