Proof of the recomine-concept

The recomine-concept deals with a variable flowsheet that comprises three major modules: (I) processing of tailings, (II) processing of solid residues and (III) water recovery. The first module deals with the output of BHP’s processing route. A bulk sulfide flotation produces sulfide concentrates and a silicate residue. Two potential processes represent the concentrate’s subsequent treatment: (a) leaching and (b) roasting of the concentrate.
The major aim of treating the concentrate by leaching is to produce schwertmannite (SMT) as a product after precipitation. Alternatively, roasting the sulphide concentrate may result in other economic products: sulphuric acid and ferric sulphate. Silicate residues from module one will appear in a sequence of processing steps in module two. This module has a twofold aim: (1) separating ferro- and paramagnetic fractions and (2) dewatering the residues. Distinct steps will accomplish a separation of concentrated, iron-rich garnet. Novel membrane technologies will treat wastewater streams from modules one and two and represent module three. The major purpose of water treatment is to maximize the amount of clean water for nearby and downstream communities.
The flotation campaign applied an overall flotation time of 20 min. Tailings contain only 0.4 % of pyrite at a recovery of 6.3 %. Bioleaching experiments were able to turnover 75 % of the pyrite maximum. SMT precipitation was successful. Infrared spectroscopy and XRD proofed a pure and fine crystalline schwertmannite. Its’ ability to adsorb arsenates has been proven in according tests and schwertmannite from Antamina Tailings is potentially suitable for decontamination of mine water from arsenates, phosphates, and vanadates. Interest from chemical industry exist in designing schwertmannite as a pigment in colour chemistry (see section C in appendix). A crude product of garnet sand was separated magnetically. The recomine-team speculates that a potential annual production of crude garnet could provide the largest deposit for industrial garnet on the planet.