Dissolution kinetics of Amazonian metakaolin in nitric acid

Lima, P. E. A. de; Angélica, Rômulo Simões; Neves, R. F.

doi:10.1590/0366-69132018643692179

Cited by 11 publications

(3 citation statements)

References 19 publications

(27 reference statements)

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“…They also found out that the process is controlled by reaction at interface between solid and liquid phases. On the other hand, leaching with phosphoric acid was researched by Hernández et al [18] working on a Mexican type of kaolin (Hidalgo).…”

Section: Introductionmentioning

confidence: 99%

Utilization of Kalapsha Kaolin to Prepare High Purity Alumina

Aly¹,

Ibrahim

Abadir

2019

Egypt. J. Chem.

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K ALABSHA kaolin was calcined at 700 o C then treated with hydrochloric acid to produce aluminum chloride hexahydrate. The hexahydrate was obtained in crystalline form through injection of hydrogen chloride gas in saturated solution and purified on several steps to obtain alumina of high purity. Acid leaching conditions, namely, acid to kaolin stoichiometric ratio(S), reaction time (t) and reaction temperature (T) were optimized using surface response methodology. A maximum alumina recovery of 83.2% was predicted on using 1.4 stoichiometric acid to solid ratio, a reaction temperature of 104 o C and a reaction time of 3 hours. This result was then assessed experimentally. The hexahydrate crystals obtained were subsequently purified in a three stage process to increase their purity to 99.961%. Calcination of these crystals for 4 hours at 1100 o C produced highly crystalline alumina with purity 99.9%.

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Section: Introductionmentioning

confidence: 99%

Utilization of Kalapsha Kaolin to Prepare High Purity Alumina

Aly¹,

Ibrahim

Abadir

2019

Egypt. J. Chem.

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“…For easy leaching of aluminium from kaolin aluminosilicate structure, the bonds holding structure must be broken down. This is achieved by calcinating kaolin, transforming its structure to amorphous metakaolin structure, which is more reactive form of kaolin towards dissolution agents than raw kaolin [37,38]. Upon heating, kaolin structure breaks down into small pieces resulting into increased surface area for dissolution agents to react with aluminium oxide easily, as in bauxite rock [19].…”

Section: Characterization Of Kaolinmentioning

confidence: 99%

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

et al. 2019

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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.

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“…e rate of extraction of aluminum from metakaolinite has been fastest with hydrochloric acid and slowest with nitric acid. Moreover, the hydrochloric acid extraction method has been suitable for selective separation of aluminum chloride from slurry solutions during the filtration process [2,14,15]. e main reaction of metakaolinite with hydrochloric acid is given by the following equation [16].…”

Section: Introductionmentioning

confidence: 99%

Characterization and Optimization of Calcination Process Parameters for Extraction of Aluminum from Ethiopian Kaolinite

Kassa

Shibeshi

Tizazu

2022

International Journal of Chemical Engineering

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The present study aimed to optimize the calcination process parameters (viz., temperature, time, and particles size) for the extraction of aluminum from Ethiopian kaolinite. The kaolinite calcination was done in the temperature of 600–700°C, time of 120–180 min, and particles size of 106–355 μm. The extraction of aluminum from calcined kaolinite was carried out at fixed acid concentration of 3 M, temperature of 80°C, liquid-to-solid ratio of 12 mL g−1, time of 120 min, and stirring speed of 700 rpm. The chemical composition of kaolinite was determined using XRF. Moreover, kaolinite, metakaolinite, and extracted aluminum were characterized by XRD, TGA, DSC, and FTIR. The XRF result of the kaolinite was mainly silicon oxide (55.76% w/w), aluminum oxide (32.02% w/w), and loss on ignition (11.17% w/w). Calcination of kaolinite produced amorphous metakaolinite due to the dehydroxylation reaction as shown by the FTIR results. Three endothermic peaks and one exothermic peak were detected in the thermal analysis of the kaolinite due to water removal, impurities decomposition, dehydroxylation reaction, and phase change from metakaolinite to spinel, respectively. The extracted aluminum proportionally increased with kaolinite calcination temperature and time. However, the extracted aluminum increased as the particles size reduced. The extracted aluminum was in the form of aluminum chloride hexahydrate and trigonal crystalline structure. The optimum values of the degree of conversion of kaolinite dehydroxylation reaction and extracted aluminum of 0.992 and 71.28% w/w were obtained at the optimum kaolinite calcination temperature of 700°C, time of 180 min, and particles size of 106 μm, respectively.

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Dissolution kinetics of Amazonian metakaolin in nitric acid

Cited by 11 publications

References 19 publications

Utilization of Kalapsha Kaolin to Prepare High Purity Alumina

Utilization of Kalapsha Kaolin to Prepare High Purity Alumina

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

Characterization and Optimization of Calcination Process Parameters for Extraction of Aluminum from Ethiopian Kaolinite

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