refiner n 1: one whose work is to refine a specific thing; "he was a sugar refiner"
Refiner \Re*fin"er\ (-f?n"?r), n. One who, or that which, refines. [1913 Webster]
Refiner The process of refining metals is referred to by way of illustrations in Isa. 1:25; Jer. 6:29; Zech. 13:9; Mal. 3:2, 3.