Abstract
The availability of polymetallic ores is getting leaner in grade and is larger but inferior in volumes than in the past, making the extraction of copper, nickel and other non-ferrous metals metallurgically more difficult to produce. The standard technologies, including enrichment and concentration, do not provide methods for obtaining monometallic concentrates and high extraction of metals into the commercial product. Pyrometallurgical processing of large volumes of poor raw materials is not economical and is complicated from the technological point of view. Conditions of chemical enrichment of poor natural materials have been studied with the use of technology of salt exchange leaching. The main impurity in sulfide ores of nonferrous metals is iron present in the forms of pyrite and pyrrhotite and the properties of chemical enrichment for nickel in pyrite concentrates has been investigated in this work. On the basis of thermodynamic analysis carried out with the use of Potential-pH Pourbaix’s Diagrams, it has been established that, with the use of nickel salt, it is possible to leach iron sulfides from ores. Based on the study of the mechanism and kinetics of the process of dissolution of iron sulfides with nickel salts, it was established that during the dissolution, the chemical composition and thermodynamic characteristics of the dissolved iron sulfides change—the residues from leaching are enriched with iron sulfides that are rich in sulfur and also result with elemental sulfur formation. Enrichment of leaching residues with sulfide iron with increased sulfur content and formation on the surface of nickel sulfide leads to increase of diffusional resistances and the process is limited by the velocity of mass transfer. To increase the velocity of the process and completeness of the reaction, it is necessary to activate the process, in particular, by grinding the solid phase.
Highlights
Metallurgical processing involves more complex and poor ores
Pyrite and pyrrhotite concentrates can be referred to such type of mineral raw materials with low content of non-ferrous metals, for example, nickel
Most of them include melting of large volumes of raw materials accompanied with high energy expenses and significant loss of metal
Summary
Metallurgical processing involves more complex and poor ores now. Pyrite and pyrrhotite concentrates can be referred to such type of mineral raw materials with low content of non-ferrous metals, for example, nickel. The process of chemical enrichment of sulfide concentrates containing nickel can be carried out either with application of selective iron leaching from original raw material or with transfer of the basic metals from ores into solution with further selective nickel precipitation. Methods of oxidizing autoclave leaching with the subsequent non-ferrous metals extraction from the solution with sorption or precipitation with hydrogen sulfide are being developed. Technologies of matte application for collective precipitation of non-ferrous metals from solutions are being developed [4]. On the basis of the technology developed in Gipronickel Institute (Leningrad), concentrates containing nickel pyrrhotite are melted at first for pyrrhotite matte, which is subjected to selective leaching with iron extraction into the solution and non-ferrous metals into a cake. Even under nickel concentration equal to 10−2 g∙mol/dm, nickel sulfide is more stable in the water phase than FeS under concentration of 1 g∙mol/dm
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
