New Technology Developments in the Production of Non-Ferrous Metals

New Technology Developments in the Production of Non-Ferrous MetalsWilliam P. Imrie

The efforts, cost and challenges for commercialisation of new technology are very substantial and the non-ferrous metallurgical industry has some examples of poor and even disastrous implementation. However lessons learned do permit risk mitigation approaches to be employed and the industry continues to seek developments that will meet the needs of today and tomorrow.

Keywords:

New technology – Technology development – Innovation – Technology risk – Incremental change – Start-up – Ramp-up – Alumina – Aluminium – Copper – Nickel – Lead – Zinc

Neue Technologieentwicklungen in der Produktion von NE-MetallenDie Anstrengungen, die Kosten und die Herausforderun-gen bei der betrieblichen Verwirklichung neuer Techno-logien sind sehr wesentlich. Die NE-Metallindustrie hat einige Beispiele für mangelhafte und sogar verheerende Implementierungen. Jedoch hat man aus diesen industri-ellen Erfahrungen gelernt, dass Risikominderungsmaß-nahmen eingesetzt werden können. Die Industrie sucht deshalb weiter nach Entwicklungen, die die Bedürfnisse von heute und morgen befriedigen.

Schlüsselwörter:

Neue Technologie – Technologieentwicklungen – Inno-vation – Technologierisiko – Stufenweise Änderung – In-betriebnahme – Intensivierung – Tonerde – Aluminium – Kupfer – Nickel – Blei – Zink

Nouveaux développements technologiques pour la production de métaux non ferreuxDesarrollo de nuevas tecnologías en la producción de metales no ferrosos

Plenary paper presented on the occasion of the European Metallurgical Conference EMC 2005, September 18 to 21, 2005, in Dresden.

1 Introduction2 Industry background

The processing of minerals and extraction of metals are recognized as among the oldest skill sets developed by modern man. By this account, society might judge us as being more experienced than most business sectors in the conceptualisation and implementation of new develop-ments. Although history provides our industry with memo-rable examples where this has been the case, we often are judged today as “old hat” or conservative in our pace of ac-commodating new concepts. What is the reality, and why? This overview, of an otherwise wide and complex topic, reviews the nature of the challenges faced in bringing a new development to its final stages, our industry performance in doing so, and how we might better circumvent the risks. Against that backdrop, some recent and current technol-ogy developments are outlined herein, with confinement to those that have reached or approaching the phase of commercial execution.

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History easily reminds us of giant technology contributors to our metallurgical industry like Bayer, Hall and Héroult, Bessemer and others. The development by Hall-Héroult represented such a breakthrough to the core chemical processing steps that it remains fundamental to the present production steps more than one hundred years later. Like-wise, in other base metal cases, the fundamental process-ing steps from mining, mineral beneficiation and metal extraction – at least by the pyrometallurgical routes – bear resemblance and adherence to some underlying principles that have been used for more that one hundred years: in some cases, much more.

It is interesting to note that while several early develop-ments bear the name of the individual most credited with its commercialisation, this has been less prevalent in recent decades since the required development stages are numer-ous, complex and involve many teams of individuals.

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William P. Imrie: New Technology Developments in the Production of Non-Ferrous Metals

the largest consumer of the three metals shown in Figure 1 and causing recent upward movement, the purpose of this

Although adherence to the underlying principles of histori-paper is to reflect on our recent past and the present, and cal developments is strong, our early industry developers not to make economic predictions. In any case, a period of – given the opportunity to visit today’s processing plants projected metal price recovery should not be a reason to – would likely be most impressed by the embellishments lessen the approach of risk mitigation for a new technology of incremental change that, in no small measure, have al-development.lowed the early developments to meet modern challenges.

The motivating influences for the extensive application 3.1 Economies of scaleof incremental technical development have included the

One very important single aspect of incremental change,

needs for:

and one that has contributed to the attainment of lower

• Cost competitivenessmetal pricing that is reflected in Figure 1, has been the • Stringent environmental and safety criteriaprocess equipment sizing development for economies of • The ability to treat lower grade or more complex ore scale. An example of this time-line trend is illustrated in bodiesFigure 2 for the case of applied grinding power to a single

SAG mill. Another example, shown in Figure 3, is the sig-• A new product or intermediate product.

