Johnson Matthey Converter Model - Case Study
The development and use of a general model for studying and
predicting the distribution of elements in the high temperature
processing of precious metals.
Precious metal containing substrates for
catalytic converters used in the
Johnson Matthey is a world leader in the production of catalysts,
precious metals and speciality chemicals. The very nature of these
products means that the ability to optimise the recovery of precious
metals from scrap or ore is highly desirable.
For a number of years scientists at Johnson Matthey Technology
Centre, in collaboration with Anglo American Platinum, have used
software tools and thermodynamic databases from the National
Physical Laboratory in order to gain a more fundamental
understanding of key production processes. However recently it has
become possible to use the NPL thermodynamic and phase diagram
software, MTDATA, in a new and exciting way.
During a year-long training secondment at NPL, JM scientist Dr
Hudai Kara developed a general modelling framework based on the
programming interface to MTDATA. The use of MTDATA provides a
rigorous and reliable way to determine the partitioning of elements
between phases. Now with the addition of process specific modelling
this becomes an even move powerful tool.
A readily adaptable general "converter" model has been developed
to study aspects of the production of precious metal from sulphide
ores, on behalf of Anglo American Platinum, and also the recycling
of precious metal scrap. Although superficially these two processes
appear very different they both involve the injection of oxygen into
a high temperature liquid and both result in the creation of a
liquid oxide phase in addition to the original liquid holding the
precious metal. The real problem is how to control the removal of
unwanted elements from the valuable phase without losing any value
into the waste oxide. A small deviation in the composition or loss
of a precious metal such as rhodium can have great economic
Screenshot of the converter simulation
This screen shot shows Dr Kara's model is able to follow the
formation of oxide and gas phases as oxygen injection proceeds and
also track the composition of the original liquid phase. In addition
to gaining a deeper understanding at the research centre this also
opens up the possibility of taking this type of modelling directly
into the plant environment and hence providing plant management and
even operators with virtual real-time and ahead-of-time prediction
to supplement the on-plant measurements.
The ability to quickly model processes of considerable
complexity, where many elements are distributed between various high
temperature liquid, solid and gas phases, gives JM and Anglo
American Platinum a significant advantage in tackling the many
challenges the modern high temperature materials processor faces.
These range from problems specific to the precious metal industry
where very close control over materials and continual sensitivity to
ever changing metal prices are required to general issues such as
coping with a variable feedstock, optimising the energy usage and
controlling waste streams.
A key aspect of this work was the ability to use an extremely
high quality and extensive database of oxide thermodynamic data.
This database has been developed at NPL over a number of years via
the sponsorship of an industrial consortium, of which JM and Anglo
American Platinum are members, coordinated by the Mineral Industry
Research Organisation. The DTI MPP Programme supported other aspects
of this work at NPL.
Further details of MTDATA, the NPL Oxide Thermodynamic Database
and their use in modelling real industrial processes can be obtained
by contacting Hugh