Processing: Going green

By Kasia Patel
Published: Friday, 07 July 2017

Although the number of industrial minerals covered by IM is far reaching and the technology required for their production often varies by sector, the mining industry is seeing increasing calls for corporate social responsibility and greener technology, particularly in light of the growing role renewable energy has to play in the everyday lives of consumers.

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The field of raw material processing is a vast one. While many industrial minerals can be treated in a similar fashion – such as filler minerals like wollastonite, talc and calcium carbonate – others require treatment specific to the mineral and its end applications. Graphite, for example, can be processed to a greater or lesser degree depending whether the material will end up in a battery or a brake pad. 

Despite these differences, there are a number of trends which are seen repeatedly across sectors regardless of end market, such as the drive for lower processing costs when commodity prices fall or a desire to reduce waste and adhere to more environmentally friendly practices as customers scrutinise their supply chains. 

Ahead of POWTECH 2017, held in Nuremberg between 26 and 28 September, the event organisers referred to the transition seen by the chemical industry on a number of levels in a news update.

"Process digitalisation helps in achieving the goal of ensuring consistently high product quality, 24/7," the news release outlined. "The focus is also on curbing production costs and increasing energy and resource efficiency." 

According to Germany-headquartered processing firm Hosokawa Alpine, which specialises in the development, design and production of powder and particle processing, customers are able to expect more from the processing technology they purchase, a demand facilitated in part by digitalisation and automation of technology.

The company’s chemicals division operations director, Sylvia Braunlein, also noted ahead of the conference that single machines incorporated into an overall processing system by in-house departments are fast becoming a thing of the past, with customer needs demanding complete systems that, at the same time, adhere to the latest safety standards and guarantee product quality.

"To make this happen, you need a high level of system automation: only once that’s in place can you optimise your productivity, ensure stable process operation and put remote maintenance and predictive maintenance in place in order to minimise downtimes," she said.

While automation may have hit headlines years ago, it continues to grow across all industries from IT to oil and gas, and its growth is by no means over, Dietmar Alber, business development director for Hosokowa’s minerals and metal segment, told IM.

"Automation has for sure not reached a stopping point, it will continue to go ahead," Alber said. Automation and digitalisation falls under Hosokowa’s service division and allows plant control panels to be connected directly to Hosokowa’s staff, enabling troubleshooting, approvals or improvements to take place remotely. 

Dietmar noted that, with the increasing costs of labour, customers are increasingly investing in automation. While it may have previously been difficult to convince a mineral producer to implement an automated system – which can require a 10 or 20 year old plant to be completely overhauled – according to Dietmar, the long term savings outweigh the cost of upgrading a plant, and customers see that.

"Basically, if you have more automation the plant works more efficiently," he said. "If you go from an old-fashioned control to a modern one you can easily increase production by 5-10% because you can work closer to the specification."

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Kaolin being sorted using Eriez separator technology. 

Going finer 

While Hosokawa is not involved in the coarse grinding and excavation of industrial minerals, it supplies technology for the processing of filler minerals into finer grades in markets such as calcium carbonate, kaolin, barytes (barite), talc, wollastonite, silica and quartz for applications like paints, plastics, paper, rubber and sealants. 

A small part of the business supplies technology for the food and pharmaceutical end markets, which require special treatment and additional considerations such as sterilisation and various body approvals. However, around 80% of Hosokawa’s business focuses on calcium carbonate, which Dietmar says is a large market that follows the growth of the population – that is around 3-4% growth globally and up to 10% growth in ground calcium carbonate (GCC) in Asian countries such as India and China.

"It’s a huge market and there has been a general trend for all these minerals to go finer," he told IM. "People are opting for finer minerals for the plastic industry and surface treated minerals like calcium carbonate. The reason for this is finer products mean you can add more filler." 

According to Dietmar, the trend for finer particle sizes is being led by global players such as Omya and Imerys, with other customers in the GCC industry following suit. 

While finer particle sizes may conjure up an image of dusty plants, Dietmar noted that owing to negative pressure as long as a plant is operated correctly and properly maintained, dust shouldn’t be an issue.

"The plants, if operated correctly, are relatively dust-free nowadays. Dust is collected automatically, so there is not much dust. For talc there is no issue at all. The issue is with silica products and quartz, where dust needs to be avoided," he told IM.

Last year, the US Department of Labor’s Occupation Safety and Health Administration (OSHA) broke its long period of silence on new rules regarding acceptable levels of respirable silica dust, announcing a final rule to protect works from exposure to respirable silica dust, which has been linked to a number of health problems. 

