Materials & Processes


‘Antec’ plastics technical conference in the US, researchers Sam Lukubira and Amod Ogale, of the department of chemical and biomolecular engineering, told delegates how they had used meat- and bone-meal (MBM) to produce bioplastic sheets, for potential use in sheets for geo-structural applications. When the relative humidity of the MBM powder was


above 55 per cent, excessive denaturation occurred, producing a dark, glue-like material. Glycerol was used as a plasticiser (in quantities of around 30 per cent by weight), and the pressed sheets were tested for mechanical properties. Those made with finely ground particles (less than 250 microns) were twice as strong as those made from larger particles.


Walking on eggshells


Scientists at the University of Leicester are looking to create new types of plastics from egg shells. A research team is led by Andy Abbott, professor of


physical chemistry and head of the chemistry department at the university, is investigating how it might make starch-based plastics from the egg shells. Food producers need to pay to dispose of egg shells in


landfill: Leicester-based Just Egg, for example, uses 1.3 million eggs per week, and spends £30,000 a year to send 480 tonnes of shells to landfill. The company’s managing director, Pankaj Pancholi, said:


“It would be great if the egg shells could be recycled into the plastic packaging that we use for egg products.” The project aims to develop a way to convert the egg shells


into a range of starch-based plastics, and test the mechanical properties such as strength. The researchers also intend to identify ways to use the egg shells as fillers that could ‘bulk up’ different grades of plastic. Potential applications include ready meal food trays and shop fittings - though the ultimate goal is to produce packaging that protects egg products. The team will also try to extract proteins called


glycosaminoglycans (GAGs), for possible use by the pharmaceutical industry.


Waste lines


Plant waste materials is another potentially fertile source that could be used to make bioplastics.


The Oil Palm Biomass Consortium (OPBC), coordinated by Netherlands-based TU Delft, and the innovation unit of the Malaysian Prime Minister’s office, will look at the use of palm waste as a raw material for the chemical industry. Malaysia is one of the world’s largest exporters of palm oil, but current production processes use only the palm fruit. “The waste of the palm plant, such as the stem, leaves


and the processed palm fruits, can form an important source of biomass for bio-fuels, bio-plastics and other products,” said Luuk van der Wielen, professor of bioseparation technology at TU Delft. “The use of such organic materials as palm waste is becoming much more attractive as a more sustainable source of raw materials for the production of chemicals. By this collaboration Dutch chemical companies can gain access to this resource as well.” But these natural materials are not always used as


chemical precursors. In some cases, they can be used as ‘fibre providers’, adding reinforcement to conventional polymers. An example is Curran, a cellulose material extracted


from carrot waste by Scottish company Cellucomp. It can be blended with a range of conventional resins – including polyurethane, polyester and epoxy – to create composites with high stiffness, strength and toughness. Cellucomp is working with Dutch farm cooperative Royal


Cosun to commercialise the material. Curran, combined with carbon fibres, was used to make the Reactor fishing rod, while sheets of the material have been used to produce a skateboard. The material is currently made in a pilot plant, but is


expected to be commercially available next year. Biowert of Germany is using grass from local farmers to


create a range of products, including a bioplastic. AgriPlast granules comprise 40-75 per cent cellulose fibres


from meadow grass (which is produced during the process of crop rotation) and 25-60 per cent recycled polypropylene (PP) or polyethylene (PE). It says that parts made from its AgriPlastic are around 20 per cent lighter than those made from PP or PE. The granules are free-flowing and can be injection


moulded into components such as spoons, brackets, machine cases, and protective caps. Biowert says the material has high flow, which ensures fast cycle times during production. l


Aqueous coalescing now effective and cost efficient T


he goal was simple: demonstrate both low cost and effective coalescence of entrained organic to improve


performance of dual-media filters; and provide a standalone solution for raffinate. SpinTek Filtration met this goal through


the creation of its new aqueous coalescing technology, the Aqualescer, a pre-treatment of organic in solvent extraction (SX) plants for hydrometallurgy applications. This system improves coalescence by


adding pressurized air in the inlet feed line, increasing efficiencies. A test conducted in


South America at the Gaby Copper Mine’s Solvent Extraction (SX) Plant offered the opportunity to use the new Aqualescer in conjunction with the CoMatrix SX system to evaluate the removal of small organic droplets and crud from the raffinate stream during service operations. The results showed low levels of


organic in the total effluent with the vast majority of organic removed by the Aqualescer. With organic inlet concentrations as low as 9ppm the average entrained organic removal was 75 per cent.


Efficiency removals rose to 88 per cent when the organic present in the feed was greater than 20ppm. The success of this test program led


to the sale of the first-ever combined Aqualescer and CoMatrix system in Central Asia. This system is under construction at Central Asia Mining, a SX copper mine in the Republic of Kazakhstan. l


For more information ✔ at www.engineerlive.com/asia


SpinTek Filtration is based in Los Alamitos, CA, USA. www.SpinTek.com


www.engineerlive.com 27


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