Since its formation in 1999,Atoll Metal Recovery (“Atoll”) has built, owned and operated (BOO)11 major gravity metal-from-slag and mineral recovery plants in Southern Africa, capable of processing between 120 and 200 t/h of feed using unique pneumatic jigs and classifiers. It has also constructed a 100 t/h plant for Sweden, 60 t/h plants for France, Romania, Georgia, Turkey and the USA and has supplied 10 t/h to 35 t/h mobile jigging plants to clients throughout the world.
Most of the plants recovered metal from ferroalloy slag, initially by toll processing for clients but more recently Atoll has begun to recover metal and slag for its own accoun t – the metal is sold to steel and alloy foundries while the slag is sold as construction and remediation material. Atoll still operates the plants in Sweden, Romania, Turkey and the USA as well as one plant in RSA. The other plants have been sold to the slag owners.
Although metal from slag recovery remains a key focus, Atoll is turning more of its attention to the beneficiation of minerals by jigging, particularly manganese and iron ores and coal.
Atoll was also a major participant in Mogale Alloys that used a unique process in a 40MVA DC furnace to smelt Stainless Steel EAF dusts to form a FeNiCr alloy and an inert slag. The BOO processing of SS EAF dusts and SS pickling acids is another major focus for Atoll.
Atoll continually strives to introduce innovative but proven technology to its clients on a BOO basis, reducing the risk to the client while providing cost effective services.
Metal from Slag
A need to recover the metal from slags was first identified by the South African metallurgical research institute, Mintek, in the 1970s, due to the rapid growth of the ferroalloy industry in South Africa.
Attempts by the mining industry at this time to use physical separation techniques such as dense media separation (DMS), spirals, tables, magnetic rolls and diaphragm jigs proved inefficient and it was not until the late 1980s that Mintek identified pneumatic jigging as the technology most suitable for metal recovery from ferralloy slags.
Initially a Batac jig was modified to achieve higher recoveries and grades of metal. At about the same time Titaco identified a need in the market for better metal-from-slag recovery technology and approached Mintek with a view to developing a complete product / process package for the market. The Titaco / Mintek joint venture (JV), formed in 1992, grew out of this interaction.
Since its formation, the JV has built 18 major metal-from-slag recovery plants in Southern Africa capable of processing between 120 and 200 t/h of slag. It has also constructed a 100 t/h plant for Sweden, 60 tph plants for France, Romania, Turkey and the USA and conducted BFS’s for 6 major plants (200 t0 300 tph) in Eastern Europe. In line with the JV’s commitment to the ongoing improvement of its technology, continual development has taken place. Initially, pneumatic jigs were only used to recover metal from coarse (+6 – 25 mm) slag fractions while diaphragm jigs were used for fine (+1 –6 mm) fractions. In the mid 1990s, however, the Batac jig was abandoned in favour of the Apic jig, the technology for which was sold to Titaco by FCB of France and which was a development of the original patented Pic pneumatic jigs. Building on the advantages of the Apic jigs, Titaco / Mintek developed a fines (+1 –6 mm) Apic jig to complement the coarse (+6 –25 mm) jigs.
Since 1998, the Apic fines jig is now standard on all Titaco / Mintek Metal Recovery Plants (MRPs) and two of the major plants were retrofitted with these circuits. In a further development, the Apic classifier was developed for ultrafines and was commercialised at Middelburg Ferrochrome in November 2000 and Transalloys Silicomanganese in April 2002.
The success of the technology was recognized by the Associated Scientific and Technical Societies who awarded Mintek and Titaco their national trophy for ‘outstanding contributions to science or the application of science in 1999. As the MRP business developed, the need of many clients for a build, own, operate (BOO) service emerged and Titaco / Mintek therefore formed the Apic Toll Treatment (Pty) Ltd joint venture company (Atoll) to provide BOO services.
Atoll has operated a 170 t/h plant at Transalloys, a 250 t/h plant at Middelburg Ferrochrome, a 150 t/h plant at Hernic Ferrochrome, a 30 t/h plant at Metalloys , a 60 t/h plant at SA Ferrochrome, an 80 t/h plant at International Ferrometals and an 80 t/h plant at ASA Metals in South Africa, a100 t/h plant at Vargön Alloys in Sweden and 60t/h plants at Boulogne-Sur-Mer, France; Tulcea, Romania; Zestafoni, Georgia; Antalya, Turkey and Johnstown, USA.
Most of the RSA plants and the Swedish and French plants were toll operations. However, the Romanian, Georgian, Turkish and USA plants all sell both metal and slag for their own account.
Mineral Ores
The Titaco/Mintek JV built a manganese ore pneumatic jigging beneficiation plant in Otjosondo, Namibia.
Atoll had a manganese ore toll processing BOO pneumatic jigging plant at Burke Mining near Kathu, RSA.
Atoll has conducted several pilot plant pneumatic jigging campaigns on both RSA and Brazilian iron ores. Two Apic iron ores jigs have been sold to Brazilian iron ore producers, several to Indian iron ore producers.
The pilot plant development done by the JV led to the first major pneumatic jigging iron ore beneficiation plant in RSA at Beeshoek.
Based on its pneumatic jigging experience, the JV built a major pneumatic iron ore jigging plant in RSA for Kumba.
Atoll ran a toll processing BOO on coal at Mooifontein during 2002.
Stainless Steel and EAF Dusts
Atoll has been able to use Mintek’s patented DC arc furnace technology to remelt and refine ulltrafine baghouse dusts and other ultrafine wastes from the ferroalloy industry (which otherwise present environmental and health threats) into valuable ferroalloys.
The first application of the DC furnace technology was to remelt and refine SiMn ultrafines from Atoll’s Transalloys metal from slag recovery plant. A medium carbon SiMn was produced in lumpy form by smelting recovered ultrafine metal with high grade Mn oxide baghouse dust.
Atoll then used the DC technology at Mogale Alloys where a 40 MVA DC furnace produces a Fe, Ni, Cr alloy from stainless steel EAF dust and chromite fines.
Ownership
Titaco merged with Bateman Engineering in 2000 and in 2006 the AIM listed Bateman Engineering N.V. (BENV) bought Mintek’s share in the South African part of the Atoll group and consolidated the Atoll companies under the BENV mantle. In 2008 Atoll was rebranded as Bateman Mineral Recovery.
A year or so after the financial crash in September 2008 which led to a collapse of commodity prices, BENV sold its interest in Atoll to the current owners who are entrepreneurs with extensive experience in the quarrying and metal recovery industry.