The economic challenges and drivers for change can be nificant growth in aluminium reduction cell amperage that illustrated in one sense by the trends shown in Figure 1. the industry has achieved over the last century, and the This plot shows some metal pricing indexed from their last couple of decades in particular. Other examples of this (arbitrary) 1963 values compared with two selected US aspect of incremental change are prevalent through the economic indicators; the US urban consumer price index metallurgical spectrum and include mine haulage trucks, (CPI) and the US average home price. Although US Feder-mineral flotation cells, smelting vessels, solvent extraction al Board Chairman, Alan Greenspan, has recently warned and electrowinning, not to mention ancillary equipment that the property boom is an “imbalance”, the US home such as sulphuric acid plants that are now regular compo-pricing index is included because it has had measurable in-nents of many metallurgical processes. In fact, when asked fluence on the US economy, with trickle through effect on in 1983 what would be the most significant technology global economy – and hence on metal commodity demand. development for the next twenty year, the author’s prompt Notwithstanding the familiar cyclical nature of metal pric-answer then was “the economies of scale”.ing, the plot shows the general relative trend of downward pressure on metal producers. This has negatively impacted producers’ cash returns and therefore would be expected to lessen any tolerance for risk. On the other hand one might conclude that the changes implemented by the metal industry are yielding “bargain” pricing compared with ear-lier years. Although China has now displaced the US as

It is worth reflecting on what has made the aspect of in-creased scale possible, particularly the accelerating growth that is shown in the examples of Figures 2 and 3. In ear-lier years, the capability for growth in equipment sizing was the product of a lot of patience, interpretation of field data, physical modelling, trials – and some errors. The accelerating capability for designing larger units is in

3 Incremental change and influences

Fig. 1:

Metal pricing trends vs. US eco-nomic indices

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Fig. 2: Economy of scale trend for grind-ing power per single SAG MillFig. 3: Economy of scale trend for alumi-nium reduction cell amperagepart attributable to the availability of powerful computing 4 What constitutes a new technology power and the development of equally powerful analyti-development?

cal software for such as static and dynamic stress analysis,

computational fluidynamic (CFD) modelling and, in the Aside from the important advantages of incremental case of aluminium reduction cells, magnetohydrodynamic change, how do we define a new technology development? modelling.There is of course no prescribed definition since we are

dealing with an attribution accorded by the general body

3.2 Process control and operational datain the industry – however we all recognize it when we see A second incremental development that is worthy of men-it and can share the recognition of examples like SAG and tion is the advancing extent and sophistication in the field of tower milling, high efficiency thickening, SX-EW, Outo-process controls and Human-Machine Interfacing (HMI). kumpu flash smelting, Mitsubishi Continuous Process, Im-Twenty years ago or so, the portion of the capital cost of perial Smelting Process, QSL, Kivcet, Ausmelt and Isasmelt a large metallurgical project attributed to the category of technologies, pressure leaching and numerous others. instrumentation and process controls would have repre-sented approximately three percent of the total. Today, the more advanced instrumentation, controls and HMI can account for eight to ten percent of the capital cost. The justification has been by way of more efficient, optimised and stabilised control of processes and equipment at higher productivity levels; plus a plentiful supply of raw data for the timely analysis by engineers and managers. World of Metallurgy – ERZMETALL 59 (2006) No. 1

I suggest that identifiers for the labelling distinction of new technology might include cases where:

• a significantly different route to the process chemistry is applied,• the process is for production of a new product,• a technology transfer from a different commodity sec-tor has been successfully applied,

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William P. Imrie: New Technology Developments in the Production of Non-Ferrous Metals

• the use of equipment and materials breakthroughs have overcome previous processing barriers,

• a reduction in the number of main processing steps is adopted in a manner that delivers efficiency and cost effectiveness, or,

• in contrast to the latter, where more complex new processing steps are necessary and successfully applied to meet the challenges of more complex ore feeds.

6 Financing

5

What are the hurdles and challenges for new developments?

The hurdles and challenges that face the developers of new technology are huge. The costs, time and persistence required to transcend from the ‘proof-of-concept” phase to commercial execution are formidable and are mostly only successfully undertaken by well founded (and well funded) corporations. The funding requirement is not only for the development phase but also for undertaking the direct cost exposures and risks for the pioneer project itself.

There are multiple phases involved in the development and implementation of any new technology. Approaches

will vary in detail, however identifiable steps that are most There is evidence that these concerns have been height-ened by our industry’s performance, such as with the recent often involved can include:

Western Australia hydrometallurgical laterite projects,

• Identification of a need and visioneering of the con-which have resulted in banks looking for increased levels of ceptdiligence through the feasibility stage evaluations. Even so, • Proof of conceptbanks recognize that new technology is complex, requires

the right mix and proven teams of experienced people, and • Bench scale tests and characterizations

• Conceptual study (including techno-economic bench-can still have results that are harmed by inexperienced

management that can impose wrong influences on teams marking against proven processes)

making complex technical decisions.

