• Description


    Falcon SB Gravity Concentrators Key Advantages

    • Unit capacities up to 400 t/h
    • The variable frequency drive (VFD) and a dynamic braking system are used to greatly reduce offline time for concentrate flushing
    • Flat lid modular design increases wear life and reduces downtime as well as maintenance costs
    • Upgraded standard fluidization control results in a higher degree of machine management
    • High G forces (highest in the mineral processing industry) allow for higher efficiency and the recovery of very fine material
    • Reduced water consumption as only the pertinent collection zone section of the bowl is fluidized
    • Fully automated, “one touch” operation that provides the least amount of offline time and highest possible mineral concentrate security

    Falcon SB Gravity Concentrators are known as “Semi-Batch” Gravity Concentrators because they continually accept feed during the run cycle, but only produce mineral concentrate during periodic rinse cycles.

    Run times range anywhere from five minutes to several hours, depending on the mining application. Rinse times are generally less than a minute as Falcon Gravity Concentrators utilize a dynamic braking system to quickly slow the bowl down, rinse out the concentrate, and then return to full operational speed. Equipped with a variable frequency drive, this gravity concentrator can operate anywhere from 50 to 200 G’s.

    The typical application for a Falcon SB Gravity Concentrator is recovering liberated precious metals (Au, Ag, Pt, etc.) within a grinding circuit. Outside of grinding circuits, Falcon SB Gravity Concentrators are also used for precious metal separation from aggregate or placer deposits. The target mineral will usually be in extremely low concentration (grams per tonne) and a very high upgrade is desired (up to 10,000x).

  • Applications

    The Falcon SB Gravity Concentrator is used in a variety of mining applications, including:

    • Recovery of gold, silver and platinum group metals
    • Recovery of gold from cyclone feed, underflow or overflow within the grinding circuit
    • Recovery of gold in alluvial gold mining operations
    • Recovery of gold from aggregate plants

    Sepro’s line of enhanced gravity concentrators provides the best value and performance for your mining application. Installed in a variety of mineral recovery processes throughout the world, Falcon Gravity Concentrators are well proven as the key selection for fine metal and mineral recovery by gravity concentration.

    Our team of dedicated metallurgists and engineers continue to research and develop Falcon Gravity Concentrator technology, resulting in much higher efficiencies on the latest machine models. Sepro Mineral Systems recognizes that each gravity concentration circuit is unique and thus offers a line of mineral recovery equipment that is unequalled in parametric flexibility.


    Treating a Portion of Cyclone U/F or Cyclone Feed







    The use of gravity concentration in gold milling flowsheets is well established. Commonly, a Falcon SB will treat a fraction (10-30% for example) of the cyclone feed, mill discharge or cyclone U/F stream.

    Grinding circuit applications are considered “Multiple Pass“ environments as the target mineral is presented to the gravity concentrator multiple times. The behavior of gold within grinding circuits closed by hydrocyclones is favorable for gravity concentration, as gold circulates several times due to it’s high density and hence presented to the batch gravity concentrator more than once – even if treating only a small portion of the circulating load.

    The fluidization water introduced to the system through the gravity concentrator must be considered for the water balance, especially in grinding circuits.

    A sizing or scalping screen is placed ahead of the centrifugal concentrator, whereas the maximum feed particle size of 2mm has become the industry standard.

    A Sepro gold room (Shaking table) or Sepro intensive leach reactor (Sepro SLR) is commonly used to upgrade gravity gold concentrates.

    Treating the Entire Circulating Load







    Where gravity gold production has to be maximized, plant operators favour processing 100% of the circulating load instead of treating only a portion of the circulating load.

    Recovery of Free Precious Metals (i.e. Placer Gold)







    Typical “Single Pass“ environments have batch centrifigal concentrators (such as the Falcon SB) treating the products of grinding or scrubbing circuits: Cyclone O/F or Screen U/S, respectively. Placer gold wash plants, where fine, precious metals are to be recovered by the use of centrifugal concentrators, are considered single pass environments. The manufacturer’s unit capacity rating of a batch gravity concentrator generally applies for a multiple pass environment and the efficient unit capacity for a single pass environment is considerably lower (less than 50% of the rated maximum capacity).



  • Specifications

    Falcon Semi-Batch Gravity ConcentratorsFalcon Semi-Batch Gravity Concentrators

  • Automation

    Each of Sepro’s high quality Falcon Gravity Concentrators are supplied with a Programmable Automation Controller (AutoPAC). Sepro Mineral Systems incorporates industry leading automation technology to enable long-term, maximum mineral recovery on site with each unit.

    The standard Falcon Gravity Concentrator AutoPAC includes a programmable variable frequency drive and dynamic brake to control various operating parameters including acceleration ramp, centrifugal field, deceleration ramp, and power draw. The dynamic brake is an integral part of the AutoPAC, as it allows the rotor bowl to come to a stop rapidly to reduce lost production time or in the event of a malfunction.

