Characterization of Sewage Sludge and Clays for

AACHEN INTERNATIONAL MINING SYMPOSIA

Second International Conference

Sustainable Developmeat Indicators in the Minerals Industry

SID11811111 2005 Institute of Mining Engineering I

RWTH Aachen University, 18 - 20 May 2005

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AACHEN INTERNATIONAL MINING SYMPOSIA Under the Auspices of European Association of Mining Industries (Euromines) German Mining Association (WVB) Society for Mining, Metallurgy and Exploration (SME) and the Federal Ministry of Economics and Labour

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Second International Conference

Sustainable Development Indicators in the Minerais Industry

SCOMMII 2005 Institute of Mining Engineering I RWTH Aachen University, 18 —20 May 2005 Organized by Institute of Mining Engineering I — Virginia Tech University — Technical University of Crete

AACHEN INTERNATIONAL MINING SYMPOSIA Herausgeber: Universitãtsprofessor Dr.-Ing. Dipl.-Wirt.Ing. P.N. Martens

• Leitung: Dr.-Ing. Stefan Mõllerherm, Oberingenieur am Institut für Bergbaukunde I der RWTH Aachen Organisation: Dipl.-Ing. Mirjam Rosenkranz, Wissenschaftliche Mitarbeiterin am Institut für Bergbaukunde I der RWTH Aachen

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Martens, P.N. (Hrsg.): Sustainable Development Indicators in the Minerais Industry Zweite Internationale Konferenz „Sustainable Development Indicators in the Minerais Industry", RWTH Aachen, 18.-20. Mai 2005 1. Auflage Aachen: Verlag Glückauf GmbH, Essen, 2005 (Vont-4e anlãsslich der Zweiten Internationalen Konferenz „Sustainable Development Indicators in the Minerais Industry", Band 4) ISBN 3-7739-5994-X 2005 bei den Autoren der Beitrüge

IV

Gelekauf Essen

Verlag Glückauf GmbH, Postfach 18 56 20, D-45206 Essen Telefon +49 (0) 20 54 / 9 24-1 20, Telefax +49 (0) 20 54 / 9 24-1 29 E-Mail [email protected], Internet www.vge.de Herstellung: Druckerei Runge GmbH, D-49661 Cloppenburg Gedruckt auf chlorfrei gebleichtem Papier

Table of Contents

Table of Contents page K. Hâge, Vattenfall Europe AG, GER Lignite and Sustainability

6

1

K. F. Jakob, German Mining Association, GER Mining in Germany — A Sustainable Concept

19

B. Tõnjes, RAG Aktiengesellschaft, GER Coal — A Key Element in Sustainable Energy and Raw Material Supply

39

Lars A. Stálberg, Amnesty Business Group, S Human Rights, Sustainable Development and the Minerais Industry

55

P. Anciaux & T. Simpson, European Commission, B Assessing the Competitiveness of the EU non-energy Extractive Industry

67

P. Klaus, KfW IPEX-Bank, GER Financing Mining Projects - KfW IPEX-Bank's Approach in Assessing Credit Risks relating to Questions of Sustainability

79

J.A. Braithwaite, International Council on Mining and Metais (ICMM), GB International Council on Mining and Metais Sustainable Development Framework: Progress in Reporting

89

S. Borner Schweizer, SAM Sustainable Asset Management, CH SAM's Corporate Sustainability Assessment: General Approach and Mineral Industries Specific Criteria and Examples

97

M. Stanley & A. Eftimie, The World Bank Group, USA Government Support for Sustainability of the Extractive Industries

111

G. Baldermann & Hüttenrauch, MIBRAG mbH, GER Occupational Health and Safety - An Element of Efficient Business Management

131

II

Table of Contents

M. Galetakis Technical University of Crete, GR F. Pavloudakis, C. Roumpos Public Power Corporation S.A., GR

The Contribution of the on-line Coal Analysers to the Sustainability of Greek Lignite Mining Sector

141

L. Kulik, RWE Power AG, GER

Sustainability in Opencast Mines of the Rhenish Lignite Mining Area — tlanning from Start to Finish

151

E. Giama, A. M. Papadopoulos & A. Macridis, Aristotle University Thessaloniki, GR

ISO 14040-42 (LCA) Standard Implementation to Stone Wool's Production for Environmental Indicators' Development — Interaction with ISO 14031 Standard

169

S. Kistinger & G. Deissmann, Brenk Systemplanung GmbH, GER

Life Cycle Assessment of Environmental Protection Measures: The Mining Industry as an Example

185

M.A. Reuter, E. Verhoef & G.P.J. Dijkema, Delft University of Technology, NL J. Villeneuve, BRGM, F

Metal Cycle: is it "LCAble"