• More extensive test work

The risk elements that bankers attribute to new technol-• Prefeasibility study and trade-off evaluations

ogy can be the same reasons that a new technology might

• Environmental baseline studiessometimes be better first applied at a smaller scale and as • Pilot scale testing (partial/integrated/demonstration an expansion to an existing operation. In this manner there

is a reduced exposure to the compound effects of any sur-level)

• Rigorous reviews (including market acceptability and prises from the feed characteristics with those of the new

technology itself. This approach is less likely to jeopardize re-examined competitiveness)

an owner’s cash flow.

• Environmental impact assessment• Final feasibility study and project financing

• Project execution including start-up and commission-ingThis listing does not include a number of steps that are shared with any major project. However two of the envi-ronmental steps are included to emphasise the need for those as early engagements, and because innovation is frequently a hard sell to the environmental agencies and NGOs. Testing by vendors and by third party laboratories will also be important steps.

The time span involved in this suite of development steps is lengthy and will see the transition of many individuals and teams, each suited to the skills required at each step. The following sections focus on the latter phases to il-lustrate some of the challenges and influences that often have to be faced at the time of project development and implementation.12

Most new projects of significant size are enabled only by external financing. While engineers are naturally enthused by innovation, the related challenges, and the professional satisfaction from breaking new ground through technical development, this enthusiasm is not shared by the financing community. While engineers and metallurgists will think in terms of metal being the product, to the banker the product is the monetary return on investment – with the least risk. Since bankers already identify mining projects as having inevitable risks associated with the ore body, ore-related customisation of the process, and environmental require-ments [1], there is little or no interest in adding to the list any risk from new technologies. This is the case even after diligent pilot plant or demonstration plant efforts, where design scale-up and long term effects are still uncertainties, and it therefore requires that an owner will be self-funding or will accept a lower debt:equity ratio in those cases. Since the banker has essentially a “Fixed” return on his invest-ment – if all goes according to plan – his tolerance for risk is lower than that of the equity player.

7

Community and environmental expectations

Most companies undertaking any mining or metals process-ing project are fully aware of the importance today of community engagement in matters of environmental influ-ence and sustainable development. Neither the political, financial, and environmental communities nor the multi-national mining corporations are willing to accept any compromising of international standards, even in return for local job and other growth opportunities that a major new project can bring. The complexities of this topic are ad-dressed by KEMP [2] who also points out the dichotomy that the appeasement of community and environmental group interests in employing “best practice” technology with its sophisticated chemistry, instrumentation, and report-ing systems can result in offsetting increased technologi-cal risk by the shortcomings of locally available skills for

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such complex facilities. Increasingly, trace metal reactions and fixation technologies are being incorporated into the metallurgical processing and production technology itself. When the technology is a new development, there are the added risks of potentially incomplete knowledge and pos-sible inaccuracy in predictions for the qualities of emissions and discharges. This is exacerbated if design margins do not sufficiently allow for start-up instabilities. The overall risk is then of a diminished level of confidence and trust by the communities and, as we all know, the uphill slope of trust restoration is always steeper.

scenario of a first-of-kind process. The results of McNulty’s analysis, summarized by McNulty’s plot shown in Figure 4, have been frequently cited and discussed. By analysing and sorting the case history information into selected category data sets, McNulty was able to illustrate the lowered start-up performance attainment associated with the various levels of novel technical content together with common shortcomings in adequately preparing for the outcomes of the related risks. The categories that McNulty devised for this purpose and used for the four curves of Figure 4 corresponded with categories of increasing involvement of novelty and/or decreasing levels of mitigation effort from the execution of mature technology (Series 1 curve) to cases of unusually complex flow sheets, incompletely understood chemistry or inadequate through testing and design (Series curve 4).

