Poland-Finland Seminar Day, Oulu, May 15th, 2014

Catalysis in Mining Industry

Prof. Riitta Keiski and the Research group

University of Oulu, Faculty of Technology,

Mass and Heat Transfer Process Engineering Research Group

PL 4300, FI-90014 University of Oulu

riitta.keiski@oulu.fi, www.oulu.fi/pyolam/

Driving forces in catalysis today – Process and Environmental

catalysis:

Environmental impact, sustainable production and energy, sustainability at large

More selective and durable catalysts

→ Improvement of yields and reduction of side products’ formation

Examples of catalyst development: Zeolites and amorphous silica-alumina compounds, New

nanomaterials and application areas of nanomaterials, CNTs, Nanofibres,…

Combining the best features of biocatalysis, heterogeneous and homogeneous catalysis

Novel hybrid materials, phenomena integration

Use of primary, secondary or substitutive materials in catalyst preparation

Environmental catalysis plays a crucial role in

NOx, SOx, CFCs, VOCs, CO, CH4, exhaust and flue gas purification and utilization

O3, N2O, CO2 abatement and utilization

Use of industrial side products/streams

Abatement of odorous compounds

Abatement of toxic gas streams

Catalysis – process and environmental - is one effective solution that

plays a major role in controlling pollution of our environment and in bringing

sustainable solutions for production processes and energy solutions!

Primary environmental challenges faced

The removal of ore from the ground leads to a number of unavoidable

environmental problems such as sedimentation, erosion, and habitat

destruction.

Each mineral has a set of unique physical and chemical properties, and therefore

requires the use of specific extraction and refining techniques.

In the case of e.g. gold mining, environmental complications vary at the sites found

throughout the world principally because of differences in geological setting, and the

fact that different chemical reagents and processing techniques are used on

different continents.

For example, gold roasting, a process in which gold-aggregated ore is heated to

remove sulphur compounds that would otherwise interfere with chemical leaching

processes, is a common activity in a number of developing countries.

In gold mining, the two most serious are Cyanide contamination and Acid Mine

Drainage (AMD)

Sustainable production processes are needed – from ore to finalproducts

Toxic mine waters – the

bath to rivers, lakes and

oceans

Sources of pollutants:

Mining

Transportation

Processing

Dumping

Mining industry related to utilization

of non-renewable resources

Mining industry is the biggest solid waste producer in the world PGM concentrations in the ppm-level, around 99.99% of the ore transferred to waste

Mining industry does not seem to be acting sustainably The most important sustainability criteria: environmental impacts and cost of the beneficiation

The production of Pt needs more energy and produces thus more CO2 that the production of

Au – the use of Au more beneficial and the role of Au in catalysis more pronounced

The use of water in mining industry is a crucial issue

Environmental concerns very important in the production of Platinum group metals — a big

challenge for sustainability

Example: Recovery and recycling of Pt-metals used in exhaust gas

purification Can be recovered up to 95 %

Recovery and recycling of catalytic converters offers an excellent source of Pt-metals

Selection if primary, secondary or substitutive materials the most sustainable solution in

metals use

Precious metal prices

YKSIKKÖ, MATTI MEIKÄLÄINEN, x.x.2006

Precious metal prices and fluctuation in the

price have an effect on the catalyst

development (Pt-DOC Pt/Pd-DOC).

Also bulk materials, e.g. CeO2 can have an

enormous influence on the price of the

catalyst (availability of REE metals)

The increased use of primary materials →

the beneficiation and production processes

need to be environmentally friendly and

sustainable

www.matthey.com ja www.molycorp.com

Pt: 49 066 €/kg

Pd 19 638 €/kg

Rh 52 261 €/kg

Use and price of CeO2

www.matthey.com ja www.molycorp.com

Potential areas for CeO2 utilization:

Fine particulate control in Diesel engines

Abatement of organic load in

wastewaters (catalytic wet oxidation,

AOP)

Promotor in oxidation catalysts (DOC)

Promotor in oxidation-reduction

catalysts (TWC) and in electrocatalysts

Fluid-bed catalytic cracking

Oxygen storage capacity in TWC-

catalysts

CeO2 is the most important REE in

industrial applications, others Nd, Lu,

La, Pr

Research areas related to mining industry at the

University of OuluThe mining industry related research includes all the research in the life cycle of mineral

processing:

