Matthias Achternbosch

Impact of the use of waste on trace element concentrations in cement and concrete

The results of model calculations carried out to identify and quantify the input pathways of trace elements into cement and concrete and to estimate the extent to which trace element concentrations in cement may change due to waste utilization are presented. As expected, primary raw materials represented the most important input pathway for trace elements into cement, but the contribution from wastes was not negligible. The use of waste led to a slight increase of the concentrations of cadmium, antimony and zinc in cement. For cobalt, lead and vanadium, this increase was less distinct and for all other trace elements considered, the effect of the use of wastes on trace element concentrations in cement could not be demonstrated clearly. The trace element content of concrete was governed by the aggregates for most elements considered. However, for arsenic, cadmium, lead and zinc, both cement and the additive coal fly ash contributed noticeably to the total trace element concentration in the concrete.

Technology Assessment and Approaches to Early Engagement

Technology Assessment (TA) emerged in the 1970s as a research-based policy-advising activity. During the 1980s, TA discovered technology development at the lab level as a subject of interest, reflection, and intervention. Since that time, TA as orientation for shaping new technology and innovation has been part of the overall TA portfolio. TA concepts and approaches to early engagement have been developed in different frameworks, e.g. as Constructive TA. In the last 10 years, a new wave of early engagement in TA occurred mainly in the field of new and emerging technologies such as nanotechnology, enhancement technologies, and synthetic biology. This wave led to many activities involving TA in early stages of development. In this chapter, we describe the most relevant approaches in TA aiming at early engagement. A deeper look will be presented into conceptual backgrounds that are specifically relevant to early engagement, such as concepts of technology determinism, social constructivism, and co-evolution. As a case study, we discuss an ongoing activity at the Karlsruhe Institute of Technology (KIT) where a major technological development in the field of new cement is accompanied by systems analysis and innovation research from its very beginning. This case allows specifically for discussing chances and opportunities of early engagement but also pitfalls and obstacles.

Cadmium Flows Caused by the Worldwide Production of Primary Zinc Metal

Material flows of the economic cycle can contain toxic substances, which enter the economy as impurities in raw materials or are intentionally added as minor or even main constituents during the manufacture of industrial or consumer goods. Cadmium, predominantly associated with zinc minerals, is a by-product of the primary zinc production. Cadmium is generated when zinc is extracted from zinc ores and concentrates, an intermediate product resulting from flotation processing after the zinc ore has been mined and milled. Information on the amount of cadmium generated from zinc extraction is rarely published. In this article, we assess generation and fate of cadmium accumulating worldwide in the production of primary zinc from ores and concentrates. Model calculations for the beginning of the 21st century show that annually about 30,000 tonnes of cadmium were generated, but only approximately 16,000 tonnes were converted to primary cadmium metal, key material for the production of other cadmium compounds (e.g., cadmium oxide), and cadmium-containing goods (e.g., nickelcadmium batteries). Hence, about 14,000 tonnes of cadmium must have been transferred somewhere else. The fate of about 5,500 tonnes can be plausibly explained, but it is difficult to determine what happens to the rest.

Ressourcen- und Abfallmanagement für eine nachhaltige Entwicklung dargestellt am Beispiel von Cadmium

KurzfassungIm vorliegenden Beitrag werden erste Ergebnisse einer Zusammenführung zweier im Institut für Technikfolgenabschätzung und Systemanalyse (ITAS) des Forschungszentrums Karlsruhe bearbeiteter Projekte zu den Themen „Abfallwirtschaft und Nachhaltige Entwicklung” und „Unterschung der Verteilung ausgewählter Schwermetalle bei Abfallentsorgungsmaßnahmen” präsentiert. Dabei werden Probleme und Zielkonflikte des Cadmiumstoffstroms vor dem Hintergrund des im ITAS entwickelten integrativen Nachhaltigkeitskonzeptes identifiziert und diskutiert.SummaryThis paper presents the first results of a project uniting two projects carried out by the Institute for Technology Assessmenind Systems Analysis (ITAS) of the Karlsruhe Research Centre. “Waste management and sustainable development” and “Analysis of the distribution of selected heavy metals due to waste management measures”. The problems involved in the material flow of cadmium are identified and discussed agains the background of an integrative sustainability concept developed by ITAS.

Analyse des Einsatzes von Abfällen als Sekundärbrennstoffe in Zementwerken — Derzeitige Situation, Potentiale und Stoffströme

Zement ist ein mineralischer Stoff und gehort zu den hydraulischen Bindemitteln. Er erhartet unter Wasseraufnahme an der Luft oder unter Wasser steinartig und kann auf diese Weise einzelne Gesteinsteile verbinden. Der Hauptabnehmer von Zement, dem wichtigsten Ausgangsmaterial fur die Herstellung von Beton, ist die Bauindustrie. Im Jahre 1998 wurden in Deutschland ca. 34 Mio. t Zement produziert. Hiervon gingen 53% in die Transportbetonindustrie, 26% an die Hersteller von Betonbauteilen und 10% in den Bereich sonstiger Silozement. Sackzement hatte einen Anteil von 12%.