GREEN MINING ANNUAL SEMINAR HELSINKI, 24.11 · originating from mining industry, To develop new...

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Prof. Riitta Keiski

University of Oulu, Faculty of Technology

Environmental and Chemical Engineering Research group

POB 4300, FI-90014 University of Oulu

SULFUR COMPUNDS IN MINING GREEN MINING ANNUAL SEMINAR

HELSINKI, 24.11.2014

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S-COMPOUNDS IN MINING WATERS

Sulphate emission into waters

(http://report.chemind.fi/sulfaattipaastot).

Sources: All the mining activities from ore

deposit to mineral processing

Harmful compounds: Depends on the geology

and mineralogy of the ore deposit and the

mineral processing

The amount of sulphate has increased:

procecssing of ore and side product has

increased

Phenomena taking part in the nature: acid

minedrainage/acid rock drainage/AMD, ARD

when sulphide minerals are in contact with

surface and ground waters

Sulphur compounds and water:

Acidification

Toxic metals and compounds

High sulphate concentrations in natural

waters

Safety and corrosion problems

AIR EMISSIONS IN MINING INDUSTRY

Air emissions from mining activities Exhaust gases (CO2, CO, HCs, NOx, SO2, fine particulates)

Prosess gases (e.g. from bioleaching, different type of beneficiation processes: H2S,

CS2, SO2, CO2 and drying processes: SO2 )

Fine particulates from soil and oils (contain S-compounds)

All mining activities cause air emissions: Particulates, heavy metals (As, Hg), CO,

VOCs, SO2 (S-compounds), NOx, CH4

Mining industry is the biggest solid waste producer in the world

Mining industry does not seem to act sustainably: Sustainability criteria: 1)

environmental impacts and 2) cost of the mineral processing

Päivi Kauppila, Marja Liisa Räisänen,

Sari Myllyoja:

Metallimalmikaivostoiminnan parhaat

ympäristökäytännöt. 2011, Edita

Prima Oy. SUOMEN YMPÄRISTÖ

29/2011.

OUTDOOR AIR POLLUTION AND HUMAN HEALTH

Outdoor air pollution the leading environmental cause of cancer deaths

17 October 2013 - The specialized cancer agency of the WHO, the International

Agency for Research on Cancer (IARC), announced that it has classified outdoor air

pollution as carcinogenic to humans (Group 1).

The IARC evaluation concluded that there is sufficient evidence that exposure to

outdoor air pollution causes lung cancer (Group 1).

http://www.who.int/gho/phe/outdoor_air

_pollution/phe_012.jpg

Prof. Riitta L. Keiski, 24.11.2014

25.11.2014/RIS SULKA

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WHY S-EMISSIONS SHOULD BE REDUCED IN MINING

INDUSTRY?

Mines are located close to ground and surface waters (appr. 30%)

S-emissions cause changes via acidification in the ecosystem

Sulphate reduces the reuse of waters in mining industry and can totally

prevent the water reuse

Sulphate causes corrosion and fouling of surfaces of process equipment

Legislation sets its own requirements (SO4 and TDS)

→ Increase in environmental and health problems, social

pressures and process/maintenance costs

SULPHUR CONTAINING EMISSIONS

IN MINING INDUSTRY – SULKA

6

2012 – 2014


SULKA - PROJECT PARTNERS

The project is realized under Oulu Mining School

(www.oulumining.fi) and SkyPro Oulu Clean Air Cluster

(www.oulu.fi/skypro)

The research is divided between 5 research groups:

(1) UOulu, Faculty of Technology, Environmental and

Chemical Engineering Research group, OULU (ECE)

(2) UOulu, CEMIS-OULU Sotkamo Unit, SOTKAMO

(CEMIS)

(3) UOulu, Kokkola University Consortium Chydenius,

KOKKOLA (Chydenius)

(4) The Geological Survey of Finland, ROVANIEMI

(GTK)

(5) Lapland University of Applied Sciences, KEMI

(TOKEM)


THE MAIN AIM OF THE SULKA PROJECT

The objectives of the SULKA project:

To generate new information about the environmental impact of sulphur emissions

originating from mining industry,

To develop new methods to measure and monitor and minimize the sulphur

containing emissions coming from mining operations.

