Calcination of mega-crystalline calcite using microwave and electric furnaces

Rapid calcination of ferrite Ni0.75Zn0.25Fe2O4 by microwave energy

“…The heat generated by the microwaves, the energy of electromagnetic wave is moved within the particles where there is a conversion into kinetic energy of electrons, ions, molecules, and crosslinked, wherein the material temperature increases. The heating by microwave energy does not rely on heat conduction, the particle is heated from the inside by the electronic polarization and interfacial polarization atomic polarization, the heat being transferred to the surface of the particles [47]. Based on the micrographs, it was observed that all Ni-Zn ferrite samples showed significant porosity degree, thus varying material density, with values close to the theoretical value of 5.30 gcm -3 , as shown in Table 2.…”

“…In the microwave energy heating, a temperature gradient occurs because the interior of the particle is at high temperature, and its outer surface is at low temperature, resulting in deformation and internal fusion, which provides a fast thermal decomposition [47]. Figure 3 shows the infrared spectra of ferrite Ni 0.75-Zn 0.25 calcined by microwave energy at 500 and 650°C for 30 min.…”

Preparation of high purity PCC from medium- and low-grade limestones using the strongly acidic cation exchange resin

“…1(a)). Calcination conditions for limestone were 950 8C for 60 min (heating rate 19 8C/min, sample weight: 500 g) [1][2][3].…”

“…However, SiO 2 in limestone directly affects the resulting purity. Generally, the impurity limit of limestone is less than 4-5% of (SiO 2 + Al 2 O 3 + Fe 2 O 3 ) and 0.1-0.2% of (Na 2 O + K 2 O) [1][2][3].…”

“…Lime of high reactivity and calcination degree can be obtained inexpensively using a microwave kiln compared to a shaft kiln or rotary kiln. However, the microwave kiln suffers technical problems that need to be solved for commercialization [1][2][3].…”