Thermo-mechanical treatment

Study of the factors influencing thermo-mechanical treatment for recycling used concrete

Summary: The liberation process developed is intended to improve the quality of concrete recyclates for the production of fresh concrete. For this end, thermal and mechanical treatment is combined. It was empirically proven that even moderate temperatures of around 300°C are sufficient to make the hardened cement paste (HCP) brittle, so it can then be removed by means of mechanical treatment. The products of this process are aggregates with properties close to those of natural aggregates as well as a fine-grained material high in hardened cement paste that can be further processed to a binder.

1 Introduction

Concrete is the most commonly used building material in our time. Around 8000 mill. t concrete are produced annually worldwide [1], including around 250 mill. t in Germany [2] and around 3000 mill. t in China [1]. At the same time, large volumes of concrete rubble are produced. The forecast for Germany, which is based on the concrete volumes produced and assumptions regarding the lifetime of concrete structures, indicates that around. 100 mill. t of concrete rubble could be produced by the year 2020 [3]. The volumes of concrete rubble expected in China range between 200 and...

Related articles:

Issue 2010-12

Limestone milling in Germany

On 23.07.2010 the Karl Kraft Steinwerke oHG in Heidenheim an der Brenz/Germany, placed an order for a LOESCHE LM 19.20 D mill (Fig.) for grinding limestone. The mill will be installed in a recently...

Issue 2014-03

Mill upgrade commissioned

ABB has commissioned an upgrade to Vale’s existing Clarabelle dual pinion semi-autogenous (SAG) mill (Fig. 1). The mill is used to reduce the size of the ore at the company’s nickel and copper mines...

Issue 2012-11

Cyclone mills – ideally suited for temperature-sensitive samples

For the grinding of solids the use of a cyclone can be beneficial, depending on the material properties. The rotation of the mill’s rotor or a connected vacuum cleaner produces a rotating air flow...

Issue 2012-06

Process development and proof of concepts on site

The dry milling of ore in Loesche vertical roller mills has shown significant process advantages, as well as economic and ecological benefits. To demonstrate these, a mobile ore-grinding plant, the...

Issue 2014-06

Revolutionizing ultrafine grinding

The Emax is an entirely new type of ball mill for high energy milling (Fig.). The unique combination of high friction and impact results in extremely fine particles within the shortest amount of time....