Zeolitic tuffs as raw materials for lightweight aggregates

作者：Roberto de’Gennaro, Piergiulio Cappelletti, Guido Cerri, M. de’Gennaro, Michele Dondi, Alessio Langella · 发表于：Applied Clay Science · 年份：2003 · DOI：10.1016/j.clay.2003.08.005 · 被引用次数：145 · 研究领域：Recycling and utilization of industrial and municipal waste in materials production、Concrete and Cement Materials Research、Geological and Geochemical Analysis

The aim of this research is to assess the possible use of Italian zeolitic rocks for the production of lightweight aggregates. In particular, both the expansion at high temperature and the technological features of fired products were investigated. Fifteen zeolite-bearing volcanoclastites from Northern Sardinia and three zeolitized tuffs from Campania and Tuscany (Sorano and Campanian ignimbrites and Neapolitan Yellow Tuff) were taken into account. The firing expansion turned out to be mainly dependent on the chemical composition (especially SiO 2 and fluxing oxides such as Fe 2 O 3 , Na 2 O, K 2 O, MgO and CaO) and the water content (largely related to the zeolite amount) of the raw materials. Other relevant parameters were the temperature of maximum expansion (ranging between 1350 and 1500 °C, without additives) and soaking time (between 2 and 5 min). Some products are highly impervious to water (water absorption below 1%) and exhibit a considerable firing expansion (>100% in volume), a low bulk density (0.5–0.7 g·cm −3 ) and fair technical properties (loose weight and strength of particles). These encouraging results make some of the investigated tuffs interesting raw materials for the production of lightweight aggregates.