At the same time, McNulty concludes that the inadequate performances can be avoided through careful management of the design and engineering phase. He encourages the use of impartial individuals and entities and emphasises (as do the bankers cited above) the need for diligent and accurate feasibility studies. CAMPBELL [6] supports this lat-ter view with some examples of successful ramp-up experi-ence during commercialisation of new processes. Campbell also looks at the potential effect on a project financial net present value (NPV) as an outcome of the four McNulty

8

Our industry history with new technology risk

The retrospective analysis of how the mining and metals in-dustries have performed in the execution of projects, with and without the added aspect of new technology, has been presented before. Charles River Associates [3] performed for the World Bank a survey and analysis of the start-up experience with new mines and processing plants in the copper, lead, zinc and nickel sectors. The report card grade was not good, and although the analysis was in 1979, the representation of inadequate performance is not confined to that era. AGARWAL and KATRACK [4], who were authors of the report for the World Bank summarized the results of the survey with the added assessment of the effects that de-layed start-up has on the retrospective net present value of the project compared with the value applicable at the time of project approval. They show, by calculated example, how easily the discounted cash flow rate of return for a project can be halved when burdened with delayed ramp-ups as witnessed by several in the survey.

More recently McNULTY [5] analysed the start-up case history of 41 metallurgical projects that included sulphide concentrators, hydrometallurgical and pyrometallurgical processing. The range of processing plant coverage in Mc-Nulty’s analysis is shown in Table 1.

The analysis covered projects of conventional and of “in-novative” technologies with results that emphasize the statistical evidence of the added risks imposed whenever the aspect of new technology is involved. For this McNulty applied the context of “innovative” to include situations where various combinations of novel processing, equip-ment or ‘largest scale’ were involved as well as for the

Type of processNo. of Start-up Processesplantsperiod1975 to 19951965 to 19951979 to 19961981 to 19941975 to 1995Fig. 4: Project ramp-up performance by categorised series (Source: McNULTY [5])

Tab. 1:

Types of processing plants ana-lyzed by McNulty (Source: MCNULTY [5])

ProductsCopper, goldCopper, lead, zincSoda ash, direct reduced iron, specialty metals/oxidesCopper, nickelCopper and gold ores and concentratesHydrometallurgical 7oxide plantsConcentratorsChemical plantsSmelters1376Agitated, heap and dump leachingSulphide flotationHydro and pyrometallurgical methodsPyro methodsAgitated ambient and pressure leaching, biological heap leachingHydrometallurgical 8sulphide plantsWorld of Metallurgy – ERZMETALL 59 (2006) No. 113

William P. Imrie: New Technology Developments in the Production of Non-Ferrous Metals

series start-up curves. His observation is that while the Se-• An execution team that is experienced in the design and ries 1 and two projects can maintain a good financial return operation of comparable facilities, as well as first-of-a-in the first three years, a Series 3 project will yield little to kind projects, and that gives a balanced attention to the contribute to debt repayment and a Series 4 project will details of the innovative and conventional aspects of suffer losses and increased debt exposure.the plant.In reviewing the McNulty analysis, COYNE [7] adds data from 24 metallurgical plants from which he had personal data and that incorporated significant innovative technol-ogy in process and/or equipment that was beyond the cat-egory of incremental change. Using the McNulty method of categorization, Coyne classed eight of the projects as equivalent to Series 1; five as Series 2; three as Series 3 and eight as Series 4. Of the 24 projects, only 33 % achieved the forecast ramp-up rate and 21 % experienced failure to a degree that the plants were abandoned. Coyne also analysed a further 19 plants that failed to meet the forecast ramp-up rate and for which the data was collected from media reports and personal communications. Of this group, twelve were classed as the McNulty Series 4 type, and of those, eight had to be abandoned due to severe problems.

To cement these principals effectively, people – the project team and other supporting individuals – are the first and most important consideration. The development of any major project through all its phases is a great learning experience and much more so for a new technology de-velopment. However, in either case, and especially for the latter, it must not be the first such learning experience for the team. There always should be room for, and meaningful contributions from, less experienced members in the team but the key guiding forces and influences should be with a suite of seasoned people with the highest levels of experi-ence and skills that can be mustered.

As already mentioned, the time span for all development steps is long and there are multiple people and entity transi-tion steps that involve the owner, test laboratories, vendors, evaluation engineer(s) for feasibility studies, EPCM contrac- tor, and other third party consulting firms and consultants.

It can be a significant challenge for the owner to manage the appropriate timing and nature of all interfaces. Sometimes an “out-of phase” involvement is prudent. For example, while the primary focus of attention during pilot plant test work is for the process itself, this phase can represent a lost opportunity if there is not also an input from an entity that may eventually design the plant. Such involvement can help ensure that the pilot plant phase also provides data that is useful or critical to the detailed engineering phase.

9 Designing and executing for reduced risk

Faced with this background filled with examples of inade-quate performance, are there methods for providing greater assurances, to ourselves and the other stakeholders, for the successful outcome of a new technology development?

