Johnson Matthey's Refining & Chemicals Europe unit embarked on a process innovation project, which eliminated health and safety risks and cut costs
The Platinum Group Metal Refining business at Royston, UK refines palladium from a range of different sources. It produces refined palladium, the majority of which is in the form of a granulated powder with an open porous structure which we call 'sponge'. This sponge is supplied to other parts of Johnson Matthey and external customers, where it used as a raw material in the production of many palladium containing end products such as emission control catalysts for cars or reagents for pharmaceutical manufacturing processes.
The original route to producing sponge involved a batch process to calcine then reduce damp palladium 'black' powder. This utilised high temperatures in two 30 kW furnaces and required high concentrations of flammable and potentially explosive hydrogen gas. In addition, multiple manual handling steps, including the transportation of hot, heavy trays of material, had led to employees suffering back injuries in the past. All in all, there was scope for improvement.
The Refining & Chemicals Europe unit embarked on a process innovation project. It designed a whole new continuous process, cutting the number of manual handling steps from eight to two. Certain steps were eliminated and process was designed to run on non-flammable, low concentrations of hydrogen.
Also eliminated was the use of fragile (essentially consumable) silica trays, previously used to transport and process the sponge. These trays had been imported from South Africa and so removing them from the overall process cut out freight miles linked to their import. A single 12kW furnace replaced the two 30kW furnaces and due to the challenging nature of making damp powders flow, a bespoke feed system was developed in conjunction with suppliers to continuously feed the 'black' into the furnace. The redesigned process, reduced heat output and new location ensured that the operators are no longer subjected to the excessive temperatures that they had been for the old process.
The operators have been trained in the new work procedures and maintenance staff have also been trained in the upkeep of the new equipment.
The benefits cover the spectrum of Johnson Matthey's sustainability targets. The changes have reduced the carbon footprint of palladium calcination and reduction. Now that the silica tray stage has been removed and trays no longer have to be heated, over 10,000kWh of electricity will be saved every year. The use of the single 12kW furnace will contribute further energy savings. In addition the use of the reducing gas (hydrogen) has been cut by over 95% compared to the old process.
On the health and safety front, the palladium operators are benefiting from the reduction in manual handling and dust exposure. With the new process running on non-flammable levels of hydrogen fire risk has also been eliminated.
Financially, the new process has provided impressive savings of over £60k and the lead time in producing the palladium sponge has been cut by two days for external customers.
In awarding this process innovation a Sustainability Award 2012/13, the judges were unstinting in their praise, describing it as "a process innovation that has eliminated many health and safety risks with good evidence of technical development, employee engagement, financial benefits… and application to other processes".