The new rule will reduce the permissible exposure limit for crystalline silica to 50 micrograms per cubic metre of air, averaged over an eight hour shift. While the new rule was set to be enforced in June 2017, OSHA announced in April this year that enforcement of the standard has been delayed to the end of September 2017 in order to conduct "additional outreach to the regulated community and to provide additional time to compliance officers".

While the rule has been touted has having the potential to save more than 600 lives annually and prevent more than 900 new cases of silicosis, providing net benefits of around $7.7bn a year, there has been pushback from the industry.

The Construction Industry Safety Coalition attacked the economic impact study performed by OSHA, which indicated that the cost impact of the proposed rule would be in the range of a couple of thousand dollars for small corporations and less than $10,000 for large corporations. The coalition said these costs could be 20% below actual impact. The administrative controls have meanwhile been criticised as a technology-forcing piece of legislation, with major costs associated with the institution of these controls.

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Filler minerals like wollastonite (pictured), talc and calcium carbonate are processed
in much the same way, but the way a material is beneficiated varies depending on its
end market.
Namaqua Wollastonite 

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Processing operations could benefit from using a non-traditional approach to
 vibrating screens by using more than one type of screen media, which will extend the
life of processing equipment and enhance efficiency, according to W.S. Tyler, which
in 2013 developed its 'Pro-Deck’ approach to vibrating screens using modular screen
media, which allows customers to benefit from the flexibility of modular panels,
extended screen life and higher production rates.
WS Tyler 

Growth in energy saving technology and IT 

Meanwhile for Hosokawa, demand for silica and quartz processing technology is improving. 

"High quality and high purity silica and quartz is used in the IT industry a lot so we have seen a lot of activity and sales in this field for very fine products like 5 µ and 10 µ, also for special grades for LCD and plasma screens for making glass," Alber told IM.

In addition to demand for finer material, Alber says the company is targeting energy-saving technology, as well as opting for wet processing over dry processing, which allows Hosokawa to produce finer products using less energy and at higher capacities – another common requirement for customers. As investment per tonne of capacity drops, companies look to production on a larger scale to increase efficiency and get ahead in a competitive market.

"A typical example is a GCC plant 30 years ago had a capacity of 1 tph on a 10 µ for example and today that same plant would have 7 tph – no one is looking for a 1 tonne plant anymore," he said.

But by far the biggest growth area for Hosokawa is graphite. 

The company is currently working on the modification of graphite and is in the process of developing machinery for specific customers. Currently accounting for around 7% of the business, Alber anticipates this could rise to 10% in the near future, with equipment sales for graphite processing potential increasing by 50-100%. 

While past forecasts for growth in graphite processing may have not come to fruition, Alber believes that the industry is on the verge of a breakthrough and the prophecies of graphite growth will finally be fulfilled. 

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Graphite is seen as one of the largest growth
areas for processors.
Leading Edge Graphite

Reducing waste in graphite

Alber emphasised the importance of yields in graphite processing, noting that waste material occurs when reaching graphite of a certain property.

"Depending on how you work, you have more or less waste and of course less waste is more interesting, so this is something we are working on," he said. 

Demand for lithium is growing at a CAGR of 15.4% over the next decade where 201,000 tonnes of LCE were consumed in 2016, and the battery sector accounted for 35% of the total market, according to the IM Global Lithium Market: Five Year Outlook Report.

For graphite, while battery end-use makes up only 10% of the graphite end-market share, it is the fastest growing market, particularly for high quality flake graphite. Flake graphite for the manufacture of spherical graphite for battery anodes is forecast to grow at a CAGR of close to 30% until 2020, consuming nearly 360,000 tonnes of flake graphite in 2020, from a base of 75,000 tonnes in 2014, according to the IM Research report: Graphite Market Outlook to 2021. 

Current global capacity for Li-ion batteries stands at around 100 gigawatt hours (GWh) annually, estimates by Lux Research Inc. show. The company predicts that Li-ion production will increase to somewhere around 240 GWh with the potential to hit 300 GWh by 2020. 

In January this year, Tesla Inc. began battery cell production at its Gigafactory in Nevada’s Great Basin, with plans for an output of 35 GWh of cells for EVs and energy storage systems (ESS) by 2018. Meanwhile in China, BYD plans to ramp-up capacity and CATL could potentially increase output to up to 100 GWh by the end of 2020. By 2025, Deutsche Bank has estimated that global battery consumption will exceed 535 GWh, with EVs accounting for 55%, e-bikes for 14% and ESS for 9%.

