Aplicaciones de hidrometalurgia

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HYDROMETALLURGY

a short course sponsored by the

TMS Continuing Education Committee

TABLE OF CONTENTS

INTRODUCTION i
Paul E. Queneau

PRINCIPLES OF HYDROMETALLURGY 1
M. E. Wadsworth

UNIT OPERATIONS IN HYDROMETALLURGY 86
H. J. Roorda

METALLURGICAL APPLICATION OF SOLVENT EXTRACTION 169
Joe B. Rosenbaum

AUTOMATIC PROCESS CONTROL 243
James E.Lawver and N. H. Ceaglske

INTRODUCTION
Paul E. Queneau

This short course is dedicated to exploring with engineers — equipped with judgment from a decade or more of experience in plant operations — some of the more important principles, procedures and potentials of modern hydrometallurgy. Its purpose is to narrow the serious communicationsgap between the laboratory scientist who -dreams creatively of better practices for tomorrow, and the responsible engineer who daily faces the hard reality of practices inherited from yesterday. The former, with insufficient knowledge of the complexity of metallurgical operations, tends to irrational worship of dangerously simplified models. However the latter, with insufficient, knowledge of thescientific foundations of process metallurgy tends to dismiss valuable new concepts as dangerously impractical. Clearly a working partnership between the learned in theory and the able in practice is essential to progress. Successful in-plant application of increasingly sophisticated technology is dependent on its fundamentals being understood and accepted by key operating personnel — hence theneed for your continuing education.

Hydrometallurgical processes normally operate with aqueous solutions in the 25° - 250°C temperature range and in the ambient to forty atmospheres pressure range. Hydrometallurgy is readily adaptable to large-scale continuous operations and is flexible in the chemical and physical nature of the end product. One of its basic applications is the selectivedissolution of a desired fraction of an ore's mineral content, leaving the bulk of it in the solid state. It Is characterized by an extremely wide choice of reactants and a high degree of control over reaction course and time — by appropriate selection of critical process parameters. Also important, adequate sensors and instrumentation are generally available for optimization-automation purposes. Abroad range of industrial corrosion- and erosion-resisting equipment developed for the chemical industry is available. It meets most of the main treatment requirements, such as heat and mass transfer, phase separation and materials handling. The intrinsic capabilities of hydrometallurgy for metal extraction and isolation are difficult to exaggerate — great and rapid expansion in its use iscertain.

Before further discussion of the subject before us, a few words of caution. The rise of hydrometallurgy does not mean the demise of pyrometallurgy. The latter does indeed have onerous environmental problems in respect to meeting man's requirements for clean air — unfortunately so does the former in meeting man's requirements for clean water. These shared problems will be solved by theengineering profession in due course. In the meantime we should avoid use of the often misleading slogan "pollution-free hydrometallurgical process." Recent environmental legislation has been a healthy goad which will result in startling advances in industrial practice. For example, autogeneous oxygen conversion of sulfide concentrates to metal and slag in high throughput, low unit cost continuousreactors will replace some of the antique furnace-trains still running in heavily polluting non-ferrous smelters. Along entirely different lines, solution mining is a promising concept which is attracting wide attention as an alternative to classical mining and minerals beneficiation operations. Ore deposits, below the water table, are severely fractured in place — by conventional or nuclear...