Agglomeration–Flotation of Finely Ground Chalcopyrite Using Emulsified Oil Stabilized by Emulsifiers: Implications for Porphyry Copper Ore Flotation

Vothy Hornn,Mayumi Ito,Sanghee Jeon,Carlito Baltazar Tabelin,Naoki Hiroyoshi,Ilhwan Park,Hiromasa Shimada

doi:10.3390/met10070912

Abstract

Flotation is the conventional method for processing porphyry copper deposits, one of the most economically important sources of copper (Cu) worldwide. The rapidly decreasing grade of this type of Cu ore in recent years, however, presents serious problems with fine particle recovery using conventional flotation circuits. This low recovery could be attributed to the low collision efficiency of fine particles and air bubbles during flotation. To improve collision efficiency and flotation recovery, agglomeration of finely ground chalcopyrite (CuFeS2) (D50 = 3.5 μm) using emulsified oil stabilized by emulsifiers was elucidated in this study. Specifically, the effects of various types of anionic (sodium dodecyl sulfate (SDS), potassium amyl xanthate (KAX)), cationic (dodecyl amine acetate (DAA)), and non-ionic (polysorbate 20 (Tween 20)) emulsifiers on emulsified oil stability and agglomeration–flotation efficiency were investigated. When emulsifiers were added, the average size of agglomerates increased, resulting in higher Cu recovery during flotation. This dramatic improvement in flotation efficiency could be attributed to the smaller oil droplet size in emulsified oil and their higher stability in the presence of emulsifiers. The utilization of emulsifiers during agglomeration–flotation not only lowered the required agitation strength for agglomeration but also shortened the agglomeration time, both of which made the process easier to incorporate in existing flotation circuits.

Highlights

Porphyry copper deposits are economically the most important source of copper (Cu) worldwide because of their wide distribution and enormous volume of minable ore materials
The results showed that the stability of emulsified oil was relatively short, so strong agitation strength is required to disperse oil droplets into water, maintain the small size of oil droplets, and facilitate particle agglomeration [4]
These results indicate that less intense agitation strength (1000 rpm) was sufficient for agglomeration–flotation when emulsifiers were present because of the smaller droplet size and better stability of emulsified oil

Summary

Introduction

Porphyry copper deposits are economically the most important source of copper (Cu) worldwide because of their wide distribution and enormous volume of minable ore materials. Metals 2020, 10, 912 from porphyry copper ores is flotation, a technique whereby fine particles of Cu-bearing minerals like chalcopyrite (CuFeS2 ) are separated from gangue minerals and collected by bubbles after surface modifications using emulsifiers called collectors [3,4]. Flotation, including its concept of using bubbles to induce separation of materials with different surface wettability properties, is a popular and widely used technique in the mineral processing and coal cleaning/washing industries and in electronic waste and plastic recycling industries [5,6,7,8,9,10,11]. Many studies have suggested ways to overcome the poor fine particle recovery during flotation using two approaches: (1) bubble size reduction, and (2) particle aggregation

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Results

Conclusion