A solidification/stabilization process for wastewater treatment sludge from a primary copper smelter

Abstract

Wastewater treatment sludge from primary copper smelter is characterized as hazardous waste that requires treatment prior disposal due to significant amount of heavy metals and arsenic. The aim of the presented study was to investigate the feasibility and the effectiveness of solidification/stabilization process of the sludge using fly ash and lime as binders. The effectiveness of the process was evaluated by Unconfined Compressive Strength (UCS) testing, leaching tests (EN 12457-4 and Toxicity Characteristic Leaching Procedure (TCLP)) and Acid Neutralization Capacity (ANC) test. All samples reached target UCS of 0.35 MPa. Calcium to silicon concentration ratio (cCa/cSi), determined by X-Ray Fluorescence (XRF) analysis, was identified as main factor governing strength development. Inductively coupled plasma-optical emission spectrometry (ICP-OES) analyses of solutions after leaching tests showed excellent stabilization of Cu, Ni, Pb and Zn (above 99 %) and arsenic (above 90 %) in samples with high Ca(OH)2 content. Results of ANC test indicated that buffering capacity of solidified material linearly depended on Ca concentration in FA and lime. Sample with 20 % of binder heaving 50 % of FA and 50 % of lime met all requirements to be safely disposed. [Projekat Ministarstva nauke Republike Srbije, br. 34033

Innovative solutions for the extraction of technology metals from complex primary and secondary raw materials

“…Ovo je široko korišćena metoda usled niske cene, a visoke efikasnosti kreča. Međutim, glavni nedostatak ove metode je nastajanje velike količine otpadnog mulja koji se smatra opasnim otpadnom i zahteva tretman pre odlaganja [17,18]. U okviru tretmana specifičnih nusproizvoda iz primarne proizvodnje bakra, istaživačka grupa je razvila integralni tretman oksidne raskrivke i efluenata iz primarne proizvodnje bakra.…”

Zeolit Kao Aditiv U Toplim Asfaltnim Mešavinama

“…In Serbia, the largest zeolite deposits are Beocin, Igros, Jablanica 1, Toponica and Zlatokop [5]. Synthetic zeolites are artificial made from the chemical reagents, mineral materials or some waste by-products of industry such as fly ash [2], which is expecially interesting because during coal combustion in thermal power plants about 5 million tons of fly ash is generated per year in Serbia [6]. The use of zeolite as additive in WMA is a new current topic, and up to now there are several published papers which deal with it, but in near future an increase in application of WMA is expected as well as more scientific papers on this topic.…”

Laboratory testings of fly ash

“…It is composed of smaller particles, consisting mainly of aluminosilicate glass, mullite and quartz, which are collected by electrostatic separators (filter) of gaseous products arising from the combustion of coal [2]. Serbia produces about 5 million tons of fly ash annually during coal combustion in the power plants [3]. The samples subject to laboratory tests were taken from the thermal power plant Nikola Tesla A (PPNT A) in Obrenovac.…”