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Title page                                                                                                        i

Certification                                                                                                    ii

Dedication                                                                                                      iii        

Acknowledgement                                                                                          iv

Table of content                                                                                              v


  1. Introduction
    1. Kaolinite
      1. Source of Kaolinite
      1. Uses of Kaolinite
      1. Chemistry of Kaolinite
    1. Occurrence of Kaolinite
    1. Aluminum
      1. Physical and chemical characteristic of aluminum
      1. Recycle  of aluminum
    1. Occurrence of aluminum
      1. Production and refinement of aluminum
      1. Compounds and halides of aluminums
    1. Application of aluminum
      1. History of aluminum
      1. Etymology of aluminum
      1. Aluminum alloys in structural application
    1. Alumina
      1. Effect of aluminum on plant
      1. Importance of aluminium to health
    1. Solvent extraction
      1. Solvent extraction of metal


  • Experimental methods
    • Materials
      • Sample collection
      • Reagents
      • Apparatus
    • Material and methods
      • Sample preparation
        • Grinding
        • Pulverilization/particle sizing
    • Characteristics of the samples
      • Aqueous metal analysis
    • Physio-analysis
      • Moisture content
      • Ash content
    • Dissolution and solvent extraction studies
      • Leaching procedure
      • Solvent extraction procedure
    • Total aluminium analysis
      • Total iron precipitation
      • Extraction of aluminum
      • Stripping process
      • Aluminum salt production


  • Result and discussion
    • Characterization studies
      • Chemical composition of ore
      • Photo-micrographic studies
      •  Aqueous metal analysis
    • Leaching studies
      • Effect of HCl concentration
      • Effect of temperature
      • Effect of particle sizes
      • Dissolution kinetic analysis
    • Solvent extraction studies
      • Total iron removal
      • Solvent extraction of copper
      • Stripping of aluminum form Dithizone

3.4       Proposal hydrometallurgical scheme

3.5       Conclusions

3.6       Recommendation

3.7       References

Extraction of Aluminium from Kaolin: a Comparative Study of  Hydrometallurgical Processes


    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-orangered 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 rainforest 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 illite 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 [8].

  1. Uses of Kaolinite

The largest use is in the production of paper, including ensuring the gloss on some grades of paper. Kaolin is or was used:

  • Ceramic: It is generally the main component in porcelain.
  • In toothpaste
  • As a light diffusing material in white incandescent light bulbs.
  • In cosmetic
  •  As paint to extend titanium dioxide (Ti02) and modify gloss levels.
  • For its semi-reinforcing properties in rubber.
  • In adhesives to modify rheology [9]
  • The production of common smoking pipes in Europe and Asia.
  •  In organic farming as spray applied to crops to determine insect damage, and in the case of apples to prevent sun scald.
  • As whitewash in traditional stone masonry homes in Napal. The most common method is to paint the upper part with white kaolin clay and the middle with red clay. The red clay many extend to the bottom or the bottom may be painted black.
  • As a filler in Edision diamond discs [10].
  • As an indicator in radiological dating since Kaolinite can contain very small traces of uranium and thorium.
  • To soot an upset stomach, similar to the way parrots (and later, humans) in South American originally, used it [11].More recently, industrially produced Kaolinite preparations were formally common for treatment of diarrhea, the most common of these was kaopectate, which abandoned the use of kaolin in favour of attapulgite and then (in the United States) bismuth subsalicylate (the active ingredient in pepto-bismol).
  • For facial mask or soap [12].
  • Rubber/rubber industries: Kaolin is used as filler in rubber industries. They need a maximum of 0/002 percent of its manganese content and 0.001 percent for its calcium content.
  •  Paper coating industries: For the production of white and fine paper its whiteness is dominant for paper coating.
  • Ceramic product: For the production of sanitary and table wares

Kaolin has many important applications and uses, kaolin used as filler, a suspending agent, extending agent and as a main continents. Because of its chemical composition, whiteness, particles size and other properties, kaolin is used as filler in the production of paints, rubber, paper and soap producing industries. Kaolin is eaten for health or to suppress hunger [13] a practice known as geophagy. Consumption is greater among women especially during pregnancy [14]. This practice has also been observed within a small population of African-American women in the Southern United State, especially Georgia [15]. There the kaolin is called white dirt, chalk or white clay chemistry of Kaolinite.

