Nickel Hydride No. 5 batteries

release time:2024-06-03 Hits: Popular:AG11 battery

Increased Nickel Hydride No. 5 batteries demand drives process technology development

Process and equipment continue to evolve

One side effect of growing lithium demand is a trend of mining companies rushing to market. “In the next few years, several companies will come online to extract lithium carbonate from spodumene ore, which is typically about 8% Li2O by weight. It’s easy to start to meet demand,” says Josh Marion, project engineer at Jenike & Johanson (Tyngsboro, Mass; www.jenike.com). This onslaught, combined with lithium’s high value and its specific physical properties, underscores the importance of proper design at all stages of lithium processing—from initial mining all the way to the final refining steps. This is forcing processors to approach bulk solids handling in new ways when trying to achieve ideal benchmarks for product purity, particle size, and density. “Many processing needs can be more like pharmaceutical production than traditional mineral processing. There are high demands on material quality for battery manufacturers, and without reliable solids handling, the required product consistency cannot be achieved,” explains Marion.

Some of the major operational issues lithium processors experience include agglomeration, buildup, and flow stoppage. To extract lithium from spodumene ore after mining, the raw ore needs to go through a series of crushing and size classification steps to produce ore of the desired particle size. The concentrate is then sent to a concentration plant, where it goes through several drying, grinding, separation, dehydration and further size classification steps to produce spodumene concentrate. The concentrate then goes to a processing plant for calcination, where various aqueous solutions, acids and other chemicals are added to extract different impurities such as iron, aluminum, silicon and magnesium. Finally, the wet cake is recrystallized and dried into lithium hydroxide (LiOH) or lithium carbonate (Li2CO3) products. "Especially in the lithium-in-wet cake step, if you don't have enough dryers or the processing equipment is not designed to handle slightly moist material, you will often have lithium and lithium lumps accumulate throughout the plant. And, because of the hygroscopic nature of lithium salts, even if the material is dry, it may absorb moisture and cake up," Marion said. He stressed that attention to detail during the equipment design phase is essential to avoid these bottlenecks and ensure consistent product quality. "It is critical to make sure that the material properties at each stage of the process are considered when selecting and designing equipment," he added.

As LIB performance requirements evolve, equipment manufacturers are developing new technologies to meet these needs. “Right now, the key parameters for lithium producers are purity and particle size,” says Ananta Islam, sales director for North America’s chemicals division at GEA Group AG (Düsseldorf, Germany; www.gea.com). The presence of certain impurities directly affects battery performance, so Nickel Hydride No. 5 batteries producers must adhere to a strict set of purity standards. “Users are looking for very low levels of sodium, potassium, sulfur, and heavy metals in battery-grade products,” explains Christian Melches, senior sales and technical manager at GEA. “Whether starting with brine materials, common in South America, or spodumene ore, a typical lithium source in Canada and Australia, these impurities are often present in significant quantities.” To address the purity issue, GEA offers crystallization units (Figure 1) that can be combined to optimize purification. “The edge comes from knowing how to direct the flow through the process itself to several crystallizers to get the purest product,” he says. Another important consideration for combined crystallization units is energy efficiency. One energy-saving measure is to use mechanical recompression of crystallizer vapors to generate the steam used to drive the process.

LiOH—Currently the majority of LIB manufacturing The preferred form of lithium by lithium ion manufacturers—requires extremely precise particle size distribution, which requires specialized spray drying equipment. Jiao explains that a typical particle size range for conventional spray drying might be 40-50μm, but for LiOH processing it is around 5-7μm. To ensure the material meets the requirements, GEA developed and patented a specific nozzle for lithium processing (Figure 2). “The Combi-Nozzle utilizes a high-pressure nozzle and compressed air for secondary atomization to further reduce the particle size,” Jiao says. Lithium producers say that smaller particle sizes are required for proper compaction of the powder, which directly affects the performance of the LIB. According to Jiao, this special nozzle was developed based on technology used by the pharmaceutical industry to spray dry particles for inhalable drugs that require very fine particles.