• Mineralogical research

• Process research including chemical and physical phenomena research

• Process development focused on

– effectiveness of industrial management

– energy

– environment

– utilization of waste rock

– occupational safety

• Instrumentation, process automation – in particular wireless automation and data communications

• Mechanical engineering and diagnostics

• Process management

Clean technology researchFocus area: Environment, Natural resources and Materials

Oulu Innovation Alliance: Centre for Environment and Energy, CEE

Clean air research

at the University of Oulu

June 3rd, 2010

University of Oulu, SaalastinsaliOulu, Pentti Kaiteran katu 1

SkyPro Conference

nortechOULU

Registrations by May 27th, 2010 to nortech@oulu.fi

http://nortech.oulu.fi/SkyPro/

Focus Areas: Bioenergy production

Energy efficiency

Power-plant automation

Emission control

Focus areas:

Catalytic abatement & utilization of compounds in flue & exhaust gases

Measurement and control of air quality

Air quality, environmental and health impacts

Environmental impacts of energyproduction

• Emissions reduction and control in energy production

• Health impacts of particulates originating from engines

• Wood Ash – a Potential Forest Fertilizer

• Chemical utilization of carbondioxide

• Socio-ecological impacts of energygeneration (hydropower) in the North

Minimization of environmental load

• Emission control and utilisation of industrial by-products and wastes

• Strategic research; National scale intensity; International collaboration; Critical mass gained

Engine emission abatement

Primary methods: Legislation as the driving force

Purification of fuels (S, N,…)

Adjustment and design of engines, e.g.

air-to-fuel ratio

Secondary methods (end-of-pipe):

Gasoline engines: Three-way catalyst (TWC)

Diesel-engines:

Diesel oxidation catalyst (DOC)

Selective catalyst reaction (SCR)

Particulate filters (PF)

Challenges

Noble metal load optimal functioningversus costs

Optimal oxygen storage OBD-diagnostics, NOx reduction

Novel substrates, washcoats and improvedthermal stability of active metals, e.g. nobelmetals

Exposure Assessment of Traffic Related

Fine Particulates

• Particulate measurements from diesel and CNG engines

• Lung deposition estimates of particulate emissions

• Traffic related particles small, mainly in ultrafine and nanoparticle size range; Traffic exhaust emissions and

wood burning cause most of the harmful long-term health effects in Finland

• The increasing traffic load and its emissions are causing significant health and environmental problems;

Urban areas especially problematic

Human lung deposition model (ICRP 66)

Estimates of the numbers of deposited particulates in five different regions of the respiratory system

Model takes into account the activity level, different human groups and physiological parameters of the subject

K. Oravisjärvi’s PhD theses

Catalysts used in VOCs’ oxidation

Noble metals: Pt, Pd, Rh, Au,…

Metal oxides: CuO, ZnO, Perovskites,

MnO2, MgO, MoO3, U3O8, smixed

oxides,

Zeolites: H-ZSM-5,...

Fixed beds, monolites

Catalytic powders

Formed substrates

Fluidized beds

Typically the used catalysts in

industrial applications are nobel

metal supported on monolite

structures

Different shaped carriers by CTI (Salindres, France)glass woolcatalyst outer glass tube

inner glass tube

Figure 1. Reactor with a catalyst bed

Catalysts from Secondary Materials:

Waste Materials and Side Products

Intrests based on economic and environmental issues (Balakrishnan et al. 2011).

As catalysts, support materials, precursors in catalyst preparation

As such or after pretreatment (mechanical/thermal/chemical)

Examples:

Slags from steel making industry: silicates as support material for Pt/SiO2 in CO and VOCs oxidation (Domínguez et al. 2008).

Industrial sludges (Cu, Cr, Fe): active components for hydrocarbon oxidation (Klose et al. 2000).

Red mud from alumina industry: Catalyst in methane oxidation (Paredes et al. 2004).

Fly ash: support material for oxidation of deSOx, deNOx, hydrocarbons and catalyst for VOCs’ oxidation (Wang 2008, review).