Significant enhancement of the know-how of companies and research institutes

active in the mining industry in the measurement and processing of sulphur

compounds.


http://puutarha.net/scripts/image.asp?kuva=1&id=24325

SULKA –PROJECT IS DIVIDED

WP0 Project coordination (ECE)

WP1 Survey of the most resent measuring and minimizing methods available for

sulphur containing emissions (ECE)

WP2 Biological and chemical reduction of sulphates/New knowledge of the suitability

and usage of reduction for the mining waters containing sulphates (ECE)

WP3 Development of the water measurements (CEMIS)

WP4 Criticality analysis from the environmental point of view and knowledge

management in preventing the sulphur emissions (LAMK)

WP5 Abatement of sulphur containing air emissions (ECE)

WP6 Treatment of sulphur containing water emissions (Chydenius)

WP7 Development of membrane technology for water treatment (ECE)

WP8 Evaluation of environmental impact of sulphur containing emissions (GTK)

WP9 Development of tools for sustainability assessment analysis (ECE)

Into 10 work packages:


TARGET IS THAT 1/2

Work Package / Result

WP0 Project coordination/Successful and timely implementation of the project, a

good economic management, new project ideas and potential

innovations. Effective information services. WP1 Survey of the most resent measurement and minimizing methods

available for sulphur containing emissions/Report on the suitable methods.

WP2 Biological and chemical reduction of sulphates/New knowledge of the

suitability and use of reduction for mining waters containing sulphates.

WP3 Development of water measurements/New methods for fast analysis/

measurement of sulfur compounds in water samples.

WP4 Criticality analysis from the environmental point of view and knowledge

management in preventing the sulphur emissions/New method for the

criticality classification of production equipment from the

environmental point of view, as well as method for decision-making

process to ensure the information reliability (Overall Efficiency

Information). Prof. Riitta L. Keiski, 24.11.2014

TARGET IS THAT 2/2 Work Package / Result

WP5 Abatement of sulphur containing air emissions/New knowledge on the most

suitable purification methods for sulfur-containing gases in the mining

processes. Reports and scientific publications.

WP6 Treatment of sulphur containing water emissions/New knowledge on the

most suitable purification methods for sulfur containing wastewaters

in mining industry. Reports and scientific publications.

WP7 Development of membrane technology for water treatment/New knowledge

and improvements in efficiency of the applicable nanofiltration

technology. Reports and scientific publications.

WP8 Evaluation of environmental impact of sulphur containing emissions/Report

on the environmental impact of suplhur emissions originating from the

mining industry, case study.

WP9 Development of tools for sustainability assessment analysis/New method

for the sustainability assessment for mining industry.


Gas

measurements

Water

measurements

Sulphur containing

gas emission

treatment

Sulphur containing

water emission

treatment

Project coordination,

Criticality analysis and knowledge management,

Environmental impact assessment,

Development of sustainability assessment method

Gaseous and

liquid sulphur

sources

THE OPERATING ENVIRONMENT


WP1: 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


WP1: SUITABLE TREATMENT METHODS FOR SULPHUR-CONTAINING

GASEOUS SPECIES Biofiltration

Bioscrubbers, biotrickling filters, biofilters use enzymatic catalytic oxidation to

break down biodegradable air pollutants such as H2S, NH3, or CO to H2O, CO2, and

salts.

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


25.11.2014/RIS SULKA

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Selection Criteria

WP1: BIOLOGICAL AND CHEMICAL REDUCTION OF SULPHATES -

MINE DRAINAGE TREATMENT TECHNOLOGY Chemical

Precipitation Membrane Treatment Ion Exchange

Biological Sulphate

Removal Proven technology on

commercial scale

Proven with many

demonstration scales, large

commercial plants

Proven, with several large

commercial plants

Demonstrated on pilot

scale, no large commercial

plants

Proven, with a limited number of

commercial plants

Specialized application General application to high

metals, high SO4 mine water

General application, but

with appropriate pre-

treatment

Demonstrated for CaSO4

type waters, with

appropriate pre-treatment

Specialized application to high

SO4 mine waters

Water recovery High water recovery > 95% High water recovery > 90% High water recovery not

confirmed

Very high water recovery

> 98%

Waste sludge/brine

production

Large waste sludge

production

Sludge and brine production Large waste sludge

production

Small waste sludge production

Potential byproducts

recovery

Potential for CaSO4 recovery Potential, but not

demonstrated

Potential for CaSO4 recovery High potential for Sulphur

recovery

Chemicals dosing High chemicals dosing Limited chemicals dosing High chemicals dosing Process depends on carbon

source dosing

Energy usage efficiency Moderate energy usage High energy usage Moderate energy usage Moderate energy usage (heating

of anaerobic reactors)

