High Efficiency Silicon for the silicone value chain

The wide range of silicone products has become a very common part of modern everyday life. The use of silicones is also increasing steadily due to its usefulness and versatility. Close to all the thousands of silicone products are produced starting from Silicon. The reaction of silicon with chloromethane (vast majority of production) to produce precursors for silicone is one of the most complex reactions industrialised. Even though it is well established that silicon strongly influences the value and effectiveness of the reaction, the catalysis and surface reactions determining the performance is not well known. The project aims at increasing understanding of catalysis and mechanisms influencing especially the unwanted formation of carbonaceous compounds in the reaction by combining catalytic expertise with mathematic modelling and advanced testing to improve the silicon used, giving increased value creation in the process. The Project has on catalysis focused on characterization of carbonaceous material formed in the process, in order to understand catalysis of formation. The project continues to work both within basic understanding of formation of carbonaceous materials but has in towards the end of the project also focused on identifying and test the most promising actions to reduce formation looking towards full scale testing in 2023.

The project has given new insight and developed knowledge into the issue of cracking in the silicone production from silicon, including measurement and simulation methods that can be used in further understanding of the issue - that is likely to be relevant for as long as the process exits. The cooperation has also been a solid learning experience for all involved, including universities and institute connected of this process that is highly important for Norwegian metallurgical industry - and that we both depend upon and influence via our silicon. The project has also identified both specific countermeasures that has been tested in lab and is and will be evaluated for full scale testing and main economic impact will clearly follow successful implementation here - and potential impacts will not be far from previous assumptions. It should not be forgotten that the project also has given methods to evaluate countermeasures, and given tools to improve understanding of the phenomenon. The project has attempted to be quite open regarding results and progress and have delivered several publications and communications (one still in the making), both internally and externally, and the project has received acknowledgement from the silicones industry for trying to understand more fundamental issues of cracking. The project has also initiated contact between participants with both Elkem Silicones Division (ESD) directly and IRCE Lyon, carrying our related research in participation with ESD. Beyond work towards industrial testing and implementation - which in one instant will be the main success factor from a value point of view, the project - other than use of the results and methodology- is now not planned continued (looking from the silicon side) at the moment. We can hope that the issue of cracking will be reduced as a result of this testing, but the issue is likely to still remain - and most likely interesting to continue working on at some point.

Silicones production is the most valuable application of silicon in chemical industry. This market is growing quickly (~5% per year) and will reach US$ 20 Billion by 2022. Raw materials for the production of silicones are silicon, methanol and hydrogen chloride. But the silicon market is very competitive leading to a price drop of 30% from May 2015 to June 2016. In order to maintain its leader position, Elkem has defined a market strategy based on increased specialisation by developing new specialty products for each market segment. In the silicones value chain market, silicon providers are facing three simultaneous challenges related to the productivity of the chemical reactor:(i) the process is continuous (silicon powder continuously injected in the reactor) which requires good material chemistry stability (ii) complex parallel reactions of different types of methylchlorosilanes which requires specific elements and phases to promote the desired reaction and (iii) presence of adverse reactions that can slow down or even kill the catalysed process. Over the last decades the first two points have drawn much attention, leading to improved silicon material properties. Nevertheless, the third point is now becoming increasingly important and needs to be addressed in order to further improve the value creation. The challenge in reducing detrimental side reactions is linked with the complexity of the chemical reactions occurring in the Fluidized Bed Reactor (FBR). Elkem with the support of NTNU and SINTEF aims to develop a premium silicon grade dedicated to silicones production. The new premium silicon grade for silicones production will have two main characteristics: - High Reliability: ensuring homogeneous material composition and intermetallic phase content - High Reactivity: ensuring that the material contains not only the right promoters but also inhibitors for the detrimental reactions.