Hydrometallurgical extraction of Al and Si from kaolinitic clays

Pinna, Eliana Guadalupe; Suarez, Daniela Silvana; Rosales, Gustavo D.; Rodríguez, M. H.

doi:10.1590/0370-44672017700006

Cited by 16 publications

(8 citation statements)

References 17 publications

(25 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given that activation energy is the energy barrier that must be surmounted for a reaction to occur; the lowering of this energy means that leaching ing it difficult for acid attack. Similar findings were reported in literature [36] [44]. As shown in Figure 10, values of activation energy varied between the extremes of the high values reported for the uncalcined clay (at ~25˚C) and those for samples calcined at 1000˚C; reaching the lowest value of 24.26 kJ/mol at 600˚C.…”

Section: Effect Of Thermal Treatment On Activation Energysupporting

confidence: 88%

“…However, the XRD pattern for the optimal clay calcine (Figure 3) shows that the sharp kaolinite peaks in Figure 2 are no longer distinct. The disappearance of the kaolinite peaks is indicative of the appearance of an amorphous phase (metakaolinite) due to thermal transformation or complete dehydroxylation of the clay [35] [36]. A study of the phase transformations of kaolinite from different deposits in Russia and Ukraine showed similar observations [37].…”

Section: Type and Composition Of Claymentioning

confidence: 99%

“…It is this amorphous metakaolinite (Al 2 O 3 •2SiO 2 ) that releases its alumina (Al 2 O 3 ) for dissolution making the clay respond to acid leaching. Thus, proper thermal treatment and transformation of the clay activates it for acid leaching [30] [36]. The extent of dissolution was expressed in percentage or as a fraction where the fraction of Al ions (X Al ) leached out of the clay into the solution was given as…”

Section: Type and Composition Of Claymentioning

confidence: 99%

See 2 more Smart Citations

Effect of Calcination Condition on Thermal Activation of Ibere Clay and Dissolution of Alumina

Mark¹,

Anyakwo²,

Onyemaobi³

et al. 2019

IJNM

View full text Add to dashboard Cite

Bauxite deposits for production of alumina are lacking in Nigeria and there is an aluminium smelter plant in the country which requires alumina for its operation. Development of alternative alumina resource using clays that are abundant in the country is the focus of this paper. The thermal activation of Ibere clay from southeastern Nigeria for optimal leaching of alumina was investigated. The clay assayed 28.52% Al 2 O 3 and 51.6% SiO 2 , comprising mainly kaolinite mineral and quartz or free silica. The alumina locked up in the clay structure was rendered acid-soluble by thermal activation which transformed the clay from its crystalline nature to an amorphous, anhydrous phase or metakaolinite. The clay samples were heated at calcination temperatures of 500˚C, 600˚C, 700˚C, 800˚C, and 900˚C at holding times of 30, 60, and 90 minutes. Uncalcined clay samples and samples calcined at 1000˚C (holding for 60 minutes) were used in the control experiments. The result of leaching the clay calcines in 1 M hydrochloric acid solution at room temperature, showed that the clay calcines produced at 600˚C (holding for 60 minutes) responded most to leaching. Samples calcined for 60 minutes also responded better than those held for 30 or 90 minutes. Based on activation energy studies, it was observed that calcines produced at 600˚C (for 60 minutes) had both the highest leaching response (50.27% after 1 hour at leaching temperature of 100˚C) and the lowest activation energy of 24.26 kJ/mol. It is concluded therefore that Ibere kaolinite clay should be best calcined for alumina dissolution by heating up to 600˚C and holding for 60 minutes at that temperature. The clay deposit has potential for use as alternative resource for alumina production in Nigeria where bauxite is scarce.

show abstract

Section: Effect Of Thermal Treatment On Activation Energysupporting

confidence: 88%

Section: Type and Composition Of Claymentioning

confidence: 99%

Section: Type and Composition Of Claymentioning

confidence: 99%

See 1 more Smart Citation

Effect of Calcination Condition on Thermal Activation of Ibere Clay and Dissolution of Alumina