Like McNulty, Coyne concluded that there is a pattern to the characteristics of the project development and engi-neering design among the projects that achieve or come close to achieving their forecasted performance. Coyne identified that a pattern of attributes, reflecting the nega-tive, is even stronger for those projects that experienced Also important are the methodologies and procedures un-total failure. der which the team will operate. Particularly for the aspects From his analysis, Coyne determined that a project that of new technology, risk identification and management will incorporates innovative technology can have a very high be a significant procedural feature. Here it is important to probability of achieving its technical and economic objec-distinguish between the commonly found methods that

identify, categorize and rank risks from the detailed engi-tives when it is characterized by:

neering approaches that are required for careful analysis

• Appropriate process investigations, generally at the and sound mitigation fixes. The former can be informative, scale of a fully integrated pilot plant, to establish de-but it is only the latter type of approach, with experienced tailed process chemistry, effect of recycle, effect of feed people involved, that will give any assurance of reducing variations, input parameters for complete mass and the risks. Typically, the engineering methodology for risk energy balances, all key process design criteria and to identification will draw upon proven methodologies but measure product quality.will be customized for the specific needs of the project.• Test work and plant design based on the same feed ma-Our metallurgical industry is not alone in its needs to iden-terial and ranges of characteristics as will be fed to the

tify and manage risk. NASA operates from the baseline of

commercial plant.

risk identification being the modus operandi. Even then,

• Use of equipment that has been commercially demon-in the case of the recent return of the US Shuttle flight to

strated at the same size and in a similar application in

the International Space Station after 2½ years and a multi-successfully operating plants.

million dollar risk reduction program, some first-of-a-kind

• Avoidance of any first-of-a-kind equipment that needs commissioning repairs still were required in the “field”!to be manufactured to achieve a key process step unless

it has been demonstrated at full scale on the expected In a NASA presentation NASA [8] for the Office of Safety

and Mission Assurance (OSMA), four levels of a risk ice-range of feed material.

• Selection of materials of construction that are within berg are identified and dramatically illustrated as shown proven ranges of application without regard to the cost; in Figure 5.

otherwise perform long term corrosion/abrasion testing The NASA categorization is a useful framework of key of alternatives.categories or prompts for flushing issues to the surface. 14

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Tab. 2: Risk iceberg level examples applied to innovative metallurgical

designKnown KnownsTest work dataOverall flow sheetIdentified first-of-a kind featuresRelevant data from any analogue project/operation of closest similarityCritical criteria for technical, economic and environmental adequacyLimited continuity of people through the multiple phasesExperience metrics for the team & identi-fied gaps“Off-ramp” criteria (managed abandon-ment)Known UnknownsThe real eventual extent of feed variability & minor elementsThe real eventual quality of emissions and dischargesOutcome of fact that test work rarely reaches steady stateThe effectiveness of communicating critical data to all partiesThe real & eventual capacity matching of integrated facilitiesThe optimized surge capacity between first-of-a-kind stepsOptimized spares requirement for first-of-a-kind facilitiesUndemonstrated hazardsUnknown UnknownsUnknown KnownsUnrecognised test work gapsPoor assumptionsApplicable information and experience by individuals not on the project team and not identified as a knowledge sourceApplicable information within the team but “lost” by poor management of data traceability or of knowledge retentionFig. 5: The risk iceberg

(source:sas.ivv.nasa.gov/conclusion2003/SoftwareAssuranceS)

Using those categories, Table 2 illustrates a few example issues that might apply in the circumstances of designing for new metallurgical technology. Once initiated, such a list will grow and change as the design effort progresses.The uncertainties shown in Table 2 can be reduced. Once again, experienced people will be key to doing so. The sub-ject of communication is listed as a Known Unknown in Ta-ble 2. That is not because of a lack of understanding of com-munication needs, but rather simply that with so much data and so many individuals involved, gaps and omissions are almost always certainties – resulting in Known Unknowns. The electronic age has provided enormous capacity for the storage and retrieval of information, however the complete-ness and relevance is still a matter of human input. Two aspects that the author has found sometimes amiss are:a) A detailed compilation of the data interpretations made from the numerous tests in a manner that is traceable and complete with respect to the values that will be-come input to the project engineer’s design criteria. Such comprehensive documentation – which can be thought of as the technology basis manual – should be a frequently referenced source as the detailed design progresses.

b) A design log for each facility that records the reasons for the numerous decisions that are made during de-tailed design to serve as a reference for the teams who will start-up and commission the project. This record might include some evaluated compromises, or pro-visions for potential retrofits, that were deliberately evaluated during the design phase. The readiness of this information can aid the commission team’s efforts for a good ramp-up.

