Effect of the limestone fabric on the fabric development in burnt lime

Summary: The lime textures have an important impact on the carbon dioxide flux transported through the material during calcination. Therefore the calcination time of the limestones is different. The texture of lime is formed by the micropores, mesopores, macropores, microcracks and macrocracks. The microcracks and macrocracks are the fast diffusion ways. Big changes in the pore sizes, microcrack and macrocrack sizes in lime are the reason that it makes no sense to use the free space hydraulic diameter in the carbon dioxide flux calculation. The texture of lime is regarded in the calculation by the use of porosity – tortuosity factor (v/t) and specific permeability (P) of lime, if the dusty-gas model is applied for the calculation. The carbon dioxide flux through lime may be calculated using the lime specific permeabilty P, if D’Arcy’s equation is applied in the calculation.

1 Introduction

The thermal decomposition time of a limestone lump depends on the type of limestone, the dimensions of the lump and the thermodynamic conditions of calcination [1]. Different values of the lime properties can be of importance [1–6]. Especially the carbon dioxide flux during calcination depends on the texture of the material. The texture [7, 8] of a porous medium is described using e.  g. specific porosity of the medium, which is related to texture and refers to the pore space in the medium, specific permeability [9], pore size distribution, mean pore size, specific surface area,...

Related articles:

Contraction in layers of particles of ­selected limestones as a result of thermal decomposition

Investigations of the contraction of layers of limestone particles were performed using samples of the Devonian, Carboniferous and Jurassic limestones of the Trzuskawica, Czatkowice and Bukowa...


Thermophysical properties of lime as a function of origin (Part 4): Thermal conductivity

1 Introduction The calcination behavior of limestone, which is a natural raw material, depends strongly on the origin. In this multi-part series, the thermo-physical material properties of limestone...

Issue 02/2010

Thermophysical properties of limestone as a func­tion of origin (Part 1): Specific heat capacities

1 Introduction The calcination of limestone is a complex process, due to the variety of parameters which exert an influence on it. These parameters are related not only to the type of kiln and its...

Issue 06/2010

Thermophysical properties of limestone as a function of origin (Part 2): Calcination enthalpy and equilibrium temperature

1 Introduction For the energy evaluation of the calcination process in kilns two enthalpy values are required: the enthalpy at normal temperature and the enthalpy at decomposition temperature. The...


Influence of material properties on the decomposition time of limestone under shaft kiln conditions

1 Introduction The decomposition of limestone is an endothermic topochemical reaction: CaCO3    +           ?HR  =            CaO   +   CO2 (solid)     (reaction enthalpy) ...