DESALINATION APPARATUS AND DESALINATION METHOD, AND METHOD FOR CO-PRODUCING FRESH WATER, SALT AND VALUABLE-MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a desalination apparatus and desalination method capable of removing multi-valent ions contained in the desalinated water from an electrodialysis unit as well as removing boron, and improving the purity of the recovered valuable-material, and to provide a method for co-producing fresh water, salt and valuable-material.SOLUTION: The desalination apparatus comprises: a desalination unit 12 for obtaining a fresh water Wwhose salt content in the supplied feed seawater (raw water) W has been removed, and a salt-content enriched water Wwhose salt content in the feed seawater (raw water) W has been enriched; an electrodialysis unit 13 for obtaining an enriched saline water Wand a diluted saline water Wby electrodialyzing the salt content enriched water W; a reactive crystallization unit 23 for recovering the residual ions in the diluted saline water Was a valuable-material 61 to obtain a desalinated water W; a boron removal unit 51 for removing boron in the desalinated water W; and a recirculation line Lfor recirculating the boron removed liquid whose boron has been removed, to the feed seawater (raw water) W on the inlet side of the desalination unit 12 as a recirculation water W.