Managing the environmental impact of processing metals
and minerals
Processors of natural resources may encounter environmental challenges
at any stage during the business of finding, extracting, beneficiating,
transporting, using, recycling and disposing of minerals and metals
products. While shareholders demand enhanced recoveries and improved
productivity, compliance with international environmental standards
and sustainable development are demanded by both the community as
well as investors and finance institutions providing the project finance.
New and existing facilities
BATEMAN has responded in several ways to the increasing pressure
on companies worldwide to meet these hallenges. In respect of new
ventures, process plants are provided that ensure sustainable development,
meet environmental challenges and control environmental impact. The
approach to minerals and metals processing has a core environmental
component which guides its traditional engineering, project management
and finance structuring capabilities to ensure that processing facilities
are provided which are aligned with the concept of sustainable development.
These facilities are environmentally friendly, have minimal environmental
impact and comply with legislation. This is accomplished through project-risk
analyses and environmental audits at regular stages of all projects
aimed at minimising and moderating the impact of the facility and
the
subsequent rehabilitation of the site.
In respect of existing processing facilities, clients can be assisted
to improve environmental compliance through assessments and the provision
of effective clean-up technologies. Life-cycle assessments on metals-
and minerals-based products manage the risks and obligations to the
community arising from the pursuit of business.
Clean-up technologies
Besides auditing the proposed process, equipment and technology to
ensure best practice, BATEMAN has also assembled a suite of technologies
for several niche, clean-up applications which either contain or minimise
the emission of pollutants from process plants.
These technologies are either proprietary, having been developed
in-house or are provided under licence from technology providers,
and the programme to expand this range of processes with environmentally
beneficial spinoffs is ongoing.
Solid-materials handling and disposal
BATEMAN’s suite of materialshandling equipment and technologies
enable the secure transport of solid materials with minimal spillage
of material or
generation of dust which could have a potentially harmful impact upon
the environment.
This includes conveyors to transport run-of-mine ores to the process
plant, with dust-control systems at the tipping points, and to move
processed materials around a plant and out-load marketable products
with minimal loss of product or generation of dust.
Metal- and slag-granulation and other solidification systems permit
the safe handling of molten materials in pyro-metallurgical plants.
Thickening technologies remove liquids from solid-liquid suspensions
and facilitate the
processing and transfer of waste materials and their safe retention
on
disposal dumps.
Air-pollution control
The BATEMAN in-house range is comprehensive and enables the selection
of the most costeffective solution to any dustcontrol, air-cleaning
or product recovery problem, large or small. Systems are designed,
manufactured and supplied as turnkey installation with full aftersales
service.
Electrostatic precipitators collect either solid or liquid particles
suspended in air up to 450 °C with particle emissions < 10
mg/Nm3.
BATEMAN’s baghouses efficiently clean large volumes of hot gas
where the fumes and dust must be collected dry with optional reverse
air-flow cleaning and pre-cooling for gas exceeding 230 °C. The
reversepulse
bagfilters have high filter rates and dust-collection efficiencies
of 99.99 %, even under variable operating conditions. High-efficiency
cyclones are used for precollecting aggressive or abrasive dusts.
BATEMAN’s compact reversepulse cartridge-filters collect dry
non-hygroscopic and non-fibrous dusts and wet scrubbers range from
static,
low-energy units for fixed dust-control volumes to hi-tech variable-volume
venturi systems for complex-process applications with gas temperatures
up to 750 °C.
Ceramic filters clean hot and process gases with outlet dust contents
of 1 mg/Nm3. They are also used for catalyst recovery and filtration
of ammonia, natural gas and mixed gas in nitric acid production. A
flue-gas
cleaning process removes noxious acidic gases such as HCl, SOx and
HF
as well as heavy metals and dioxins.
BATEMAN’s recently acquired license for NORAM’s sulphuric-acid
plant technologies in the sub- Saharan area has enabled the company
to now undertake projects on sulphuric-acid facilities across the
entire spectrum, from plant audits to feasibility studies, design,
procurement, construction and commissioning of complete new plants,
and upgrading facilities.
Environmentally friendly process technologies
BATEMAN’s suite of superior process technologies generate stable
wastes with no commercial value and replace or enhance the traditional
metallurgical processes which generate potentiallyhazardous solid,
liquid or gaseous wastes. The replacement of existing technologies
in the mineralsprocessing industry is often driven by the need to
comply with more stringent statutory requirements being introduced
by most countries globally, but can also usually be justified financially.
This includes technology for large, submerged-arc furnaces with closed
roofs to minimise the emission of hazardous fumes. DC-furnace and
hydrometallurgical technology process steelplant dusts, generating
valuable products and minimal waste.
Air-pulsed jigging technology recovers alloys from slag dumps typically
discarded by the ferroalloy industry, simultaneously generating environmentally
stable wastes and extracting the remaining value from
the slags.
Pulsed-column solvent-extraction enables base-metals processing in
sealed circuits, preventing the emission of potentially-hazardous
organic vapours, minimising fire hazards and limiting crud formation.
Ion-exchange technologies recover metal values from liquid effluent
streams which traditionally have been neutralised and dumped.
Bacterial and pressure leach processes for copper sulphides avoid
the traditional need for smelting and the resulting production of
sulphuric acid and undesired release of sulphur dioxide, heat and
even carbon dioxide to the atmosphere.
A new process for platinum-group metal concentrates has environmental
advantages over the traditional smelting and converting route as it
removes the sulphur in a single step in a concentrated-gas stream
suitable for acid production. A new chloride-based technology offers
considerable environmental and cost benefits over the conventional
sulphate and chloride routes for the production of titanium dioxide
pigment.
Water and effluent treatment
BATEMAN has an impressive trackrecord in the supply of innovative
but proven plant and technology for domestic and industrial water
and waste water treatment, ranging from low-cost rural facilities
to zero discharge and integrated industrial systems. These produce
affordable water of suitable quality that complies with demanding
regulations and meets
environmental obligations.
More information on BATEMAN’s environmental impact management
capabilities may be obtained from Paul van de Vyver, General Manager,
Pneumatic Conveying and Environmental Control on +27-11-201-2300 or
email environmental@BatemanEngineering.com.
For more information on BATEMAN’s environmental process technology
initiatives, contact Steve Burks, Chief Technology Officer,
on +27-11-899-9111 or email technology@BatemanEngineering.com.
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