While much has been made of the importance of Li-ion batteries in facilitating the growth of green energy solutions, the "greenness" of Li-ion’s raw materials is rather more questionable. In terms of raw materials, lithium and cobalt as used in cathode production and graphite is a key component for anode manufacturing. With Li-ion consumption anticipated to continue on its growth trajectory, raw material producers are gearing up for higher demand and production.

According to Superior Graphite’s vice president of marketing, Gerard Hand, this growth will pose a challenge for graphite producers.

"The problem is that, particularly with natural graphite, there’s a rounding technology that must be used and the yield is only around 40%. When you need around 3,500 tonnes of graphite you’re going to need 10,000 tonnes to start with," he told IM.

"That means you’re going to have to find something else to do with the 6,000 tonnes of material that isn’t suitable for batteries, and that’s going to pose a significant challenge to the graphite industry."

Hand added that, in some cases where natural graphite is mined, for every tonne of graphite produced, 10 tonnes of ore would need to be mined and separated.

With demand for graphite set to be driven by battery onsumption, Hand pointed to the expanding amount of hopeful junior developers.

"There is probably room for one or two new mines – particularly with the Chinese cutting back on some of the poorer performing and polluting mines. I think they will be able to meet the demand, but it might take some additional mines to come on stream," he told IM.

"That’s a good thing as long as they are brought online correctly," he added.

"[Producers] have come a long way in terms of not polluting the environment – in particular China, who produces around 70% of all the natural graphite that’s used around the world," Hand said. "It has cracked down significantly over the last few years on water pollution, air pollution, and shut down a significant amount of mines that weren’t really following protocol, so production is improving, which is a good thing."

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Leading Edge Minerals, which owns the Woxna Graphite project in Sweden, has
a graphite processing facility on site so that it can tailor its output to suit its
customer base.
Leading Edge Graphite 

Energy vs waste

The "greenness" of graphite production depends heavily on the technology used, raw material, grade requirements and end application. Natural graphite ranges from 75% C through to 99% C depending on whether the material is to be used in refractory applications or batteries.

"The issue with natural graphite – particularly crystalline graphite – is that it is mined in an ore zone, then it is crushed and separated through flotation cells. But after that it has to be leached using a chemical process. That acidic material isn’t very green at all, and to a certain extent that’s where our technology comes in," Hand said. "We can take natural graphite and upgrade it to 99.9 plus carbon without using an acid at all."

Superior Graphite operates a heat treatment facility in Hopkinsville Kentucky, US, and a similar facility in Sundsvall, Sweden. While the company does not mine any of its own graphite, it purchases material and processes it for use in applications such as steel production and Li-ion batteries among others, for customers in the Americas, Europe and Asia. 

Superior Graphite’s advanced electro-thermal purification process is a continuous process utilising temperatures in excess of 2,500°C, resulting in a material with a high carbon content of above 99.99%. The technology purifies a range of carbons including natural and synthetic graphite and coke variants. 

According to Hand, while the technology has been fine-tuned to improve efficiency and cost, in essence the basic principle has not changed over the years.

"We spent an incredible amount of money making sure that we’re taking many things out of the graphite and capturing that, and ensuring that the only thing that comes out of the furnaces is steam," he told IM. "That does cost a great deal of money but we care a lot about the environment and about people. So when we make hundreds of thousands of metric tonnes of this purified type material we’re taking care of the environment as well."

Though the process is an energy intensive one, Hand believes that the energy and higher costs are outweighed by a higher quality product and the elimination of a need for harsh chemical leaching technology, which then requires the disposal of chemicals. 

"There are a lot of people, particularly the battery companies, that are interested in our material certainly because of the performance but also because they feel the technology is more green and sustainable in the long run," he told IM

As such, Hand anticipates a move away from the chemical leaching route towards greener technologies: "Where it can be substituted I believe it is happening."

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Hosowaka Alpine have developed milling solutions for wet and dry processing. 

Researching new technologies

To stay ahead of the competition, mineral producers and processors are having to invest in research in order to refine their technology and become the more environmentally-friendly option customers are placing an increasing emphasis on.

Superior Graphite is currently working with a number of universities and customers to perfect new materials and processes.

"We’re working with universities in Europe of some of the battery technology issues and we work with customers on technology that might be applicable to their particular applications. We do devote a lot of time to R&D," Hand told IM.

In addition to looking at battery technology, Hand says the company is working on a process to produce a material called few layers graphite, or FLG, which he believes is a process that to a certain extent competes with nano technology and graphene technology.

"True graphene is not commercially viable by any stretch – it would cost tens of thousands of dollars to make it – so what we’re doing is working on a material that is multi-layered by much thinner than most available material," he said.

The company is also building on its furnace technology to develop a new process and material for a compressible carbon, which is extremely resilient, for use in pressure mitigation or oil drilling.

