subject: Main Factors Working On Perlite Expansion [print this page] The experts have done a lot of experimental research, vitreous ore content and expansion ratio (K) is generally positive correlation between the correlation coefficients> 0.70. If the ore has a large number of phenocrysts, devitrified strongly the formation of crystalline mineral or young crystal or visible flow pattern is constructed or brecciated structure, the expansion of multiples will be lower. But in addition, also the main are the following:
(A) preheating temperature
Perlite expansion process, the internal driving force for expansion of the remaining water in the perlite, but too much water will cause swelling to rupture to affect the expansion factor, moisture content too little makes the expansion of the lack of will also affect the expansion of multiples, and only in moderate amounts containing water case, the perlite in the final expansion process (the actual use of the process) in order to achieve the greatest expansion of multiples, perlite ore mining, the original water content too much, therefore, after crushing and screening, generally, in under certain temperature warm-up to the size of the different, with the preheating temperature to remove excess water, the final expansion of multiples are not the same.
(2) warm-up time
Warm-up time multiples of the final expansion, because the length of the warm-up time for perlite in the residual water content, the longer the warm-up time, the less residual moisture content; the contrary, more. To this end, the warm-up time on the final expansion in multiples.
(3) screening granularity
Relatively certain other conditions, if the particle size is too small, due to softening of the excessive influence popping fold, particle size is too large, occur puffing phenomenon of particle core part, resulting in reduced popping fold.
(4) expansion temperature
Expansion temperature is too low, without the risk of puffing the perlite failed to meet the softening temperature; temperature is too high over ore softening or melting the smaller particle size, the parcel could not stressful steam. Only in the proper range, puffed effect was the best.
(5) expansion time
Expansion of the time will also affect the puffing effect, a long time, perlite particle moisture lost too much, puffed effect is not good.
(6) pressure
In addition to the above factors, the pressure is also a factor. The size of the pressure, a direct impact on the external pressure of the expanding perlite. Thus affecting the expansion process of perlite.
Residual water content (7)
Perlite by the residual water content after the warm-up is caused by expansion of the main reason for the residual water content in the perlite is caused by a major factor in expanding perlite.
(8) The chemical composition
Perlite of different origin have different chemical composition, but with different chemical composition of perlite, its expansion properties are not the same. SiO2 and AI2O3, is the cause of the chemical composition of perlite when the temperature quickly soften and maintain a certain viscosity at high temperatures, so their content will directly affect the perlite at a high temperature viscosity, thus affecting the performance of perlite expansion ; Na2O/K2O ratio of the increase of the ratio can lead to high temperature the perlite viscosity reduction, resulting in perlite softening point decline; Fe2O3 + FeO, its content will lead to lower multiples of perlite expansion.