The chemical formula for Kaolinite as used in mineralogy is AL2SI2O5 (OH4) [16]. However, in ceramic applications the formula is typically written in terms of oxides, thus the formula, for Kaolinite is Al2O3.2SiO2.2H2O [17] cement chemist notation is even more tense: AS2H2, with the oxides represented as A=Al2O3, S=SI02. H=H20. Kaolinite group clays undergo a series in air at transformations upon thermal treatment in air at atmospheric pressure. Endothermic dehyxylation (or alternatively, dehydration) begins at 550-600˚c to produce disordered metkaolin, Al2Si207, but continuously hydroxyl loss (-OH) s observed up to 900˚c and has been attributed to gradual oxolation of the metakaolin [18] because of historic disagreement concerning the nature of the metakaolin phase, extensive research has led to general consensus that metakaolin is not a simple mixture of amorphous silica (SIO2) and Alumina (Al2O3), but rather a complex amorphous structure that retains some longer range order (but not strictly crystalline) due to stacking of its hexagonal layer [18].

          2AL2Si2O5 (OH)4 →2Al2Si207 + 4H20                         (1)

            Further heating to 925-9500c converts metakaolin to an aluminum silicon spinal Si3Al4O12, which is sometimes also referred to as gamma-alumina type structure.

            2AL2Si2O7 →SiAL4 012 + SiO2                                                   (2)

Upon calcinations to ˜1050˚c, the spinal phase (S13 Al4 O12) nucleates and transforms to mullite, 3Al2 O3.2SiO2, and highly crystalline cristobalite, SiO2

           3Si3 Al4 O12 → 2Si2 Al6 O13 + 5SiO2                                          (3)


Kaolinite is one of the most common mineral; it is mined as kaolin, in Vietnam, Brazil, Bulgaria, France, United Kingdom, Iron, Germany, India, Australia, Korea, the people’s republic of China, the Czech republic and the United State [19]. Kaolinite clay occurs in abundance in soils that have formed form the chemical weathering of rocks in hot-moist climates for example in tropical rainforest areas, comparing soils along a gradient towards progressively cooler of drier climates, the proportion of Kaolinite decrease while the properties of other, clay minerals such as illite (in cooler climate) or smeetite (in drier climate) increase, such climatically related differences in clay mineral content are often used to infer changes in climates in the geological past, where ancient soils have been buried and preserved [4].     

In the institute national pour L΄Etude Agronomiqueau Congo Belge (INEAC) classification system, soils in which the clay fraction is predominantly Kaolinite are called kaolisol (from kaolin and soil) [20]. In the US the main kaolin deposits are found in central Georgia, on a stretch of geological fall line between August and Macon. The deposits were formed between the late cretaceous an dearly paleogene, about 100 million to 45 million years ago, in sediments derived from weathering igneous and metamorphic rocks [21] kaolin production in the US during 2011 was 5.5 millions tones [16]. 


Aluminum (or aluminum) is a chemical element in the boron group with symbol Al and atomic number 13, it is silvery white, and it is not soluble in water under normal circumstance. Aluminums is the third most abundant element (after oxygen and silicon), and the most abundant metal, in the earth crust, it makes up about 8% by weight of the earth’s solid surface. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments instead, it is found combined in over 270 different minerals [22]. The chief or of aluminium is bauxite. Aluminium is remarkable for the metal’s low density and for its ability to resist corrosion due to the phenomenon of passivation. Structural component made from aluminums and its alloys are vital to the aerospace industry and are important in other areas of transportation and structural materials. The most useful compounds if aluminum, at least on a weight basis, are the oxides and sulfates. Despite its prevalence in the environment, aluminum salts are not known to be used by any form of life. In keeping with its pervasiveness, aluminums are well tolerated by plants and animals [23] owing to their prevalence, potential beneficial (or other wise) biological roles of aluminum compounds are of continuing interest.

  1. Physical and chemical characteristics of aluminums

Physical characteristics

Aluminium is a relatively sot, durable, light weight, ductile and malleable metal with appearance ranging from silvery to dull gray, depending on the surface roughness. It is non-magnetic and does not easily ignite. A fresh film of aluminium serves as a good reflection (approximately 92%) of visible light and an excellent reflector (as much as 98%) of medium and far infrared radiation. The yield strength of pure aluminium is 7-11Mpa while aluminium alloys have yield strength ranging form 200Mpa to 600Mpa [24] aluminiun has about one-third the density and shiftiness of steel. It is easily machined, cast, drawn and extruded. Aluminium atoms are arranged in a face-centered cubic (fcc) structure. Aluminum has stacking-fault energy of approximately 200mj/m2 [25]. Aluminium is a good thermal and electrical conductor, having 59% the conductivity of copper, both thermal and electrical, while having only 30% of copper’s density. Aluminium is capable of being a superconductor with a super conducting critical temperature of 1.2 Kelvin and a critical magnetic filed of about 100 gauss (10 milliteslias) [26].