Mark¹,

Anyakwo²,

Onyemaobi³

et al. 2019

IJNM

View full text Add to dashboard Cite

show abstract

“…On the other hand, the silica was easily soluble in alkaline solutions, especially NaOH, and was able to penetrate the capillaries in ash and consequently dissolve the silica. According to Pinna et al (2017), the magnitude of the concentration of alkaline solution will affect the power to dissolve the solute; the greater the concentration of the alkaline solution, the greater the yield produced. Figure 2 shows the characterization results of the alumina and silica extracted.…”

Section: Characterizationmentioning

confidence: 99%

Triacetin Production From Glycerol Using Heterogeneous Catalysts Prepared From Peat Clay

Yanti¹,

Hesty²,

Putra³

et al. 2019

IJTech

View full text Add to dashboard Cite

Glycerol, an abundant by-product of biodiesel production, is urgently considered to increase its usage. Triacetin produced from glycerol is an important material, used in polyester, cryogenics, cosmetics and as a biodiesel additive. Using homogeneous catalysts in triacetin production involves high product separation costs. The purpose of this study is to synthesize heterogeneous catalysts based on alumina and silica from peat clay for use in the production of triacetin from glycerol. The conversion of glycerol for triacetin production using such alumina and silica catalysts yielded levels of 82.7% and 87.4%, respectively. These values were greater than the conversion value of 71.2% using a sulfuric acid homogeneous catalyst. An optimum conversion of 91% was obtained at the mole ratio of glycerol to acetic acid of 8.9. The potential heterogeneous catalysts were confirmed by the results of SEM, XRD and BET characterization. Therefore, the production of triacetin using heterogeneous silica catalyst could be an alternative approach in commercial processes which currently using homogeneous catalysts.

show abstract

“…Such combination tannings are reported to produce leather with quality comparable to those tanned by chromium-based salts [11,14,16]. Normally, commercial Al 2 (SO 4 ) 3 is industrially produced using bauxitic rocks as a raw material (20-30% of aluminium content) [17][18][19]. However, relying on bauxite has some limitations as it is globally diminishing and scarcely present in commercial quantity in most of the developing countries [20].…”

Section: Introductionmentioning

confidence: 99%

Preparation of aluminium sulphate from kaolin and its performance in combination tanning

et al. 2019

View full text Add to dashboard Cite

Leather making commonly use chromium salts to produce high quality products. However, the use of chromium salts is compromised by environmental safety concerns. Combination tanning using vegetable tanning coupled with aluminium sulphate can sustainably replace chrome tanning system. Adversely, the use of commercial aluminium sulphate poses economic burden that entails for cost effective sources. Abundance of kaolin on earth's crust with scarce utilization is an opportunity towards cost effective aluminium sulphate for tanning. Therefore, in the present work aluminium sulphate was prepared from kaolin and its performance for combination tanning was studied. Diffraction and vibrational spectroscopic studies were carried out to confirm the prepared aluminium sulphate. Combination tanning was carried out with mimosa vegetable tannins. Leathers tanned with the combination of aluminium sulphate from kaolin and mimosa vegetable tannin exhibited hydrothermal stability of up to 118 °C as compared to mimosa alone that showed the average of 80 °C. Physical strength characteristics met the standard norms. Fibers separation was good as confirmed through microscopic studies. The study provides a new insight on accomplishing self-sustenance through available resources and eco-friendly manufacturing system.

show abstract

Hydrometallurgical extraction of Al and Si from kaolinitic clays

Cited by 16 publications

References 17 publications

Effect of Calcination Condition on Thermal Activation of Ibere Clay and Dissolution of Alumina

Effect of Calcination Condition on Thermal Activation of Ibere Clay and Dissolution of Alumina

Triacetin Production From Glycerol Using Heterogeneous Catalysts Prepared From Peat Clay

Preparation of aluminium sulphate from kaolin and its performance in combination tanning

Contact Info

Product

Resources

About