Reduction roasting

It is made from manganese dioxide ores through a reductive roasting process (31—33). 

Laterite Reduction roasting 2 NiO + C —> 2 Ni + C02 Ammonia-ammonium carbonate leaching in the presence of oxygen... 

Nevertheless, manganese nodules can, at best, be considered to be similar to land-based nickel laterites, and consequently most of the processing techniques that have been tried are similar to those used on lateritic ores. Reduction roasting followed by ammonia leaching, as in the Nicaro process, and high-temperature sulfuric acid leaching, as in the Moa Bay operation, have been extensively tried to process nodules. 

Ammoniacal leaching is typically applied to oxidic nickel-bearing materials that have been subjected to a reductive roast, which converts the cobalt and nickel present to their metallic form (or as ferro-alloys) and most of the iron to Fe11.106,107... 

Caron A process for extracting nickel and cobalt from lateritic ores by reductive roasting, followed by leaching with ammoniacal ammonium carbonate solution in the presence of oxygen. Developed by M. H. Caron at The Hague in the 1920s and used in Cuba (where the location of the mine is named Nicaro, after the metal and the inventor) and in Australia. 

Hydrometallurgical treatment of lateritic ores, by the reduction roast/ammonia leach process is one of the methods used for the recovery of nickel from low grade lateritic ores. In a recent study Chander and his associates (19, 20) used such... 

Table 9.2-2 summarizes the various methods used for the treatment of direct leaching ores. Typical minerals are listed, and those that can be leached by nonoxidative dissolution (NOX) are indicated, lliose requiring oxidants (OX) are also indicated. In some cases pretreatment is required, as in the case of reduction roasting of nickel laterites or vanadium ore which may be subjected to an oxidative salt roast prior to nonoxidative dissolution. Also indicated in Table 9.2-2 are the typical lixiviants used in the process, die methods used for metal recovery, and the form of the final product produced. 

L. F. Power and G. H. Geiger, The Application of the Reduction Roast-Anunoniacal Anunonium... 

Caron Process reduction roast - ammonia leach)... 

The major ore of manganese is pyrolusite [4—7]. If manganese ores are not soluble in an acid, they are reductively roasted at 700 °C to produce manganese oxide (MnO), and manganese is removed with sulfuric acid. Fe, Al, Mo, As and Si as impurities are removed from solution by neutralization. As a small amount of As, Cu, Pb, Ni and Co are contained in the neutralized solution still, these are removed as their sulfate by adding H2S and 99.97% pure manganese is prepared by the electrolysis of the solution as the electrolyte [4—7]. 

Once an ore is concentrated, it may be necessary to convat the mineral to a compound more suitable for reduction. Roasting is the process of heating a mineral in air to obtain the oxide. Sulfide minerals, such as zinc ore (containing the mineral sphalerite, ZnS), are usually roasted before reducing them to the metal. 

RESEARCHES ON REDUCTION ROASTING OF LOW-GRADE MANGANESE OXIDE ORES USING BIOMASS CHARCOAL AS... 

Key words low-grade manganese oxides, reduction roasting, biomass charcoal... 

The main reactions occur in the process of reduction roasting of Mn02 reduced by carbon is given in Table II. 

Table II. Main reactions existing during the reduction roasting...

Shufang Yan et al., Research on Direct Reduction Roast and Magnetic Separation Process of A... 

Researches on Reduction Roasting of Low-Grade Manganese Oxide Ores... 

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