recent developments undertaken within the non-ferrous metals sectors. This is not a complete listing and any omis-sions from this listing are not a reflection of ranking by any metric.10.1 Alumina

Refined alumina production from bauxite continues to be based on process steps developed by Karl Bayer before the turn of the twentieth century. However numerous incre-mental improvements have been undertaken throughout the industry for increased productivity and efficiency. This has been successful to the point that the recent Comalco Alumina Refinery in Queensland, Australia is the first new greenfield alumina project, outside of China, in the last decade. It is interesting to note that Comalco used this op-portunity to integrate into the new plant the selected best improvements from those that have been already demon-strated in other operating plants.

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10 Recent and current development

examples

Notwithstanding the preceding backdrop of the challenges most likely to become manifest during a new technology development, our industry appropriately continues to seek advantage through continuing improvement and innova-tion. This section outlines some examples of current and World of Metallurgy – ERZMETALL 59 (2006) No. 1

William P. Imrie: New Technology Developments in the Production of Non-Ferrous Metals

generated in the pressure leach balances the consumption needs of the parallel oxide heap leaching and ore stockpile

Aluminium smelting technology is still based on the molten leaching operations. Copper production from the oxide salt electrolysis developed by Hall and Héroult circa 1900. and sulphide leach routes is by electrowinning to market Investigation of carbothermic reduction as a potential al-grade cathode.ternative continues, however commercialisation is not yet

expected in the short term. Likewise the investigated step 10.3.3 Bioleachchanges for dimensionally stable anodes and/or cathodes

and for drained cathode cell design are not yet commer-Development work continues on bioleaching technology, cialised. As already mentioned in Section 2, the economy as applied to both heap and stirred tank environments. of scale by increased cell amperage has been a major devel-Although natural mesophile bacterial oxidation is adopt-opment. Along with this, major advancements have been ed practice in the gold sector and common in heap and made to enable larger and more serviceable reduction cells dump leaching of copper from secondary sulphides, no

commercialisation of copper primary sulphide leaching and silicon carbide cell lining systems.

technology based on engineered systems for mesophiles or thermophiles has yet been realized. The closest to 10.3 Copper

commercialization would seem to be the industrial scale

10.3.1 Grindingconcentrate leach plant presently being implemented by The use of SAG milling, which grew out of the develop-Copper Alliance in Chile. Other new bioprocess technolo-ment of the Aerofall AG mill in the sixties, was an indus-gies under development involve the use of thermophilic try response to the need for higher grinding capacities microbes in engineered heaps, and the consideration of as large ore bodies of lower grade came into production. ecological and genomic information relating to bioleaching The increasing scale of SAG mills has already been shown microorganisms. in Figure 2. However it has always been known that the

10.4 Nickel

overall plant economies made possible by the use of large

SAG mills have not been synonymous with high energy 10.4.1 Laterite – hydrometallurgicalefficiency. An alternative comminution approach that has

gained attention in recent years is high pressure grinding In the hydrometallurgical laterite nickel sector, the Goro rolls (HPGR) that are already standard equipment in the Nickel project [10] is the most significant new develop-diamond, iron ore and cement sectors. Cyprus Minerals ment currently being commercialised. This project em-braces Inco proprietary technology developed for this

(now Phelps Dodge), at its Sierrita operation, might have

project and comprises a number of novel steps to permit

been one of the first to test HPGR in a hard rock mining

the co-processing of both the limonite and saprolite ores

operation, however severe wear on the roll surfaces de-by pressure acid leaching. The technology development

terred industry adoption. More recent test work by New-over a ten-year period includes laboratory, mini-plant and

mont at their Lone Tree Mine, along with equipment and

integrated pilot plant test work, supplemented by related

wear material advancement by Polysius AG, is now one

tests for equipment and materials of construction.

basis for renewed interest and a present commitment to

this method of size reduction ahead of ball milling by Some of the aspects of the Goro Nickel Process that easily Phelps Dodge at its the Cerro Verde project in Peru and by earn the classification as innovative technology include:Newmont, Newcrest and AngloGold for their Boddington • Higher (270 °C) than normal leach temperature (for copper-gold project in Australia. faster kinetics)

• Use of solvent extraction for nickel and cobalt recov-10.3.2 Pressure leaching of copper concentrates

ery and using a new (Cyanex 301®) extractant for high selectivity and good phase separationWhile some 80 percent of the global supply of primary

copper is via the route of smelting sulphide concentrates, • Use of Bateman pulsed column SX – as a transfer from the most significant shift towards commercialisation of a the uranium industry – instead of conventional mixer-pressure leaching alternative to smelting is probably rep-settlers (except for washing/scrubbing of the loaded resented by Phelps Dodge’s Concentrate Leach Project organic)