195

F. Cherubini, S. Bargigli, M. Raugei & S. Ulgiati, University of Siena, I

LCA of Magnesium Extraction and Processing Technology Overview

211

M. Zhuravkov & O. Konovalov, Belarus State University, BY

Modelling of Geomechanics and Geoecological State of Massif in Region of LargeScale Mining Work with Using of Supercomputer Technology

221

J. Kudelko, D. J. Pyra & W. Korzekwa, Copper Research and Design Center CUPRUM, PL

Evaluation of Pollution of Mining Areas in Aspect of their Future Use and Development

237

A. van Schaik & M.A. Reuter, Delft University of Technology, NL

The Effect of Design on Recycling Rates for Cars

261

T.O. Dauda, Farming System Research And Extension Program, NIG L.O. Ojo, University of Agriculture, NIG

Evaluating the Status of Omo Forest Reserve

277

■

Table of Contents

III

J. Y. P. Leite, A. L. C. Araújo & F. S. D. Araújo, CEFET-RN, BR M. P. D. Ingunza & O. F. Santos Júnior, UFRN, BR Characterization of Sewage Sludge and Clays for Application in Ceramic Bricks

283

V. Arad & S. Arad, Petrosani University, RO Environmental Aspects of Continuous Mining in Jiu Valley, Romania

•

293

C. Cigna, E. Lovera & M. Patrucco, DITAG Politecnico di Torino, I D. Savoca, Regione Lombardia, 1 Noise and Dust Emissions from Non-Metal Mining Activities: Analysis of Suitable Techniques of Measurement, Prediction and Control

297

G. Woíniak, R. Rostaúski & E. Sierka, University of Silesia, PL G. Aschan & H. Pfanz, University of Duisburg-Essen, GER Diversity of Spontaneous Vegetation on Post-Industrial Sites — Importance in Reclamation Process

315

J. Loredo, N. Roquerii & F. Pendás, Universidad de Oviedo, E Mine Water and Sustainable Development in the Mining Industry

325

E. Nordheim & G. Barrasso, European Aluminium Association, B The Selection of Sustainable Development Indicators, Industry Survey and Reporting of Results for the European Aluminium Industry

339

S. Mõllerherm, P.N. Martens, E. Drüppel. & J.B. Pateiro Fernandez, RWTH Aachen University, GER Development of Sustainability Indicators for the German Mineral Industry

349

R. K. Singh & H. R. Murty, Steel Authority of India Limited, IND S.K. Gupta, & A.K. Dikshit, Centre for Environmental Science & Engineering, IND Development of Environmental Performance Indicators based Environmental Management Systems for Steel Industry

359

A. Chamaret & G. Récoché, BRGM, F M. O'Connor, C3ED-University of Versailles St Quentin, F Proposal for a top-down/bottom-up Approach to build up Indicators of Sustainable Development for Use in the Mining Industry in Africa

381

Leite et.al.: Characterization of Sewage Sludge and Clays for Application in Ceramic Bricks

283

Characterization of Sewage Sludge and Clays for Application in Ceramic Bricks J. Y. P. Leite, A. L. C. Araújo & F. S. D. Araújo, CERET-RN, BR M. P. D. Ingunza & O. F. Santos Júnior, UFRI'f, BR

ABSTRACT Wastewater sludge is a problem for environmental control and it is necessary alternative researches for its reuse. Industries can research the association of clay and sewage sludge as a source of ceramic mass. This procedure can contribute for the industry sustainability including in its raw materiais, wastes of environmental concern. This paper presents the results of sewage sludge and clays characterization being analyzed particle size distribution (sedimentation), mineralogical (X-ray difflaction), chemical composition (X-ray fluorescence), thermal analysis, density, and Atterberg proprieties (liquid and plastic limit; plasticity índex) and also their applications in ceramics. Results were used to determine moisture for mass of raw material and sewage sludge and there were realized tests of fired in kiln at temperatures used in ceramic industry for bricks production. In the test pieces were analyzed the properties for application as bricks.

INTRODUCTION Sludge production in sewage treatment plants has been causing many environmental problems in Brazil. Designers have concerned about effluent final destination, however, few attention has been giving to the solid part of sewage (sludge), which has been generally disposed in the plant cite or dumping in landfills. Today is a consensus that projects may pay attention to sludge production and many researches have been developed in order to fmd sustainable solutions for sludge treatment, reuse and disposal. All sewage treatment plant produce sludge being its quantity and quality a function of the process used for the treatment. In the Rio Grande do Norte State (RN), northeast of Brazil, the main technology for treatment is waste stabilization ponds (Araújo et al., 2004). These ponds may work as sedimentation tanks, forming a sludge layer on the bottom which, eventually, will need be removed and finally disposed.