Reliable and robust

performance

Robust process Process good performance,

but sensitive to pre-treatment

IX process performance and

resin recovery subject to

interference

Biological process sensitive to

toxics, fluctuating feed water

quality and environmental

conditions

Capital investment cost

(per m3/day capacity)

$ 300 – 1,250 $500 – 1,000 No commercial scale $800 – 1,500

Operations and

maintenance cost ($ per

m3 treated)

$0.2 – 1.5/m3 $0.5 – 1.0/m3 No commercial scale $0.7 – 1.5


WP2: BIOLOGICAL AND CHEMICAL REDUCTION OF

SULPHATES

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Biological reduction of sulphate – well-known, application ready technology

Chemical reduction of sulphate compounds in aqueous environments - new research field

(thermodymanic calculations, materials development, laboratory experiments)

Advantages: Reduction does not lead to new side products, the end products are new products

Disadvantages: Several hindering effects; S- and metal concentrations and other conditions may

restrict the process

Combined with other technologies?

New information/research data needed!

ECE/ Ritva Isomäki

The Paques process scheme

In theory, sulphate removal by inorganic

reduction possible by reducing

sulphates further to S or H2S

The known kinetics of sulphate

reduction in the order of geochemical

timescale

In the absence of catalysts and/or

extreme reaction conditions reactions

not occurring in a reasonable time

scale.


WP3: DEVELOPMENT OF THE WATER MEASUREMENTS

Goals of the WP3:

Fast online measurement for sulphur compounds in waters and wastewaters.

Methods: 1) Capillary electroforesis ja 2) sensors

Measurements: 5 – 250 mg/l

METHOD 1:

Capillary electroforesis

The goal is to have a fast

analysis method for sulphate

and sulphide measurement.

In addition to sulphuric compounds (sulphate, sulphite and sulphide) other anions, such

as chloride, can also be monitored simultaneously by CE, and thus more information for

process control and environmental monitoring can be provided

25.11.2014

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Sulphate and sulphide analysis using capillary electroforesis.

CEMIS-Oulu/Mari Jaakkola Prof. Riitta L. Keiski, 24.11.2014

Properties and applicability tested with standard solutions, natural waters and discharged mine water samples -

this type of sensor not previously tested for measuring mining wastewaters

Potentiometric sensor can be used in sulphate analysis in real samples, certain anions present in the sample

cause interference - enhancement of the selectivity of the sensor needed

Sensor technology a promising method: fast, cost-efficient, easy-to-use

Measurements: 1 – 1 000 mg/l

METHOD 2: Electrochemical sensor

Potentiometric sensor selective for sulphate detection

WP3: DEVELOPMENT OF THE WATER MEASUREMENTS

CEMIS-Oulu/Mari Jaakkola Prof. Riitta L. Keiski, 24.11.2014

WP5: ABATEMENT OF SULPHUR CONTAINING AIR EMISSIONS

Objectives: Abatement of SO2, SO3, H2S, TRS (total reduced sulfur)

Adsorption, catalytic materials from industrial side-streams

Potential sulphur tolerant catalysts

New knowledge on the most suitable abatement methods for sulfur-

containing gases in the mining processes

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ECE/Satu Ojala

Results: The modified red mud can be used in the abatement of S-

containing emissions

HTC can be used to make AC-type matarial from sugar cane

bagasse for the abatement of S-containing emissions

Industrial by-products can be used as adsorbents and catalysts

in flue gas purification

Silica improves the stability of alumina-supported catalysts against

S poisoning

Zr-supported catalysts active in the production of formaldehyde

from methanol and methyl mercaptan emissions

Cu, Pt and Au are active catalysts in dimethyl disulphide oxidation

30 bar, 180°C-240°C,

600°C/N2; 200-400 m2/g

+ Precursor salts


WP6: TREATMENT OF SULPHUR CONTAINING WATER

EMISSIONS

Chydenius/ Lassi, Runtti ja Tolonen

Chemical precipitation, adsorption and electrocoagulation

Precipitation: lime consumption and quality (effect of Na and Mg), effect of polymers

(better sludge quality) and othr additional chemicals (improved sulphate reduction)

Adsorption: active carbon and industrial side products (carbon residue from a gasifier,

modification and activation with ZnCl2, BaCl2, CaCl2, FeCl2, FeCl3; silica-based

adsorbents; fibre sludge)


WP7: DEVELOPMENT OF MEMBRANE TECHNOLOGY FOR WATER TREATMENT

ECE/ Piia Häyrynen

Results: Commercial nanofiltration membranes can remove

sulphate compounds from synthetic and real mine

wastewaters, the rejection coefficient of 99.8%.

