Milling is a critical step in processing any ore as it liberates the value minerals. We have a range of milling equipment to develop your flowsheet. Our team of engineers and metallurgists work with you and a team of mineralogists to understand the milling and liberation requirements for your ore. Whether it is milling curves, bond indices or liberation analysis that is required, our engineers can assist.

Hydroyclones separate or classify particles suspended in a slurry based on their size and density. Our engineers and metallurgists are experienced in designing and operating closed and open circuit classification tests to upgrade your ore. For example, we have upgraded a silica deposit by removing the ultrafine feldspar component, and we have upgraded a chrome tailings deposit.

Shaking tables take advantage of the principle of gravity and fluid mechanics to achieve efficient separation of particles based on their density and size. Our team of engineers and metallurgists have used our dedicated shaking table laboratory to successfully upgrade ores such as gold ores and tin ores.

T-type classification separates fines from course slimes. Our team of engineers have used our teeter bed rig to upgrade chrome ores for our clients.

Attritioning is used to remove impure minerals from the surface of larger particles. Our team of metallurgists have assisted several clients by conducting test work programs to upgrade their silica sand material by attritioning and classification.

Magnetic separation is an important technique in minerals process. Our team of metallurgists are experienced in running magnetic separation test programmes and Davis tube tests. For example, we have assisted clients in upgrading their silica sand deposits, beneficiation of an iron-bearing converter slag, and removing magnetic minerals in tin samples.

Froth flotation is probably the most widely used mineral separation technique. Our team of scientists and engineers are experienced in developing flotation circuits, testing flotation circuits, running on-site optimization and improvement programmes, and modelling the results of sampling campaigns in float plants. Using our wide range of flotation cells and our unique modelling capabilities, our engineers are well positioned to assist whatever your flotation requirements are, whether it be gold flotation, polymetallic (copper, lead, zinc) or platinum flotation.

Filterability is characterised by the filtration rate as a function of cake thickness. Our team of engineers are experienced in pressure and vacuum filtration test work and translating these test results into design information. Our projects include leaching residues, flotation concentrates, fine coal, amongst others.

Calcination is usually applied to convert carbonate minerals into their oxide form. This is valuable as a chemical transformation, such as the production of lime, or to reduce the consequences of gas volatilization in furnace operations or pressure leaching autoclaves. Our team of engineers is skilled in calcination test work using tube and muffle furnaces. In addition, we use our sophisticated models of rotary kilns and fluidized bed roasters to translate test results into engineering designs.

Cyanidation is the leaching of gold and silver using cyanide. Our engineers and metallurgists have developed bespoke test protocols for cyanidation (for example, cyanidation under auto-controlled cyanide concentrations, and oxygen consumption tests). Our scientists have also advanced the understanding of cyanidation. Our metallurgists can assist you develop and optimize your process through diagnostic leaching, bottle roll tests, agitated vessel tests, (batch and continuous) carbon-in-pulp and carbon-in-leach tests.

The application of pressure allows the leaching vessel to operate at temperatures above the boiling point of the solution. Our engineers are experienced in tests involving gold, nickel, and copper ores at temperatures up 250C. For example, our engineers have assisted in developing pretreatment processes for gold using our POX test facility. In another example, our team of engineers assisted a client test the leaching characteristics of a new furnace product for PGM processing.

Chlorine is typically used in all modern platinum-group metal refineries to digest concentrates containing 50 to 70% PGM. Chlorine is also used in the digestion of gold in gold refineries (non-Miller process). Our team of metallurgists are experienced in the safe handling of chlorine gas for leaching and other test work. They can assist you develop new process options for your flowsheet. Our team has assisted clients with the digestion of PGM-containing materials arising from primary production and autocat recycling.

HPAL is the technology used for leaching nickel from laterite ores at temperatures exceeding 250C. Our team of metallurgists can assist you in developing your HPAL flowsheet. Our engineers combine the leaching and other test work information into a model of the process that can be further developed into an engineering study.

Heap leaching is a technology where a stack of ore is irrigated with an acid solution (copper and nickel) or a cyanide solution (gold) to extract the payable metal. The runoff, called pregnant leach solution, is collected for further purification and recovery. Our metallurgists are experienced running column tests for copper, nickel (including the novel use of ammonia) and other metals. We have developed and patented processes for heap leaching. Test work on your ores is complemented with sophisticated modelling, enhancing understanding and predictability of the industrial outcome.

