Advanced Alumina Solutions

Transcription

1 Advanced Alumina Solutions

2 2 Bauxite crushing & grinding World s largest Rod Mills on Bauxite at Gove, Australia 4400 t/h Primary ABON Sizer crushing bauxite Bauxite Bauxite ore is the major mineral source for extraction of alumina and subsequently aluminium, the most abundant element found in the earth s crust. The name bauxite originates from France where it was discovered. There are three (3) main structural types of bauxite: Gibbsite Al(OH)3 Boehmite AlO(OH) Diaspore AlO(OH) Each of these three types of bauxite has different chemical and physical properties that make them more or less difficult to mine and subsequently use for economically refine to alumina. Of the bauxites currently being mined, the dominant form is gibbsite, followed by a mixture of gibbsite and boehmitic. The main impurities are compounds of iron, silicon and titanium. A large quantity of the world s bauxite is mined from large blanket type deposits with an overburden from 0 to 70 m of rock and/or clay, which may require blasting before being loaded by front end loader or shovel and transported by truck, rail or conveyor to the refinery. Processing At the refinery, the bauxite is stored in a stockpile by a stacker for later reclaiming and processing into alumina. Roller screening of the bauxite to remove coarse waste material may be the first unit operation before the bauxite is crushed in one or more stages to a particle size of about mm, before being mixed with a hot caustic soda solution in the grinding mills. ABON sizers Since most bauxite mines are located in the tropics with its rainy season, bauxite processing equipment must, as a rule of thumb, be able to handle wet and sticky bauxite as well as dry and dusty bauxite, which makes the ABON Mineral Sizer the preferred type of crusher selected for both primary, secondary and tertiary crushing of the bauxite in many cases. Ball or rod mills, rod-ball mill or SAG mill After crushing, wet grinding of bauxite is accomplished in either open or closed-loop milling circuits using various types of grinding mill designs, tailor made to the bauxite. FLSmidth has operating experience with all the above equipment and cover the complete equipment flow sheet from Run-of-Mine bauxite up to and including the de-silication tank reactor prior to digestion t/h Secondary ABON Sizer crushing bauxite

3 3 Solid liquid calcination (SLC) The SLC process converts spent plant liquor and Sodium Oxalate to Sodium Aluminate and recovers the Caustic from Sodium Carbonate using Bauxite and/or Alumina Dust as solid feedstock. Liquor productivity is increased by decreasing content of organic agents and sodium carbonate in the liquor, allowing an increase in caustic concentration. Quality of hydrate and alumina is improved by reduction of sodium in alumina and production of a coarser hydrate. Improved plant efficiency is achieved by: Recovery of dissolved caustic and alumina Lower viscosity of plant liquor and pumping power Increased settling rates and less foaming Utilization of high organic bauxite deposits without decreasing plant efficiency Environmentally sound processing of salt cake to sodium aluminate without additional residue generation R&D timeline of SLC process 1st generation 120 TPD Solid Liquid Calciner with Alcan and Alumina Espanola : Equipment Selection : 24 tpd Pilot Testing : Construction of 120 tpd Unit : Commissioning, Demonstration, Consolidation and Optimization; 2nd Generation SLC Process developed with Alcan for Liquor Purification at Gove, Northern Territory 2002: Pilot Testing - Gas Suspension 2003: Pilot Testing - Environmental 2004: Basic Engineering 2004: Environmental impact study 2005: Detailed Engineering : PAM Construction 2 x 300 SLC Units arrives (as PAM) to the Gove Refinery in Australia Liquor Purification with the Solids Liquid Calcination Process (SLC)