For the simultaneous removal of sulphates and

nitrates a hybrid system that combines precipitation

and nanofiltration technology could achieve rejection

coefficients up to 99.8% and 92.9%

Task 1. Applicability, evaluation and improvement of

commercial nanofiltration membranes for the

separation of sulphur compounds from synthetic and

real wastewaters.

Task 2. Preparation of tailor made nanofiltration

membranes with the objective of obtaining novel

nanofiltration membranes that have better rejection

coefficients, higher permeability and less fouling.


WP7: DEVELOPMENT OF MEMBRANETECHNOLOGY FOR

WATER TREATMENT

25.11.2014

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ECE/ Piia Häyrynen

Cross section images of the sublayers a)

polyethersulphone and

polyethersulphone with the incorporation

of b) 1 % TiO2, c) 1 % SBA-15 and d) 1

% functionalized SBA-15 with carboxylic

groups

Results: Tailor-made nanocomposite membranes with

different membrane nanoparticle sublayers →

membrane sublayer morphology creating

bigger macrovoids and better pore

connectivity → water flux was enhanced

Addition of mesoporous silica with carboxylic

functional groups (SBA (COOH)) affected

substantially the performance of the tailor-made

polypiperezine amide NF membrane →

membrane permeability enhanced without

lowering the sulphate rejection coefficients.

Membrane capability to remove sulphates

improved when adding TiO2 into the sublayer.

Overall, the addition of nanoparticles into the

polymeric sublayer matrix enhances the

process performance of NF membranes.


TP8: EVALUATION OF ENVIRONMENTAL IMPACT OF SULPHUR

CONTAINING EMISSIONS

Study of ground and surface waters, lake and stream sediments, mosses and soils of the boreal

forests before and after mining activities (studies before the mining activities in 1994-1995

and after mining activities had started 2012-2013)

Method development – are the sediments proper indicators when assessing the environmental

impacts of sulphur compounds?

Increases in salinity and in concentrations of S, Cl, alkali (earth) metals in some water

samples – geochemistry does not explain the salinity

Figure 3 (a) Distributions of total S concentration (mg/kg) and loss of ignition (LOI %) and (b)

those of acetate extractable S and total S concentrations in mineral and organic sediments .

Raija Pietilä / GTK

(b) (a)


WP 9: SUSTAINABILITY ASSESSMENT

Economic impacts

Health impacts,

REACH

Social

impacts,

REACH

Environmenta

l impacts,

REACH

Assessment tool

Questionery,

qualitative

-1, 0 ,1

12 principles of

green chemistry

Process data

(e.g. conditions,

material and energy

flows, assumptions,

limitations)

2) LCA (Life-cycle assessment)(SimaPro) Standardized method(ISO 14040 ja 14044) including four steps:

1. Defining goals and application areas: system boundaries

2. Life-Cycle Inventory: material flows

3. Life-Cycle Impact Assessment: selection of the assessment method

4. Analysis of results (e.g. sensitivity analysis)

1) NEW ASESSMENT TOOL , SAT – based on GREEN CHEMISTRY PRONCIPLES


WP 9: SUSTAINABILITY ASSESSMENT, SAT TOOL

Wastewater treatment with a hybrid process


Normalized results of the LCA; comparison of the

three AMD treatment methods. Impact categories

with results greater than 0.0019 were included.

SAT: a qualitative questionnaire, easy to perform,

requires basic knowledge of the process, can be

conducted with Microsoft Excel

Evaluation of processes and products in early

design phase easy with SAT

Each chemical is evaluated in the same way

according to REACH regulation

Further development: a wider scale of evaluation

values (now being -1, 0, 1), possibility to use

weighting for the key indicators, transparent

instructions to ensure consistent assessments

Environmental, safety, health aspects and

economic efficiency

COMPANIES INVOLVED IN THE SULKA PROJECT

• Mining industry:

• Agnico-Eagle Kittilä Mine

• Talvivaara

• Endomines

• Sotkamo Silver

• Chemical industry:

• Kemira Oyj, Espoo R&D Center

• Metallurgical industry:

• Outotec


COMPANIES INVOLVED IN THE SULKA PROJECT

• Mining industry:

• Agnico-Eagle Kittilä Mine

• Talvivaara

• Endomines

• Sotkamo Silver

• Chemical industry:

• Kemira Oyj, Espoo R&D Center

• Metallurgical industry:

• Outotec


Bioeconomy – Biomass and GHGs’ utilization

Catalysis for the Support

of Sustainability

Separation Processes for

the Support of

Sustainability

Focus on Sustainable Production and

CleanTech Innovations

OUR APPROACH AT UOULU

CATALYSIS AND PHOTOCATALYSIS

SEPARATION PROCESSES

MODELLING AND SIMULATION

SUSTAINABILITY ASSESSMENT

CATALYSIS AND SEPARATION TO

HYBRID STRUCTURES - Use of

modelling & sustainability assessment

Development of sustainability

assessment tools and criteria:

Presently, for social impact

evaluation, toxicity, and health

effects of emissions


The strategy: ‘Optimizing the consumption of resources

(energy, water, materials…) and preventing emissions or if

not possible, reducing, recovering and recycling compounds

present in emission streams’

Final Seminar on December 11 at the University of Oulu Rikin yhdisteet kaivostoiminnassa – ympäristövaikutusten arviointi, mittaus ja minimointi - SULKA 1.7.2012-31.12.2014 Päätösseminaari 11.12.2014 klo 8.15-16.00, Oulun yliopisto, Saalastinsali Ohjelma: 8:15 Kahvit 8:45 Seminaarin avaus, hankkeen koordinaattori Satu Pitkäaho 9:00 Rikin muodostuminen ja hyötykäyttö, professori Risto Laitinen, Oulun yliopisto 9:30 Rikki kaivosteollisuudessa, laatupäällikkö Anita Alajoutsijärvi, Agnico Eagle, Kittilä 10:00 Sulfaatin hallinta prosessi- ja jätevesissä, Tuomas van der Meer, Outotec 10:30 Ympäristövaikutusten arviointi, maaperägeologi Raija Pietilä, GTK

11:00 Lounas (omakustanteinen) 12:00 Vesimittausten kehittäminen, tutkija Mari Jaakkola, CEMIS-Oulu 12:30 Vesipäästöjen käsittely - Saostus ja adsorptio, professori Ulla Lassi, Oulun yliopisto 13:00 - Kalvoerotusmenetelmä, tutkija Piia Häyrynen, Oulun yliopisto 13:30 Ilmapäästöjen käsittely, yliopistotutkija Satu Ojala, Oulun yliopisto

14:00 Kahvit 14:30 Kunnossapito, riskien hallinta, tutkija Aslak Siimes, Lapin ammattikorkeakoulu 15:00 Kestävyyden arviointi, tutkija Paula Saavalainen, Oulun yliopisto 15:30 Vaikuttavuus ja tulevaisuuden haasteet, hankkeen joht., prof. Riitta Keiski, Oulun yliopisto

Ilmoittautuminen 1.12.2014 mennessä: [email protected]

Activity and motivation in research and

support for research:

Members of our research group (ECE) and the ProChemE RC at the

University of Oulu

Research partners all over the world

The Council of the Region and EU Regional Funds

University of Oulu

Academy of Finland

Finnish Funding Agency for Innovation, Tekes

Graduate Schools in Energy Science and Technology, in

Environmental Science and Technology, for Chemical Engineering

EU FP7, ESF and COST Office (COST Actions 543 and CM0904)

Foundations

ACKNOWLEDGEMENTS


Thank you!


Riitta Keiski, Prof., Dr., Dr. h.c.

Responsible leader

[email protected]

+358 40 726 3018

Satu Pitkäaho, Dr.

Coordinator

[email protected]

+358 40 359 3434

Ritva Isomäki, Lic.Tech., M.Sc.

WP2

[email protected]

Satu Ojala, Doc., Dr.

WP1 and WP5

[email protected]

Jarkko Räty, Dr.

WP3

[email protected]

CONTACTS Seppo Saari, Dr. WP4 [email protected]

Ulla Lassi, Prof., Dr.

WP6

[email protected]

Junkal Landaburu-Aguirre, Dr.

WP7

[email protected]

Raija Pietilä, Geologist

WP8

[email protected]

Paula Saavalainen, M.Sc.

WP9

[email protected]

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