With traditional markets losing steam – for example in the consumption of flake graphite, refractory, foundry, friction products and lubricants has a CAGR of only 0.4-2.2% vs a CAGR of 15.7% in Li-ion batteries according to Pro-Graphite GmbH – many companies are opting to pour their research dollars into this area. And, taking 1,000 tonnes of graphite to produce 1 GWh of Li-ion battery capacity, the Chinese car market is anticipated to be the biggest driver for Li-ion batteries.

"The EV craze has been coming for decades now. I think the forecast for EVs – which I think has been wildly inaccurate over the years – is actually beginning to come to fruition," Hand said, adding that with Tesla ramping up production of EVs on target to an estimated 500,000 by 2018, there is huge scope for growth in the sector with roughly 35kg of graphite used per EV depending on the type.

Examining the supply chain

Escalating instability last year in the Democratic Republic of Congo (DRC), where over 50% of the world’s supply of cobalt is mined, shone a light on the metal and its supply chain. Predictions of a shortage of cobalt owing to lower nickel extraction – in which cobalt is produced as a byproduct – and mounting pressure on companies such as Apple to find sustainable and ethical sources of raw material, has led end users such as battery producers and car manufacturers to identify problem areas in their supply chains. 

Which leads us to lithium, the namesake for Li-ion batteries, and an area where growth in demand took producers by surprise. Global bank Citigroup has forecast a CAGR in demand for lithium of 11% to 2020, which would bring global demand to around 324,000 tpa lithium carbonate equivalent (LCE) by the end of the decade from 212,000 tpa in 2016. 

EVs are likely to account for around 40% of global lithium demand in 2020 up from around 20% now, according to Citi’s estimates, resulting in a flurry of activity around new lithium projects and investments. 

Among recent newcomers are ASX-listed Galaxy Resources Ltd, who restarted mining at the past-producing Mt Cattlin operation in Western Australia (WA) after refurbishing the site in 2016. By January 2017, the company had shipped around 10,000 tonnes lithium concentrate. 

Fellow Australian producer Neometals Ltd was the first real newcomer to lithium production in Australia. The company has a minority state in the Mt Marion project in WA alongside Mineral Resources Ltd and Chinese firm Ganfeng Lithium Co Ltd. The project made a maiden shipment of 15,000 tonnes lithium in February and by May 2017 had transported a fourth shipment of 30,055 tonnes lithium concentrate. 

Traditional lithium extraction via hard rock mining is carried out via drill and blast, concentration and chemical processing. Meanwhile traditional extraction via brine processing comprises the construction of evaporation ponds, the movement of bulk salt waste and chemical processing. 

However, whether or not the process of lithium extraction is environmentally friendly is a matter of opinion, according to Neometals. 

"Each operation of course must comply with environmental regulations that prevail in the operating jurisdiction and comply with operating licence conditions," the company told IM. However, it added that absolute standards vary from region to region.

There are various processing factors affecting the quality of the final lithium product that will be sold for use in Li-ion battery consumption. On the one hand, Neometals notes that geographic and sovereign risk issues coupled with production and delivered cost economics probably play a greater role than the selection of raw materials.

"The important issue for battery raw materials are consistency of specification, reliability of supply and appropriate chemical analysis," Neometals told IM. "Provided these attributes are delivered by a chemical producer and production process, there should be less importance on the type of mine that produces the lithium chemical."

The company outlined that the production of lithium compounds from hard rock vs salt lakes is relatively straightforward but difficult to achieve well. 

The process of producing lithium hydroxide from hard rock, the company added, is usually more standard than production from brines as the chemistry of each brine is different and tends to require a bespoke flowsheet. The challenge then is to produce a product consistently and at a competitive cost to maintain a stable business. Additionally, as with most cases in mining, success is to a large part determined by resource grade, mineralogy and location. For processing the location, logistics and reagent availability and cost are important, while QA control and process control are essential. 

While the output of a high-quality lithium hydroxide or lithium carbonate depends on a refined and consistent production process, according to Neometals the benefit of using lithium hydroxide for the cathode material is a higher performing battery. The production process for Li-ion battery cathodes can consist of various chemical combinations and compositions, potentially using two different routes – a "wet" and "dry" process. 

"LiOH is used as the raw material in the "wet" process type. The development of batteries into higher power density and faster recharging is leading to the use of cathode materials that are made using a wet type process so lithium hydroxide use is increasing faster than that of lithium carbonate," Neometals told IM

"This puts more need on expansion of suitable grade lithium hydroxide than it does on expansion of lithium carbonate capacity although both have to be increased," the company added.

