29 kesä PuMi – Purification and monitoring concept for mining water treatment based on new water technologies
Duration: 1.1.2013 – 31.12.2014
Total costs (€)/Tekes support: 700 k€/420 k€
Leading research organization partner: VTT Technical Research Centre of Finland, www.vtt.fi
Contact persons: Hanna Kyllönen, VTT, hanna.kyllonen(at)vtt.fi
Research organization partner: Lappeenranta University of Technology, mika.manttari(at)lut.fi
Company partners: Outotec, Sofi Filtration, Pöyry, Liqum
International partner: University of Hong Kong
Number of reviewed publications, incl. submitted manuscripts: 2 (VTT 1, LUT 1)
Number of other publications and reports: 12 (VTT 10, LUT 2)
Number of thesis: Master 1
Need and motivation of the project: The limited availability of water resources in many countries has become a primary topic for the water intensive industry and water reuse is considered helping this problem. Mineral processing requires large quantities of water, also high quality water. On the other hand, mining industry produces water effluents which contain large quantities of metals and sulphate. The limits for those vary from site to site but there is a trend of tighter limits in future.
Main set targets: The PuMi-project was focused on building membrane based water treatment concepts especially for reuse but also for discharging according to environmental regulations. The technologies would
- be based on the expertise of Finnish companies and research institutes.
- consist of conventional separation technologies and novel separation technologies, such as forward osmosis.
- be designed to cover the whole process surrounding for the purification of mine waters, including the main separation technology, pre-treatment, reject treatment, and required measurements and monitoring.
- be tested at bench-scale.
Conventional membrane filtration was a technology to reach good water qualities. Nanofiltration (NF) and reverse osmosis (RO) were workable technologies to remove metals and sulphates for neutralizing pond (NP) water treatment and water recycling in flotation. Pre-treatment improved the performance of membrane filtration. Microfiltration (MF) of mine water as such or chemically pre-treated worked well. Gypsum scaling was an issue and antiscaling was needed to increase water recoveries. Forward osmosis (FO) is an emerging technology to improve water treatment/concentration concepts. Business in this technology is starting. It was found to be a good option for waters having high fouling tendency in NF/RO, such as acid mine drainage (AMD) or membrane concentrates. Draw solution is an issue in FO and the most economical way was found when process solution or sea water acted as draw solutions. However, there were not many such process waters available in mining industry.
The Liqum probe seemed to have the possibilities for early stage scaling warning but the ability should be tested using other NP waters and other mine waters. Early stage warning for scaling would assist to minimize chemical usage and maximize water recovery in membrane filtration. The usage of antiscalants enabled higher water recoveries than with no antiscalant usage. However, antiscalants can hinder the further treatment of concentrate, such as precipitation. According to literature, one of the possibilities for scaling prevention on the membrane surface and increase in water recovery is the usage of ultrasound in crystallization before undesired scaling. Results obtained indicated that when crystallization point is pretty close even a short burst of ultrasound is sufficient. The concept including precipitates removal should be studied further.
Commercialization measures and/or potential:
Membrane filtration is a usable technology for the mining industry. There are Finnish technologies, such as MF and scaling measuring, which are potential for mine water concepts. Business in emerging FO technology is starting. It is also opportunity for Finnish companies e.g. in concentration of mine water concentrates.
- Boy, V. and Mänttäri, M. 2014. Review – Applications of membrane separation in mining industry. PuMi-report.
- Heimala, S and Heimala, E. 2013. Kolmen eri mineraaliprosessin eri vaiheiden veden laatu ja niiden tärkeimmät perusteet. PuMi-report.
- Hintukainen, M.S. 2915.Purification of filtrates from dewatering part of the mineral concentrating plant. MSc. Thesis, 2015.
- Kinnunen, P., Heikkinen, J., Grönroos, A., Särkilahti A., and Kyllönen, H. Literature review in PuMi-project; Water Recycling and Treatment Technologies in Mining Industry; Finnish Metal Mines. PuMi-report.
- Kyllönen, H., Grönroos, A., Järvelä, E., Heikkinen, J., and Tang, C.V. 2015. Experimental aspects of scaling control in membrane filtration of mine waters, submitted to Journal of International Mine Water Association.
- Kyllönen, H., Grönroos, A., Heikkinen, J., and Kinnunen, P. 2015.Mine water reuse for flotation by membrane filtration. Poster presentation in EUROMEMBRANE 2015 Conference. Aachen. 6th -10th September 2015.
- Kyllönen, H., Järvelä, E., Miettinen, V., Grönroos, A., Tukiainen, P., Pajari, H., Heikkinen, J., Pirkonen, P, Kinnunen, P. 2015. PuMi – Final report.
- Kyllönen, H., Heikkinen, J., Järvelä, E. and Tang, C. 2014. Forward osmosis for acid mine drainage. Poster presentation in IFOA World Summit September 18-19 2014. Lisbon.
- Kyllönen, H., Järvelä, E., Grönroos, A. and Arnold, M., 2014. Forward osmosis as a part of mining water concept. Proceedings in Membrane Conference and Exposition. March 10-14 2014. Las Vegas.
- Kyllönen, H., Järvelä E. and Tang, C. 2013. Energy efficient FO concept for concentrating neutralizing pond water in the mining industry. Oral presentation in Industrial reuse, Specialty conference. December 9-10, 2013. Long Beach.
- Kyllönen, H., Kinnunen, P., Järvelä, E., Miettinen, V., Grönroos, A., Tukiainen, P, Pajari, H., Heikkinen J., Pirkonen, P., Mänttäri, M. and Häkkinen, A. 2014. Purification and reuse concepts of mining waters. Poster presentation in Green Mining Annual Seminar 24-25th of November 2014.
- Mänttäri, M., Nevalainen, M., Hintukainen, M. and Kallioinen, M. 2014. Purification of process water from the mineral concentrating plant – Methods to increase water recovery, Case Pyhäsalmi mine. PuMi report.
- Nevalainen, M., Kallioinen, M. and Mänttäri, M. 2015. Nanofilration enhanced with antiscalants to maximize water recovery in mining industry processes, Book of abstracts, Euromembrane 2015, September 6-10, Aachen, Germany. P. 194.
- Nevalainen, M., Kallioinen, M., Hintukainen, M. S., Mänttäri, M. 2015. The effect of temperature and antiscalants on the recovery rate of mining process water by nanofiltration, submitted.
- Tukiainen, P., 2014, Feasibility of waste waters/concentrates in producing raw materials as by products from mining process – Literature review, PuMi-report.