Role of Test Work in Process Engineering2013)_Testwork_in_Process_Engine… · Case Study Tailings...
Transcript of Role of Test Work in Process Engineering2013)_Testwork_in_Process_Engine… · Case Study Tailings...
Orway Mineral Consultants (WA) Pty Ltd
Role of Test Work in Process Engineering
Orway Mineral Consultants (WA) Pty Ltd
Overview
Test Work and Project Development Stages
Ore Preparation Test Work
Leach Test Work
Case Study
Tailings – Geochemistry
Radionuclide Considerations
Orway Mineral Consultants (WA) Pty Ltd
Overview
Test Work and Project Development Stages
Ore Preparation Test Work
Leach Test Work
Case Study
Tailings – Geochemistry
Radionuclide Considerations
Orway Mineral Consultants (WA) Pty Ltd
Test Work and Project Development Stages
Stage of development % Estimate Accuracy Test work guidance
Proof of concept +/- 50 - Single batch leach test
Concept +30, -15 - Batch tests on extraction
Pre-feasibility +25, -15 -Comminution test work
- Batch and lock cycle test work
Feasibility +15, -10
-Variability test work
- Pilot plant
- Vendor equipment test work
- Geotechnical and geochemical test work
Test work requirements vary
according to:
Process risk areas
Environmental regulation
Financing requirements
Internal requirements
Orway Mineral Consultants (WA) Pty Ltd
Overview
Test Work and Project Development Stages
Ore Preparation Test Work
Leach Test Work
Case Study
Tailings – Geochemistry
Radionuclide Considerations
Orway Mineral Consultants (WA) Pty Ltd
Ore Preparation Test Work
a) Gyratory Crusher
b) SAG Mill
A complete comminution characterization requires approximately 200
kg of sample in the form of either rock chips or PQ core (85 mm
diameter)
Orway Mineral Consultants (WA) Pty Ltd
Ore Preparation Test Work
Parameter Unit Value
- Abrasion index (Ai) 0.142
- Crush work index (CWi) kWh/t 15.0
- Bond rod work index (RWi) kWh/t 22.5
- Bond ball work index (BWi) kWh/t 14.7
- SAG mill comminution (SMC) – parameter A*b 29.0
- SAG mill comminution (SMC) – parameter ta 0.27
- Ore SG 2.65
Criteria Units
Primary Crusher
Crusher Type Jaw
Model Sandvik CJ615
Installed Motor kW 200
Secondary Crusher
Crusher Type Cone
Model Sandvik CH660 EC
Installed Motor kW 290
SAG Mill
Diameter – Inside
Shell m
8.53
EGL m 4.80
Motor Power MW 6.5
Recycle Crusher
Crusher Type Cone
Model Sandvik CH440 MF
Installed Motor kW 190
1) Ore comminution characteristics
from test work
2) Specific energy
calculations
3) Equipment selection
Database information
Simulation models
Orway Mineral Consultants (WA) Pty Ltd
Overview
Test Work and Project Development Stages
Ore Preparation Test Work
Leach Test Work
Case Study
Tailings – Geochemistry
Radionuclide Considerations
Orway Mineral Consultants (WA) Pty Ltd
Leach Test Work
Leach:
Acid
Alkaline
Heap leach
In-situ leach
Tank leach
Pressure leach
Orway Mineral Consultants (WA) Pty Ltd
Leach Test Work
Acid leach
Insoluble tetravalent uranium requires oxidation to the hexavalent state;
this is done via ferric iron:
Alkaline leach
Carbonate leach of hexavalent uranium (e.g. Carnotite)
Any tetravalent uranium present requires an oxidant: oxygen, air or
hydrogen peroxide
Orway Mineral Consultants (WA) Pty Ltd
Leach Test Work
Mainly used in acid leach; some
application on alkaline leach
Used for low grade ores
Require a careful environmental review
regarding ripios disposal and emergency
pond storage capacity
Design inputs from test work
