Showing papers by "Francisca Puertas published in 1996"
TL;DR: In this article, the chemical and structural stability of Spanish sepiolite from Vallecas, Spain was studied in 0.04 N NaOH (pH = 12.6), a saturated solution of Ca(OH)2 and deionized/ distilled water.
Abstract: A B S T R A C T: The chemical and structural stability of a Spanish sepiolite from Vallecas, Spain, was studied in 0.04 N NaOH (pH = 12.6), a saturated solution of Ca(OH)2 (pH = 12.6) and deionized/ distilled water (pH = 7). The chemical stability was evaluated by determining the concentrations of Mg, Si and Ca in the solid residues during the kinetic test. The structural stability was studied by determining the changes in specific surface area and 'crystallite' size. The specific surface was determined by the BET method and the 'crystallite' size by the profile of the X-ray diffraction line. The main conclusion was that sepiolite is a material with high chemical stability in neutral and alkaline media, with no significant structural changes. However, in alkaline media, greater dissolution of silica was observed than in neutral media, the silica being derived from the most external tetrahedra attached to the OH- groups.
15 citations
TL;DR: In this article, the burnability of white cement raw mixes made using CaF2 and CaSO4 as fluxes/mineralizers is studied and modelled using a methodology based on a statistical method called experimental design.
13 citations
TL;DR: In this paper, the influence of KOH presence on the evolution of hydration and carbonation of high alumina cement mortars at two different curing temperatures (4 and 40 °C) has been studied.
Abstract: The influence of KOH presence on the evolution of hydration and carbonation of high alumina cement mortars at two different curing temperatures (4 and 40 °C) has been studied. It has been confirmed that hydration reactions at both temperatures are accelerated with KOH presence and it has a great influence on hydrated and carbonated species. The massive deposition of carbonation products leads, in all cases to a decrease in mortar porosity which leads to an increase of mechanical strengths.
12 citations
TL;DR: The influence of sand nature on the burnability of white cement raw mixes manufactured using CaF2 and CaSO4 as flux and mineralizer has been studied in this article, where a methodology based on a statistical method called Experimental Design is used to establish a model.
8 citations