References: Balakrishnan, M., Batra, V. S., Hargreaves, J. S. J., Pulford, I. D. Green Chemistry 13 (2011)

16–24.; Domínguez, M. I., Barrio, I., Sánchez, M., Centeno, M. Á., Montes, M., Odriozola, J. A. Catalysis

Today 133–135 (2008) 467–474.; Klose, F., Scholz, P., Kreisel, G., Ondruschka, B., Kneise, R., Knopf, U.

Applied Catalysis B: Environmental 28 (2000) 209–221.; Paredes, J. R., Ordóñez, S., Vega, A., , Díez, F., V.

Applied Catalysis B: Environmental 47 (2004) 37–45.; Wang, S. Environmental Science and Technology 42

(2008) 7055–7063.

S. Antikainen’s PhD thesis

Sulphur containing emissions in mining

industry – SULKA, 2012 – 2014

The project is realized under

Oulu Mining School (http://www.oulumining.fi/)

and SkyPro Oulu Clean Air Cluster (http://www.skyprooulu.fi/)

The main aim is to generate new information about the environmental impact of sulphuremissions originating from mining industry, and to develop new methods tomeasure, monitor and minimize the sulphur containing emissions coming frommining industry.

Hybrid Membrane Process for Water Treatment

(Hymepro) for mining and industrial waters:

Hybrid structures combining photocatalysis,

adsorption materials and membranes

HYBRID

The Finnish Funding Agency for Technology and Innovation

Sustainability Assessment– DTU, CAPEC (Technical University of Denmark, Computer Aided Process

Engineering Center) has developed ICAS (Integrated Computer Aided System)

program. ICAS has computer-aided tools for modelling and simulation, including

SustainPro portion for sustainability evaluation.

– Selection of most important sustainability indicator for the process

– Defining process steps for chosen alternative process routes

– Collecting data and evaluation of process efficiency and sustainability

Kevitsa Mining Oy

Nortec Minerals

Environmental indicators Greenhouse gas emissions, i.e. kg CO2 equivalent/€ of product sold

Freshwater use; Measured against the availability of renewable fresh water

supplies

Fossil fuel use; Measured against the rate of use of or integration of renewable

alternatives

Solid waste emissions; Measured against the availability of landfill capacity

Resource usage

Acidification

Mass intensity; i.e. total mass in/€ of product sold

Energy intensity

Photochemical Ozone Creating Potential

Eutrophying Substance

Ecotoxicity

PhD thesis of Paula Saavalainen

Case Sulphur: Suitable treatment methods for sulphur-containing

gaseous species

• Control of gaseous sulphur-emissions: absorption, adsorption, combustion,

condensation, biofiltration, membrane separation, and selective catalytic reduction.

(Theodore et al. 2008)

• Inorganic gases such as SO2 and H2S, organic compounds such as methyl mercaptan

and dimethyldisulphide.

• In catalytic incinerators the waste gas is typically heated by auxiliary burners to around

320 to 430C before entering the catalyst bed and the maximum design temperature of

catalyst exhaust is between 540-675 C . (Moretti 2001)

• Catalytic oxidation can be realized with or without heat recovery and as a regenerative

process, S-VOCs oxidation in lower concentrations because of heat recovery and lower

temperature required. (Engleman 2000)

• Catalytic materials used for S-VOC treatment: noble metals (Pt, Pd) and metals oxides.

• Sulphur is known to be a catalyst poison, however, the poisoning can be reversible and it

is dependent on temperature → Precious metals give better resistance to poisoning and

fouling, which are typical problems occurring with sulphurous compounds. (Moretti 2001)

Ojala, s. et al., Survey on measurement and removal methods for sulphur-containing compounds in air

and water, report by SULKA-project, 2013

Suitable treatment methods for sulphur-containing gaseous

species• Catalytic oxidation can be coupled with other techniques, emerging technologies

– In photocatalysis UV-light is used to activate the catalyst: TiO2 or silica-titania

composite catalysts.

– In plasmacatalysis: a combination of non-thermal plasma and catalyst, plasma

affecting the catalyst properties, adsorption process and thermal activation. Catalysts

such as BaTiO3, MnO2, TiO2, Fe2O3, CuO, CeO2 and zeolites have been investigated.

