Macrotec Gold Recovery

T: +27 32 552 2676 | F: +27 86 608 2866 | W: www.macrotec.co.za



MacroBurn Gold Recovery

C100 and C150

Macrotec’s new design has revolutionised the way Gold is recovered from fine activated carbon particles. The design has had global success, with units operating in South Africa, Tanzania, Ghana and the USA, with projects also underway in Asia and Africa.

The system utilises a semi fluidised bed hearth designed to burn off the carbon within the primary chamber. This releases the Gold residue in the resultant fly ash. The fly ash is then caught within a Ceramic Filtration plant, and forwarded to the smelting procedure, with 93-95% of the Gold content recovered.

The entire process is fully automated to increase productivity of the plant. It also uses advanced burning methods with a secondary Ceramic Filtration plant to remove any pollutants.

The Problem

During the elution process, activated carbon that is deemed too fine for re-use is removed. This fine carbon residue contains on average between 50 to 200 grams of Gold per ton, though it can vary between 30 to 800 grams of Gold per ton.

How does it work?

Carbon is fed into the unit through a rotary valve preventing blow-back from the unit reaching the rest of the plant. An elbow in the pipe from the rotary valve protects the valve blades from radiant heat.

The unit consists of two chambers. The primary chamber, where the carbon is fed, is the bottom chamber. Although the burner dries out and ignites the carbon, it is also specifically located to provide secondary heat. The heat is used for the complete combustion of entrained particles and volatiles. Air is blown through perforations in a cast iron hearth plate in sufficient quantities to keep the burning carbon above the hearth. Additional air for combustion, plus a certain amount of excess air, is blown in through air jets in the side walls designed to create a vortex. The vortex minimises entrained ash and the carryover of unburnt carbon.

Any fine particles of carbon carried over from the primary chamber must pass through the secondary chamber that is designed to create a high degree of turbulence. This will burn out entrained smoke or other combustible particles. Extra air for combustion and quenching when temperatures become excessive is provided by a second set of air jets, similar to those in the primary chamber. This air will periodically blow accumulated ash in the second chamber up and into the outgoing gas stream.

The outgoing gas stream will pass through a Ceramic Filtration plant, where the Gold particles are captured. Air jets placed in the Filtration plant will periodically blast the Gold particles into a collection pot.



Return on Investment

Return on investment is usually between 8 and 12 months, depending on the Gold concentration in the carbon particles, and daily operating hours, with the unit able to recover 93-95% of Gold content.

When operating at full capacity, the C100 is able to treat 25 to 30 tonnes of carbon a month. This includes start-up times and downtime for maintenance.

Due to the potential loss of Gold in these fine carbon particles, most Gold producing firms use some process to try recover some of the Gold, which is usually sent offsite to be processed. These processes are complex, expensive, time consuming and usually involve harmful chemical processes.

Macrotec offers a simplified solution. But not only simplified, when taking into account the return period, it’s also highly efficient. The process is also faster than other options, dramatically increasing productivity, and is scalable to customer requirements.

Environmental Impact

Macrotec has designed these units to combat every possible threat they could pose to the environment. We make use of advanced designs in our plant that completely regulates the combustion rate, temperature in the different chambers, turbulence, gas velocities and supply of oxygen. This prevents formation and eliminates all carbonaceous matter, entrained ash, and chemically formed compounds.

EMISSION POST FILTER TYPICAL EMISSION LIMITParticle Matter < 8 10CO < 35 50HCI < 5 10SO < 10 50HF < 0.15 1Heavy Metals < 0.05 0.05

*All measurements are in mg/m³ (11% O2, STP).

Typical Emissions

2


Model Range

There are two models available, the C100 and the C150, with both models available with Diesel or Gas burners.

Plant Design

Macrotec is able to inspect your setup, and design a plant to integrate with your current process to ensure maximum productivity for your installation. Our technicians will investigate and advise on issues such as moisture in the carbon particles, methods of feeding the carbon, fuel and air lines, Gold outlet to smelting, and basic security measures for the installation.

Once the plant has been installed our technicians will calibrate the plant and PLC system to your requirements, taking into account altitude, ambient temperature, temperature range, and Gold content among other factors. Upon project completion Macrotec will have designed a maintenance schedule taking into account the above factors.

Maintenance and Repairs

Since every company values productivity and continuous operations, Macrotec has made client service in such regards a priority. All our units are designed and manufactured to ensure reliability under all conditions, with replacement of critical parts made fast and easy. To this end we include a critical spares pack with each unit to ensure that no matter where a client may be located, they will have the tools and parts available on site that they might require.

Our technicians are also available at all times to assist telephonically, and should a problem remain they are available to travel to any location on the planet at short notice to ensure all problems are resolved. Our technicians are also available for routine maintenance on all equipment, and should you require a maintenance plan please advise us upon quotation.

SPECIFICATION C100 C150Feed Rate 60 kg/h 90 kg/hFuel Consumption (start-up) 30l/h 60l/hFuel Consumption (at temp) 5l/h 10l/hStart-up Time 2 HoursOperating Temperature 750°C - 850°CBurner Diesel / GasPower Supply 380VAC + Neutral; 100 AmpCompressed Air Requirement 8 Bar; 15 CFMHeight (excluding stack) 4013 mm 5836 mmStack Height 15450 mmPlant Size 74 m²Weight 17,500 kg 19,000 kg



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Tel: +27 32 552 2676Website: www.macrotec.co.za Email: [email protected]

Documents

Macrotec Gold Recovery