Technology Request

Ref: 07 GB EAST 0HRE

Date: 04/04/2007 15:15:30

Title: Environmentally cleaner solutions for refractory aggregate binding technologies

Abstract: A UK company is searching for novel, environmentally cleaner solutions for refractory aggregate binding technologies, used for moulds and cores in the production of metal castings. The type of collaboration is flexible. The company can access global markets.

Description: In the making of moulds and cores, silica sand is mixed with a small quantity (1-3%) of organic binder material, then pressed into a mould and set by some external physical (e.g. heat) or chemical (e.g. gaseous catalyst/hardener) influence. Molten metal is then poured into and around the resulting product to provide the desired shape of the metal part being cast. The bonded sand is a disposable product, which is broken down (e.g. heat causing collapsing or later dissolved) after a single casting, although the sand after treatment is often recycled for future use. Due to the chemical nature of the current binders most commonly used, each of these stages produces environmentally damaging emissions, as well as raising various health and safety issues. There is an urgent requirement therefore, for a robust, environmentally acceptable aggregate/binder system. Technical Specifications / Specific technical requirements: Such a system must provide: • No more than 5% binder by weight (preferably of the order 1 to 2%). • Bench life of mixed aggregate & binder to be at least several hours. • Rapid (i.e. less than 1 minute) curing into a rigid shape with immediate strength when required (exposure to trigger mechanism such as gaseous catalyst). • No deterioration (preferably at least a 50% increase) in strength on ambient storage for several days. • Easy breakdown and removal after casting (preferably via the heat from the casting: ca 750ºC for aluminium, 1400ºC for ferrous material). • Easy recycling/reclamation of used aggregate/binder either as a unit sand or within other sand systems (hence should be chemically benign). • No adverse chemical reaction between the aggregate/binder and the metal during the casting process. It is anticipated that the desired solution will be found outside of the foundry industry and will probably be an inorganic technology, although more acceptable organic binders or hybrid mixes of inorganic and organic will be considered if demonstrably effective. Natural binder systems with some aromatic compounds are also potentially of interest. With the right solution, there will be a quick access to global markets. Please note the following systems are currently known and not of interest: - Organic: Amine-cured polyurethane, SO2-cured furan or epoxy, ester-cured alkaline phenolic, CO2-cured alkaline phenolic, heat-cured urea-formaldehyde/phenol formaldehyde/furan (by furan is meant polymers or blends with furfuryl alcohol). - Inorganic: CO2-cured sodium silicate, microwave-cured sodium silicate, heat-cured sodium polyphosphates, heat-cured magnesium sulphate, machinable salt (sodium chloride) blocks.