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Research » Technology Metals (Extraction and Recycling)

Title

Direct low-process extraction of solar silicon from raw silicon while avoiding silane chemistry

Type

No information

Sponsorship

Deutsche Bundesstiftung Umwelt

Duration

01.10.2006 – 31.3.2008

Partner

ACCUREC GmbH Mülheim-DE

Description

The aim of the project is the development and testing of an innovative process for the production of high-purity silicon, which is required for the production of solar wafers. Today, this silicon, known as solar grade (SG), is obtained almost exclusively from so-called off-grade material, i.e. scrap material from the semiconductor industry, and is a by-product of a process that is far oversized in terms of purity for SG silicon. Thus the available quantity is limited and can no longer satisfy the demand of the accelerating photovoltaic market. In addition to the price-driving shortage of this input material, the technically complex and expensive production processes for ultrapure silicon prevent a necessary cost reduction so that solar energy can compete in the future without subsidies. Significant savings in the process chain of a solar wafer can only be achieved if an alternative process to today’s SG-Si extraction process can be found, the Siemens process which involves the chlorination, gasification, condensation and dechlorination of silicon.

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