THE PROCESS
The Minex Process is a halogen-based, pyrometallurgical vaporisation process which uses a fluidised bed reactor to extract contained metals in a single operation – typically more than 90% of the targeted metals – and results in a non-hazardous and stable residue.
Early in its development, the Process was carefully secured by world-wide patents and this protection continues today.
The Minex Process has been developed over a number of years with the assistance of professional mining engineers and consultants. Originally targeted at metalliferous waste, the process is equally applicable to newly mined complex ores.
Summaries of the test work completed are included in reports by independent consultants. Minex recommends that an optimisation programme is run for each type of material to ensure the efficiency of the Process is maximised.
METAL RECOVERY FROM PRIMARY ORES
Minex Technologies has developed a complementary proprietary process for the pre-treatment of bauxite ore ahead of the Bayer Process. The Bayer Process was developed at the turn of 20th Century and is the most widely used process to extract aluminium from bauxite, the primary aluminium ore. Typically, Bauxite ores are highly weathered rocks, normally found in the tropics. The significant weathering of the host rock leaves behind a mixture of oxides and silicates of aluminium, iron oxide, some titanium oxides and various trace elements. The Bayer Process selectively extracts aluminium from the ore and leaves a problematic Bauxite Residue, often known as ‘Red Mud’. To date no significant reuse of this waste material has been realised and so it is left in purpose built mud dams. Occasional these storage facilities have failed and when they do so can have a significant environmental impact.
In the Minex Bauxite Process (MBP) the crushed Bauxite is continually treated with a proprietary reagent at high temperature, pyrometallurgically, in order to selectively mobilise the iron within the Bauxite. Mobilising the iron in to a gaseous stream achieves a separation and the iron can be easily condensed from this stream, collected and forms a saleable commodity. Trials at an independent laboratory indicate that >80% of the iron can be mobilized. The collected iron will offset the expense of the thermal treatment and the proprietary reagent. Depending on the chemistry of the feed ore there is also the potential to collect other commodities at this stage. The pre-treated Bauxite can then continue through the Bayer Process and the aluminium recovered. By removing a significant proportion the iron ahead of the Bayer Process there is a notable reduction in Bauxite Residue, and the handling characteristics of the residue are also improved.
Another potential advantage of the thermal treatment of the Bauxite ore is that some of the more difficult aluminium phases, i.e. boehmite and diaspore, are converted to a more readily available form.
No competing technologies
METAL RECOVERY FROM METALLIFEROUS WASTE
Minex Process
Metalliferous wastes are a product of the metal smelting industry. In the base metal smelting industry as the target base metal is refined, the associated base metals, present as contaminants in the feed, are concentrated in to the waste stream or slag. For example, at a lead smelter the slag waste can contain significant quantities of zinc, some lead, copper and associated trace elements such as indium and silver, the exact values vary depending on the original feed stock. As these associated metals are concentrated in the waste there are potential significant values associated with them but as these wastes are refractory, to date it has proven difficult and not cost effective to recover them. To address this issue Minex Technologies has developed a proprietary process to unlock this potential revenue stream.
In the Minex Metallurgical Process (MMP) the crushed slag is treated with a proprietary reagent at 350C to selectively promote the formation of target compounds, whilst leaving the low value iron untouched. The treated waste is then removed from the reagent stream and subjected to a pyrometallurgical process whereby the target compounds are volatilised in to a gas stream. Independent laboratory trials indicate that >90% of the associated metals can be mobilised by this proprietary process. This gas stream is subsequently condensed and traditional hydrometallurgical processes are then utilised to separate each commodity in to a saleable form. The residual waste now has significantly less base metal content and forms an environmentally acceptable waste.
This process has the potential to make available a significant quantity of wastes and convert them to Secondary Resource Materials (SRM) as opposed to the Primary Resource Materials (PRM) from which there were refined.
Competing Technologies:
Zinc fuming, whilst successful in recovering zinc from recycled galvanised steels the process has had limited success with other wastes. The Waelz Process is a variation of this.
Numerous hydrometallurgical processes have been tried but fail due to excessive wear of grinding components by the refractory wastes, as the hydrometallurgical processes all require a very fine particulates in order to work effectively.
ENGAGEMENT WITH MINEX
LICENSING TERMS
Licensing terms are designed to be client and task specific, but will normally include an initial license fee and economic participation in the benefits of the adoption of the process. Final terms will be based on the results of the material optimisation programme.
MATERIAL OPTIMISATION PROGRAMMES
The material optimisation programme is performed for every material that is to be subject to the Minex Process in order to finalise plant design and optimised plant performance.