4 4 Settler & washer trains Deep Cone paste thickeners Maximum underflow slurry solids and minimum thickener footprint Produce uniform, nonsegregating paste consistency underflow slurry State of the art approach for dry stacking of red mud Torque capacities available to 13,500,000 Nm 138 Deep Cone Paste Thickeners sold to over 45 operating sites Main features E-Duc autodilution and flocculation feed systems (for washers) Mud bed in compression Rakes with pickets for increase of solids concentration High torque drives Steep floor slope Mud discharge cone with centre scraper Designs without bottom bearing available Hi-rate thickeners Technology for high specific capacity at reduced footprint In combination with red mud drum filters for mud disposal at highest solids concentration and minimum soda losses Advanced mud level and thickener control systems available New generation of drive heads A-type State-of-the art design for bridge type thickeners Multiple efficiency planetary gears replacing traditional worm gear arrangements Heavy duty, high precision 4-point contact ball bearing designed to handle tilting forces Reverse rotation feature Permanent torque measurement by load cell(s) High safety span between design torque, 100% - alarm and cut-off at 180% resulting in extended reaction time for corrections

5 5 Red mud filter Red mud filters 22 mm high flow filter cells for highest hydraulic and pneumatic capacities Air sweeping device at both ends of the drum cell to assure quick filtrate and cake discharge Large diameter (1000 mm dia.) vacuum valve and wear plate with large sealing area for long resistance to wear Dedicated discharge roller drive system allowing for optimising ration of drum vs. discharge roller speed Agitator drive is designed for easy maintenance access to the drive, the bearings and the eccenters; especially the agitator shaft is divided in such a way, that also inside eccenter-bearings can be dismantled and replaced without disassembling the eccenter and the outside bearing Agitator drive is supported on the filter vat (not on the foundation) for best fit of components in the workshop and after site erection Robust cake discharge comb in special red mud design Agitator pivot bearings can be replaced from the outside without disassembling the drum. They are provided with lubrication points to assure to the bearings a long life Mud pockets with sluicing pipes and drainage nozzles to temporarily drain out the settled sand

6 6 Pressure filtration Shriver Filter Press The FLSmidth Shriver automated membrane filter presses are supplied with overhead filter plate suspension and automatic indexing plate shifting. These rugged construction filter presses are fitted with automatic high-pressure cloth washing mechanisms for filter cloth cleaning at pressures up to 100 bar. Years of experience and thousands of installations have resulted in a wide array of designs, features and styles of Shriver filter presses. A variety of plates, skeletons, opening mechanisms, shifters, and special designs with patented Shriver options provides FLSmidth the knowledge and experience to handle the most complex to the simplest application. Benefits High-solids red mud filter cake Maximum caustic recovery Overhead Plate Suspension Automatic filter cloth washing at 100 bar Filtration area up to 1,000 square meters Features Over 100 years experience in process and design More than 30,000 installed units worldwide Flexibility in design to meet special needs Qualified and experienced technical staff North American technologies combined with local manufacturing, local service and spare parts AFP IV automatic filter presses The FLSmidth AFP IV automatic filter press offers considerably reduced cycle time as compared to conventional filter presses. The mechanical time between cycles is minimal and, as a result, more production is achieved. The selection of AFP IV filter presses can greatly reduce the number of installed filters for a given installation. These filters not only provide high throughput, efficient solids capture and low moisture content red mud filter cakes, but they also operate continuously and automatically in harsh environments, and can handle abrasive or corrosive slurries. Benefits High-solids red mud filter cake Maximum caustic recovery Positive, fully automatic cake discharge Easier operation and maintenance accessibility Lower maintenance costs and higher performance Filtration area up to 2,000 square meters in a single filter Features Push closure cylinder mounted at centerline of filter press Rolling cross-head for extra long plate-stacks Fast opening & closing w/shaker for quick cake discharge Heavy-duty design specially adapted for minerals service Automatic cloth washing apparatus Recessed chamber and membrane plate designs Filter Press Control Packages Automatic filtration, cake wash, membrane squeeze, & discharge. Local process control and DCS communication.