The ELi process

Focusing on the refining of lithium hydroxide production, Neometals has developed the ELi processing technology for applications in both brine and hard rock production with an aim to reduce reagent consumption, energy costs and environmental impact, the company said. 

"The anticipated benefits include minimal reagent consumption, minimum draw on brine water table, minimum loss of water to evaporation, minimum emissions and minimised waste generation," Neometals told IM. "We consider this is where the future of lithium production lies. The ELi process can also be used in production from hard rock and minimises reagent consumption and transport."

While the process is in the commercialisation phase and not currently in use at an operating site, Neometals continues to develop its technology through pilot testing over the next six to 12 months, in the anticipation that final product grade will be better than that from a conventional carbonation and cauticising process. In addition to higher customer demand, the development of the process was driven by the need for lower production costs, an improved competitive position and a smaller environmental footprint.

Battery recycling

Rocketing lithium prices, demand driven up by EV production and the current supply tightness has begged the question, why not recycle the lithium from Li-ion batteries?

In contrast to graphite, lithium has experienced a much steeper price increase (cobalt prices have risen more), making it an obvious contender for recycling. However, speaking to IM in January, Linda Gaines, transportation system analyst at the Argonne National Laboratory in Illinois, said that recycling remains uneconomical.

"The price of lithium would have to go way up before it seriously impacted the cost of the battery," she said, adding that with lithium accounting for a relatively small proportion of Li-ion battery, cobalt is a bigger concern to battery producers. 

Despite this, in June this year Neometals lodged three US provisional patent applications associated with its previously announced battery recycling technology to recovery high-value materials from spent lithium batteries. The company said that scoping studies have confirmed that the technology can recover high-value cobalt at a rate of 99.2% at potentially the lowest quartile operating cost. Neometals previously said in May that it planned to build a 100kg/day pilot plant in Canada to test recoveries of cobalt, lithium, nickel and copper from NMC-cathode lithium batteries used in EVs. 

The process will extract metal values from used and off-spec materials from the battery manufacturing chain, refine them and return them as new raw materials to the supply chain, the company told IM.

It will process the most commonly used battery chemistries – LCO, NCA and NCM – and is anticipated to be ideal for multiple regional locations close to battery material production. It is characterised by low opex, small capex and small operating footprint.

Neometals concedes that so far viable battery recycling for Li-ion batteries has been very limited, but the forecast for battery consumption and the resultant demand for battery minerals makes it imperative that a solution to recycling be found.

"The start of large scale production of large Li-ion batteries hastens the day when those large batteries reach the end of their service life," the company told IM.

"Cobalt is in short supply, is produced as a by-product and in often difficult locations, so recovery of cobalt into the supply chain will provide some relief for battery cathode makers," the company added.

Piloting of the process is planned for Q3 2017, with an aim to commission the first commercial scale plant at the end of 2018.

The future for growth

PricewaterhouseCooper’s (PwC) 2017 mining report noted the new record lows set by the Top 40 mining companies, which experienced their first ever collective net loss in 2015, resulting in their lowest return on capital employed and unprecedented capex containment. In 2016, meanwhile, Capex fell dramatically again by an addition 41%, to a new record low of $50bn.

While significant pressure was felt as attention turns to the next wave of productivity increases – requiring rethinking of structures, processes, systems, technology, organisation designs and capability needs – the industry in 2016 largely played it safe with efforts to repay debt, innovate and adopt new efficiency measures. 

PwC pointed to the new opportunities and hazards on the horizon.

"Do we take it seriously when Apple poses the question 'Can we one day stop mining the Earth altogether?’ or when Elon Musk puts forward a 100-day guarantee to fix a state’s energy crisis with battery technology? The industry [must] more carefully consider how it responds," PwC said.

PwC previously singled out the potential of the energy industry, where new developments and technical innovation are likely to continue, noting the significance of a lithium company making the top 40 in 2015. Adding that the energy landscape was likely to pave the way for new world disrupters. 

In its most recent report, the company emphasised increasing demands by the community for exceptional corporate and social responsibility, adding that mining players will need to adapt to these challenges.

"Already well-known is the rising importance of battery technology and its impact on coal and new world lithium, cobalt and graphite," PwC said. While the sole lithium player in the Top 40, Tianqi Lithium Industries, maintained its rank, PwC noted that the future may be about integration, with emerging market companies focusing on new world minerals also being increasingly integrated. 

"In the traditional markets, we are seeing new players seeking to secure supply and even calls by stakeholders for BHP to get on board the battery train," PwC said, adding that it remains to be seen if a major will pivot in this direction. And, if they do, we can expect far more innovation in integrated production solutions.