Stabilizacija matrice letećeg pepela primenom kalcijum-oksida, hidroksida i karbonata

Abstract

Sagorevanjem uglja u termoelektranama nastaju velike količine letećeg pepela koji u svom sastavu sadrži teške metale i metaloide čije izluživanje može naruštiti stanje životne sredine u ve- likoj meri. Cilj ovog rada jeste optimizacija procesa stabilizacije matrice letećeg pepela upotrebom oksida, hidroksida i karbonata kalcijuma, kao i ispitivanje stepena desorpcije (izluživanje) ele- menata u desorpcionim rastvorima. Stabilizacijom letećeg pepela omogućila bi se njegova dalja upotrebe u građevinskoj industriji ili u svrhu adsorbenta. Kako bi se dobili optimalni uslovi korišćeno je nekoliko različitih stabilizatora (CaO, Ca(OH)2 i CaCO3) u različitim koncentracijama (5% i 7%). Variraran je i sastav desorpcionog rastvora (dejonizovana voda i 4% i 8% sirćetna kiselina) kao i odnos letećeg pepela i desoprcionog rastvora (1:10 i 1:30). Koncentracija jona teških metala i metaloida (V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb) određivana je metodom masene spektrometrije sa indukovano spregnutom plazmom (ICP- MS). Za obradu podataka rađena je multivarijaciona statistička analiza (korelaciona analiza, ana- liza glavnih elemenata i klasterska analiza). Korišćen je statistički softver MINITAB.

Combustion of coal in thermal power plants produces large amounts of fly ash, which contains heavy metals and metalloids, and their leaching can greatly damage the environment. The aim of this paper is to optimize the process of stabilization of the fly ash matrix using calcium oxide, hydroxide and carbonate, as well as to examine the degree of desorption (leaching) of elements in desorption solutions. Stabilization of fly ash would enable its further use in the construction industry or as an adsorbent. In order to obtain optimal conditions, several different stabilizers (CaO, Ca(OH)2 and CaCO3) were used in different concentrations (5% and 7%). The composition of the desorption solution (deionized water and 4% and 8% acetic acid) is also variable, as is the ratio of fly ash to the desorption solution (1:10 and 1:30). The concentration of heavy metal ions and metalloids (V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, Pb) was determined by the method of Inductively coupled plasma mass spectrometry (ICP-MS). Multivariate statistical analysis (correlation analysis, principal component analysis (PCA) and cluster analysis (CA)) was performed for data processing. MINITAB statistical software was used.