Particle size
Agglomeration process
Uranium and gangue extraction extent
Reagent consumption rates
Leach cycle time
Irrigation rate, heap height and ore (fresh and spent) permeability
Heap Leach
Orway Mineral Consultants (WA) Pty Ltd
Leach Test Work
Mainly used in acid leach; some
application on alkaline leach
Applied in safe locations
Applied to shallow sandstones with
acceptable permeability
Employs a perched selected
aquifer
Test bore is required to assist with predicting
Uranium recoveries and reagent utilisation
Gangue element extraction
Cycle time
In-situ Leach
Orway Mineral Consultants (WA) Pty Ltd
Leach Test Work
Acid or alkaline
High temperature (70 – 95°C) or low
temperature (20 – 40°C)
Gas exhaust system needed to remove
radon for high grade ores
Feed to leaching may require thickening
to achieve a high pulp density
Design inputs from test work
Temperature
Uranium and gangue element deportment
Reagent consumption
Residence time
Slurry density (35 – 70%)
Agitated Tank Leach
Orway Mineral Consultants (WA) Pty Ltd
Leach Test Work
Acid (190 – 210°C)
Alkaline (110 – 120°C)
Low impurity levels in leach product
Oxidation via oxygen or air
Faster leaching kinetics and higher
extractions than atmospheric leach
Pressure Leach
Design inputs from test work
Temperature
Oxygen partial pressure
Uranium and gangue element deportment
Reagent consumption
Residence time
Slurry density (35 – 70%)
Orway Mineral Consultants (WA) Pty Ltd
Overview
Test Work and Project Development Stages
Ore Preparation Test Work
Leach Test Work
Case Study
Tailings – Geochemistry
Radionuclide Considerations
Orway Mineral Consultants (WA) Pty Ltd
Case Study
Case Study:
Batch and Pilot Leach Tests
Agitation
Solid-Liquid Separation
Thickener
Filtration
Uranium Recovery
Ion Exchange
Solvent Extraction
Product Precipitation
Orway Mineral Consultants (WA) Pty Ltd
Case Study
Case Study:
Batch and Pilot Leach Tests
Agitation
Solid-Liquid Separation
Thickener
Filtration
Uranium recovery
Ion Exchange
Solvent Extraction
Product Precipitation
Orway Mineral Consultants (WA) Pty Ltd
Case Study Leach Test Work
Batch test work Grind size
Temperature
Slurry SG
Pilot plant Leach efficiency
Reagent consumption rates
Materials of construction
Particle suspension (Agitation test)
Pilot plant set-up
Coupon test
Orway Mineral Consultants (WA) Pty Ltd
Case Study Leach Test Work
Parameter Unit Value
Apparent viscosity mPa.s 300 – 2000
Slurry density %w/w 65 – 70
Specific torque Nm/m3 37 – 58
Power/unit value kW/m3 0.6 – 3.7
Baffle – aspect ratio 0.10 – 0.12
Impeller type Pitch blade
turbine
Surface response at 75%
solids
Surface response at
70% solids
Surface response at
65% solids
Agitation Tests
Orway Mineral Consultants (WA) Pty Ltd
Case Study
Case Study:
Batch and Pilot Leach Tests
Agitation
Solid-Liquid Separation
Thickener
Filtration
Uranium Recovery
Ion Exchange
Solvent Extraction
Product Precipitation
Orway Mineral Consultants (WA) Pty Ltd
Solid-Liquid Separation
Thickeners
Prior to filtration
In lieu of filtration (CCD
arrangement)
Filtration
Vacuum belt filter
Pressure filtration
Non-Newtonian slurries resin in pulp has been used
Absorption
Elution
Barren slurry to tailings facility
Equipment
Orway Mineral Consultants (WA) Pty Ltd
Case Study Solid-Liquid Separation
Settling flux vs. flocculant dose
Optimum settling performance at
feedwell solids concentration of
7.5% w/w
Underflow solids content vs.
