Additional test work on London-listed Blencowe’s Orom-Cross graphite project, in Northern Uganda, has been completed by two graphite technical specialist laboratories in both China and the US, resulting in an uncoated spheronised purified graphite (SPG) product with a 99.96% purity and promising size distribution and characteristics. 

"The ultimate prequalification test for all graphite is how the concentrate upgrades to the 99.95% SPG product that then gets coated before going into the anode within the lithium-ion battery, and . . . exceptional SPG products will be produced from Orom-Cross.  

“Not only are we at the highest levels on most relevant indicators but testing has shown we can deliver other valuable products from waste material generated within the process which further strengthens our commercial model,” Blencowe executive chairperson Cameron Pearce said. 

Wuhan University, in conjunction with Qingdao Jinhui Graphite, in China, and American Energy Technologies Company (AETC), in Illinois, in the US, are experts in the field of upgrading graphite concentrate to uncoated battery-ready SPG product.  

Blencowe said on October 30 that this work was critical to understanding the commercial potential of the fines concentrate, specifically for use as anode materials in the lithium-ion batteries for electric vehicles (EVs) and wider rechargeable battery markets. 

In line with this test work flow sheet, graphite concentrate, which is comprised of robust and thick natural flakes, was first purified then converted into a range of value-added graphite products, with a focus on the production of spherical uncoated and spherical surface-coated materials intended for use in lithium-ion battery anodes. 

Wuhan University Qingdao Jinhui Graphite, which is one of the largest SPG producers in China, completed preliminary assessment of Orom-Cross fine concentrates with the generation and subsequent testing of uncoated SPG products, following a recent 100 t pilot test programme.  

The samples generated by Wuhan University have been forwarded to battery manufacturers for coating and initial battery testing. 

In parallel, Blencowe also commissioned AETC to complete an assessment of the SPG potential of the Orom-Cross product. This testing was completed at the AETC facilities, in Chicago, using AETC's thermal conversion process.  

Blencowe said the value-added downstream processing of concentrate from Orom-Cross occurred in accordance with the unique inverted flow sheet practiced by AETC.  

The company added that it chose AETC to undertake comparable test work in part due to its capacity to deliver the uncoated, coated and battery test work within a non-acid production process. Producing SPG products in a non-acid process would have significant environmental advantages that would boost Orom-Cross' environmental, social and governance credentials. 

After purifying the material using high temperature – but no acid or alkaline treatment – to a level of 99.99% carbon, AETC subjected it to spheroidisation and classification. Blencowe said that the resultant graphite has a good tap density of 1.1 g/cm³, with a surface area of less than 10 m²/g. Both of these indicators highlight a high-grade end product, Blencowe said. 

The uncoated graphite was tested in the industry-standard CR2016 coin cells against Li/Li+ counter electrode at C/10 charge-discharge rate. The material was seen to deliver a reversible capacity of 367.58 mAh/g, which is defined as "near theoretical" electrochemical performance, considering that theoretical capacity is 372 mAh. 

“Hardly any graphite has been able to achieve this historically in practical applications. This indicator alone ranks Orom-Cross graphite as high as any other SPG product elsewhere,” Blencowe noted. 

The uncoated material was also surface-coated to form coated SPG, which is the ultimate form of battery-ready graphite that goes into the anode. Application of surface coating makes batteries that use such graphite safer.  

Additionally, graphite anodes which are composed of surface-coated graphite tend to have lower irreversible capacity loss, a key property linked to management of electrolyte levels inside an operating lithium-ion battery. 

The coated material was put into batteries and subjected to short- and long-term cycling. The carbon-coated version of this graphite displayed strong electrochemical performance, with a reversible capacity loss and reversible capacity constituting near theoretical electrochemical behaviour. Blencowe states that this positions the material in the class of super-premium anode grade graphite for use in lithium-ion battery anodes. 

The long-term cycling of the material has retained stability of performance characteristics as a function of cycle life, having scored only 1.39% degradation. Test work suggested that Orom-Cross graphite can support 1 438 cycles, while the US Advanced Battery Consortium requirement for EV batteries is 1 000 charge-discharge cycles. Therefore, with nearly 50% additional cycles, Blencowe said that the Orom-Cross material was confirmed as premium quality and that it would be ideally suited for application in the lithium-ion battery anodes. 

The non-spherical portion of Blencowe's graphite, which accounted for about 25.6% of feed into the AETC spheroidising process, generated expanded delaminated graphite and spheroidisation process rejects, which were formulated into the composition of alkaline, lead acid batteries and an electrically conductive can coating. 

In all instances, the non-spherical portion of the material performed well, Blencowe said, indicating a strong likelihood that nearly 100% of all the graphite which enters a downstream processing circuit will find use in value-added applications within batteries. 

Blencowe said it would proceed with additional metallurgical test work with additional samples of uncoated SPG and other flake sizes distributed to potential off-takers and battery manufacturers for upgrades to large flake, as well as opportunities for use of SPG wastes.  

“We are into one of the most important aspects of our definitive feasibility study, where these tests ultimately prove the quality of the various end products we will produce, and therefore determine offtake interest and contracts.  

“Passing these tests with flying colours is further proof that Orom-Cross is a standout project, and in a world where graphite is becoming increasingly under the spotlight as the supply chain tightens, this is of significant value," Pearce claimed.