284

Many alternatives can be used to reuse sludge and so decrease the quantity to be disposed in landins or in the environment. As a soil conditioner or soil recovery, for example, it is rich in nutrients, organic matter and moisture. This work studied the incorporation of sludge as a part constituent of the mass used in the ceramic industry for the fabrication of structural bricks, which can be another sustainable form of reuse for • sludge. There are many ceramic industries in the RN State and the possible orporation of sludge as a resource for this activity may represent an environmental friendly solution for sludge, and besides, increase the natural resources of clays soils.

MATERIAL AND METHODS Figure 1 present the procedures sequence realized for characterization of samples used in this work. Samples Homogenization / Quartering Chemical Composition

•

Samples for Tests

Size Distribution

Mineralogia) Plastic Limit

Liquid Limit

Linear Retraction

Temary Diagram — Sizing Distribution

Casagrande Diagram (Ceramic Products) Moisture Composition Sinterizing Qualit Products

Figure 1:

Flow sheet of methodology applied in this work (Leite, 2002)

Samples of clays and sludge were homogenised in ratios of 10, 15, 20, 25, 30 and 35% of sludge, followed to determination of liquid and plastic limit and plasticity index. Results were analysed in Casagrande diagram. Liquid and plastic limit were realized using Brazilian norms (ABNT, 1983; ABNT, 1985; ABNT, 1992). For the best mixtures were realized tests using an extrution.


285

RESULTS AND DISCUSSIONS The samples for the development of this work were collected in the following places: the sludge was collected in the Sewage Treatment Plant of the Federal University (Rio Grande do Norte State), and clay in the city of São Gonçalo do Amarante, an important ceramic production center in the State. The results of chemical composition of samples are presented in the Trible 1.

Table 1:

Composição

Plastic Clay (%)

Semi-plastic Clay (%)

Sludge (%)

Si02

46.78

44.64

42.68

TiO2

1.60

1.56

1.34

Al203

28.47

29.61

17.82

Fe 2 0 3

11.37

11.67

8.46

MnO

0.13

0.15

0.12

MgO

3.25

3.29

2.95

CaO

2.45

2.26

9.56

Na20

O

0.84

2.53

K20

5.16

5.23

2.53

P2O5

0.13

0.11

5.80

S03

0.21

0.13

2.77

BaO

1.75

ZnO

0.90

CuO

0.18

Zr20

0.18

Chemical composition of raw material using X-ray Fluorescence.

Chemical composition of sludge was realised pos-ignition in temperature range of 500-550 ° C, for extraction of organic material. In relation to clay, the results were common for the clay mineralogy in the region. Thermal analyses are presents in the Figure 2.

286


Semi-plastic Clay

Sdudge 0.

Amostra B

Amostra

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Plastic Clay Amostra D

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Thermal analysis of samples of semi-plastic clay, plastic clay and sludge

Themal analysis of sludge and mass loss after ignition (500-550 °C) present a similar result of 32.78. The loss mass in bricks contributed for density reduction that will influence in the reduction of the weight of the building. Mineralogical composition using X-ray diffraction is present in Figure 3.

Semi-plastic Clay

.......

Sdudge

g

Plastic Clay

Amostra C

1200

Amostra O G - am.o -.Ia

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.• .• • 0..............570.

100-

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Figure 3:

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Mineralogical composition of samples of semi-plastic clay, plastic clay and sludge

Mineralogical composition of sludge is associated with sewage and the treatment process, and quartz minerais and feldspar are commonly present in sewage in the State. These minerals are available in materiais of construction and the area where the treatment plant is located is


287

characterizes for dunes that have this mineral in abundance. The biological processes that occur during the treatment of sewage do not have enough time for the formation of species commonly found in sludge, such as apatite, for example. In relation the mineralogical species of clay, the plastic clay was found a bigger concentration of clay minerals in relation to the semi-plastic characterizing its major plasticity.. Sizing distribuition of samples were realized using Stock' s law. Results are presents in relation to the application in ceramic industry (Figure 4). Where: sludge — lodo; moisture clay — argila misturada; plastic clay — argila plástica; semi-plastic clay — argila semi-plástica.

• Lodo Argila Mistura • Argila Plástica ■ Argila Semi Plástica 1

Argila 50 40 30

100 100

90

80

70

60

50

40

30

20

10

Sitte

Sizing distribution of samples of semi-plastic clay, plastic clay and sludge

As shown in Figure 4, it is possible to consider a mixture of these materials based in size distribution associated to the chemical and mineralogical composition. To verify the ideal composition it is necessary to know the properties of liquid and plastic limit and plasticity index. These data are located in Casagrande diagram and verify the region of better application of mixture for production of ceramics material. Figure 5 present the results of liquid limit and plasticity index of material used in the work.


