DISSOLUTION KINETIC AND SOLVENT EXTRACTION OF ALUMINIUM FROM KAOLIN

CHAPTER ONE

1. INTRODUCTION
   1. Kaolinite

Kaolinite is one of the rare earth compounds that contain high concentration or percent of alumina and silica in the earth crust, and it has the chemical composition Al₂Si₂O₅(OH)₄. Rare earth (RE) compounds are “hi-tech” materials used in electronics automotive catalytic converter, glass/ceramic permanent magnets and nuclear energy. High demand/tight supply issues prompt the need for intensive research in the field of rare earth recovery/purification, with emphasis on development of new sources to secure sustainable access to supply in the future. Due to the abundance of Kaolinite in the superficial layers in nature, high specific surface area for adsorption and relatives ease of mining/processing [1].The Kaolinite or rare earths are leached and we can recover high purity and product by solvent extraction.

In April 2008, the US Naval medical research institute announced the successful use of a Kaolinite derived aluminosilicate nonoparticles infusion in traditional gauze, known commercially as Quick clot combat Gauze [2]. The purpose of this study is to explain the geochemical principles that govern acid chloride aluminum leaching and to provide a basis for understanding the testing application of acid leaching to the undeveloped resources base [3].

Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al₂Si₂O₅(OH)₄. It is a layered silicate mineral with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina Octahedral [4]. Rocks that are rich in Kaolinite are known as Kaolin or china clay [5]. The name is derived from kao-ling (Chinese word: gaoling) a village near Jingdezhen jlangxi province, china [6]. The name entered English in 1727 from the French version of word “Kaolin” following François Xavier d Entrecolles’s reports form Jindgezhen [7]. In Africa, kaolin is sometimes known as Kalaba (in Gabon [8] and Cameroon [9]) Calaba and calaba chop (in Equatorial Guinea).

Kaolinite has a low shrink-swell capacity and a low cation exchange capacity (1-15meg/100g), it is a soft, earthy, usually white mineral (dioctahedral phyllosilicate clay), produced by the chemical weathering of aluminum silicate minerals like feldspar. In many parts of the world, it is colored pink-orange-red by iron oxide, giving it distinct rust, lighter concentrations yield white, yellow or light orange colour. Alternatively layers are sometimes found as at providence canyon state park in Georgia, ssssUnited State commercial grades of kaolin are supplied and transported as dry powder, semi-dry noodle or as liquid slurry.

1. Source of Kaolinite

Kaolinite or kaolin mineral has its name derived form Gaoling (kao-ling) which is a high hill in the Jindgenzhen, Jiangxl province of china, although it was mined in that Chinese province, the mineral was first described as mineral species in Brazil in the year 1867. Kaolinite is mined as kaolin. Brazil, United Kingdom, Germany, India, Korea, France, China, and the Untied State of America are some of the known countries on which premium Kaolin clay is sourced. The mineral is typically found abundant in soils that are found o chemical weathering of rocks and have hot and moist climate such as tropical rain forest areas. In comparison along a gradient that leads towards progressively cooler or drier climate, the proportion of Kaolinite decreased while other clay minerals such as illicit and smectite which are formed in cool and dry climates increase. The climatic factors in the formation of Kaolinite tell soil much of the mineral’s relation to its sources areas geologic history. [8]. Kaolin clay is included in the group of hydrous aluminum silicates, healing stones kyanite and dumortierite are aluminum silicate. Aluminum is also found in the healing stone sapphire, amethyst, heliotrope (bloodstone), ruby, anyolite, emerald, idocrase, rhodonite, tiger iron, green tourmaline, alexandrite and moldavite. The kaolin mineral group includes other common clay mineral such as dickite, halloysite, nacrtie, Kaolinite and allophone. The kaolin mineral group is usually found in sediments, soils, hydrothermal deposits and sedimentary rocks. It takes the bulk of the mineral that are formed in the pouter crust of the earth at a wide range of geologic environment. Many of these silicates are of economic importance. Most of them are used ion various industries, the clay minerals that form the main constituent of kaolin are commonly formed through the cycles of rock formation. Although it may share the same chemical composition with their clay minerals in its group, it differs in its optical or physical properties.