Carrier Flotation of Hematite

The production of fine materials is unavoidable during the comminution of iron ore. Due to the difficulty of recovering iron from this fine material by various gravity separation methods, flotation can often be a more attractive process producing high-grade material at high recovery. One variation of the flotation process, that can be useful for recovering ultrafine minerals (<10 mm), is known as carrier flotation. This process involves the utilization of coarse particles (> 150 mm) which act as flocculation centres to which the fine hematite particles (10-40 mm) become attached and are carried or “piggy-backed” into the froth phase.

Aggregation mechanisms are important interactions between particles in a flotation process. These interactions may include hetero-aggregation (i.e. occurring between particles of different minerals and size), mutual aggregation (i.e. occurring between particles of the same mineral and size) and selective aggregation (i.e. occurring between coarse carrier particles and the fine particles of one mineral in a mixture). Selective aggregation can be considered the same as mutual aggregation when the carrier and desired mineral are the same.

The objective of this paper is to demonstrate that carrier flotation is a significant phenomenon in the flotation of hematite fines using oleic acid as a collector.

ВАРІАНТ V

Technological Trends in Mining

In step with industrial and technical advances the tempo of mining activity has accelerated rapidly.

Shallow mines containing high-grade ore deposits either have been or are being rapidly mined out and their place can only be taken by deposits lying at minerals greater depths.

Scientists consider that the nature and characteristics of individual minerals al deposits will not differ greatly, except i minerals n the matter of average depth from those of today.

Though more and more useful in the world are mined by open-pit mining, the importance of underground mining is still great because the average grade of ore m minerals underground is higher than that of open-pit ore.

In mining deeper and lower grade deposits there is a tendency to use in situ mining which seems to be a promising process and the one on which research is concentrated on the international scene.

Another problem of mining is further mechanization and automation of mining process. Thus, in underground mining great attention is paid to designing efficient winning complexes consisting of self-moving powered supports incorporated with shearer or plough operating in productive faces.

It is of interest to note that computers have become valuable tools in many mining applications. They are especially useful in mine design, ventilation, simulation, monitoring, and in other fields. The computer software deals with information on seam thickness, borehole data, the nature of disturbances, faulting and folding and other details. Computers can help determine production levels of different extraction strategies, carry out mine planning. Microcomputers also find more wider use in mining and exploration projects.

Special attention is paid to mine safety as part of mechanization and automation of mining processes. Automatic instruments and systems along with safety devices effectively monitor the working environment and ensure human safety in all mining operations.

The mining industry today is to continue to satisfy the world’s rapidly growing demands for minerals and metals. To meet this challenge the most important requirement is the efficient use of modern machinery and human resources based on scientific and technological progress.

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ВАРІАНТ I