While brine and spodumene produce today’s large Some lithium is available, but in the coming years, other sources may be produced due to high demand. "Mining companies are starting to invest in alternative lithium sources, so in the future processing equipment may need to be adjusted to handle more impure raw materials," Melches said.

To expand resource utilization and reduce LIB costs, technologies are emerging that introduce more feedstock flexibility for different lithium formulations and lower-grade raw materials. NanoOne Materials (Vancouver, British Columbia, Canada; www.nanoone.ca) has developed a proprietary process for manufacturing battery cathode materials in a variety of chemistries. Table 1 lists the most common LIB chemistries on the market, such as NMC, NCA, and LTO. Unlike typical solid-state cathode production technologies, NanoOne's technology is solution-based. "Solution-based processes allow us to make battery materials more cheaply, and the process is flexible so it can be used to make multiple formulations of lithium cathode materials," said Stephen Campbell, chief scientist at NanoOne Materials. . As battery manufacturers try to optimize LIB capacity, stability and cost, efforts are underway to reduce cobalt content while increasing the nickel content of the cathode. To make these high-nickel materials, LiOH is the preferred lithium feedstock, but it's becoming increasingly difficult and expensive to obtain. NanoOne's technology can make cathode materials using either LiOH or the more abundant and inexpensive Li2CO3, providing a more direct path for Li2CO3 producers to avoid investing in expensive processes to convert Li2CO3 into lithium hydroxide. "We can loosen up the supply chain by using a lithium source that others can't," Campbell said.

NanoOne's solution-based technology dissolves lithium in water (under ambient conditions) with other transition metals, so the type of lithium doesn't matter - both LiOH and Li2CO3 are processed the same way. The dissolved metals are precipitated out, creating a crystalline precursor with an ordered lattice structure of all existing cathode metals. Campbell said this ordered structure facilitates faster firing in a furnace. “We can get material out in 7 hours because the metals are already mixed in an ordered fashion. Traditional methods of grinding lithium with other metals require long-distance diffusion, which can take 1 to 2 days to complete,” he added. Another benefit of NanoOne’s technology is that crystal uniformity dilutes impurities, making the process more tolerant of low-grade raw materials, further reducing operating costs. NanoOne is currently testing lithium samples of varying purity to assess the technology’s ability to handle a variety of contaminant species. “We’re seeing that the impact of certain impurities is not as bad as some people think. For example, magnesium can act as a dopant and actually improve performance,” Campbell explained. NanoOne is currently able to produce cathode material in 300 kg batches at a pilot plant that can produce up to 1 ton/day. The team recently began sending product samples to third-party organizations for validation.

Battery Recycling

Used batteries hold an astonishing amount of high-demand materials, and many organizations are working to develop efficient recycling technologies to make the most of this untapped resource. American Manganese has developed a process to recycle cathode metals (including lithium, cobalt, manganese, nickel, and aluminum) from EV batteries (Figure 3). Larry Reaugh, president and chief executive officer (CEO) of AMY, said the company is currently building a kilogram-scale pilot plant to demonstrate the technology, which uses a proven continuous process to recover manganese from low-grade ores (Figure 4). A 3 t/d commercial plant is under construction, which will utilize scrap or off-spec metal from LIB producers. In laboratory testing, 100% of cathode metal was recovered from LIB materials and scrap, which typically ends up in landfills or smelters with inefficient metal recovery or even failure to recover any cathode lithium. Reaugh explained that the AMY process should be easy to scale up because it has a proven history of continuous operation at high levels of manganese production.

Using sulfur dioxide and other low-cost reagents and an automated battery disassembly process, AMY's recovery technology produces virtually no waste as 100% of the metal is recovered and process water is recycled. Reaugh said the revolutionary part of the hydrometallurgical process simplifies the precipitation step, improves metal yields, and has the flexibility to work with many metals and cathode chemistries.

Considering the future supply and demand for battery materials like lithium and cobalt, Reaugh believes the advantages of recycling processes are clear when compared to mining. “The price of cobalt is going through the roof, and there doesn’t seem to be any immediate production about to start, and for new mines you need to think about years and years of lead time,” he added. “I think our economics for recycling are better than mining.”

