The SMI technology has been developed as an extraction process of magnesium hydroxide from a magnesium silicate (chrysotile asbestos), serpentinite and/or magnesite source, and the removal of impurities, resulting in an ultra-high-grade product.  Magnesium sulphate can likewise be produced during the process.  The raw material source can be mine tailings or run of mine (RoM).

 

Asbestos is a potentially hazardous mineral consisting of fibres.  Asbestos deposits, many of which contain between 5% and 50% asbestos, are a source of various metals and minerals, including magnesium.  Although attempts have been made to extract magnesium products from asbestos mine tailings, high purities have not been obtainable and commercial extraction using hydrochloric acid has been unsuccessful.  Most asbestos tailings facilities are exposed to the elements, increasing the risk of this potentially hazardous material being leached into local water systems due to rain, and dispersed in the air by wind.  Removal of the asbestos and the rehabilitation of the environment are therefore also priorities.  Abundant magnesite mine tailings are much less hazardous but an environmental liability nonetheless.

 

Furthermore, the production of magnesium oxide products from magnesite has been predominantly pyro-metallurgical, using coal, resulting in large scale production of carbon dioxide.

 

The SMI technology provides an extraction process which overcomes most of the abovementioned problems. 

 

The technology provides an extraction process of magnesium hydroxide from raw material sources, by subjecting the raw material to a refining process to obtain a suitable feedstock material and using a leaching agent within precisely defined leach parameters, including temperature, viscosity, and pH levels before differential precipitation is used to remove impurities.

 

Salamander Magnesium Process Development

 

The Salamander Magnesium Process has been refined through 5 stages of a comprehensive 6 stage development process.

 

Theoretical Development

During this stage Prof. Johan Labuschagné and his team studied a variety of scientific reports, and a document was produced which detailed a sequence of chemical reactions, to digest magnesium silicate using a sulphuric acid leach, and treating the dissolved magnesium sulphate produced with sodium hydroxide to produce a magnesium hydroxide precipitate.  Controlling parameters such as temperature, acidity (pH), duration and agitation would be key to improve purity and yield.

 

Laboratory Testing and Experimentation

SMI prepared batches of sampled material for testing and Prof. Labuschagné and his team proceeded to test this material according to the protocols set out in the document, in the laboratory.  Various parameters were adjusted and the purity and yields of each batch was determined.

 

A set of optimal parameters was determined, which were retested to confirm.  A second document was produced detailing the much more refined process with the specific conditions and parameters included.

 

Small Scale Pilot Plant Testing

SMI constructed a small pilot plant at premises in Westonaria, capable of processing raw material sample batches of up to 20kg.  Sample material was prepared for testing.  Prof. Labuschagné and his team tested numerous samples over a period of several months and produced several kilograms of magnesium hydroxide powder.  Samples of the magnesium hydroxide produced were sent to an independent laboratory for analysis and were determined to be >99.5% pure.

 

Large Scale Pilot Plant Testing

During August of 2022, SMI was able to procure a chemical plant which was set up at the CSIR in Pretoria.

 

This plant, which had been set up to manufacture various calcium-based nano-particle products, consisted of the same type of equipment which was required to test and refine the process, but on a much larger scale (up to 250kg of raw material per batch).

 

From August 2022 to March 2023, numerous batches of both chrysotile and magnesite material were processed through this pilot plant and several hundred kilograms of magnesium hydroxide was eventually prepared, together with samples of magnesium sulphate, and several other useful byproducts including, sodium sulphate, gypsum and silica.  Samples were taken of each batch and the process was adjusted accordingly to improve both yield and purity.

 

It was during this period that SMI applied for a patent for the process which covers the processing of both chrysotile and magnesite.

 

It was also during this period that the SMI pilot plant technicians developed, perfected and documented a novel and highly efficient wet processing methodology to extract the valuable chrysotile component from the run-of-mine (RoM) tailings material.

 

Pre-Production Testing

With the development of this extractive technology, combined with the improved and refined chemical process, the team was able to produce several batches of extremely pure magnesium hydroxide.

 

Samples of magnesium hydroxide produced from commercial grade magnesite were sent to a local pharmaceutical laboratory, where they were rinsed using purified water and then centrifuged. 

 

The resultant dry powder was sent to an independent laboratory for pharmaceutical analysis and was found to be >99.5% pure and well within acceptable pharmaceutical grade limits, proving the efficiency of the process.

 

A further noteworthy achievement during this period was the collaborative work, which was undertaken with Minxcon, a mining consultancy contracted by SMI to study and assess both the Kobolondo rehabilitation project, as well as the associated processes developed by Prof. Labuschagné and the SMI team, with the aim of obtaining a SAMVAL compliant Competent Persons Report.  This report was completed in July of 2023.

 

Commercialisation

As mentioned previously, the pilot plant which SMI owns and which was used to develop and perfect the process, is in fact a small production plant, and, once relocated to the Salamander Magnesium premises in Nelspruit, will be able to process up to 100 tons of magnesite per month.  The pilot plant will need to be thoroughly cleaned and refurbished prior to commissioning and there are some additional components that are required to improve efficiency and ensure consistent product yield and purity, namely-

  • Larger capacity filter presses;

  • Integrated electronic temperature, weight and volume measuring equipment;

  • Integrated PLC system, linked to electrical valves and pumps to ensure accurate dosing of reagents; and

  • MVC (Mechanical Vapor Compression) units to efficiently concentrate filtrates and produce purified process water.

 

Once commissioned, the plant will only process magnesite which will be obtained from the Nyala Magnesium Plant in Limpopo.  Initially it will produce magnesium sulphate and magnesium hydroxide, until the first two bulk magnesium modules have been completed, after which it will undergo an upgrade and expansion process, and once recommissioned and certified to produce pharmaceutical grade magnesium products, it will form the backbone of SMI’s pharmaceutical division, producing not only pharma grade (BP and USP) magnesium sulphate heptahydrate (Epsom salts), magnesium hydroxide (Milk of Magnesia), but also magnesium stearate, gluconate and other chelates for the pharmaceutical industry.

 

Commercialisation might be the last stage in the development of the Salamander Magnesium Process, but it is also the first step to developing and expanding SMI’s magnesite-based operations in Nelspruit and elsewhere, and SMI plans to eventually become a significant regional and global business in the processing and supply of magnesium-based commodities.