– Catalytic oxidation assisted with microwaves: microwave radiation to heat reactants,

oxidation of adsorbed pollutants. (Ojala et al. 2011)

ADVANTAGES DISADVANTAGES

Simple operation

Possibility of steam generation or heat

recovery

Complete destruction of organic

contaminants possible

Relatively high operation costs especially

when auxiliary fuel is necessary

Risk of flashback and subsequent

explosion hazard

Catalyst deactivation due to poisoning

Incomplete oxidation

High maintenance requirements especially

if operation is cyclic

Oxidation systems (combustion):

Ojala, S. et al., Survey on measurement and removal methods for sulphur-containing compounds in air

and water, report by SULKA-project, 2013

Suitable treatment methods for sulphur-containing gaseous

species• Biofiltration

– Bioscrubbers, biotrickling filters, biofilters use enzymatic catalytic oxidation to break

down (metabolize) biodegradable air pollutants, e.g. H2S, NH3, CO to H2O, CO2, salts.

– The oxidation catalysts (enzymes) are produced and maintained within moist, living,

active biomass which operates near ambient temperature and pressure.

– Biodegradation of compounds containing sulphur, nitrogen, and halogens

produces benign by-products, biomass, and inorganic ions (e.g. SO4-2, NO3

-, Cl-), which

require little or no subsequent treatment prior to their release into the environment.

– Biological processes do not transfer the identified pollutants into another phase nor

produce additional, collateral air pollution from fuel combustion. (Theodore et al. 2008)

Biofiltration:

ADVANTAGES DISADVANTAGES

Natural biological processes and materials

Relatively simple and economical

High abatement efficiency for oxygen-rich

low-concentrated pollutant gas streams

Waste products are CO2 and H2O

• Treated gas stream must not be deteriorating

to the microorganisms

Temperature and humidity of the gas stream

must be controlled properly

Heavy particulate quantities may block the

porous structure of filter bed

Ojala, S. et al., Survey on measurement and removal methods for sulphur-containing compounds in air

and water, report by SULKA-project, 2013

PhD thesis of Ritva Isomäki

FPC Fuel Performance Catalyst unique in several material ways

Effect of a Fe-based homogeneous catalyst on diesel engine emissions

The fuel properties not altered by the addition of the catalyst

The catalyst led to 4% fuel saving under the tested conditions

The catalyst reduced engine emissions by up to 39% smoke, 21% CO and 13%

UHC

(1) The fuel properties not altered by the addition of the FTC and FPC catalysts due to their extremely

low dosage ratios. Catalysts can be used without any engine modifications.

(2) Compared with the reference diesel, the homogeneous combustion catalysts decrease in brake

specific fuel consumptions under all test conditions. A maximum of 3.7% fuel saving observed at 3200

rpm engine speed and 0.14 MPa BMEP.

(3) The homogeneous combustion catalysts treated fuels generate remarkably less PM, CO and UHC

emissions in the engine exhausts compared with those from the reference diesel fuel. Slightly elevated

NOx emissions were also observed with the application of the ferrous picrate-based catalyst, which

was consistent with the improved fuel combustion efficiency and reduced PM, CO and UHC emissions

from the test engine.

By Yu Ma, Mingming Zhu, Dongke Zhang, Applied Energy 102 (2013) 556–562)

Catalysis in mining industry – Fuel performance catalysts

• Catalytic flow reverse reactor (CFRR): Mitigation—demonstrated

Catalytic Flow reverse reactor with regenerative bed Utilisation—not demonstrated

• Catalytic monolith combustor (CMR): Mitigation—demonstrated

Catalytic Monolith reactor with a recuperator Utilisation—not demonstrated

• Catalytic lean burn gas turbine:

Gas turbine with a catalytic combustor and a recuperator

Mitigation—combustion demonstrated

Utilisation—being developed in

a lab-scale unit

• Fugitive methane, emitted from coalmines around the world, approx. 8% of the world’s

anthropogenic methane emissions that contributes 17% to total anthropogenic GHG emissions.

• Methane is emitted in three streams: (1) mine ventilation air (0.1–1% CH4), (2) gas drained from

the seam before mining (60–95% CH4), and (3) gas drained from worked areas of the mine,

e.g. goafs, (30–95% CH4)

• Ventilation air methane contributes app. 64% of coalmine methane emissions from typical gassy

coal mines.

