THE USE OF HYDROMETALLURGY IN TREATMENT OF SECONDARY RAW MATERIALS AND LOW – GRADE ORES

Jari Aromaa,Olof Forsén

doi:10.12776/ams.v19i3.160

Abstract

The available raw material types for metals production are primary high-grade ores, primary low – grade ores and secondary raw materials. Treatment of primary raw materials is often easier than treatment of secondary materials as the latter ones can have metals in combinations never found in nature. The basic phenomena in treating primary and secondary materials are the same. Thermodynamics and reaction kinetics are the same when applied to pure metals or compounds. The differences are in the complexity of the raw material that has strong influence on selectivity. Leaching of complex low – grade materials and secondary materials can result in higher chemical and energy consumption. The solution purification after leaching complex low – grade and secondary materials can also be technically more difficult than when operating with primary high – grade materials. This is due to higher number of metals in the solution. The origin of raw materials has no influence on production of metals from purified solutions.

Highlights

In 2010 the European Union identified a list of 14 economically important raw materials, which are subject to a higher risk of supply interruption
Thermodynamics and reaction kinetics are the same when applied to pure metals or compounds
Leaching of complex low – grade materials and secondary materials can result in higher chemical and energy consumption

Summary

Introduction

In 2010 the European Union identified a list of 14 economically important raw materials, which are subject to a higher risk of supply interruption. When leaching primary high – grade raw materials it is not too difficult to select suitable leaching conditions for sharp separation of wanted and unwanted metals. In primary raw materials extraction reduction is done in certain cases but in utilisation of complex, low-grade sources and secondary sources the potentially large number of different metals will again make the purification more demanding. Solvent extraction is better suitable for large amounts of metal and ion exchange for dilute solutions Both methods are used in primary raw material extraction and they will likely become a main purification method in handling solutions from secondary raw materials leaching. Purification of solutions from low – grade primary and secondary raw materials leaching will require very selective methods. Gaseous reduction and electrolysis produce pure metals and both methods are tested for many metals

Findings

Discussion

Conclusions