7 7 Mobile conveyors & dry stacking Mobile conveyors The mobile stacking conveyor can be used to handle various materials. It is a single conveyor supported on a series of truss frames and crawler tracks. The trusses are connected by a specially developed joint that allows the machine to follow uneven ground conditions and relieve stresses that could damage the structure. A single conveyor belt flight runs along the top chord of the trusses the length of the mobile conveyor. The belt drive typically is located at the end of the machine where it is closest to the electrical power. The mobile conveyor tripper travels along the top chords of the mobile stacking conveyor. The tripper trips ore onto the cross conveyor belt and discharges the material onto the stack. The cross conveyor is long enough so the pile can be built to the design height while keeping the crawler track back from the advancing toe of the pad. The mobile conveyor s control system combines human interface and automatic controls for various functions. The operator can override the automatic controls if needed as well as control the upstream equipment. Manual controls such as the tripper speed and cross conveyor position can be used to build the smoothest possible leach pad. Automatic controls generally monitor frame alignment, leveling, and other conveyors upstream for the operator. The controls system is unique to the equipment and allows the MSC to handle material while it moves. It is important to point out that ore handling does not stop when the tripper or the entire machine moves. Waste Stacking System This is a very efficient and costeffective method of stacking waste ore. The Mobile Stacking System advance stacks in a radial mode, as indicated by the arcing sweeps. Once a lift has been completed, additional lifts can be stacked on top through the use of elevating conveyors. By stacking in lifts, several years of waste material can be stacked on a small footprint, thereby reducing the environmental impact. A stacker, such as a Mobile Bridge Boom Stacker, can be added to the Mobile Stacking System to increase the distance between the edge of the pile and the stacking system, depending on geotechnical requirements of the stacking plan. The addition of a stacker can also increase the flexibility of the stacking system when filling complex valleys.

8 8 Hydrate classification & slurry pumping Hydrocyclones Hydrocyclones are used in many alumina refineries to enhance classification efficiency. A partial list of applications includes Bauxite grinding Bauxite refinement Sands separations from red muds Sand washing, Hydrate classification Product size control Seed size control Hydrate thickening Deliquoring Agglomeration Preferential separation/reduction of oxalates Spent liquor solids recovery Cooling tower water clean-up Lime slurry degritting The most common applications are sands separation from red muds and the various duties in the hydrate classification and debottlenecking area. The versatility of hydrocyclones suggests they may be suitable problem solvers in many applications and this must be determined by a step-by-step evaluation. Solutions are tailored to meet the individual plant and operating conditions with hydrocyclones which are a low cost investment item. High efficiencies and outstanding flexibility are combined with simple operation and maintenance without any special space or installation requirements. FLSmidth Krebs is an innovative hydrocyclone supplier offering experience and value in proving benefits, thorough testing, optimum equipment design, suitable controls, maintenance friendly, and an appreciation of the limits of performance. KREBS millmax for the alumina industry KREBS millmax Pumps treat the cause of pump wear and loss of efficiency. In most established millmax installations, wear life of parts has been even and in the majority, overall wear life has generally improved by 100%. The increase in wear life is achieved together with a reduction in power consumption typical in the 10-20% or lower range. The reduction in power consumption can be as a cost saving, or additional pumping capacity with the same installed motor. Patented design feature to reduce degradation of solids High Chrome Iron Construction Reduced energy consumption for same flow/head Longer, more uniform wear life Optional drimax slurry mechanical seal High temperature elastomer seals Stainless steel fasteners

9 9 Seed & product hydrate filtration Seed hydrate filtration High capacity, large diameter disc filters The large diameter, high capacity disc filter is the state-of-the art filter for filtration of seed and product hydrate in the precipitation circuit. HiFlow hydraulic design for highest filtration capacity and lowest cake moisture Reliable cake discharge by advanced blow back design Large diameter discs with 5.5 or 6.0 m diameter High speed filter with up to 6.0 rpm disc speed Multiple discs with up to 6 discs per filter Multi-channel design providing 40 channels for 40 sectors per disc Optimum slurry agitation by discs running in multiple low volume troughs Special design for quick and simple disc replacement Improved sector and rim fixing system resulting in proven long-term mechanical and operating reliability Extended cloth life time due to modern sector design and improved cloth cleaning features Product hydrate filtration High capacity horizontal pan filters The high capacity horizontal pan filter is a highly reliable filter specially designed for the actual needs in the alumina industry. The filter design envelopes a modern synthesis of latest process achievements with reliable and rugged equipment design for highest customer satisfaction Advanced filtration rates are combined with most efficient counter current washing technology Enhanced product hydrate characteristics achieved through heel cake filtration Large diameter pan filters with up to 10 m diameter in successful conventional (71m²) operation Advanced self-control features Lowest cake moisture through using vacuum steam drying technology Special uniform slurry distribution device resulting in even cake build-up Reliable cake discharge by wear-resistant discharge scroll Highest filter productivity due to extended operation cycles Preventative maintenance friendly design

