Use of zeolitic tuffs as cement additives, building stone and removal of heavy metal cations

Abstract

The chabazitic and phillipsitic tuffs presented in this study are located in the south of Sandi{dotless}kli{dotless} (Afyon-west Anatolia). In this district there are important zeolitic resources. In petrographic investigations of tuffs, optical microscopy, SEM, and XRD methods were used for mineral analysis. Trachyte/ trachyandesitic tuffs contain chabazite and tephriphonolitic tuffs contain chabazite and phillipiste. According to the XRD results, chabazite occurs in the Ca-form; phillipsite is in the Na-K, K, and K,Caforms. Zeolite contents of tuffs (52.41-58.59 wt. %) were determined by using a heavy liquid method. Physical and mechanical tests of tuffs for using as building stone have been done in accordance with the Turkish Standard (TS 699). Zeolitic tuffs according to rock classification based on porosity fall in to the "very porous rock" category, and according to rock classification based on uniaxial compressive strength fall in to the "very low strength rock" category. The removal performance of heavy metal ions (Cu2+, Zn2+ and Ni2+) in aqueous solution were investigated by adsorption process on chabazitic and phillipsitic tuffs. The selectivity sequence was determined as Cu > Zn > {all equal to}Ni for chabazitic tuffs, and as Cu > Ni > {all equal to}Zn for phillipsitic tuffs. The major chemical components of the trass, along with the flexural and compressive strengths of the pozzolana mortar, conform well to the requirements of both the ASTM and the Turkish Standard TS 25 (TS EN 196-1). The chemical, physical, and mechanical properties of the blended cement mortar prepared with 15% and 30% zeolitic tuff additive are in accordance with the Turkish Standard (TS EN 197-1), and according to the results of experiments they can be mixed in the OPC and used as blended cement. These results show that zeolitic tuffs are used as blend materials and building stone, and to remove heavy metal ions from domestic wastewater because cation exchange properties provide economical and environmental advantages.