Taking Mineral Processing to the Next Level

Future requirements for improved recovery while simultaneously minimizing waste, emissions and energy
consumption require a new generation of technologies

Extracting metals from mined ores requires robust equipment, energy and water. Today, German suppliers are looking at ways to reduce those inputs through advanced separation techniques and machines that produce a finer grind with less energy. The ideal mineral processing plant of the future will use less energy and water. By better recovering metals from a preconcentrated feed, it will generate less waste.

German-Russian Duo Harness HPGRs for Process Efficiency

Over the past 40 years, the technology for processing ore using high-pressure grinding rolls (HPGRs) has steadily developed. After the successful introduction of HPGRs into the cement industry, this technology has also taken on an important role in the mining industry.

Köppern has played a key role in this. The group, which is headquartered in Hattingen, Germany, has more than 120 years of experience in manufacturing and operating roller presses for briquetting and compacting processes, as well as mineral and cement applications.

In May 2016, Köppern joined forces with JSC Stoilensky GOK (S-GOK), a subsidiary of the NLMK Group based in Novolipetsk, Russia, to commission the first HPGR for the crushing of ferruginous quartzite in Russia. The project was so successful that seven more machines were implemented over the following 18 months.

S-GOK uses HPGR technology alongside traditional cone crushers, upstream of its ball mills. As a result, the company has been able to increase the output of its plant by 12%-15%. This has boosted the production of iron-ore concentrate by 1 million metric tons (mt), to 16.6 million mt/y. In addition, S-GOK has seen significant reductions in its energy consumption and consumption of grinding media.

As a follow-up project, two more HPGRs are currently being installed at S-GOK for the regrinding of iron-ore concentrate. This will increase the productivity of the existing pelletizing plant, while at the same time improving the quality of the pellets produced.

Together, S-GOK and Köppern have applied state-of-the-art technology to an existing flowsheet and demonstrated a prime example of Russian-German cooperation on a complex project.

Read more: www.koeppern-international.com

EnviroChemie Group’s Treatment Methods Improved by a Unique Add-on

On a global scale, dwindling easy-to-mine gold deposits demand a change in technical solutions when it comes to marrying economical gold extraction with as little ecological impact as possible.

In addition to the risks associated with tailing dams, the management of cyanide, soluble cyanide complexes and thiocyanates, especially related to the impact sulphide minerals have on the consumption of reagents, is increasing in significance.

EnviroChemie Group’s plant engineering has more than 40 years of experience in designing treatment plants for industrial water and wastewater treatment as well as water recycling in the mining sector. The range of treatment methods includes oxidation, with ozone being a major part of the oxidation processes.

Ozone, in combination with classical gas dissolution techniques, is known to be effective for many applications, but is often still perceived as an expensive treatment process. However, ozone generators have improved a lot over the last 10 years, making ozone economically feasible for many different water and wastewater applications.

What if it were possible to make ozone even more effective and more economically feasible by adding a component that increases the gas mass transfer and enhances reaction rates?

EnviroChemie Group, with its group member up2e!, offers such a solution either as a retrofit or as a full-scale treatment. With the Roturi, up2e! extends the product portfolio of the EnviroChemie Group in all ozone applications. The Roturi offers a unique and highly efficient way of gaseous mass transfer, making ozone treatment the perfect answer for many challenges in the mining industry.

One example is the pre-oxidation of refractory ores with ozone for lowering cyanide consumption in the process and increasing the gold recovery rate. Another example is the oxidation of thiocyanate for the regeneration of cyanide.

Studies show an increase in gold recovery of 25% and 70%, and that ozone is an effective oxidant for cyanide and soluble cyanide complexes.

Tailored and ready to operate full-treatment plants as well as pilot plants for pre-evaluation are available for client’s looking for the best available oxidation technology in the mining sector.

Read more: www.envirochemie.com/en/sectors/mining-ore-processing/

Steinert Supports Southern Africa With New Test Plant

In October 2020, Steinert, a global leader in separation technologies for the mining and metals industries, established a new test center in Namibia to service its southern African client base. Area manager, John Knouwds, discussed the new facility and the role ore sorting technology could play in the future of the mining industry.

“We needed to re-establish our test center in Africa,” Knouwds explained. “We were looking for a place to establish a plant, and one of our clients who we have a long relation with,” said ‘bring your machine so we can do tests and use the site to carry out tests for the rest of your clients in southern Africa.’

“So, we installed the plant at the Navachab Gold mine in Namibia, which is owned by QKR Namibia. The plant can test anything from 5 to 100 metric tons per hour (mt/h) depending upon the nature of the material. We’ve completed quite a few tests for various clients, and we’re also working to upgrade the mine’s ore sorting equipment based on their own test results.”

Steinert installed Navachab’s first two XRT sorters in 2016. Combined, they have a throughput of 200 mt/h and, having seen the benefit of the technology, Navachab is now working to expand its production.

When asked if the test facility would become a permanent arrangement, Knouwds said it would run until it is needed.

The plant features Steinert’s latest KSS XT | CLI 100 ore sorter. This includes an X-ray transmission (XRT) sensor, a color sensor, a laser sensor and an inductive sensor. The rocks run through the machine in a mono layer on a 1-meter-wide conveyor belt, and each particle is detected and analyzed individually by each sensor. The data generated is then processed, integrated and each rock is classified by the software. The inbuilt algorithms decide whether a rock should be ejected or sent for further processing based on its mineral content.

“Some applications require two or three sensors to get really accurate results and some only need to use one. This plant is set up to give us flexibility and to see which combination works best depending upon the geology and lithology of the rocks,” Knouwds said.

The beauty of the STEINERT KSS | XT CLI 100 having four sensors is that it combines both penetrative and non-penetrative sensing technologies to create exceptional accuracy and flexibility. The XRT unit (penetrative technology) remains the primary sensor, analyzing the full composition of the rocks, while the laser, color and inductive sensors analyze their surface qualities.

Of course, this also cuts down operating costs (energy, water, reagents, etc.) significantly and allows the mine to run a completely dry process. Something that is hugely valuable in a water-scarce environment.

“There are several software programs you can set up with the sensors as well,” Knouwds said. “A client with a gold mine operation in Tanzania can call us to report that they’ve encountered a new challenge or technical problem. Provided they have internet connection, our engineers in Germany can immediately access their sorter data and develop new programs to help.

“The sensors can also be adjusted based on the data retrieved from the rocks. We’re running the same sorter, exactly the same unit, at both gold mines and coal mines. But we develop a different software programs for each application and teach the machine, which rocks are valuable to that operation and which are not.”

Because so much is dependent upon the software programs, Steinert’s data scientists play a key role; not only do they develop and train the necessary algorithms, but they also further develop the sensors to generate different quantities and types of data that might be helpful in interpretation.

Steinert is developing a new final-stage sorting algorithm for Navachab to increase the plant’s capacity and help reduce its losses.

“One of our client’s is of the opinion that ore sorting technology will become part of processing in every mine over the next 20 years,” said Knouwds confidently. “And seeing how fast the technology grows and the capabilities it delivers, I think it might even be faster than that.”

Read more: https://steinertglobal.com/mining/