Methods for the separation and/or purification of metals

A method for separating at least two metals from each other in a metal refining process, comprising; injecting a metal comprising feed solution 66 into a column or flow pipe 60 comprising a monolithic body 62 having a plurality of channels 64 through which the feed solution can flow; wherein the feed solution is mixed with an immiscible extractant liquid 68 using a distribution plate 72 comprising a plurality of through-holes or nozzles 74 through which the feed solution and/or extractant liquid are injected into a mixing chamber 76 and then flowed through the channels to separate the metals, with at least one metal extracting into the extractant liquid; wherein each hole or nozzle, or droplet produced by such, and each channel have a diameter of at least 1 mm; wherein the distribution plate and the monolithic body are separated by at least 1cm; and wherein the width and length of the monolithic body perpendicular and parallel to a flow direction respectively are at least 0.1 m. The monolithic body may be a 3D printed organic polymer. The metals to be separated may include platinum group metals or battery metals, such as cobalt, nickel, lithium, and manganese.