City of Kemi

Kemi, Finland

City of Kemi

Kemi, Finland

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Nurmesniemi H.,Stora Enso | Poykio R.,City of Kemi | Watkins G.,Aalto University | Dahl O.,Aalto University
Chemical Speciation and Bioavailability | Year: 2010

The utilization of solid residues allows industry to reduce and recycle waste materials and produce beneficial by-products. The total heavy metal concentrations in slaker grits originating from the chemical recovery process of a pulp mill are lower than the current Finnish statutory limit values for fertilizers used in agriculture and in forestry. In addition, slaker grits are strongly alkaline pH (13.1), have elevated total calcium concentration (331 g kg-1; d.w.), contain calcite (CaCO3), as well as a neutralizing value of 39.4% (Ca equivalents, d.w.). Thus, 0.96 tonnes of slaker grits would be required to replace 1 tonne of a commercial ground limestone product. This indicates that slaker grits have great potential as an industrial residue-based fertilizer and liming agent for use in agriculture and forestry. Since, before such use, it is necessary to assess the mobility of elements in the grits, the three-stage BCR sequential extraction procedure was carried out. Results from sequential extractions showed that the partitioning of Mn (47%), Co (47.1%), Ni (43.1%) and S (94%) was highest in the exchangeable fraction, in which acetic acid (CH3COOH) is used as extractant. The partitioning of Fe (96.5%) and Ti (75.6%) was highest in the easily reduced fraction, in which hydroxylamine hydrochloride (NH2OH-HCl) is used as extractant. The partitioning of Cr (90.8%), V (75.4%), Zn (78.3%), Ba (62.1%), Al (99.4%) and P (99.8%) was highest in the oxidizable fraction, in which hydrogen peroxide (H2O2) is first applied to a heated medium (i.e. 85°C) for dissolving organic matter, after which ammonium acetate (NH4COOH) is used as extractant.


Makela M.,Aalto University | Valimaki I.,Suomen Ymparistopalvelu Oy | Poykio R.,City of Kemi | Nurmesniemi H.,Stora Enso | Dahl O.,Aalto University
International Journal of Environmental Science and Technology | Year: 2013

During carbon steel manufacture, slag residues are generated to remove material impurities from liquid metal and thus control the quality of carbon steel. As the utilization of secondary metallurgical slags is not as efficient as those of primary slags, a comprehensive characterization of steel ladle slag was performed. Pseudo-total concentrations of a wide range of elements were determined during a 6-week sampling period with relevant physical and chemical properties, sequential extraction of trace elements, and parallel mineralogical characterization of extraction residues from a representative combined sample. According to the results, only Cr and V occurred in elevated concentrations with respective 6-week mean values of 198 and 310 mg kg-1 (d.w.). The residual standard deviation of the weekly pseudo-total concentration values of the aforementioned elements (24 and 31 %, respectively) indicated that significant variation in the concentration of trace elements can occur due to fluctuation in process conditions and/or slag characteristics. The sequential extraction procedure suggested potential phytoavailability of V (123 mg kg-1, d.w., amounting to 41 % of the respective pseudo-total concentration) through, e.g., changes in prevailing redox conditions. Although the analytical approach was validated by the analysis of a certified reference material and the calculation of extraction recoveries, the mineralogical characterization of parallel extraction residues indicated non-selectivity of the procedure coupled with potential redistribution phenomena during extraction with hydrogen peroxide and ammonium acetate. © 2013 Islamic Azad University (IAU).


Makela M.,Aalto University | Watkins G.,Aalto University | Dahl O.,Aalto University | Nurmesniemi H.,Stora Enso | Poykio R.,City of Kemi
Journal of Residuals Science and Technology | Year: 2010

Beneficial utilisation of process industry residues provides possibilities to reduce energy consumption, to avoid environmental impacts caused by increasing land-filling and promotes sustainable management of natural resources. As traditional utilisation of steel industry residues lies within the realm of civil construction, complementary applications could be found from the integration with pulp and paper industry residues to promote sustainable forest management through forest soil amendment. In our study we show that three different soil amendment matrices, providing slow release and materials handling advantages, were successfully produced according to conventional cement testing practices. The concepts we develop for forest soil amendment incorporate the use of fly ash in tandem with granulated blast furnace or steel slag as binder materials, the utilisation of paper mill sludge as reactive aggregate and the use of green liquor dregs and lime waste from chemical pulping as alkaline components. The neutralising (35.8-38.6%) and reactivity (33.3-38.0%) values (expressed as Ca-equivalents d.w.) with supporting high pH-values (12.9-13.0) indicate liming and buffering capacities of the test matrix materials are comparable to commercial ground limestone products. Additionally, concentrations of Ca, K and Mg and concentrations of Cu, Mn and Zn were found to be higher than organic and mineral soils normally found in the Ostrobothnia region of Northern Finland. Only under severe leaching test conditions (HNO 3 and HCl microwave digestion) did the total concentration of Cr in the soil amendment matrix exceed respective Finnish statutory limit value set for the use of fertilisers in forestry. However, as illustrated by the leaching procedure, less than a fifth of the total Cr is likely to become mobile in conditions normally found in nature. © 2010 DEStech Publications, Inc.


