Abstract: A container formed of polymer concrete in which minerals such as copper are purified in an electrolytic process. The container includes a bottom and end and side walls for containing a corrosive electrolyte, such as, a sulphuric or hydrochloric acid solution. An overflow box is integrally formed in a first formation extending vertically along one end wall of the cell and an overflow pipe is molded into the first formation and extends from the overflow box outwardly of the cell. A vertical covered inlet chanel or cast-in pipe is provided at the opposite end of the container and extends from its upper to its lower end.