diseño de procesos gravimetricos para obtencion de oro fernando palomino
DESCRIPTION
Diseño de Procesos GravimetricosTRANSCRIPT
FALCON SB
Sepro Mineral Systems History
1986
Falcon Concentrators LTD
Founded in Canada by today’s director Steve McAlister
World leaders in the design and supply of Centrifugal Gravity Concentrators
1987
Sepro Mineral Processing International
Founded in the UK by a dedicated team of engineers led by founder Mike Burton
Developed tyre driven mineral processing equipment: Scrubbers, Agglommerators, Mills
2008
Sepro Mineral Systems
Created through the purchase of Sepro MPI by Falcon Concentrators
Numerous installations world wide
Offices in Canada, UK, Ghana, Austria
World wide representative network
Sepro Equipment Lines
Falcon Semi-Batch Concentrators
Falcon Continuous Concentrators
Falcon Ultra-Fine Concentrators
Sepro Scrubbers
Sepro Grinding Mills
Sepro Agglomeration Drums
Sepro Dense Medium Separators
Sepro Crushers
Sepro-Sizetec Screens
Sepro Leach Reactors
Sepro Pumps
Sepro Mobile / Modular Plants
Falcon SB Introduction
Periodically discharges a high grade concentrate
Centrifugal fields up to 200G’s
Single unit capacities from 1-400t/h
Typical concentrate yield of <0.01%
Typical concentrate grade: +1000 gAu/t
VFD and Dynamic Brake to reduce offline time
Recovery and upgrade down to ~20 microns
Mostly used within grinding circuits (cyclone feed or U/F)
Falcon SB – Applications
Recovery of gold from cyclone feed, underflow or overflow within the grinding circuit
Recovery of gold in alluvial gold operations
Recovery of gold from aggregate plants
Recovery of precious metals in recycling
Falcon SB – How it Works
Water manifold
SFC Water Manifold + AutoPAC
Sepro Flow Control (Fully Automatic)
Strainer (Filter)
Rinse + Flush Solenoid Valves
Flowmeter + Flow Control Valve
MFC Water Manifold + VFD
Manual Flow Control
Strainer (Filter)
Rinse + Flush Hand Valves
Flow Control Hand Valve
Processing cycles
Fluidization water spray Concentrating cycle Rinse cycle
9
Test Work
L40 Low Mass Yield (LMY) test with SB bowl
GRG test – The industry standard: 3-pass LMY test with intermediate grind
Mathematical modelling of potential gravity recovery based on the bahaviour of gold in a grinding circuit:
Gold grinds 6 to 20 times slower than gangue
Gold reports to Cyclone U/F at a smaller particle size than gangue due to high SG
GRG (Gravity Recoverable Gold) may turn into NON-GRG by over-grinding and smearing
Increased Recovery: Flotation
Gravity circuit reduces overgrinding and the amount of coarse gold reporting to flotation
Recovery of GRG by flotation is lower at the fine and coarse end of particle sizes
Overall gold recovery increase potential of 1-10%
11
Increased Recovery: Leach
Gravity circuit reduces overgrinding and the amount of coarse gold reporting to leach
Finer distribution of gold reporting to conventional leach circuit = faster leaching / shorter leach retention
Reduced carbon stripping effort
Intensive leach for gravity concentrates
Overall gold recovery increase potential of 1-3%
12
Metallurgical considerations
Most important parameters for gravity circuit gold production (LaPlante):
1. Centrifuge Throughput in relation to plant throughput (Percentage of circulating load treated)2. Cyclone Efficiency3. Centrifuge Availability4. Centrifuge Stage Recovery (G-Force) (Fluidization) (Cycle time)
PERCENTAGE OF CIRCULATING LOAD TREATED
POTENTIAL BENEFIT
(%) (%)
0 0
10 48
25 70
50 88
75 95
100 100
FLUIDIZATION WATER
G FORCE
60 100 140 180
14 psi
2.274 kg34.9% Rec
2.882 kg35.0% Rec
3.032 kg77.3% Rec
4.525 kg66.3% Rec
20 psi
2.115 kg31.9% Rec
2.611 kg32.6% Rec
2.868 kg46.4% Rec
3.712 kg65.4% Rec
26 psi
1.781 kg31.0% Rec
2.201 kg32.6% Rec
2.747 kg40.1% Rec
3.487 kg70.4% Rec
Placement considerations
Gold grade
Liberation
Pulp density
OPEX
CAPEX
SB
SB
SB
Location of the gravity concentrator
-
Cyclone Underflow Mill discharge / Cyclone Feed Cyclone Overflow
+ Multiple pass environment (Circulating load)Generally 25% or 100% treated
+ Multiple pass environment (Circulating load)Generally 25% or 100% treated
- Single pass environment(Open circuit)Generally 100% treated
+ High gold grade (Circulating load)
+ High gold grade (Circulating load)
- Lower gold grade (Open circuit)
- Potentially low liberation + Increased liberation + Maximum liberation
- Coarser FeedHigh wear
o Finer feed than Cyclone U/F Reduced wear
+ Fine FeedLow wear
- Suboptimum feed pulp density for screening (+60%-wt. solids)
+ Suitable feed pulp density for screening (45-60%-wt. solids)
+ Protection screening not urgently necessary
- Fines by-pass - Fines by-pass (Mill discharge)
+ Treatment of fines (Cyclone O/F)
- Higher structural elevation of mill building
+ Lower structural elevation + Lower structural elevation
o Increased head for cyclone feed pumpNo additional pumps required
- Additional pumps normallyrequired
- Additional pumps may be required
15
Feed Scalping Screen
Scalping at 2mm (slotted screen panel) is today’s standard
Scalping at 1mm screen aperture requires more screen area
Additional effort is often offset by reduced wear on the BCC
Finer screening has metallurgical advantages especially for recovering fine gold (- 53 micron)
VSMA guidelines recommend dilution of both cyclone feed and cyclone U/F for optimum screening. Less dilution required when screening cyclone feed
16
Bypass
Bypass during rinse cycle: approx. 2 min
Gold trap in feed line rather than by-bass line
Pinch Valve or Knife Gate Valve
OSHA Office of Training & Education 17
Published fluidization water consumptions: Falcon SB5200: 25 - 35 m3/hKnelson KC-XD48: 28 - 86 m3/hAnnual difference: 200,000 m3 (8000 h/a)
Affects water balance around grinding mill
Affects operating costs, downstream capital costs
High quality, clean water required, typical specification: < 100 ppm solids< 5 micron
Poor water quality affects maintenance and downtime
Typical minimum supply pressure: 40-50 psi
OSHA Office of Training & Education 18
Rotor comparison
ImpellerStratification zone: Acceleration and stratificationRetention zoneOptimum fluidization water utilization at most effective point
19
Availability – Zoned approach
Mechanical availability of gravity circuit is second largest determinant of gravity gold production.
Zoned approach: ImpellerLower strike point Lip ring
Major wear parts are not recovery related
Wear items are separate exchangeable parts
20
Concentrate Handling Options
Blend gravity concentrate with Flotation concentrate
Sell gravity concentrate separately
Shaking table (to Smelting)
Intensive Leach (to Electrowinning/Smelting)
Caso Práctico
OSHA Office of Training & Education 21
Recuperación diaria por Gravimetría
OSHA Office of Training & Education 22
Recuperación mensual
OSHA Office of Training & Education 23
Prueba GRG
OSHA Office of Training & Education 24
OSHA Office of Training & Education 25
Gravity Devices
27
Sepro Mineral Systems
Thank You For Your Time and Attention