Study on sylvite flotation through controlled crystallization methodology

Abstract

With vast reserves on earth and high value, various types of minerals have been extracted, well purified and applied in multiple fields including architecture, transportation, technology, etc. The key of flotation process is to realize a hydrophobic state of mineral surfaces which always relies on the proper chemical reagent-collector. Numerous researchers devoted much into the designing of collector or back-end processing of mineral particles shape, ignoring the fact that most minerals belong to different types of crystals. In this work, the main idea is to understand minerals as crystals so as to put up with a novel strategy through crystallization controlled flotation with great application prospect for soluble and semi-soluble minerals. Here, the modulation of crystallization as well as following flotation behaviors were detailed researched by taking potassium chloride as an example which is the main resource for extraction of potassium element. The various crystallization paths were also unveiled through surficial studies and related flotation mechanisms were elaborately researched, paving a path to the strategy of crystallization modulated flotation for other soluble and semi-soluble minerals. Chapter I and II briefly introduced the justification, objectives and previous researches of antecedents about this research. In Chapter III, the materials, researching methods and characterization in this thesis were shortly introduced. Chapter IV focused on a development of green supersaturation method for preparing KCl crystals with various shapes. Chapter V was about the preparation of KCl samples with two different exposing facets as (200) and (222), where their corresponding flotation behavior with ODA as collector and the related mechanism were studied in detail. Chapter VI presented the successful growth of KCl samples with needle-, hopper- and cubic-like structure, and their growing mechanism, flotation behaviour as well as mechanism were elaborately unveiled. In the Chapter VII, we further demonstrated the influence of ethanol on crystallization and flotation process of KCl, where the mechanism of promoted KCl flotation behavior induced by ethanol addition was well researched. At last, Chapter VIII summarized the conclusions of this thesis and provided a few perspectives on soluble salt flotation research.