• Utilization via catalysis: Coal mine methane use in methanol production, Conversion of coal

mine methane into synthetic fuels

Catalysis in mining industry – Mine methane mitigation

and utilisation technologies

By Shi Su et al., Progress in Energy and Combustion Science 31 (2005) 123–170

The advantages (A) and disadvantages (D) of bioleaching in comparison with the chemical

leaching, thermal treatment, and other traditional processes for metal extraction:

Chemical Leaching, Thermal Treatment, Other traditional processes for metal extraction: Shortest process time (A)

Requires complex process plant and maintenance cost (D)

Requires large amount of acid (D)

Requires large amount of alkali (D)

High-energy requirement (D)

High operational cost (D)

Liability of hazardous chemical usage during the treatment (D)

Requires sufficient (high) concentration of elements in ores (D)

Not applicable for highly contaminated materials(D)

Hazardous Emissions (D)

Bioleaching (Bacterial and Fungal leaching): Environmentally friendly (green technology) (A)

Longer period of operation compared to chemical leaching (D)

Low cost (A)

Dependency on several atmospheric conditions (D)

Low-energy requirement (A)

Simpler and cheaper to operate and maintain than traditional processes (A)

Conditions of operation at ambient pressure and non-excessive temperatures close to ambient (A)

Most efficient method in terms of heavy metal solubilization (A)

Higher removal efficiency for heavy metals (A)

Without strict requirements of raw material composition (A)

Intensively applied at industrial scale for low grade ores (containing heavy metals at a concentration less than 0.5% wt.) (A)

Applicable for highly contaminated materials (A)

Safety Emissions (A)

Catalysis in mining industry – Bioleaching as a

beneficiation method

Bioheapleaching in Talvivaara A natural, cost-effective and environmentally

friendly process utilising locally occurring bacteria

Leaching process accelerated through crushing, aeration and irrigation

Acidity of leaching solution controlled by sulphuric acid to provide ideal conditions for bacteria

Primary leaching for 18 months; expected nickel recovery approx. 80%

Secondary leaching for additional 3.5 years; total expected nickel recovery >90%

Conclusion: Catalysis for the Support of Sustainability

Catalysis an enabling technology to promote sustainability

Increasing interest on catalysis and fast evolution of this area going on, e.g. novel catalytic materials, new and unconventional application areas – also mining industry

Factors driving the changes in catalysis research

- Diminishing climate change, sustainable land use

- Modular-designed sustainable beneficiation processes

- Use of secondary and substitutive materials

- Use of solar energy and electrocatalysis

Full implementation of catalysis phenomenologically

Our target:

To bring sustainable solutions to mining industry based on catalysis and other novel technologies (unit operations, separation processes):

Process and environmental catalysis – heterogeneous, homogeneous, biocatalysis

Catalysis and photocatalysis

Novel materials and materials development

Wise use of primary, secondary and substitutive materials in catalysis

Hybride methods and structures combining catalysis and separation

New ideas in unit operation structures

Assessing sustainability of the developed technology

Conclusions

Catalysis an enabling technology to promote sustainability in mining industry

Technology for the abatement and utilization of air, water and soil pollutants in (e.g. flue, exhaust, circulating gases, wastewaters, contaminated land)

Technology for beneficiation of ore – e.g. bioleaching

Photocatalysis versatile and promising in e.g. abatement and utilization of air and water pollutants

Design of novel catalytic materials for new and unconventional application areas

Combining phenomenologically the best features of different catalysis areas, i.e. homogeneous, heterogeneous and biocatalysis – a great challenge

Use of primary, secondary and substitutive materials as catalytic materials

New catalytic materials and improved materials recovery, finding substitutes for expensive natural resources (e.g. industrial side products)

Addressing key societal issues, e.g. CO2 minimization, sustainable energy and production, environmental catalysis

Developing sustainability assessment analysis and metrics, and combining the assessment to process design in an early stage of a process design project in mining industry processes

Contact information

Prof. Riitta Keiski

Docent, D.Sc.(Techn.)

Laboratory of Mass and Heat Transfer Process Engineering

Faculty of Technology

FI-90014 University of Oulu, POB 4300

Phone: +358-40-726 3018; +358 294 482 348

E-mail: riitta.keiski@oulu.fi, firstname.lastname@oulu.fi

http://www.oulu.fi/pyolam/

Thank You!