KINETIC MODEL FOR IDENTIFYING THE RATE CONTROLLING STEP OF THE ALUMINUM LEACHING FROM PEAT CLAY

The aluminum (Al) leaching kinetics from peat clay was investigated using various acid concentrations 1 M to 6 M, particle sizes +70-120 mesh to +200-325 mesh and temperatures 30 °C to 90 °C. They all have significant effects on aluminum leaching process. The Al leaching recovery was best found to be 91.3 % at 4 M hydrochloric acid (HCl), using a particle size of +200-325 mesh with solid/liquid of 0.02 g·ml-1. Leaching kinetic study was applied to the two rate equations proposed that is acid diffusion via product layer and surface chemical reaction using the shrinking core (SC) model to analyze the leaching data. The product layer diffusion is controlling Al leaching process for one-stage model, while for two-stage model, it was controlled by surface chemical reaction. The activation energy in the two rate controlling step was 82.79 kJ mol-1 and 27.08 kJ mol-1, respectively.

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Dissolution kinetics of cerussite in an alternative leaching reagent for lead

Chemical Papers ◽

10.1515/chempap-2015-0034 ◽

2015 ◽

Vol 69 (3) ◽

Cited By ~ 6

Author(s):

Qi-Cheng Feng ◽

Shu-Ming Wen ◽

Yi-Jie Wang ◽

Qin-Bo Cao ◽

Wen-Juan Zhao

Keyword(s):

Dissolution Kinetics ◽

Product Layer ◽

Surface Chemical ◽

Surface Chemical Reaction ◽

Mixed Control ◽

Shrinking Core ◽

Two Stages ◽

Kinetics Of ◽

And Diffusion ◽

Rate Controlling Step

AbstractThe dissolution kinetics of cerussite was investigated using methanesulphonic acid (MSA) as an alternative leaching reagent. The effects of particle size, stirring speed, acid concentration, and reaction temperature on the lead dissolution rate were determined. The dissolution process followed the kinetic law of the shrinking-core model, and a corresponding mixed control model was found suitable for representing the rate-controlling step. The mixed kinetic model comprised two stages: surface chemical reaction (283 K to 303 K) and diffusion through the product layer (303 K to 323 K). The activation energies of these sequential stages were 43.20 kJ mol

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Kinetics of Atmospheric Acid Leaching of a Limonitic Laterite

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.319.14 ◽

2013 ◽

Vol 319 ◽

pp. 14-18

Author(s):

Kui Liu ◽

Xi Liu

Keyword(s):

Atmospheric Pressure ◽

Acid Leaching ◽

Shrinking Core Model ◽

Surface Chemical ◽

Surface Chemical Reaction ◽

Nickel Laterite ◽

Shrinking Core ◽

Semi Empirical ◽

Kinetics Of ◽

Rate Controlling Step

A limonitic nickel laterite was leached by sulfuric acid at atmospheric pressure. Kinetics of leaching within the temperature range of 75-100°C was studied. The leaching kinetics followed the shrinking core model. The diffusion through the liquid film could be negligible under the agitation speed of 600rpm or above. Surface chemical reaction was the rate-controlling step. The semi-empirical kinetic equation was determined and the activation energy was 52.843kJ/mol.

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Leaching Kinetics and Seperation of Antimony and Arsenic from Arsenic Alkali Residue

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.402.57 ◽

2011 ◽

Vol 402 ◽

pp. 57-60 ◽

Cited By ~ 1

Author(s):

Gui Sheng Zeng ◽

Hui Li ◽

Su Hua Chen ◽

Xin Man Tu ◽

Wen Bin Wang

Keyword(s):

Shrinking Core Model ◽

Leaching Kinetics ◽

Surface Chemical ◽

Leaching Rate ◽

Kinetics Equation ◽

Surface Chemical Reaction ◽

Liquid Ratio ◽

Shrinking Core ◽

Solid Liquid ◽

Kinetics Of

The separation of antimony and arsenic and leaching kinetics of arsenic from arsenic alkali residue were investigated. The influencing factors such as solid/liquid ratio, stir speed, temperature and time on leaching of arsenic were studied. The results show that the leaching rate reaches 87.75% at the condition of solid/liquid ratio of 1:4 , stir speed of 600r/min ,temperature of 90°C and time of 60min. The leaching process was controlled by the surface chemical reaction and the kinetics of leaching arsenic followed the model of shrinking core. The activation energy was found to be 666.57kJ/mol. The kinetics equation was expressed as shrinking core model.

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