INCO R&D: Process Development, Product Development and Cyanide Destruction

The J. Roy Gordon Research Laboratory (JRGRL), located in Sheridan Park, Mississauga, some 20 minutes from Inco Limited’s corporate office in downtown Toronto, is home to Inco’s research and development activities. As can be seen from the many patents on display in the reception area, JRGRL is a focal point for the innovation that has been a key Inco strength throughout the company’s 100-year history.

JRGRL forms an integral part of Inco Technical Services Limited, together with Inco’s exploration and major projects activities. Pilot plant facilities located at Port Colborne, Ont., about 100 km away, have extensively been used in the past to assist Inco’s technology development.

All of Inco’s primary nickel production through the mid-1960s had been from Canadian sulphide ores. In the late 1960s, Inco began to invest in offshore nickel laterite reserves. The research centre, which started operation in 1967, was mandated to develop processing methods for the laterite ores. The laboratory and pilot plant efforts lead to the design of the PT Inco plant in Indonesia, where nickel matte is produced from laterite ore.

Today, the research centre carries out 90% of the research for Inco’s worldwide operations, providing process research, metallurgical and nickel product research. The head of the Sheridan Park R&D activities is Dr. W. Gordon Bacon, Inco’s vice-president of technology & engineering. Reporting to Bacon are the Process Research and Product Research teams, as well as Inco Tech, a commercial unit that markets Inco’s proprietary cyanide destruction process.

Process Research – The Goro Process Development

Dr. Eberhard Krause, the director of Process Research, arrived at the J. Roy Gordon Research Laboratory the year it opened, as a young immigrant from Hamburg, Germany, and has been there ever since. “In 1992 when we started the Goro process development, I was head of the hydrometallurgy section and was therefore in charge of the Goro process development work at the laboratory. I’ve been blessed with many very good people around me that have led us to develop this new process.”

After 10 years of work, Inco has developed and successfully tested a new metals recovery process for ore from the world-class Goro deposit in New Caledonia. The process and its development are significantly different from the three recent Australian nickel laterite projects that have failed to live up to expectations.

The Goro process begins with a pressure acid leach (PAL) stage in an autoclave that uses a higher temperature–270C–than is used at the other plants. The effect is to reduce the leach time to less than half the time needed at the Australian plants, thus reducing the number of autoclaves needed–a cost saving.

The metal recovery part of the process at Goro is based on solvent extraction using a new reagent–Cyanex 301–that has not had any prior commercial use. This reagent is both very strong and very selective for nickel and cobalt, without requiring any neutralizing agent–another cost saving. (For a full description of the operations, see the Goro article starting on page 65.)

The development of the metallurgy, including both the optimum PAL conditions and the use of Cyanex 301, was done using a miniplant set up at the J. Roy Gordon lab. Although the miniplant worked at a very small scale, most of the processing steps were linked in an integrated fashion, closely mimicking the functions of a full-scale plant.

During the miniplant campaign, Krause’s team discovered a potential problem with Cyanex 301–that it would readily oxidize and be destroyed if exposed to air. “It took us about a year to solve this problem in the lab,” says Krause. “We chose to build a solvent extraction pilot plant in Port Colborne, to assure ourselves that the method we had found in the laboratory to prevent oxidation would work at a larger scale.” As a second benefit of the laboratory work, a process was developed to regenerate the reagent to “as new” condition. The pilot plant campaign at Port Colborne proved out the solvent extraction and the regeneration process.

The company then committed US$50 million to build and operate a complete, integrated pilot plant in New Caledonia. Piloting commenced late in 1999 with assistance from the R&D team at Sheridan Park. The pilot plant campaigns are almost completed, and detailed engineering is in progress. “From here we continue to give support on the process engineering side, to help assure that we will build a plant that performs as planned,” says Krause.

Seven years of development at laboratory and miniplant scale, and almost three years in a full-scale pilot plant: isn’t this being a little too careful?

“Even in the first miniplant campaigns, we were seeing essentially what we saw in the last pilot plant campaigns,” says Krause. “Certainly we got the confidence into the process starting with the miniplant stage. Nevertheless, because this is a roughly US$1.5-billion project, the company made the wise decision to build and operate a full-size pilot plant in New Caledonia to mitigate the technological risk.

“The Western Australian competitors did not do any piloting. They probably did even less than we did in our miniplant, because they did not run it in an integrated fashion. Consequently, they had, and still have, problems with their plant startup. Because we have so much experience with the on-site pilot plant, which also trains our future plant operators, I’m very confident that our plant startup will be much, much faster.”

Adds Bacon: “Inco has a very strong project owner’s group, because a lot of its people have many years of experience in nickel, whereas Anaconda [owner of the largest of the Australian nickel laterite mines] had no in-house nickel strength.” He feels the engineering firms working on the Australian projects were also lacking nickel laterite experience, whereas Inco’s process design company, Hatch Engineering, was well experienced in this area.

Bacon knows what he is talking about. Although he has only been with Inco five years, he has over 30 years of research and engineering experience, including 21 years with his own consulting firm, Bacon Donaldson and Associates in Vancouver, and five years with Sherritt International Corp., half-owner of the Moa Bay nickel laterite mine in Cuba. In fact, he licensed Sherritt’s laterite processing technology to Anaconda.

He cautions that people who are not process-oriented tend to think that, if you maintain the budget and schedule, you get a working process plant. Not necessarily. “You get the process plant to work successfully by paying attention to the details of building a process plant, and developing the mine and all the ancillary plants that go around it–designing for operability and maintenance.”

Bacon’s enthusiasm for the project is infectious: “Goro is a really big project. For Inco, it’s our largest project ever, in one shot. It’s the largest laterite limonitic pressure acid leach plant in the world, and it’s exciting as hell. It’s stressful. We’re right in the throes of getting it all geared up and ready to go.”