[9] at its Bagdad operation, Arizona. The project is novel • Use of hydrochloric acid for stripping the loaded or-in that it captures integrated processing synergies between ganic

oxide and sulphide leach operations. The pressure leaching • Specially developed/adapted fluid bed pyro-hydrolysis component was co-developed by Phelps Dodge and Placer technology for production of nickel oxide from the Dome to provide high-temperature and medium-tempera-nickel chloride extracted by solvent extraction

ture leach capability according to the most favourable

extent of acid production desired from the concentrate For an earlier project phase, Inco had also developed and sulphide. In the Bagdad project case, the final operating considered the following innovative features – as a transfer version commissioned in 2005 comprises ultra fine grind-from the alumina industry:

ing of sulphide concentrate ahead of medium temperature • Use of direct and indirect heat exchangers for feed (140 °C to 180 °C) leaching in sulphate media. The acid slurry heating without feed dilution.10.2 Aluminium16

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• The use of deep-bed tailings thickening and paste depo-sition

10.5 Lead

Compared to the examples given for the nickel sector,

For the current project execution these are now replaced primary lead production has seen no major new technol-by conventional steps.ogy commercialisation in recent years. Of the technologies

established in the last two decades, Ausmelt in particular

10.4.2 Pyrometallurgical laterite processing

has been successful in extending its portfolio of new lead

The most innovative technology currently intended for smelting plants. Sharing the core Top Submerged Lance commercialized pyrometallurgical processing of saprolitic (TSL) technology with Xstrata’s Isasmelt technology, this nickel ore is the Falconbridge Nickel Smelting Technology could be because TSL technology offers several features of (NTS) [11]. Falconbridge has developed this technology attraction such as:

specifically for the Koniambo saprolite and anticipates a • Feed flexibility (quality; preparation; primary, recycle or commitment in 2005 to the execution phase of that project. secondary material)The technology development phase has spanned a ten year

• Cost competitiveness from high smelting intensity

investigation and test work period, and has culminated in

a major processing change from the Rotary Kiln Electric • Vessel and process adaptability to smelting, slag reduc-tion and slag fumingFurnace (RKEF) process that currently is the predominant

technology for producing ferronickel metal from saprolitic Although there is a current absence of new lead smelting ores.technology commercialisation, and the sector has seen With goals that included cost competitiveness, energy ef-closures of Imperial Smelting Furnaces, numerous efforts ficiency and environmental improvement through reduced have continued for the enhancement of production from opportunities for particulate releases, the Falconbridge existing technologies and operations. concept development phase embraced evaluation of rel-evant technologies within other industry sectors. The re-10.6 Zinc

sulting features of NTS as proposed for the Koniambo In the zinc sector, there are two significant recent new tech-project include the following innovations (compared with nology developments; both involving atmospheric leaching conventional RKEF):of zinc concentrates. • Use of hammer mill and flash dryingIn the first case, Anglo-American has commissioned its • Flash calcining – as a transfer from cement and other greenfield Skorpion project in Namibia based on the use

of SX/EW technology in which zinc concentrates are at-industry sectors

mospherically leached with sulphuric acid to yield a zinc

• Fluid-bed calcine reduction – as a transfer from iron ore

PLS for solvent extraction followed by electrowinning to

reduction applications

SHG zinc. Anglo-American anticipates that the new mine

• Use of DC electric smelting – as a transfer from fer-and use of this technology will enable it to be the World’s roalloy and ilmenite applicationslowest cost zinc producer.

• The counter-current use of smelting and reduction stage The other case is the Outokumpu process [12] for direct off-gas flows through the upstream stages including the atmospheric leaching of zinc concentrates instead of roast-flash dryer.ing or of direct oxygen-pressure leaching. This has been

successfully applied at the Outokumpu Kokkola plant in

10.4.3 Pyrometallurgical sulphide nickel processingFinland and by Korea Zinc at its Onsan plant. This is an

interesting and novel development in which the new tech-Although it is now a decade since Outokumpu commis-nology operates in parallel with conventional concentrate

sioned its Direct Outokumpu Nickel Smelting Process

roasting and allows expanded production while using ex-(DON) at its Harjavalta plant (now owned by New Boli-isting solution purification and electrowinning systems but

den) in Finland and seven years since the same process

without increasing sulphuric acid production since the use

was commissioned by RTZ at its Fortaleza plant (now

of atmospheric leaching allows the production of solid

owned by Votorantim Metais) in Brazil, it is noteworthy

sulphur.

