A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
The dissolution behavior and mechanism of kaolinite in alkali-acid leaching process
AbstractKaolinite is a typical silicate impurity in microcrystalline graphite ore. Removal of kaolinite from graphite ores is important to achieve high purity graphite product. Alkali-acid leaching is effective to remove silicate impurity in microcrystalline graphite. For in-depth understanding of phase transformation of kaolinite in microcrystalline graphite purification process, dissolution behavior and mechanism in alkali-acid leaching process were studied in this paper. As shown in alkali-acid leaching tests and analyses (FTIR, XRD, and SEM-EDS), silicon extraction of kaolinite was mainly affected by sodium hydroxide concentration, alkali-leaching temperature, and alkali-leaching time. The dissolution mechanism of kaolinite was regarded as a three-stage process: kaolinite firstly dissolved in alkaline solution in form of soluble silicate and aluminate. Dissolved silicate and aluminate in alkaline solution then reacted with each other and aluminosilicate transient phase with Si/Al≈1 precipitated when silicon ion concentration exceeded its equilibrium concentration. Finally, the aluminosilicate precipitate composed of nepheline and sodalite dissolved in hydrochloric acid solution. As a consequence, kaolinite dissolved completely in alkali-acid leaching process.
HighlightsIncreasing alkali-leaching temperature, alkali concentration and alkali-leaching time would all improve the solubility of kaolinite.Dissolution of kaolinite in alkali-acid leaching process was a three-stage process.The main aluminosilicate phase was zeolite HS and sodalite when alkali-leaching temperature was below 513K and nepheline-hydrate at 513K
The dissolution behavior and mechanism of kaolinite in alkali-acid leaching process
AbstractKaolinite is a typical silicate impurity in microcrystalline graphite ore. Removal of kaolinite from graphite ores is important to achieve high purity graphite product. Alkali-acid leaching is effective to remove silicate impurity in microcrystalline graphite. For in-depth understanding of phase transformation of kaolinite in microcrystalline graphite purification process, dissolution behavior and mechanism in alkali-acid leaching process were studied in this paper. As shown in alkali-acid leaching tests and analyses (FTIR, XRD, and SEM-EDS), silicon extraction of kaolinite was mainly affected by sodium hydroxide concentration, alkali-leaching temperature, and alkali-leaching time. The dissolution mechanism of kaolinite was regarded as a three-stage process: kaolinite firstly dissolved in alkaline solution in form of soluble silicate and aluminate. Dissolved silicate and aluminate in alkaline solution then reacted with each other and aluminosilicate transient phase with Si/Al≈1 precipitated when silicon ion concentration exceeded its equilibrium concentration. Finally, the aluminosilicate precipitate composed of nepheline and sodalite dissolved in hydrochloric acid solution. As a consequence, kaolinite dissolved completely in alkali-acid leaching process.
HighlightsIncreasing alkali-leaching temperature, alkali concentration and alkali-leaching time would all improve the solubility of kaolinite.Dissolution of kaolinite in alkali-acid leaching process was a three-stage process.The main aluminosilicate phase was zeolite HS and sodalite when alkali-leaching temperature was below 513K and nepheline-hydrate at 513K
The dissolution behavior and mechanism of kaolinite in alkali-acid leaching process
Wang, Hao (author) / Feng, Qiming (author) / Liu, Kun (author)
Applied Clay Science ; 132-133 ; 273-280
2016-06-19
8 pages
Article (Journal)
Electronic Resource
English
The dissolution behavior and mechanism of kaolinite in alkali-acid leaching process
| Online Contents | 2016
The dissolution behavior and mechanism of kaolinite in alkali-acid leaching process
| Online Contents | 2016
Some Aspects of hydrochloric acid-leaching of kaolinite clay
| TIBKAT | 1985