10 10 Gas suspension calcination (GSC) Electrostatic Precipitator Fabric Filters The gas suspension calciner (GSC) for alumina was developed by FLSmidth from 1976 to The first unit at Hindalco, India, has now been in operation since The GSC units at Queensland Alumina in Gladstone, Australia, shown on the cover page were the first calciners in the alumina industry with application of a bag-house for air pollution control located directly after the calcination process. This calcination facility comprises 3 x 4500 t/day of GSC units, the world s largest calciners producing alumina. Today, FLSmidth has proven GSC operation with Heavy Fuel Oil, Natural Gas and Coal Gas from a gasification plant. Typical annual calciner availability exceeds 98% with particulate dust emission not exceeding 20 mg/nm3 (dry) exhaust gas. GSC Technology Feature Operation below ambient pressure Calcination in one furnace pass only, without recirculation of partly calcined alumina Four (4) direct heat recovery stages Hot stand-by operation without alumina production GSC Customer Benefits Safe on line maintainability Minimum down time for maintenance Minimum mechanical impact on alumina Minimizing particle breakdown Minimum thermal energy consumption, CO 2 -Emission and heat lost to the cooling water Minimum thermal shock of refractory Maximizes service life of refractory Air pollution control More than 7,500 Air Pollution Control Installations - State-of-the-Art Gas Distribution using CFD Modelling Electrostatic precipitators for low dust emission Minimum spare parts stock 65 years of experience Emission < 15 mg/nm³ High availability > 20 years of lifetime Low pressure drop Back corona eliminated Low power consumption Multi-level collecting plates rapping Automatic performance optimization Unbreakable discharge electrodes Fabric filters for cement & minerals Industry Tailor-made to alumina & cement Low maintenance costs On line maintenance High availability On line supervision Own bag fabrication Constant low emission Low air consumption Star-shaped cages Smart pulse control Down flow between bags Low cleaning pressure

11 11 Alumina handling & storage in refinery and smelter Handling of primary alumina, secondary alumina, crushed bath, fluoride, calciner dust and petcoke Loading and unloading of trucks, railcars and ships Pneumatic and mechanical transport Screening, Dosing and Blending Storage in different silos Silo feeding and discharge with special systems on silo top and bottom in Anti-Segregation Design for low separation of finest particles Direct pot feeding systems Storage Mechanical Belt Conveyors for 1,200 t/h from Ship Unloader to Transfer Towers with Weighing and Dust Extraction Systems Large Capacity Silos up to 85,000 m 3 (and more, if required ) Transfer Towers with Airlift Systems 600 t/h each for 65 m vertical transport Distribution Airslide Conveyors to various Storage Silos Anti-Segregation Silo Feeding Systems downstream mechanical conveyors and Airlift Anti-Segregation Silo Reclaim Systems, designed also to limit dead stock volumes to smallest possible extent Downstream pneumatic transport equipment such as Airlift, Dust Pump or Pressure Vessels with TURBUFLOW Pipe Tanker and Railcar Loading and Discharge Stations FLSmidth s proprietary Möller technology Pneumatic MÖLLER TURBU- FLOW pressure vessel systems High dense phase conveying High conveying capacities over long distances up to 250 t/h and more First and only 3,000 m direct conveying project worldwide (Sumitomo Kashima Steelworks, Japan) Airslide systems for distribution and storage facilities Airlifts for vertical conveying MÖLLER dust conveying pumps (screw conveying) Small, medium, and large steel and concrete silos for short and long-term storage Special silo feeding and discharge equipment to minimize particle segregation and to achieve uniform particle size distribution for the material passing through the silos Direct pot feeding technology for alumina smelter plants TURBUFLOW features High dense phase conveying High loading ratio (kg bulk/kg air) Very low air/bulk velocity at the beginning and the end of the conveying pipe Low wear due to very low velocities Very low particle segregation during conveying of alumina No plugging Start-up with bulk loaded pipe Self-regulating system

