Assessing potential forest and steel inter-industry residue utilisation by sequential chemical extraction

by Mikko Mäkelä

Institution: Aalto University
Year: 2012
Keywords: Environmental science; soil amendment; solid residue; solubility; trace element; waste management; haitta-aine; liukoisuus; maanparannus; poiste; sivutuote; jätehuolto
Record ID: 1135013
Full text PDF: https://aaltodoc.aalto.fi/handle/123456789/6047


Traditional process industries in Finland and abroad are facing an emerging waste disposal problem due recent regulatory development which has increased the costs of landfill disposal and difficulty in acquiring new sites. For large manufacturers, such as the forest and ferrous metals industries, symbiotic cooperation of formerly separate industrial sectors could enable the utilisation waste-labeled residues in manufacturing novel residue-derived materials suitable for replacing commercial virgin alternatives. Such efforts would allow transforming the current linear resource use and disposal models to more cyclical ones and thus attain savings in valuable materials and energy resources. The work described in this thesis was aimed at utilising forest and carbon steel industry residues in the experimental manufacture of novel residue-derived materials technically and environmentally suitable for amending agricultural or forest soil properties. Single and sequential chemical extractions were used to compare the pseudo-total concentrations of trace elements in the manufactured amendment samples to relevant Finnish statutory limit values for the use of fertilizer products and to assess respective potential availability under natural conditions. In addition, the quality of analytical work and the suitability of sequential extraction in the analysis of an industrial solid sample were respectively evaluated through the analysis of a certified reference material and by X-ray diffraction of parallel sequential extraction residues. According to the acquired data, the incorporation of both forest and steel industry residues, such as fly ashes, lime wastes, green liquor dregs, sludges and slags, led to amendment liming capacities (34.9-38.3%, Ca equiv., d.w.) comparable to relevant commercial alternatives. Only the first experimental samples showed increased concentrations of pseudo-total cadmium and chromium, of which the latter was specified as the trivalent Cr(III). Based on sequential extraction, dominant cadmium and chromium contents were respectively made available only through aggressive oxidation or dissolution by acid digestion. However, the pseudo-total concentrations of barium and vanadium, of which 17-31% and 12-46% were respectively recovered through desorption/dissolution by the use of acetic acid and moderate reduction by hydroxylamine hydrochloride, suggest the need for further research. The analytical performance during sequential extraction was validated through the analysis of a certified reference material as the analysis of parallel sequential extractions only suggested non-selectivity towards sample periclase coupled with potential redistribution of magnesium and the premature dissolution of sample silicates. Perinteiset prosessiteollisuuden alat Suomessa ja ulkomailla ovat kohtaamassa kasvavan jätehuolto-ongelman johtuen läjitykseen liittyvien kustannusten kasvusta sekä läjityskohteiden saatavuuden heikkenemisestä. Suurille tuotannonaloille, kuten metsä- ja metalliteollisuudelle, erillisten toimijoiden…