Number

255-EN

Section

General Section

Use

Abstract

Pickling with strong acids like hydrochloric and sulphuric, for removing the scale after hot rolling, can be replaced by a non-chemical method. A German SME developed an alternative using water jet and waste scale as abrasive material. Avoiding chemicals and cost reduction are the advantages of the alternative.

Substituted substances

Reliability of information

Evidence of assessment: there is evidence of an official (positive) assessment of the substitution

Reason substitution

CMR
skin/respiratory sensitizing

Other type of alternative

Hydro-mechanical technology using collected scale as abrasive material

Hazard Assessment

Substances to be substituted: Sulphuric acid causes severe skin burns and eye damage. Strong inorganic acid mists are group 1 carcinogen (IARC) as listed in the Substance Database according to SUBSPORTplus Screening Criteria (SDSC). Hydrogen chloride is not listed in the SUBSPORTplus Database and has no harmonised classification according to Annex VI of Regulation (EC) No 1272/2008 (CLP Regulation).. Alternative substance: Non-chemical alternative.

Description of Substitution

Research carried on in an EU Life co-funded project resulted in the development and implementation of a non-chemical process for removing scale after steel hot rolling. Scale is formed right after the rolling, because of the high temperature of the metal and its exposure to atmospheric air and moisture. Removing scale is necessary for further processing of the steel. The method developed within the project can totally eliminate pickling for scale removing, in some cases, e.g. for construction steel that is zinc coated afterwards, or in other applications for which 95% scale removal is sufficient. If pickling is however needed, it is significantly reduced (by half). The method was nominated Best Life-environment project and discussions on its acquisition and implementation by a larger company started at the end of the project period. The method uses a cleaning hood divided into a blasting part and an aspiration and drying part. Blasting is performed by high pressure water rotating jets and waste scale as abrasive material. The system uses high vacuum to absorb the newly removed scale and the blasting mixture. The mixtures separated allowing recycling of water and scale particles.

Case/substitution evaluation

The substitution totally avoids or reduces the consumption of strong acids like hydrochloric or sulphuric acid. Pickling with heated acid solutions or with acid spraying generates strong acid mists that are classified as carcinogens to humans by IARC. Avoiding or reducing the use of hazardous chemicals also lowers the costs for managing the substances and the wastes they generate. The design of the cleaning system keeps emissions to a minimum, improving working conditions as far as chemical risks are concerned. The substitution needs technological changes but the cost reduction that it generates makes the pay-back time short.

State of implementation

Pilot study

Date and place of implementation

2007

Availability ofAlternative

In 2009 implementing  the project results at full scale was discussed with industry representatives.

Producer/Provider

http://www.airmatic-filterbau.de

Type of information supplier

Producer / distributor
Research

Type of publication and availability

Layman project report, freely available on internet

Publication source: author, company, institute, year

The presentation is based on the Layman report HVD - Hydro-Mechanical Descaling Process based on High-Pressure Vacuum Technology Using Scales as Abrasive Blast Medium LIFE05 ENV/D/000207, published on the website of the EU Programme  Life Environment

Publication source

Type of publication and availability

http://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=home.createPage&s_ref=LIFE05%20ENV/D/0002

Date, reviewed

November 26, 2021