Ironstone and Hatch develop metallurgical keyNew chloride segregation process could open up oolitic iron reserves around the world
New chloride segregation process could open up oolitic iron reserves around the world
By Chris Balcom
December 05, 2014
An innovative process to develop the Clear Hills iron/vanadium deposit in northwestern Alberta has the potential to unlock more than 300 billion tonnes of iron trapped in similar oolitic ore deposits across the globe. While oolitic iron deposits are abundant in several countries including China, Algeria, Russia, and Canada, they have been impossible to exploit on a commercial scale. Ironstone Resources Ltd. and Hatch Ltd. are hoping to change all this with a new iron beneficiation technique to produce direct reduced iron (DRI) from oolitic deposits: the Hatch-Ironstone Chloride Segregation process (HICS).
Ironstone Resources was founded and incorporated in 2007, with the aim of developing the enormous potential at Clear Hills, which it acquired that same year. The deposit had previously undergone extensive exploration and drilling in the 1950s and early 1960s, but has been sitting idle for nearly 50 years. In the 1960s and 1970s, the Alberta Research Council (ARC) even looked into chloride segregation as a means of opening up the resource and patented some of its advances (e.g., the “Grain Enlargement Process”). However, that research never made it out of the lab. As Ironstone CEO Barry Caplan explains, developing the deposit simply did not make financial sense at that time: “In those days, with iron concentrates selling for $30 a ton, it didn’t prove to be economic, because a lot of these rich iron deposits in Australia and Brazil came on stream and precluded commercial development in Clear Hills.”
Aware of the previous research and the now-expired ARC patents, Ironstone was able to collaborate with the original researchers, and former project leader Ed Bertram was hired as an advisor early on. Ironstone then went searching for partners to help develop a commercial process, eventually selecting Mississauga-based Hatch in early 2011.
While chloride segregation techniques have been developed with various degrees of success at small lab-scale for lateritic nickel deposits, adapting the technology to iron is a significant and innovative step. As Victor Hernandez-Avila, a process specialist with Hatch, points out, the obstacles to commercial development have revolved around the technical process rather than the chemistry. “[The issue] was not so much about the chemistry, as [it was] the commercial implementation of such a chemistry,” he explains. A paper presented at this year’s Conference of Metallurgists and co-authored by Hatch and Ironstone employees, reiterates this point, noting: “There is considerable understanding of the basic chemistry and thermodynamics of the chloride segregation process. The implementation of such knowledge into developing a commercial process to extract [nickel, copper or iron] has proved to be challenging.”
The challenge with oolitic deposits
Aside from occasional experimental forays, most oolitic iron deposits have been left alone, and for good reason. The deposits have a number of challenging characteristics that make traditional methods of iron beneficiation (or even direct reduction) inadequate in several respects. First, the low concentration of iron and relatively high levels of silica and phosphorous render standard techniques unfeasible. The mineralogy of oolitic iron is often non magnetic and therefore cannot be concentrated by magnetic separation. Second, the minerals that do contain iron are extremely fine and randomly scattered among ooids, so even after the micro-grinding necessary to separate them is completed they cannot be concentrated by flotation. Third, a significant fraction of phosphorous is part of the iron-bearing crystal itself, so mechanical means of separation cannot be employed. “The content of iron is low, the content of silica is too high, and the phosphorous is too high,” sums up Hernandez-Avila.
HICS is a pyrometallurgical process capable of turning iron ore into at least a 90 per cent metallic iron product through direct reduction. The process revolves around forming an iron chloride, vapourizing the iron and leaving behind the phosphorous and waste (which may contain other economic minerals such as vanadium). Then, a reaction with carbon (through added coal) reduces the iron chloride into metallic iron.
Eighty per cent of the HICS process involves conventional DRI technology. Indeed, the first two of the five HICS stages, ore preparation and calcination, rely entirely on conventional technology and the waste heat of later stages. The third stage, described as “the heart of the process” by Liam Murphy, a geologist with Ironstone, is the chloride segregation itself, and he says it involves some custom equipment including a specially designed kiln. Once the iron has been transformed into its metallic form, it is concentrated by magnetic separators in the fourth stage (at which point byproducts such as vanadium can be extracted from the remaining tails). In the final stage it is agglomerated into hot briquetted iron.
With Hatch leading the way, the partners have been working with two testing plants in the United States: Hazen Research in Golden, Colorado, and FLSmidth in Bethlehem, Pennsylvania. So far, HICS has been demonstrated at a continuous laboratory scale, and testing recently concluded at Hazen, processing at four kilograms per hour (kg/h). The outcomes have been encouraging so far, Hernandez-Avila says: “We got very good results there.” They are now planning to move to the FLSmidth facilities to begin some pilot testing on commercially scalable equipment. In the coming year, they aim to ramp up to testing to 100 kg/h. With that under their belt, they intend to attract more investment and demonstrate the process on a commercial scale at a demonstration pilot plant just south of Clear Hills, in Hines Creek, Alberta. So far around $30 million has been invested in the project, and another $50 million will be needed through the demonstration phase. Total capital expenditure estimates to begin production at Clear Hills, which Ironstone hopes to have operational within the next five years, stands at $1.75 billion.
Given the current low price of iron, it may seem like an odd time to invest in such a technology. But Hatch and Ironstone are thinking long term and want to be ready when the good quality iron ore deposits run out, at which point more challenging deposits will come into play. “If we don’t work at it now, we won’t have the right technology to process the resources when they are depleted,” Hernandez-Avila explains.
As far as the Clear Hills deposit goes, Ironstone is confident in the profitability of the project for a number of reasons. The mine has a minimum of 50 years of production, and Ironstone aims to put out 2.5 million tonnes a year at full production of hot briquetted iron, a scrap metal-like product that sells for roughly $450 a tonne today. The company could also produce up to 20 million pounds of vanadium pentoxide each year in either flake or electrolyte form, making Ironstone one of the largest vanadium producers on the continent. Furthermore, the Ironstone team hopes to capture enough waste heat to sell as much as 500 megawatts of power back to the grid and use it to power its own operations. There is also a coal deposit practically on site that could potentially allow for further savings, as coal is a necessary input for the process. “We will have a very profitable venture here because we’re able to reduce our operating expenses, and we’re able to sell two very high-value products,” says Caplan.
Of course, Ironstone and Hatch plan to license the process, with Hatch leading the marketing push. They have agreed to share the HICS intellectual property rights 50:50, while FLSmidth will own the rights to any custom equipment developed by them for the process. The companies have already initiated a discussion with some interested parties and expect things to really take off once commercial-scale testing is completed at FLSmidth. “We’re quite encouraged by the level of work, and we’re very impressed with the results to date,” says Caplan. “I think it’s fair to say that [Hatch has] gone beyond what our early expectations were.”
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