Gangue Acid Consumption (GAC) is the amount of acid consumed in the leaching by minerals other those that yield payable metals. Our team of engineers provides this information as a separate test or as a calculation using data obtained from the leaching tests. GAC and total acid consumption data of high quality is important in the evaluation of the economic benefits of treating the ore.

Diagnostic Leaching is a sequential procedure to assist with the identification of the mineralogical composition of (typically) a gold ore. Our metallurgists conduct these tests under highly controlled conditions, and the interpretation of the results is done in conjunction with our associated mineralogists.

TCLP tests are a defined protocol for reporting the leachability of elements in a waste material. The test simulates the leaching of metallic elements from the waste in landfill conditions. Our team of scientists use the TCLP test to determine the environmental stability of organic and inorganic substances in wastes and the probability of releasing hazardous elements into the environment. This information assists you to design your flowsheet with confidence that it will meet the environmental requirements.

Precipitation is a key step in the purification and recovery of metals from solution. Our team of engineers has designed batch and pilot plant rigs for testing a wide range of precipitation chemistries and scenarios. Through our test work and engineering, our highly experienced team has assisted our clients in designing processes for FAM (iron, aluminium, manganese) precipitation, copper precipitation, germanium recovery through precipitation, arsenic removal and antimony recovery circuits, cobalt precipitation, amongst others.

Solvent extraction is a major purification step in hydrometallurgy. Our team of engineers has assisted clients by obtaining data using:

• Isotherm test – Isotherms provide key information for the evaluation and design of the SX circuit, including the choice of solvent, and the specification of pH and temperature. Our team of experienced scientists have assisted clients in designing circuits, for example, for (i) the removal of calcium, (ii) the removal of magnesium, (iii) the removal of zinc, and (iv) the removal of copper.
  
• Diluent evaluation – The diluent is a low-viscosity organic solvent in which the extractant is dissolved. The addition of diluent reduces the viscosity of the organic phase and increases the settling rate from the aqueous-organic emulsion, and thereby making the organic mixture suitable for practical use. Our team of scientists is experienced in conducting the phase disengagement tests, and assessment of the solubility of the extractant, and other chemical parameters for the assessment of a diluent.
  
• Continuous test work – Our team of engineers have designed pilot plant rigs of various scales for testing the circuit configuration and the chemistry of different solvent extraction systems. Our team of engineers is experienced with the LIX range, D2EHPA, versatic acid, the Cyanex range of extractants, amongst others, for, for example, Cu, Ni, Co, Mn, Zn extraction.

Ion exchange is typically used in hydrometallurgy to purify solutions to a high degree. Our team of scientists are experienced in performing ion exchange studies to assist you achieve the purity of solution and ultimately of product that maximizes the value of your ore. Our skilled scientists determine the adsorption isotherms and kinetics, the breakthrough curves, determine the elution requirements, and other parameters, that allow the design and scale-up to an industrial operation. Using our wide range of laboratory and pilot columns, we have assisted our clients to remove a variety of impurity metals from their processes, including cadmium, calcium and magnesium, from background solutions containing cobalt, nickel or platinum-group metals.

Electrowinning is the use of electrolysis to recover (or ‘win’) metal ions from solution. Metals such as copper, gold and silver, zinc, nickel and cobalt are commonly produced by electrowinning. Our team of engineers have developed test rigs of different sizes for clients to test a variety of aspects of electrowinning. For example, our team has tested the impact of surfactants on the development of acid mist during electrolysis, and the effect of flocculants on surface roughness. In addition to these types of studies, our team has also, for example, evaluated copper plating and electrolytic manganese dioxide production.

Carbon adsorption is the most widely used process for the recovery of gold from leaching/cyanidation liquors. The rate of leaching and the carbon adsorption isotherm and kinetics determine the parameters required for the specification of the CIL circuit. Our team of metallurgists is experienced in determining these parameters. Mostly importantly, our engineers use this data to prepare a report on the performance of different CIL/CIP configurations and equipment sizes. Our clients use this information to specify the option that optimizes the value of their ore.