The test work done before got reasonable recoveries for a first...

The test work done before got reasonable recoveries for a first try as it always takes time and trials tweeking things adding this and that before you get recoveries up in most new type operations. They have found now most of the cobalt is in the zinc sulphide mineral sphalerite so a different cocktail of chemicals is required.
Even this process done by SGS in 2017 got an 88% recovery with a longer residence time that could just mean adding more cells etc. However im sure a good recovery process will be sorted out as has been many very complex ores that lay in the ground for decades that are being mined now or have been mined the process was figured out.
Even long ago refractory gold was difficold to extract but processes were developed to get the gold out and thats all been mined and getting mined.


ASX: CLAwww.celsiusresources.com.auMr. Brendan Borg reportserth, WA / November 30, 2017 / JMN Wire / Celsius Resources Limited (ASX: CLA) (“Celsius” or “the Company”) ispleased to provide an update on the ongoing metallurgical test work program at its 95% owned Opuwo Cobalt Project(“Project”) in Namibia.The initial phases of test work being completed at SGS Australia have been focused on maximising recovery of sulphideminerals into a mineral concentrate. Currently, a recovery of 88.0% of the cobalt and 87.3% of the copper present in the feedsample (head grade 0.14% Co) has been achieved in the rougher sulphide concentrate. This demonstrates that themineralisation at Opuwo is amenable to conventional sulphide flotation techniques. A concentrate grade of 1.11% wasachieved during the initial 2 minutes of flotation, with a recovery of 64.2% of the cobalt recovered in this short timeframe.Recoveries increase to 88.0% with additional flotation time, offset by reduction in the grade of the concentrate.Celsius Managing Director, Brendan Borg commented:“The metallurgical test work program for the Project has demonstrated that conventional sulphide flotation techniques can beemployed to produce mineral concentrates at Opuwo, with optimisation ongoing to further improve grade and recovery. Theassessment of the ability to produce cobalt sulphate from this concentrate potentially adds significant value to the Project”HighlightsUp to 88% of cobalt recovered in rougher sulphide concentrate, through conventional flotationGrade of 1.11% cobalt achieved with short 2-minute flotation time, with 64.2% recoveryOptimisation of flotation process ongoing, to further improve recovery and grade of cobalt and copper in concentrate.Leaching test work to commence next week, with a view to demonstrating the viability of producing cobalt sulphatechemical from the sulphide concentrates