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Equipment
Every step in nickel laterite processing requires specialized facilities and equipment. Whether your project is at the bench-scale where flowsheets are developed or being verified at the pilot-scale, SGS Minerals Services has the equipment needed for sample preparation, leaching, purification, precipitation and metal recovery. We also have the analytical laboratory facilities to ensure fast turn-around time and accurate results for circuit control and mass balancing.
Feed Preparation/Beneficiation
Laterite ore feeds are typically prepared using scrubbers, open mills with trommel screens or ball mills.
Further processing steps can include ore upgrading by gravity separation, attrition milling and/or cycloning.
Extensive Atmospheric and Autoclave Leaching Equipment
The prepared slurry is preheated and fed into the autoclave or atmospheric leach circuit where it is mixed with concentrated acid. The laterite ore is then leached, releasing Ni and Co from the oxide host. This pregnant leach solution (PLS) with the leached solids exit the leach circuit at 100C.
The heart of nickel laterite processing is the leaching system. SGS Minerals Services has continuous high-pressure autoclaves at its facilities in both Australia and Canada that meet the rigorous safety, construction and operational parameters needed for this type of processing. Both facilities have a number of options for testing a variety of atmospheric leaching circuits.
Purification and Counter-current Decantation (CCD)
The autoclave or atmospheric leach discharge slurry is neutralized and purified to remove iron and other elements. The PLS is then separated from the solids by wash thickeners (CCD train, below left).
Precipitation of Intermediate Product
A mixed hydroxide or sulphide product can be continuously precipitated from the PLS during downstream processing to recovery Ni and Co. (Above right, part of a hydroxide precipitation circuit).
Releach and Metal Recovery
The intermediate mixed product can be releached providing a solution suitable for Ni recovery by solvent-extraction and electrowinning or by hydrogen reduction.
Assaying
Our comprehensively equipped assay laboratories operate 24/7 to continuously provide key data to guide project decisions. Analytical instrumentation is linked to a networked data management system allowing speedy access by the project team worldwide.
Mineralogy
Our mineralogy group has a variety of equipment including optical microscopes, XRD, a SEM/microprobe and a QEMSCAN™ unit for quickly resolving operational issues in the pilot plant The example below shows zoning of precipitated species in nickel hydroxide precipitates.
Environmental Testing
SGS Minerals Services has unique experience in environmental testing for metal processing, particularly in assessing the acid generating potential of metallurgical products, tailings and process waters. Environmental studies supporting nickel laterite processing can involve acidbase accounting, leachate toxicity testing and effluent testing.
Stabilization studies for geotechnical review are an essential part of the laterite treatment program. SGS Minerals Services has completed a number of tailings studies covering the design of laterite tailings disposal.
Process Control, Data Management and Analysis
Distributed control systems and process control instrumentation are available in both Canada and Australia to control and operate all aspects of the flowsheet and to provide rapid feedback to refine operating conditions.
Expertise
Scale of Operations
Internationally, SGS Minerals Services metallurgical group, through it’s offices in Canada and Australia has completed over 10,000 projects. Fundamentally, we help you ask the right questions and make the right choices, whether you are at the scoping-test stage, performing bench-scale investigations or running a fully integrated pilot plant to demonstrate a flowsheet and generate design data and market samples.
Distributed control systems and process control instrumentation are available in both Canada and Australia to control and operate all aspects of the flowsheet and to provide rapid feedback to refine operating conditions.
Innovation and Responsiveness
Unforeseen problems can arise during pilot plant operations, usually revealing issues that are better addressed before full-scale operation.
As a result of many years of experience, our staff can quickly assess viable alternatives and implement solutions directly to the pilot operation.
Project Management and Staffing
SGS Minerals Services has staffed nickel laterite programs that required over 75 skilled professionals to operate them around the clock. A typical nickel laterite technical team is composed of a senior metallurgist who has has responsibility for defining the scope of work, scheduling, controlling budgets, an engineering manager who coordinates day-to-day operations, shift engineers and an experienced technical staff backed by an on-site mechanical shop.
Experience
SGS Minerals Services has done bench and pilot-scale testing on a large number of the nickel laterite flowsheets used today. Partial Project List Below:
Canada - Pinares
- Ramu River
- Ravensthorpe
- Koniambo
- Weda Bay
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Australia - Murrin Murrin
- Cawse
- Bulong
- Ravensthorpe
- San Felipe
- Syerston
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Special Investigations
Specific projects may have unusual requirements, sometimes logistical or operational in nature. We have the depth to develop techniques to resolve these requirements for you.
For instance, we have used our equipment base, our process modeling skills or our diverse technical base to:
- Evaluate the impact of using reagents sourced near project site (e.g. water,limestone).
- Measure properties in the autoclave during leaching (i.e. heat capacity, on-line off-gas analysis).
Determine the high and low temperature rheology of autoclave feed and related products.
- Selectively reject Mn from autoclave solutions
- Assess various equipment options
- Determine solid/liquid separation characteristics for CCD circuits
- Investigate acid production in autoclave processing
- Develop a 5m deep bed-thickening column for mud compaction and ultimate slurry density studies
- Comparative testing and development of atmospheric leach circuits
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