Hi Ali

It is dependent to the ore type and Mn mineralogy. I test Mn dissolution with a mixture of H2SO4 and HNO3 and recoveries are sufficient.

You can also try hydrogen peroxide, ferrous, sulphur dioxide as reducing agent for Mn leaching.

dear Sina Ghassa

Thanks for the answer. I've used H2O2, N2H4 and even iron in sulfuric acid and it was promising but it took a long time or added impurities to the solution. I'm searching for a better one. is nitric acid better than agents above?

SO2 is an effective reductant, however the challenge is managing the resulting iron in solution during the leach step. The economics will be strongly dependent on the ore qualities...

Dear Justin Lamb

SO2 is effective but it must be managed because it's a toxic gas and environmentally forbidden. Of course the method is strongly depends on the grade. Maybe it's good to say that the grade that I have is low (22% of Mn).

Hi,

The best reducing agent is SO2 in sulfuric acid medium (or Na2S2O5). The benefits of SO2 reside in its reaction rate, the low temperature needed, its affordability and ease purification of solutions after reduction. Its disadvantages are its toxicity and the constraints related to its use.

With my best regards

Dear Doufnoune RACHIDA Rachida

Thank you for the answer. The toxicity is so important to me so I have to not use SO2.

Following.

Hi Ali

You asked for the best reductant. SO2 is the best, the toxicity is manageable and is done quite effectively in most countries.

Of course other reductants are available but cost and other issues such as safe handling are significant issues to be dealt with. Given the ore is 22% Mn it is more likely to be cost effective to remove the impurites through a leaching step.

Thanks

Justin

Hi Justin Lamb

Thank you. It was useful.

best regards