12 12 Expert control system (ECS) & simulation More than 39 years of process knowledge and experience Gain access to FLSmidth s unparalleled knowledge and experience with process control, entailed in our ECS range of adaptable solutions. ECS/control center solution More than 39 years of process knowledge and process experience is unparalleled in the industry and is a unique support in our control centre solutions SCADA/PLC system with DCS functionality providing highly flexible solutions that are independent from PLC platform More than 700 ECS/ ControlCenter solutions commissioned since our first computer based Plant Control and Supervision system was installed in 1972 ECS/process epert solution Our ECS/ProcessExpert applications have a field proven track record since 1978 providing significantly improved process stability through continuous, accurate and consistent process evaluation and control actions The ECS/ProcessExpert solution entails uniform control strategy improving end-product quality regardless of individual operators skills Improved process stability and flow providing Lower operation costs Increased throughput Improved temperature control => more consistent quality Less blockages => less down time => less wear Typical results in the industry, with variations in production type, product type, maintenance level, etc.: Production increase:...3-8% Fuel savings:...2-8% Quality improvement:up to 30% Decreased standard deviation: 10-20% Remote services Remote Process Troubleshooting Remote Process Support Remote Software Maintenance Remote Engineering Remote Optimization Simulator State of the art in computerbased training Risk free environment enabling learning about: Processes behaviour Control system behaviour Provide hands-on experience with a true-to-live plant Enable faster start-up and productivity in new plants Built-in operator evaluation and certification

13 13 Quality control by x-ray (QCX) & RoboLab solutions First automated quality control solution in operation in FLSmidth has a unique experience in the quality control market, with a proven track record of more than 500 automated laboratories commissioned in the industry. QCX/RoboLab FLSmidth s Quality Control Solutions are supported by more than 36 years of process knowledge and process experience The unique QCX/RoboLab solution s ability to operate 24/7 at constant, high pace and high accuracy will provide an improved and precise overview on production Thus achieving significantly reduced variation in product quality An automated sampling process will procure correct representative sampling at the process and at the specified locations supported by fast delivery of samples to the lab Improved health and safety environment by releasing operators from heavy lifting and working in a dusty and noisy environment The QCX/RoboLab solutions range from sampling to analysing in the Bayer Process as well as in the Refinery and Smelter Process Our robotic cell structure clearly defines each cell s functionality providing a high degree of flexibility in design, layout and development of the laboratory The flexible concept allows for partial and step-by-step automation, e.g. step one; focus on quality and/or health and safety issues; expanding to fully automated operation at a later stage Centralized laboratory or dedicated in-situ lab FLSmidth s alternative to the centralized laboratory is an automated container laboratory solution, transportable to any location, close to the process requiring time critical analysis Fully self-contained solution with electrical and compressed air distribution, de-dusting ensures the optimum environment for high quality analysis The typical configuration includes the following analysis equipment: Sample milling machine PAL-MIL R Sample handling robot Optical emission Spectrometer SPECTROLAB QCX metal control system

14 14 Refinery capabilities

15 Smelter capabilities 15

16 Copyright 2011 FLSmidth A/S. ALL RIGHTS RESERVED. RTA settler-washer technology presented with authorization of Rio Tinto Alcan. FLSmidth is a (registered) trademark of FLSmidth A/S. This brochure makes no offers, representations or warranties (express or implied), and information and data contained in this brochure are for general reference only and may change at any time. Rev. 10/19//2011 al-us Australia FLSmidth Pty Ltd Tel: info.australia@flsmidth.com Germany FLSmidth Wiesbaden GmbH Tel: +49 (0) 6123 / wiesbaden@flsmidth.com USA FLSmidth Salt Lake City, Inc. Tel: info.slc@flsmidth.com Russia FLSmidth Russia CIS Tel: info@flsmidth.ru Brazil FLSmidth Ltda. Tel: flsmidth@flsmidth.com.br India FLSmidth Private Ltd Tel: flsm-in@flsmidth.com USA FLSmidth Krebs Inc. Tel: krebs@flsmidth.com Denmark FLSmidth A/S Tel: info@flsmidth.com