Retention time
Thickener Test Work
Orway Mineral Consultants (WA) Pty Ltd
Case Study Solid-Liquid Separation
Thickener Test Work
Underflow rheology
High rate thickener: 20 – 40 Pa
Deep cone thickener: 150 – 250 Pa
Other Data
Suspended solids: ~150 mg/L
Rise rate: ~8 m/h
Bed solids: 68 – 71 % w/w
Flux: 0.98 t/m2/h
Orway Mineral Consultants (WA) Pty Ltd
Case Study Solid-Liquid Separation
Test work results:
Optimum flocculant dose: 75 – 140 g/t
Cake moisture: 15 – 20%
Optimum cake thickness: 19 – 24 mm
Drying time: 20 seconds
Flux: 1500 – 1600 kg/m2/h
Wash ratio: 0.8/tonne
Expected wash recovery: >98%
Filter Test Work
Vendor test work equipment
a) Vacuum belt filter
b) Pressure filter
a
b
Orway Mineral Consultants (WA) Pty Ltd
Case Study
Case Study:
Batch and Pilot Leach Tests
Agitation
Solid-Liquid Separation
Thickener
Filtration
Uranium Recovery
Ion Exchange
Solvent Extraction
Product Precipitation
Orway Mineral Consultants (WA) Pty Ltd
Uranium Recovery Ion Exchange
Ion exchange
Fix bed
Carousel
Fluid bed
Orway Mineral Consultants (WA) Pty Ltd
Case Study Ion Exchange
Continuous Ion Exchange Pilot Plant
Resin moves counter-current to
aqueous stream
Resin loading simulates tray loading
Suspended solids: 1000 – 3000 mg/L
Pilot plant confirmed:
Resin loading
Impurity element transfer
(NO3,F,Cl,etc)
Silica fouling and subsequent
regeneration
Orway Mineral Consultants (WA) Pty Ltd
Uranium Recovery Solvent Extraction
Solvent extraction
Mixer settler Pulse columns
Orway Mineral Consultants (WA) Pty Ltd
Case Study
Case Study:
Batch and Pilot Leach Tests
Agitation
Solid-Liquid Separation
Thickener
Filtration
Uranium Recovery
Ion Exchange
Solvent Extraction
Product Precipitation
Orway Mineral Consultants (WA) Pty Ltd
Case Study Product Precipitation
Sodium route to precipitate sodium diuranate (SDU)
Intermediate Product - Diuranate
Orway Mineral Consultants (WA) Pty Ltd
Case Study Product Precipitation
Dissolution in sulfuric acid
Conversion to uranium tetraoxide
Final Product - Oxide
Element Assay
U 67.0%
K 0.02%
Mn 0.01%
V 0.09%
C <0.01%
Zr 0.02%
Th < 0.001%
Fe < 0.01%
Mo < 0.0001%
P < 0.001%
Orway Mineral Consultants (WA) Pty Ltd
Overview
Test Work and Project Development Stages
Ore Preparation Test Work
Leach Test Work
Case Study
Tailings – Geochemistry
Radionuclide Considerations
Orway Mineral Consultants (WA) Pty Ltd
Tailings - Geochemistry
Composition
Acid potential (AP)
Neutralisation potential (NP)
Net acid generation capacity (NAG)
Toxicity characteristic leach procedure (TCLP)
Kinetic test (ASTM D5744-96)
Radionuclides
Liner systems
Orway Mineral Consultants (WA) Pty Ltd
Overview
Test Work and Project Development Stages
Ore Preparation Test Work
Leach Test Work
Case Study
Tailings – Geochemistry
Radionuclide Considerations
Orway Mineral Consultants (WA) Pty Ltd
Radionuclide Considerations
Radon-222 gas
Sealing and extraction ventilation of:
mills
leach tanks
Radium-226, Bismuth-214 and Lead-
214 can precipitate in sludges in the
solid-liquid separation equipment
Bismuth-214 accumulates in SX
circuits and cruds
Radium-226 present in aqueous
effluents
Orway Mineral Consultants (WA) Pty Ltd
Thank You