Engineers at the University of California, San Diego (www.ucsd.edu) have developed another new technique for recovering cathode materials from discarded LIBs. The process begins with a nondestructive particle separation step involving binder dissolution, suspension, filtration and washing, followed by a hydrothermal lithiation process in which cathode particles are pressurized in an alkaline solution in the presence of a lithium salt. A subsequent annealing step helps correct the material’s crystal structure, which may have degraded during previous battery use, explained Zheng Chen, a professor of nanoengineering at UC San Diego. According to the team, the battery materials recovered in the process are restored to their original performance in terms of charge storage capacity, charging time and battery life.

A major benefit of the process, Chen said, is its energy efficiency compared with other battery recycling techniques. “We don’t destroy much of the particle structure and composition, which consumes a lot of energy to recreate. Avoiding the repetition of these manufacturing steps helps conserve energy,” he said. The process has been demonstrated at gram scale and has been shown to work for both LCO and NMC cells, giving it the flexibility to process LIBs from electric vehicles and consumer electronics.

Metals in Fossil Fuel Processing

The growing global demand for LIBs has forced the industry to consider alternative energy sources for many metals and, in some cases, look to traditional oil and gas processes for inspiration. A new technology developed by MGX Minerals Inc. in partnership with Highbury Energy Inc., of Vancouver, is designed to recover metals used in LIBs from petroleum coke, a major byproduct of petroleum refining (coke). The petroleum coke is fed into an advanced thermochemical gasification process that generates hydrogen and an ash byproduct from which high-priced metals, including nickel and cobalt, and various rare earth elements in smaller concentrations, are recovered. The high demand for hydrogen and the abundance of cheap petroleum coke feedstock make this project very attractive. Key to its effectiveness for metal recovery is the precision of the gasification fluidized bed reactor technology to eliminate the tar and residue buildup that typically plagues gasification operations. “This process requires low-tar gasification and a clean ash byproduct. The last thing we want is tar or organic material in the ash, which can make metal processing quite difficult,” explains Jared Lazerson, president and CEO of MGX Minerals. Another benefit of this gasification process is its ability to process a very wide range of particle sizes, including very fine material. Since the gasification unit acts as a concentrator, the metal recovery step is relatively simple.

According to Lazerson, the ability to co-locate the petroleum coke gasification and metal recovery processes with the oil sands processing site eliminates logistics and transportation issues. Highbury Energy has been operating a gasification pilot plant for several years using its proprietary fluidized bed reactor technology. “We are just starting to figure out whether the next phase is going to be a pilot or a small commercial plant,” Lazerson says. In addition to petroleum coke, other projects have proposed using coal as a source of bitumen.

On the lithium side, MGX Minerals is advancing nanofiltration technology for lithium recovery. In this process, a patented high-intensity flotation process uses microbubbles to remove residual oil, metals and small particulate matter from the feedstock—typically brine, tailings or lithium-containing wastewater from oil and gas or chemical processing sites. Lazerson said this step removes 99% of the physical particulate matter, providing a very clean brine source for the nanofiltration step, which then further refines the lithium stream to the purity levels required for LIB manufacturing. “Basically, it’s adsorption technology with highly specialized nanofilters,” he added. “We remove impurities like sodium, magnesium and calcium in the first step, so what you end up with is a very pure lithium concentrate, along with other salt concentrates that can be monetized,” Lazerson mentioned. The company is nearing completion of its first commercial plant and is evaluating where to put the next one. The current plant is operating at a 750 b/d capacity, and initial construction work is underway to produce 7,500 b/d. MGX Mining is also working with partners in South and North America, including potential deployments at large-scale natural brine sites associated with geothermal processing in Southern California. The company also recently announced joint development projects with Orion Laboratories LLC and LightMetals International to commercialize a new modular thermochemical process to produce high-purity Li2CO3 or LiOH from spodumene concentrate.

