Technological leadership displayed by Bateman in process engineering forum

Bateman Engineering showcased its technological expertise at a successful Process Engineering Forum held recently in Johannesburg, South Africa for its clients and staff. Introducing the Forum, Steve Burks, Chief Technology Officer of Bateman Engineering, outlined how the Group is employing technology to redress the global skills shortage, via a structured three-year growth plan. This plan includes establishing centres of excellence focused on unit processes or products, such as DC furnaces or SX plants, and which have many advantages including the ability to develop standard designs for re-use thus reducing skills requirements, cost and duration in all phases of the projects. Forming technology partnerships and acquiring or developing proprietary technology in house are also high focus areas with benefits such as a reduction in flowsheet development time, effort and failure rate.

The establishment of a multi-centred hub in India to provide detailed engineering services in all disciplines other than process engineering to the Group worldwide will release high cost resources to focus on technology supply packages, while the procurement office in China offers the advantages of access to high quality, low cost products and shorter delivery time. Other important elements of the growth plan include training, using a variety of avenues such as post graduate technical programmes, inhouse training modules, sponsor bursaries and mentorship programs, a focus on development and retention of technology specialists, and the upgrading of the Group’s enterprise resource planning and IT communication systems.

Bateman Engineering’s development program for diamonds was presented by Darrell Olivier and highlighted the design competencies offered to the market through this well defined centre of excellence in diamond process engineering. These cover the complete value chain from ore reception, washing and screening through comminution and liberation, dense media separation, recovery, slimes and tailings disposal to simulation, process control and efficiency measurement, process plant commissioning and operations management.

The diamonds division also launched a consulting services competency in 2007, which has immediately proved successful with a number of audits already completed. The services cover process technical audits, sampling campaigns and process modelling, project viability evaluations, process plant equipment testing and plant operations and skills training.

The development of Bateman Grease Recovery Systems presented by Neels van Niekerk outlined the advantages of these systems over X-ray separators including their ability to recover low-luminescent diamonds, their higher recovery efficiency on small diamond sizes (-4 mm) and their higher unit feed rates when treating finer size fractions.

Other advantages include lower capital and maintenance cost and lower electrical and instrumentation complexity. These advantages, combined with the fact that the operating parameters are either controlled or monitored, thus minimising operator error, have meant that Bateman Engineering’s range of grease-belts has proven very successful in diamond recovery plants in both primary and secondary applications.

Two basic grease belt designs are available tailored to treat DMS or Pan concentrates or to be used as a scavenger recovery system after X-ray recovery: the Bateman Conventional Grease Belt 1000 and the Bateman Compact Grease Belt 800. With regard to the latter, different designs are available to treat -32 +1 mm and -50 +32 mm particle sizes where a thicker belt and larger separation tank are required. The Bateman Conventional Grease Belt 1000 has also been modified to treat -50 mm material.

The option of containerisation has proved popular due to the benefits of trial erection and factory testing and the ease of installation and relocation.

In a presentation on the Bateman Engineering jig – a modern marvel, Andrew Jonkers noted the Group’s impressive reference list of over 50 jig installations in most major mineral producing regions. Bateman Engineering’s under-bed pulsed jig is used to clean coal, iron ore, manganese, metal from slag and any ore application with a moderate density difference and particle size. This will be discussed in more detail in IM‘s September feature on iron ore.

Bateman Engineering is also a world leader in advanced process models for jig design, sizing and scaling based on batch test work. For example, the ASTRAD process model was used very successfully for Manganese Ore India Ltd (MOIL) to size jigs on what proved to be an extremely difficult separation. MOIL commissioned its jigs in November 2007 exceeding all client expectations in both grade and yield, easily meeting performance guarantees and outperforming manual separation.

Furthermore, the jigs could not have performed in this separation without the key gate and control advances supplied by Bateman Engineering.

In A new design approach for large mills, August Durow highlighted the design philosophy behind Bateman Engineering’s full range of SAG mills, AG mills, ball mills and scrubbers. This will be discussed in more detail in October when IM features comminution.

The future of pyrometallurgical FeNi production by Chris Naude and Mike Shapiro outlined the process development dating back to the small scale DC furnace test work in 2004 at Mintek, South Africa. Testing three types of ore with nickel contents of 1.41%, 1.15% and 0.87%, this work indicated a 90% nickel recovery for all types of ore and a nickel grade obtained of 15% – 20%. Stable operating conditions with hot feed were obtained, the copper coolers were shown to perform adequately and several critical parameters were established for commercial furnace design. In a grinding, drying and preheating test at Polysius in 2004, it was established that nickel ore can be effectively calcined and preheated in a POLCALTM preheater.

With the required equipment identified, the copper cooler technology was developed to create and maintain a slag freeze lining and, after a successful pilot test campaign and commercial installations, DC furnace technology now offers the industry the following advantages over the old AC furnace technology. It is able to process lower grade ore; it can process fine material without the need to increase the feed particle size in an upstream agglomeration process; carbon addition can be rapidly adjusted to achieve the desired degree of reduction; process adjustments during operation can be rapidly implemented; close control of power to feed ratio can be obtained; and reaction kinetics can be maximised.

In addition, the process is more tolerant of variations in raw material chemical composition and different types of reductant; a larger electrical parameter operating window is provided, facilitating the optimisation of throughput, recovery, grade and slag chemistry without compromising power input levels; and the open bath operation means easier tapping operations.