as the most recent new development in the pyrometal-lurgical sulphide nickel sector. The DON process elimi-11 Conclusionsnates the costs and environmental issues associated with

Peirce-Smith matte converting by producing a high nickel The development and commercialisation of new metal-low iron matte directly from the flash smelting furnace. lurgical technology is a lengthy, high cost undertaking that Operating with an electric slag cleaning furnace, the tech-involves significant risks. A key driver for such ventures is nology permits the choice of recycling electric furnace the pursuit of competitive overall costs. At the same time matte to the flash furnace to yield a single matte product the industry has many examples where inadequate execu-or to transfer flash furnace and electric furnace matte tion of a new development has curtailed the investment (high iron) as individual feeds to the hydrometallurgical return and some where the project has been abandoned refinery. The elimination of matte converting significantly after the heavy investment. On the other hand there are enhances cobalt recovery.abundant lessons learned that can be applied to reduce World of Metallurgy – ERZMETALL 59 (2006) No. 1

17

William P. Imrie: New Technology Developments in the Production of Non-Ferrous Metals

these risks and there are fortunately sufficient examples of successful commercialisation that have enabled the indus-try to produce metals for society at lower costs (in real term pricing) than in the past.

[7] COYNE, K.R. (2002): Commercialization of Innovative Technology.

Bechtel Internal Report.[8] NASA (2003): NASA, OSMA Software Assurance Symposium, July

2003; Internet published at sas.ivv.nasa.gov/conclusion2003/Softwar-eAssuranceS. [9] MARSDEN, J.O. (2004): Pressure Leaching of Copper Concentrates,

Pressure Hydrometallurgy 2004. – Proceedings of the 34th Annual Hydrometallurgy Meeting of CIM, Banff, Alberta, Canada. Montreal, Canada (Metallurgical Society of CIM) – ISBN 1-4475-54-2.[10] BACON, W.G et al. (2005): Development of the Goro Nickel Process.

– ALTA 2005, May 2005, Perth, W.A. Australia (ALTA Metallurgical Services).[11] KING, M.G., GRUND, G. & SCHONEVILLE, R.H. (2005): A Mid-Term

Report on Falconbridge’s 15 Year Technology Plan for Nickel. – Pro-ceedings of EMC 2005, Dresden, Germany: pp. 935-95; Clausthal-Zel-lerfeld, Germany (GDMB Society for Mining, Metallurgy, Resource and Environmental Technology).[12] TAKALA, H. (1999): Leaching of Zinc Concentrates at Outokumpu

Kokkola Plant. – ERZMETALL, 52: 37-42.

Literature

[1] HAYSTEAD, B. (2005): CIBC, Personal communication; June 2005.[2] KEMP, D.J. & WISEMAN, M. (2004): The Implications of Sustainability

in Developing a Nickel Laterite Project. – Proceedings International Laterite Nickel Symposium 2004: pp. 45-53; Charlotte, N.C., USA, (The Minerals, Materials and Metallurgical Society) – ISBN 0-87339-550-6.[3] Charles River Associates (1979): Startup of New Mine, Mill-Concen-trator and Processing Plants for Copper, Lead, Zinc and Nickel: Sur-vey and Analysis, prepared for The World Bank, Washington, D.C.[4] AGARWAL, J.C. & KATRACK, F.E. (1983): Economic Impact of Startup

Experiences of Smelters – Advances in Sulfide Smelting. Proceedings of the 1983 International Sulfide Smelting Symposium and the 1983 Extractive and Process Metallurgy Meeting: Vol. 2; pp. 1129-1140; San Francisco, CA, USA (The Metallurgical Society of AIME) – ISBN 0-520-463-0. [5] McNULTY, T.P. (1998): Developing Innovative Technology. – Mining

Engineering, 50: 50-55.[6] CAMPBELL, F., McCONAGHY, E. & VARDILL, W. (2004): Startup and Reli-ability of Nickel Laterite Plants. – Proceedings International Laterite Nickel Symposium – 2004: pp. 25-42; Charlotte, N.C., USA (The Min-erals, Materials and Metallurgical Society) – ISBN 0-87339-550-6

William P. Imrie Bechtel Corp. 50 Beale St.

San Francisco, CA 94110-3965 USA

18World of Metallurgy – ERZMETALL 59 (2006) No. 1