288

DIAGRAMA DE CASAGRANDE

45 -

40

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02908 SP Lodo /63202,183

k• 25-

91•949 NI_ 1518 •

AlieturaP4L 2011

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Maura 96.2514

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Mblure 841.3014

• 1.0

1.5

20

2.5

40

45

50

55

65

7.0

75

20

95

90

9.5

100

LL

Figure 5:

Casagrande diagram with data of the materiais and mixtures of sludge and plastic clays

The mixture of 25% of sludge and plastic clay was found to be better and was used in the work. Mixtures were prepared to test in a pilot plant to obtain ceramic bricks with the following dimensions: 45.0 mm; 45.0 mm and 31.50 mm. In the bricks, were realized drying study and the results are presented in Figure 6. Environmental conditions were: average temperature of 30.5 °C (minimum = 28.5°C; maximum = 32.0 °C) and average relative humidity of 55.7% (minimum = 49%; maximum = 59%). These data were collected between 8-14 of Dezember of 2004 (between 7:00-18:00 h) in laboratory of the CEFET in Natal city. 10.

• 2500%

10

1.5

20

50

I_ 55

00

6.00% 85

70

75

80

85

93

05 .

110 115 120 125

♦8.N 94

—

Figure 6:

—80003941

Behaviour of the produced material through drying in the environment


289

It was observed that was necessary 55 h to linear retraction and relative humidity present a constante behavior or small variations. These data are important to design the drying in industrial area.

In relation to linear retraction, the addition of sludge represents 7.8% while in the normal mixture used in ceramic it is of 4.9%. Values above 6% may represent dificulties to the indutrial process of • extrusion, in which a stoff plastic ceramic mass is force throgh a die oriffe having the desired cross-sectional geometry that can be adjusted. After drying, the pieces were fired at temperature range of 900-1.000 °C. Figure 7 present its visual characteristics and the data of linear retraction pos-fired are presents in Table 2.

Figure 7:

Table 2:

Ceramics brick forming by extrusion and fired

Temperature (°C)

% Linear Retraction

900

2.65

950

3.63

1000

4.85

Linear retraction of ceramics brick prepareted with 25% of sludge.

290


Results show that an increase in temperature (900-950 °C) leads to reduction in pieces of 2.65 up 4.85% showing that has a limit for industrial process. Retraction will decrease the pores in the pieces causing an eventual decrease of water absorption, inhibiting adhesion of mass in the superfícies of ceramic pieces. Average temperatures used in industry that produce structural ceramic are between 900-950 °C, thus the linear retraction for fired is 2.65-3.63% and the total linear retraction to the process (drying and firing) will be between 10.45 up 11.43%. Dates of water absorption are presents in Table 3. Norm NBR-897 showed that the structural ceramics must have water absorption between 8-25% and the dates presents here are approved for the Brazilian norm.

Table 3:

Temperatura (°C)

Water Absorption (%)

900

23.8

950

19.6

Data of water absorption in ceramics bricks prepared with mixture of 25% of sludge

Apparent density of common bricks produce in RN State (Brazil) were of 0.72 g/cm 3, while the produce in laboratory was 0.66 g/cm 3 indicating that the sludge addition reduce to apparent density improving the characteristic of the structural ceramic. It is expected that the properties must have better standards in the industrial scale. Tests of compressive strength with the brick (25% sludge in mixture and fired in 950 °C) had results above of the requested the Brazilian Norm (above 1.0 N/mm 2) and for bricks produced the result average was of 1.9 N/mm2 (standard deviation = 0.36).

-1,

Leite et.al : Characterization of Sewage Sludge and Clays for Application in Ceramic Bricks

291

CONCLUSIONS Results presents in the work showed that addition of sludge from a sewage treatment plant in the ratio of 25% is approved in Brazilian norms for the structural ceramic production, however it is necessary to reduce to linear retraction for optimize the industrial process. An altemative to solve this problem is to add semi-plastic clay in the mixture, rich is available in the mineral deposits of mining industry, and keeping 25% of sludge of mixture.

LITE RATURE [1] Araújo, A.L.C., Duarte, M.A.C., Vale, M.B. The performance of four WSPS in northeast Brazil. In Proceedings of the 661 International Conference on Waste Stabilization Ponds (CDROM), held in Avignon-France, September, 2004. [2] Associação Brasileira de Normas Técnicas, NBR 6461/83. 1983. Brasília — DF [3] Associação Brasileira de Normas Técnicas, NBR 7171/92. 1992. Brasília — DF. [4] Associação Brasileira de Normas Técnicas, NBR 8947/85. 1985. Brasília — DF. [5] Bruguera, J., Manual Práctico de Cerâmica.Ediciones Omega, Barcelona, 1984. pp. 334. [6] Leite, J. Y. P., Atividades de Mineração na Cerâmica Estrutural. Anais do XX Encontro Nacional de Tratamento de Minérios e Metalurgia Extrativa, Recife - PE, Brasil, 2002.