Now that most of the Goro work is being done offshore, what is happening back at the miniplant in Sheridan Park? A new hydrometallurgical miniplant will be put together to test the hydrometallurgical process for the Voisey’s Bay project.

Developing New Products–“Teeny Little Things”

The activities of the Product Research team are closely linked to the strategies of Inco Special Products. The director of Product Research at the J. Roy Gordon laboratory is Dr. Sam Marcuson, whose accent reveals his southern Virginia origins. He emphasizes that, while his group is a research group, it only works on products that can be used and sold at a high margin. The group does laboratory research at all scales–lab size, pilot plant and commercial development and research work.

When CMJ met Marcuson in his office in mid-February, he told us about a developing application for nickel powders–multi-layer ceramic chip capacitors, or MLCCs for short.

Capacitors are electronic
devices that accumulate and hold an electric charge. They are used in all kinds of electronic equipment. Cell phones, computers and personal data assistants are of particular interest, because these applications require small size and high electronic performance. Cell phones and computers contain a lot of capacitors, so each one has to be really, really small–Marcuson describes them as “little teeny things” (see photograph). It is the need for small size that is the driving force behind MLCC development today.

MLCCs are made of layers of non-conductive material (ceramic) interlaced with layers of conductive material. One material of choice for the conductive layer in the past has been palladium. When the price of palladium started to rise sharply a few years ago, peaking last year at over US$1,000/ounce, people looked around for substitute metals. Nickel powder is one of several materials that fit the bill. “Nickel powders have taken over a significant part of the market and this trend is continuing,” says Marcuson.

Nickel powders need to have a well-defined set of physical and chemical properties in order to fit into these applications. They must conform to very tight specifications in terms of their size distribution (up to 1-micron diameter), shape (reasonably spherical) and composition. The powder is turned into a paste with inorganic dispersants, and then printed onto the ceramic layer as an ink, sort of like a photocopy. The ink paste is applied to alternate layers, which are cut and formed into a capacitor.

This is new territory for Inco–the company has not made powders for this application before. But its experience in making large quantities of nickel powders to tight specifications may yield an advantage over its competitors.

Inco SO2/AIR Cyanide Destruction Process

If you have been around North American gold mines in the last 20 years, you may have noticed that Inco’s SO2/AIR process is the predominant method used to destroy cyanide in gold leach tailings slurry as it exits the plant. Yes, the unit really is the creation of Inco, the nickel company, in one of its lesser-known, but nonetheless profitable sides. The proprietor of the Inco SO2/AIR cyanide destruction technology is Inco Tech, a wholly-owned business unit of Inco Limited.

The SO2/AIR technology was developed at Inco’s research facility in Mississauga as a result of research using cyanide to depress pyrrhotite. Commercialization of the process began in the late 1970s, and it was patented in Canada in 1984. The technology’s distinct advantages over the two main alternatives–alkaline chlorination and hydrogen peroxide–include its ability to handle slurries with ease, the removal of total cyanide speciation, low-cost reagents and single-stage continuous treatment. Many regulatory agencies throughout the world consider the Inco technology to be state-of-the-art within the industry.

Inco Tech provides its expertise throughout the whole process, from laboratory testing (which is conducted at the J. Roy Gordon complex, or on-site as is often requested) to commissioning of full-scale plants. Inco’s specific know-how lies in the optimization of process variables and the ability to develop process design criteria. Says Dr. Eric Devuyst, vice-president of Inco Tech, “This translates into the lowest capital cost for an SO2/AIR facility and minimum reagent consumption for our customers.”

In the mining industry, treatment is typically for carbon-in-pulp and carbon-in-leach slurries, Merrill-Crowe barren bleed solutions, flotation tails and pond water. Sulphur dioxide and oxygen (air) provide the essential ingredients to the process, which is catalyzed by a small amount of copper in solution. The SO2 required for the process can be obtained in a variety of forms ranging from sodium metabisulphite (a white salt form) to off-gas from an elemental sulphur burner. Typical cyanide values of effluent exiting an INCOsystem, are in the range of <1 ppm total cyanide.

The technology also readily applies to the treatment and rinsing of gold heap leach operations and to other industrial waste streams such as plating shop rinses. Every installation is customized, depending on the rate of flow of the slurry or effluent, the viscosity, pH, cyanide species and concentration, and dissolved metals levels.

To date, the SO2/AIR technology has been transferred to 79 sites around the globe. One of the most recent installations was at Boliden Mineral AB’s BAO gold operation at Boliden, Sweden. Here the treatment is for a carbon-in-pulp slurry from a 2,500-tonne/day mill. At BAO, the INCOsystem is the kingpin in a four-stage cyanide management process that serves as a model to the world mining community. The Boliden program blends chemical treatment for cyanide and metals removal with natural wetlands polishing.

Other recent customers for Inco’s SO2/AIR technology include Goldcorp Inc.’s Red Lake operation in Ontario, Normandy Mining Ltd.’s Ovacik mine in Turkey, Newcrest Mining’s Gosowong operation in Indonesia and Newmont Mining Corp.’s newly-acquired Midas operation in Nevada–all slurry treatment applications. However, the technology can be applied to most any industrial waste stream containing cyanide. At Cameco Corp.’s Kumtor gold operation in Kyrgyzstan, the Inco process is being used to treat tailings pond water.

In February 2002, Inco announced that it is teaming up with specialty chemical giant Degussa AG of Dsseldorf, Germany, to jointly develop a new cyanide destruction process. Both parties believe that the new process will not only meet the required limits for mining effluents set in the gold mining industry, but it will achieve these at significantly reduced capital and operating costs.