Another potential source of lithium is wastewater from hydraulic fracturing activities. The University of Texas at Austin (UT; www.utexas.edu), in collaboration with Monash University in Melbourne, Australia (www.monash.edu) and CSIRO (Melbourne, Australia; www.csiro.au), have developed a membrane process using metal-organic frameworks (MOFs) to selectively extract lithium from wastewater (Figure 5). “Given that the specific MOFs used in this work have pore sizes that can accommodate partially dehydrated lithium ions, but not large or highly hydrated ions, this makes them selective for lithium relative to larger partially dehydrated ions such as sodium, potassium and rubidium,” explains Benny Freeman, Professor of Chemical Engineering at UT. “Our current hypothesis is that the lithium ions partially dehydrate into the MOF pores, where they undergo very rapid transport through the nanocrystalline voids within the MOF crystals. This mechanism implies favorable interactions with the lithium ions within the MOF, resulting in at least partial dehydration of the ions,” Freeman adds. Currently, the MOF membranes have been demonstrated at a laboratory scale, but the UT group is working to adapt the technology for a continuous flow process established by CSIRO to produce larger quantities of MOF. The team believes that this technology is not limited to lithium, MOF can be usedfor desalination purposes, or tuned to selectively permeate monovalent anions, such as removing fluoride from drinking water or nitrates from agricultural runoff. For more information on membrane applications in litihum recovery, read Expanded Membrane Coverage in CPI.

Sourcing Cobalt Closer to Home

The increase in LIB manufacturing capacity has put a unique pressure on the supply of cobalt. Not only is cobalt mined in politically unstable regions, but it is also primarily recovered as a byproduct of nickel and copper mines, so its economics are closely tied to demand in those markets. Recognizing that new primary cobalt is needed to meet demand, Fortune Minerals Ltd. (London, Ontario, Canada; www.fortuneminerals.com) is developing an extensive cobalt project in North America that produces very little cobalt. Fortune Minerals' project includes mining cobalt, gold, bismuth, and copper ore at a large deposit in Canada's Northwest Territories, and a processing metals refinery in Saskatchewan that will process metal concentrates from the mine. "This project essentially mitigates supply chain risk by having a vertically integrated source of supply chain transparency in North America," explains Robin Goad, president and CEO of Fortune Minerals. The project has already undergone feasibility and front-end engineering design (FEED) studies, and the group is currently completing a new feasibility study to consider a 30% increase in production rates. “We aim to produce about 7,000 tonnes of cobalt sulfate heptahydrate per year, the material of choice for NCA and NMC batteries used in the automotive industry,” Goad said.

The Saskatchewan plant will process metal concentrates from the mine, starting with bismuth. In the bismuth processing unit, a secondary flotation step produces a gold-bearing cobalt sulfide concentrate, which is subsequently sent to the cobalt processing unit (Figure 6). Here, the cobalt concentrate undergoes high-pressure acid leaching at 180°C in an autoclave. “The cobalt sulfide dissolves into solution in an exothermic reaction. Since the sulfide minerals produce acid during the dissolution process, very little acid is consumed,” Goad explained. Next, the gold is recovered and sent to a separate process unit, where the cobalt material is neutralized and impurities—iron, copper, and most critically, arsenic—are precipitated out, producing a relatively pure cobalt stream. “We remove the arsenic impurity and use the excess iron in the solution to convert it into ferric arsenate. This arsenic, which would otherwise be toxic, is now in a non-hazardous, stable state and can be safely landfilled at the project site,” Goad added. This arsenic conversion step is particularly important in enabling the plant to process metals from other mines, as much of the new cobalt production is arsenic-based and there are restrictions on exporting arsenic-containing compounds. “In addition to processing concentrates from our own mines, we think the refinery will be well-positioned to process concentrates from other cobalt projects in North America,” Goad said. Fortune Minerals expects construction of the plant to begin in early 2019. Commissioning and commercial operations are expected in 2021. “The long-term business plan is to diversify into recycling, as we will have a facility that is able to remove residues, metal shavings or spent batteries and recover the metal,” mentioned Goad. He stressed that an infrastructure to support collection points for these waste streams needs to be in place before large-scale recycling can occur.