Bateman Engineering’s expertise in base metal tankhouse design, presented by Linus Sylwestrzak, is underscored by the Group’s impressive reference list. That and Galvanox, a novel atmospheric leaching process for copper concentrates, presented by KenBaxter, will be described in detail in IM‘s World Copper feature in August.

An Edge in uranium solvent extraction by Alan Miller outlined services provided through the Solution Purification Group (SPG), a cooperative joint venture between Bateman Litwin and Bateman Engineering giving the latter direct access to the latest technologies for SX, ion exchange and electrowinning plants. Uranium SX services commence at laboratory analysis of extraction and stripping mass transfer and kinetics, followed by pilot plant test work to size the SX equipment (Bateman Pulsed Columns (BPC) and Reversed Flow Mixer Settlers) as well as develop a preliminary cost estimate. At the FEED stage, the basic engineering is accomplished and the design and supply stage covers complete detailed engineering, supply of equipment to site, assistance in construction, training and assistance in commissioning and performance testing.

The advantages of using the BPC for SX include the efficiency and safety (lower fire hazard) of the process and the ease of operation. SX installations are cost effective for extraction and stripping, while delivery to site, commissioning and start-up are executed speedily. The SX portfolio also features a cost effective, efficient and layout-friendly Reversed Flow Mixer Settler installation.

Bateman Litwin and SPG’s track record with BPCs includes Haifa Chemicals in Israel, Olympic Dam in Australia, Dominion Reefs mine in South Africa and Wengfu, China. Recently, Bateman Litwin, through SPG, has provided two industrial plants using conventional uranium SX (250 -400 ppm uranium in the feed) and is currently supplying a plant for an unusual organic combination (80 – 90 ppm uranium in the feed). It has also recently tested BPCs for various feed conditions and achieved 6 – 10 ppm to less than 1 ppm uranium in the raffinate. On the stripping side it has successfully run a BPC for a strong acid strip and recently for a conventional ammonia strip.

Dr Clive Brereton of NORAM Engineering & Constructors presented on NORAM-Bateman Acid Plants – the benchmark in the use of the most modern process and mechanical technology to solve problems and to improve reliability in acid plants. Noram has traditionally serviced the acid industry in North America and Europe, with a milestone being the design for Europe’s largest converter (3,000 t/d). In 2006 a technology alliance was formed with Bateman Engineering for Sub-Saharan Africa with the prospect of expanding to other geographic areas. The first Bateman acid plant is being designed for the Ambatovy Nickel Project, Madagascar, comprising 2 x 2,750 t/d trains.

A number of design advances to the traditional sulphuric acid plant, essentially a series of heating, cooling, reaction and absorption steps carried out in converters up to 40 ft diameter and ducts up to 8 ft diameter, have improved operability and performance in the NORAM-Bateman acid plants. For example, old-style carbon steel and mixed carbon stainless converters with post supports have been replaced with lighter, more cost-effective all-stainless converters with catenary plate construction. These converters are easily coupled with internal heat exchangers to minimise ducting, and can often be largely shop-fabricated for improved quality control, therefore requiring minimal site fabrication.

Similarly, replacing the old-style brick lined absorption towers with flat plate packing supports and arches has overcome problems such as expense, complicated construction and poor draining. The modern tower has a dished base for draining, a ‘smart’ distributor for low carryover, and ease of inspection and maintenance, and supports the packing on a selfsupporting dome.

NORAM’s patented SFTM ‘split flow’ exchanger has overcome problems associated with conventional ‘cold heat exchangers’, greatly reducing condensation and corrosion, while other design advances include overcoming high NOx emissions from the sulphur furnaces. Dynamic simulation helps handle variations in smelter off-gas concentrations that cause plant instabilities. Also, considerable attention is paid to what might seem simple problems like the mixing of gas streams of different temperatures. Failure to provide such mixing can result in, for example, a superheater seeing non-uniform temperature and performing sub-optimally.

NORAM’s philosophy of working with the client to debottleneck their old plant or provide the optimum in a new plant has also seen considerable engineering improvements. For example, at a plant in Sherritt, Alberta, design improvements to a plant have increased its production to 850 t/d acid from the original design of 650 t with reduced maintenance costs and lower emissions.

In answering the question as to why the industry uses autoclaves, in his presentation on Autoclave expertise, Johann Verster briefly outlined the advantages of this technology and gave technical reasons why certain projects implement high pressure leaching as part of the optimal flowsheet.

Bateman Engineering’s track record features numerous studies and seven projects with autoclaves as part of the flowsheets in the past 10 years. These autoclaves have various conditions and different process objectives. All these autoclaves were successfully commissioned within three months, a proud record for Bateman Engineering.

Other highlights were mentioned: one of the projects has an autoclave circuit with the most heat recovery stages ever built. Another project features the first heat recovery that operates under a vacuum and the Sepon Copper project in Laos won the prestigious RW Hawken Award.

In addition to these project successes, often in difficult locations, there are other reasons why Bateman Engineering is a good choice for autoclave design and supply. Autoclave technology is only one of a suite of leaching technologies available from the Group. Other competing technologies that Bateman Engineering offers include Galvanox and atmospheric leaching. The most suitable technology is always selected for each specific application. In addition, Bateman Engineering has developed standard design calculation sheets to facilitate cost effective design and construction and its international procurement centres facilitate delivery of equipment.