Poykio R.,City of Kemi | Nurmesniemi H.,Stora Enso
Environmental Engineering and Management Journal | Year: 2010

The bottom ash investigated in this study was sampled from a 32 MW municipal district heating plant incinerating peat (60 %) and clean bark, wood chips and sawdust (40 %) at a bubbling fluidized bed boiler. The bottom ash has high dry matter content (99.7 %), which is a disadvantage, since it can cause dust problems during handling. The highest extractable concentrations of metals in the artificial sweat were for Al (22.0 mg/kg; d.w.), As (2.7 mg/kg; d.w.) and for Ba (12.8 mg/kg; d.w), whereas in the artificial gastric fluid for Al (2210 mg/kg; d.w.), As (12.5 mg/kg; d.w.) and for Ba (91.4 mg/kg; d.w.). Therefore, we conclude that the careful handling of this residue is recommended in order to prevent the penetration of ash particles associated with heavy metals into the human gastrointestinal tract through inadvertent wiping of mouth with dirty hands or through the inhalation of ash particles.


Manskinen K.,Stora Enso | Nurmesniemi H.,Stora Enso | Poykio R.,City of Kemi
Chemical Engineering Journal | Year: 2011

The total heavy metal concentrations in green liquor dregs investigated in this study were clearly lower than the current Finnish statutory limit values for fertilizer used in forestry. This is an advantage if applying for an environmental permit to utilize the green liquor dregs. They contained only carbonate minerals, were strongly alkaline (pH 11.7), and had a neutralizing value of 34.2% (Ca equivalents; d.w.), according to which 1.1 tonnes of green liquor dregs would be required to replace 1 tonne of a commercial ground limestone product produced by SMA Mineral Ltd. These properties support the utilization and re-use of this residue, for instance as a soil conditioning agent. Before such use, it would be necessary to assess the mobility of non-process elements in the dregs. Three-stage sequential extraction procedure development by the European Community Bureau of Reference (BCR) was therefore carried out, in which elements in the residue were fractionated between acid soluble (CH 3COOH; BCR 1), reducible (NH 2OH-HCl; BCR 2) and oxidizable (H 2O 2+CH 3COONH 4; BCR 3) fractions. Except for Co and Ni, the highest extractable concentrations of non-process elements (Al, As, Ba, Be, Cd, Cr, Cu, Fe, Mn, Mo, Pb, Sb, Se, V and Zn) were in the oxidizable fraction, although certain non-process elements were also extractable and quantitatively detectable in fractions BCR 1 and BRC 2. The results are discussed from various perspectives and in relation to observations in the literature concerning the release of heavy metals and sulphur from the sample matrix under different extraction conditions. © 2010 Elsevier B.V.


Makela M.,Aalto University | Watkins G.,Aalto University | Poykio R.,City of Kemi | Nurmesniemi H.,Stora Enso | Dahl O.,Aalto University
Journal of Hazardous Materials | Year: 2012

Industrial residue application to soil was investigated by integrating granulated blast furnace or converter steel slag with residues from the pulp and paper industry in various formulations. Specimen analysis included relevant physicochemical properties, total element concentrations (HCl+HNO 3 digestion, USEPA 3051) and chemical speciation of chosen heavy metals (CH 3COOH, NH 2OH·HCl and H 2O 2+H 2O 2+CH 3COONH 4, the BCR method). Produced matrices showed liming effects comparable to commercial ground limestone and included significant quantities of soluble vital nutrients. The use of converter steel slag, however, led to significant increases in the total concentrations of Cr and V. Subsequently, total Cr was attested to occur as Cr(III) by Na 2CO 3+NaOH digestion followed by IC UV/VIS-PCR (USEPA 3060A). Additionally, 80.6% of the total concentration of Cr (370mgkg -1, d.w.) occurred in the residual fraction. However, 46.0% of the total concentration of V (2470mgkg -1, d.w.) occurred in the easily reduced fraction indicating potential bioavailability. © 2011 Elsevier B.V..


Nurmesniemi H.,Stora Enso | Manskinen K.,Stora Enso | Poykio R.,City of Kemi | Dahl O.,Aalto University
Journal of the University of Chemical Technology and Metallurgy | Year: 2012

The bottom ash and fly ash investigated in this study originated from the large-sized (115 MW) combustion plant of a pulp and board mill complex. This combustion plant uses a bubbling fluidized bed (BFB) boiler for energy production. During the sampling period, when the bottom ash was sampled from the outlet of the boiler and the fly ash from the boiler's electrostatic precipitator (ESP),approximately 97% or the energy produced by the BFB boiler originated from the incineration of clean forest residues (i.e. bark, woodchips and sawdust), and 3% from the incineration of sludge from the primary clarifier of a wastewater treatment plant. The current Finnish legislation, which regulates the utilization of ash in forestry, sets minimum or maximum concentration limit values for Ca, the sum of phosphorous and potassium, as well as for As, Cd, Cr, Cu, Hg, Pb, Ni and Zn. Although the total element concentrations infly ash were between 1.5 (K) and 40 (Cd) times higher than those in bottom ash, all element concentrations, as well as the sum of the phosphorous and potassium concentration in the bottom ash and fly ash, fulfilled the requirements of the Finnish fertilizer act for forest fertilizer, which came into force on 13 September 2011.


