Mining and metals company AB Minerals is introducing a new disruptive processing technology, which has been developed to assist African columbite- tantalite (coltan) mining countries with the low-cost production of metallurgical-grade tantalum powder and niobium oxide using an industrial-scale processing plant.

The company, which has been focused on concluding the engineering and financing of the plant, has developed the solution over the past decade and completed the final plant design this year.

“We are now preparing to do a large-scale production run in the US and, once we complete this phase, we will be ready to build our first modular, skid-mounted plant. It is expected that the plant will be in operation at a site in Africa by the latter half of 2017,” AB Minerals CEO Frank Balestra tells Mining Weekly.

The company is evaluating opportunities in Africa for the location of its initial plant, as Balestra notes that there are several countries that produce enough ore to warrant the construction of a processing facility.

However, the Great Lakes region in Africa is the world’s largest producer of coltan and, thus, a key location that AB Minerals is considering for its first processing plant.

“Once the first plant is up and running we will consider additional locations in Africa and South America,” says Balestra.

He explains that, internationally, there is significant interest in delivering a lower-cost processing solution for tantalum, which is widely used in the manufacture of modern electric products, and niobium, which is used in the production of high-strength low-alloy steels.

The use of tantalum in manufacturing is currently limited, owing to the high cost of the metal, as a result of the expensive processing methods employed. “Industries look for alternatives for this sole reason; the metal will have a far greater range of use if its cost can be reduced,” states Balestra.

Further, 100% of the coltan ore produced in Africa is exported as mineral ore concentrates, rather than metals or high-value intermediate products, as there are no coltan processing plants near the mines, he notes.

Balestra explains that, while a significant amount of tantalum bearing ores, such as coltan, is mined in African countries including the Democratic Republic of Congo, Rwanda, Ethiopia, Nigeria and Sierra Leone, it is exported to other continents for processing at its lowest value as raw concentrate. This creates far less value for the miners and the country from which the ore is exported than if the coltan was upgraded on the continent before export.

Foreign entities elsewhere can significantly increase the value of the coltan through smelting, separating all the minerals in the concentrate and upgrading them to oxides and finished products.

“AB Minerals intends to change this value proposition by building the first coltan processing plant in Africa, closer to the source of the minerals. In time, we would like to have plants located in numerous locations in Africa and other parts of the world where coltan is being produced to enable these countries to reap greater value from the commodity and fuel further development.”

“The mining industry has always had a strong, positive impact in Africa. Smelting coltan to yield tantalum and niobium oxides will certainly boost revenue collections from mineral exports,” Balestra states.

Additionally, he points out that tantalum- bearing ore has varying levels of radiation and, as more ports increase their monitoring of radiation levels, more ore will be rejected if it is not processed in Africa before being exported.

In addition, Balestra notes that mineral traceability and the due diligence system to ensure that the minerals mined are conflict- free are important developments in Africa’s mining industry. Tantalum, tungsten and tin from the continent are required to be certified as conflict-free and tagged under this system prior to export.

However, costly and unreliable power supply in many African countries is a challenge and has prompted AB Minerals to focus on developing a low-power coltan processing solution that can be sustainably operated, despite inconsistent power supply or high electricity tariffs.

New Technology
Unlike current coltan processing technologies, AB Mineral’s solution does not use hydro- fluoric acid – a highly polluting substance that Balestra describes as “one of the most dangerous chemicals available today”. He highlights that plants using hydrofluoric acid require high capital investment and a significant power source, greatly raising the cost of tantalum production.

“The processing technology that is being used currently has not changed significantly in the past 60 years; however, our solution is innovative and highly beneficial. It has been designed with simplicity and safety in mind, as well as being environmentally sustainable. The capital cost to set up a processing plant is substantially reduced and the facility has been designed to be modular so that we can scale the plant’s capacity according to the available ore in different locations.”

The process developed by AB Minerals offers a nearly 100% recovery of tantalum and niobium, and produces niobium hydroxide and potassium fluorotantalate, which is upgraded to metallurgical-grade tantalum powder. The company has advanced the final product to a significantly high-purity metallurgical-grade tantalum, which Balestra highlights has substantially higher value than was initially planned.

AB Minerals has received interest in off- take agreements for the finished product from several multinational companies.

The company has also developed good relations with local governments, which support its project; however, these governments and the large mining companies active in coltan mining in Africa will not be the only ones benefiting from the solution.

“Major beneficiaries of the project will be the artisanal and small-scale mining companies and cooperatives, which represent a significant portion of the African mining industry. Miners will be able to receive higher prices for their ore by selling directly to a local smelter rather than to agents.”