    Some of the key automated features include: vibration sensor/monitor, safety limits, alarms, timers, solenoid control, data trending and automatic shut-down. The splash proof AutoPAC cabinet also houses a touch-screen Human Machine Interface (HMI). This HMI is used to control and monitor the operating parameters which assist with the optimization of concentrate production. Optionally, the AutoPAC can also be connected to an on stream analysis system which allows the Falcon Gravity Concentrator to maintain optimum metallurgical performance while operating conditions change.

    The comprehensive Falcon Gravity Concentrator AutoPAC is simple to operate as all controls and programmable features are factory preset before commissioning. The standard version offers the flexibility of being a complete control package that can operate as a stand-alone unit or can also be integrated into onsite MCC, DCS, PCS, SCADA, etc.

    SB B Gravity Concentrator Model (Standard)

    The fully integrated process water manifold on the SB-B Gravity Concentrator is capable of automated rinse, run and flush cycles. An enhanced process water manifold is now standard on Gravity Concentrator models SB750 through SB5200, featuring an electric actuator (24VDC), coupled with a split body flanged ball valve. This latest instalment replaces the traditional Singer valves and allows for fully automated precision control as well as an option for manual override. This sophisticated technology is paired with an electromagnetic flow meter and pressure transmitter.

    The combination of the RED LION HMI and VACON NXS/NXP drive eliminates the need for a local PLC in the SB-B Falcon Gravity Concentrator series. This union is key for optimum, reliable performance and operational efficiency.

    Process Water Manifold
    SB400 Gravity Concentrator

    • Solenoids for Rinse and Run

    SB750 – SB5200 Gravity Concentrators

    • Electric Actuated Flow Control Valve
    • Magnetic Flow Meter
    • Pressure Transmitter
    • Solenoids for Rinse and Flush


    • Single NEMA 3R / IP54 panel
    • Red Lion 5.6″ Colour Touch Screen HMI with Ethernet
    • Vacon VFD with Ethernet
    • Complete with Pushbuttons, Relays, Mains Disconnect and Protection Devices
    • 24VDC Control Voltage for Solenoids/Instruments
    • Dynamic Braking package

    SB SE Gravity Concentrator Model (Special Edition)

    The fully integrated process water manifold on the SB-SE Gravity Concentrator models (SB750 to SB5200) is capable of automated rinse, run and flush cycles. The process water manifold features an electric-pneumatic actuator, coupled with a rotary plug-valve.

    The SB-SE Falcon AutoPAC features an Local Control Console (LCC) as well as a Variable Frequency Drive Cabinet (VFDC) which provides enhanced control over machine parameters. The LCC allows operation of the Falcon SB Gravity Concentrator locally or by remote DCS in a way that optimizes the grade/recovery function for each individual application while at the same time minimising operator attention. It contains the PLC (Programmable Logic Controller) and a touch screen HMI. The VFDC works in conjunction with the LCC to control operating parameters.

    Process Water Manifold

    • Electro-Pneumatic Flow Control Valve
    • Magnetic Flow Meter
    • Pressure Transmitter (x2)
    • Solenoids for Rinse and Flush

    Variable Frequency Drive Cabinet (VFDC)

    • NEMA 3R / IP54 Enclosure for Remote Mounting
    • Siemens VFD with Ethernet
    • Complete with Mains Disconnect, Power on Indication, Relay and Protection devices
    • Dynamic Braking Package

    Local Control Console (LCC)

    • NEMA 4 / IP66 Operator Panel
    • Siemens 7″ Colour Touchscreen HMI with Ethernet
    • Siemens PLC with Ethernet
    • 24VDC Control Voltage for Solenoids/Instruments
    • Complete for Pushbuttons Relays and Protection Device
  • FAQ

    What are the major industries that use Falcon SB Gravity Concentrator technology?
    Falcon SB Gravity Concentrators are used for Au, Ag and PGM’s applications.

    What is Falcon SB Gravity Concentration technology?
    Falcon SB (Semi-Batch) technology is a family of batch enhanced gravity concentrating machines that has been proven in commercial applications to be able to withstand 200G concentrating fields while delivering superior metallurgical and mechanical performance at throughputs in excess of 400 t/h. Each machine consists of a single moving part. A feed stream enters the machine and is divided into high and low density fractions. Rinse times are generally less than one minute as the machine utilizes a dynamic breaking system.

    Why should I choose a Model SB Falcon Gravity Concentrator?
    Model SB Falcon Concentrators

    • Have the industry’s best concentrating surface area to footprint ratio
    • Are designed from the ground up to withstand 200G concentrating fields
    • Have the best unit fluidization water requirement in the industry
    • Produce very high-grade concentrates
    • Require almost no operator attention
    • Offer extremely low maintenance and operating costs
    • Have a two-stage bowl design that delivers superior performance and service access.
    • Are realistically priced

    What are the differences between the Falcon SB, C and UF Gravity Concentrators?
    Falcon SB Gravity Concentrators are batch-type gravity concentrators that use fluidization water to obtain a high-grade mineral concentrate and a mass pull to concentrate << 1%. SB’s are used primarily for the recovery of precious metals in the free, metallic state.