According to the XRD spectra, both ashes contained microcline (K(AlSi 3O 8)) and quartz (SiO 2). However, hematite (Fe 2O 3) and dolomite (CaMg(CO 3) 2) only existed in fy ash and bottom ash, respectively. Te total element concentrations were 1.1 (Zn) to 45.1 (S) times higher in fy ash than those in bottom ash. According to three-stage sequential extraction procedure of the European Standards, Measurement and Testing (SM & T) Program (formerly the Community Bureau of Reference (BCR), in which elements in bottom ash and fy ash were fractionated among acid-soluble (CH 3COOH; BCR 1), reducible (NH 2OH-HCl; BCR 2) and oxidizable (H 2O 2 + CH 3COONH 4; BCR 3) fractions, the concentrations of most elements were higher in all fractions of fy ash than those in bottom ash. However, in the BCR 1 fraction, the extractable concentrations of Al, Ba, Be, Cu, Fe, V and Zn, as well as of Fe and Zn in the BCR 3 fraction and Ti in all BRC fractions, were higher in bottom ash than the corresponding heavy metal concentrations in the fy ash. Te results are discussed in relation to observations in the literature concerning heavy metals and sulphur release from a sample matrix under diferent extraction conditions. © 2012 Lietuvos mokslu̧ akademija.


Nurmesniemi H.,Stora Enso | Dahl O.,Aalto University | Watkins G.,Aalto University | Poykio R.,City of Kemi
International Journal of Materials Engineering Innovation | Year: 2010

The total heavy metal concentrations in the slaker grits were clearly lower than current Finnish limit values for fertilisers used in agriculture and in forestry. This result, together with the strongly alkaline pH (13), the elevated total calcium concentration (331 g kg -1; d.w.), the existence of calcite (CaCO 3), as well as the neutralising value of 39.4-% (Ca equivalents, d.w.), according to which, 0.96 tonnes of slaker grits would be required to replace 1 tonne of a commercial ground limestone product, indicate that the slaker grits are a potential fertiliser and liming agent material for use in agriculture and forestry. © 2010 Inderscience Enterprises Ltd.


Poykio R.,City of Kemi | Manskinen K.,Stora Enso | Nurmesniemi H.,Stora Enso | Dahl O.,Aalto University
Energy Exploration and Exploitation | Year: 2011

Two ash samples were taken from the large-sized (77 MW) multi-fuel boiler (MFB) at the power plant of Stora Enso Oyj Heinola fluting board mill in Finland. The samples were analysed by X-ray diffraction (XRD) and inductively coupled plasma optic emission spectroscopy (ICP-OES) techniques. The results indicate that only hematite (Fe 2O 3) and quartz (SiO 2) existed in both the bottom ash and fly ash, whereas anorthite (CaAl 2S 2O 8) and anhydrite (CaSO 4) were only detected in the bottom ash. The element concentrations in the fly ash were within 1.1 (Sb) and 3.5 (Pb) times higher than those in the bottom ash. Only the concentration of sulphur in the bottom ash (8030 mg/kg; d.w.) was higher than that in the fly ash (5380 mg/kg; d.w.). In the bottom ash, the extractable Mo (8.2 mg/kg; d.w.) and sulphate (15.900 mg/kg; d.w.) concentrations exceeded the limit values for the acceptance of waste at inert waste landfills. In the fly ash, the extractable concentration of Cr (1.8 mg/kg; d.w.) and sulphate (7200 mg/kg; d.w.) exceeded the limit values for the acceptance of waste at inert waste landfills, and in addition, the extractable concentration of Mo (37.0 mg/kg; d.w.) exceeded the limit value for the acceptance of waste at non-hazardous waste landfills. According to a three-stage sequential extraction procedure, in which elements in the bottom ash and fly ash were fractionated between acid-soluble (CH 3COOH), reducible (NH 2OH-HCl) and oxidisable (H 2O 2+ CH 3COONH 4) fractions, the concentrations of most elements were higher in all fractions of the fly ash than those in the bottom ash. However, in the bottom ash, the extractable concentration of As (3.2 mg/kg; d.w.), Mo (8.2 mg/kg; d.w.), Pb (1.3 mg/kg; d.w.), S (7850 mg/kg; d.w.) and V (52.1 mg/kg; d.w.) in the acid-soluble fraction (CH 3COOH), as well as the extractable concentration of Cu (40.2 mg/kg; d.w.) in the oxidisable fraction (H 2O 2 + CH 3COONH 4) were higher than those in the fly ash. Approximately 52.7% of Mo in the fly ash was partitioned in the oxidisable fraction. Thus, molybdenum is not considered to be very mobile or bioavailable.

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