Chemical characteristics

            Corrosion resistance can be excellent due to a thin surface layer of aluminium oxide that forms when the metal is exposed to air, effectively preventing further oxidation, the strongest aluminium alloys are less corrosion resistance due to galvanic reactions with alloyed copper [24]. This corrosion resistance is also often greatly reduced by aqueous salts, particularly in the presence of dissimilar metals. Owing to its resistance to corrosion, aluminium is one of the few metals that retain silvery reflectance in finely powered form, making it an important component of silver0colored paint. Aluminium mirror finish has the hugest reflectance of any metal in the 200-400nm (uv) and the 3, 000-10000nm.

(Far IR) regions, in the 400-700nm visible range it is slightly out performed by tin and silver and in the 700-3000 (near IR) by silver, gold and copper [27].

            Aluminium is oxidized by water to produce hydrogen and heat.

                           2Al + 3H20 – Al2)3 + 3H2                                       (4)

            This conversion is of interest for the production of hydrogen. Challenges include circumventing the formed oxide layer which inhibits the reaction and the express associated with the storage of energy by regeneration of all metal [28].

  1. Recycling of aluminium

Aliminium is theoretically 100% recyclable without any loss of its natural qualities. According to the international resources panel’s metal stocks in society report, the global per capital stock of aluminum in use in society (i.e. in cars, building, electronic etc) is 80kg, much of this is in more-developed countries (350-500kg per capital) rather than less-developed countries (35kg per capital0 knowing the per capital stocks and their approximate life span is important for planning recycling. Recovery of the metal via planning has become an important use of the aluminum industry. Recycling was a low-profile activity until the late 1960s, when the growing use of aluminium beverages cans brought it to the public awareness. Recycling involves melting the scrap, a process that requires only 50% of the energy used to produce aluminium from ore, through significant part (up to 15% of the input material) is lost as dress (ash-like oxides) [29], the dross can undergo a further [process to extract aluminum. In Europe aluminum experiences high rates of recycling, ranging form 42% if beverage cans, 85% of construction materials and 95% of transport vehicles [30].

Recycling aluminum is known as secondary aluminium, but maintains the same physical properties as primary aluminium. Secondary aluminium us produced in a wide range of formats and are employed in 80% of alloy injections. Another important use is for extrusion. White dross from primary aluminium production and form secondary recycling operation still contains quantities of aluminium that can be extracted industrially [31]. The process produced aluminium billets, together with highly complex waste materials. This waste releasing a mixture of gases (including, among others, hydrogen, acetylene and ammonia), which spontaneously ignites on contact with air, [31] contact with damp air result in the release of copious quantities of ammonia gas. Despite these difficulties, the waste has found use as filler in asphalt and concrete [32].


In the earth’s crust, aluminium is the most abundant (8.3% by weight) metallic element and the third most abundant of all element (after oxygen and silicon) [23]. Because of its strong affinity to oxygen, it is almost never found in the elemental state; instead it is found in oxides or silicates. Feldspars, the most common groups if mineral in the earth’s crust, are aluminosilicates. Native aluminium metal can only be found as a minor phase in low oxygen fugacity environment, such as the interiors of certain volcanoes [34].

In the Northern Eastern continental slope of the south China sea and Chen et al [35] have proposed a theory of its origin as resulting by reduction from tetrahydroxoaluminate Al (OH)4 to metallic aluminium by bacteria [35].

It also occurs in the minerals Berl, Cryolite, garnet, spinel and turquoise. Impurities in Al2O3, such as chromium or iron yield the gemstone ruby sapphire, respectively. Although aluminium is an extremely common and widespread element, the common aluminium minerals are not economic sources of the metal. Almost all metallic aluminium is produced form the ore bauxide (AlOx (OH)3-2x). Bauxide occurs as a weathering product of low iron and silica bedrock in tropic climatic condition [36]. Large deposits of bauxite occur in Australia, Brazil, Guinea and Jamaica and the primary mining areas for the ore are in Australia, Brazil, China, India, Guinea, Indonesia, Jamaica, Russia and Suriname.



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