    The Falcon C Gravity Concentrators, on the other hand, do not require any fluidization water and are mainly used for pre-concentration and scavenging where high mass recoveries are required. C machines can pull up to 40% of the feed mass as concentrate.

    Falcon UF Gravity Concentrators are the latest addition to the Falcon Gravity Concentrator family with a very specialized function: the recovery of ultra-fine concentrate down to 3 microns. The UF Gravity Concentrator uses a variable lip controlled by air pressure to achieve maximum particle recovery.

    How do I compare machines from different manufacturers?
    Concentrating surface area (CSA), centrifugal field, machine power and weight are most important.

    What operating costs can be expected?
    The simple and robust design of the Falcon SB Gravity Concentrator means that unit operating costs are the lowest in the industry, normally a few cents per tonne treated.

    What operating availabilities does Sepro Mineral Systems equipment attain?
    Sepro Mineral Systems maintains mechanical availability >95% if equipment is installed and maintained according to our recommendations.

    What do your model numbers mean?
    The model prefix designates the machine type. The suffix is the approximate concentrating surface area of the machine in square inches. A SB5200 Gravity Concentrator is batch unit with approximately 5200 in² of concentrating surface area.

    What is the biggest machine you have?
    The Model SB5200 Gravity Concentrator has a rated capacity of 400 t/h solids in grinding circuit applications. View Falcon SB Gravity Concentrator Specifications for more information.

    In a grinding circuit application, should I design for maximum recovery across the Falcon?
    In Sepro’s opinion, gold production should be maximized as opposed to maximizing efficiency of the SB Concentrator. This may mean deliberately overloading the machine and accepting lower recovery but achieving higher overall yield from the circuit. Fortunately, Falcon Gravity Concentrator machines are built to handle overloading.

    Does pulp density have an effect on enhanced gravity concentrator performance?
    The thicker the pulp density the more difficult it is for fine gold particles to migrate to the riffle collection zone. Pulp densities of greater than 60% are not recommended for this reason. Treating more dilute streams in the order of 40-50% solids will maximize fine gravity gold production. Sepro Mineral Systems has numerous installations operating at 60 – 70% solids primarily recovering coarse gold from grinding mill circuits.

    What is the best location for a Falcon SB Gravity Concentrator?
    Although conventional wisdom dictates that the best stream for installing gravity concentrators within a grinding mill circuit is cyclone underflow, more and more mines are achieving better results with mill discharge or cyclone feed. Download a detailed report on this topic.

    What top size should be fed to Falcon SB Gravity Concentrator machines?
    Maximum tolerable size for Falcon SB Gravity Concentrators is 6 mm but Sepro strongly recommends reducing the top size to 2 mm or less in most situations. Preferably, SB Gravity Concentrator feed should be sized slightly coarser than the maximum gold particles in the stream for these reasons:

    1. Screening off barren coarse material saves money as it is less expensive to buy and operate a unit of screening capacity than a unit of concentrating capacity.
    2. Metallurgical performance will improve as the target and gangue particles become more closely sized.
    3. Operating costs for the Falcon SB Gravity Concentrator are a function of maximum particle size. As the maximum feed particle size becomes smaller, so do the operating costs for the Falcon Gravity Concentrator.

    How do you calculate the G forces produced by a centrifugal field?
    Centrifugal Field in G’s = Rotor Diameter (inches) x RPM2 ÷ 70471.

    Are there ‘gravity-only’ flowsheets available?
    Yes, Sepro Mineral Systems has developed unique flowsheets to help clients achieve previously unobtainable recoveries without using any reagents such as cyanide. Visit Falcon SB Applications for several example ‘gravity-only’ flowsheets.

    Who is the originator of the fluidized bowl design?
    MacNicol, 1935 in Australia.

  • Technical Papers

    Sepro Mineral Systems devotes a substantial amount of time and revenue to the design and metallurgical performance of its mineral processing technology. A large portion of this is conducted by Research Institutes, Universities and onsite trials.

    Our company appreciates the commitment and research conducted by the various parties throughout the mining industry. The technical papers contained herein are our proof of the time spent on designing the best range of mineral processing equipment for the mining industry, and a tribute to those involved with Falcon Gravity Concentration technology.

    1. The Gravity Recoverable Gold Test and Flash Flotation View PDF
    2. Development of the Falcon Concentrators View PDF
    3. Falcon Fine Recovery View PDF
    4. Gravity Concentration of Gold From Cyclone Feed In Grinding Circuits View PDF
    5. Centrifugal Concentrators in Gold Recovery and Coal Processing View PDF
    6. University of Liege Comparison of the Knelson and Falcon Centrifugal Separators View PDF
    7. Enhanced Gravity Concentration for Precious Metal Recovery
    Cyclone Feed and Base Metal Circuits
    View PDF