Water Treatment

Mill Feedwater Pressure Control

Success Story: Mill Feedwater Pressure Control Copper is a valuable metal used in many residential, commercial, and industrial products. From wiring and consumer electronics to HVAC systems to electrical vehicles, copper is an essential element necessary to produce such products. Copper mining is a complex process and water is its’ lifeblood. It allows for the separation and recovery of salable copper. Throughout the milling and flotation cell processed, over double the amount of water is required throughout the crush-grind-flotation-concentrate circuit. Poor control of the mine’s water supply can negatively impact process run-time, leading to constrained production levels and hurting the bottom line. Additionally, as a mine ages, copper ore grade generally decline. To maintain target recovery rates, mines must process more material called ore tons. As time passes this adds to the mine’s overall water consumption.  Around the world mining companies are working to develop a more sustainable production method to address environmental concerns and maintain stable operations. Chile is home to the world’s largest copper mine and it is the country’s largest water consumer. In 2018, the mine underwent an expansion project to implement a desalination plant and added a necessary pipeline to feed the operation. The goal was to operate entirely on desalinated water by the year 2030. In 2020, 10 years ahead of the planned schedule, that goal was achieved. The mine’s water source is pumped over 3,100 meters above sea level to a reservoir near the mine. From there, the water is then delivered through a 36-inch discharge line and is controlled with an 18-inch globe valve. The pond is the sole water supply to the mill andconcentrator.  Greater process control is the hallmark of REXA’s Electraulic™ Actuators. Our actuators are more precise and accurate in performance than pneumatics and more reliable than traditional hydraulic technologies. This mine’s location is remote, arid, and the ambient temperature can drop below 0°C in the winter. For this project, themine had considered pneumatic actuators. The decision was made to not use the pneumatics because of their marginal positioning accuracy and reliability. To keep the concentrator process running, it is crucial that there is water present. Mine operators chose to rely on REXA Electaulic™ Actuators as the final control element to control water flow rate and emergency shutoff. Upon an unexpected loss of power, the linear actuators, equipped with accumulator bottles, produce up to 20,000 lb (89,000 N) of thrust that can safely close the valves using pressurized nitrogen.  In 2021, desalinated water is now used to supply all the copper mine’s water requirements. REXA actuators played a vital role in this successful four-year transition. Our self-contained Electraulic™ system locks the cylinder in place, when no movement is required, minimizing wear and tear on moving components and eliminating unnecessary power consumptions. REXA Electraulic™ Actuators have been engineered for use for constant modulating duty cycle and precise positioning independent of load variation. REXA’s actuation package supports various control system protocols including HART (Highway Addressable Remote Transducer) and Ethernet IP. Pipeline flow control is an excellent example where reliable positioning performance is necessary to prevent and minimize unscheduled downtime! Copper is a valuable metal used in many residential, commercial, and industrial products. From wiring and consumer electronics to HVAC systems to electrical vehicles, copper is an essential element necessary to produce such products. Copper mining is a complex process and water is its’ lifeblood. It allows for the separation and recovery of salable copper. Throughout the milling and flotation cell processed, over double the amount of water is required throughout the crush-grind-flotation-concentrate circuit. Poor control of the mine’s water supply can negatively impact process run-time, leading to constrained production levels and hurting the bottom line. Additionally, as a mine ages, copper ore grade generally decline. To maintain target recovery rates, mines must process more material called ore tons. As time passes this adds to the mine’s overall water consumption. Around the world mining companies are working to develop a more sustainable production method to address environmental concerns and maintain stable operations. Chile is home to the world’s largest copper mine and it is the country’s largest water consumer. In 2018, the mine underwent an expansion project to implement a desalination plant and added a necessary pipeline to feed the operation. The goal was to operate entirely on desalinated water by the year 2030. In 2020, 10 years ahead of the planned schedule, that goal was achieved. The mine’s water source is pumped over 3,100 meters above sea level to a reservoir near the mine. From there, the water is then delivered trhough a 36-inch discharge line and is controlled with an 18-inch globe valve. The pond is the sole water supply to the mill and concentrator.     Literature Download the entire Success Story here to learn more!  Download

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Filter Flow Control

Filter Flow Control The filtration process removes suspended particles from water by passing the water through a medium. After a period of run-time, a filter needs to be “backwashed” to remove the captured particles from that run-period. Particle capture rate is important in ensuring filtered water contains no micro-organisms that could be harmful to people. Micro-organisms can be difficult to disinfect/remove from water, so operators measure the turbidity of water to gauge the capture rate of a filter. Ideally, an efficient filter runs the longest and captures the most particles (has the lowest turbidity).  In a traditional gravity fed filtration system, the most critical valve application is the effluent control valve (commonly a butterfly valve). This valve typically sits at the bottom of the filter where it controls the rate of water flow moving through the filter. Commonly, accurate modulating control of filter flows with this valve is imperative to maintaining a constant, stable flow in a filter. The more stable the flow, the greater the capture rate. Surges in flow can occur when flow rates are not stable, which can allow suspended matter to pass through the filter – effectively increasing the turbidity of the filter effluent.  REXA  Linear  and  Rotary  Actuators have a history of success in the water treatment industry with controlling filter effluent valves. Maintenance-free operation of these modulating valves over decade-long periods is common. More importantly, the position accuracy of REXA  Linear  and  Rotary  Actuators (dead-band as tight as 0.05) can modulate a filter effluent butterfly valve disc in very finite increments that eliminate hunting. Precise position accuracy will stable flows through a filter, allowing for more efficient particle capture and lower turbidity.  Literature Download the Filtration Filter Effluent Control Application Spotlight! Webinar Download

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Water Storage

Water Storage REXA has a history of providing solutions for water storage applications. Some of our customers have sought the modulating capabilities of REXA to accurately meter flows into and out of their water storage infrastructure. Others have required the reliability and fail-safe capabilities of REXA for applications used to protect the stored water during emergency conditions. In either case, REXA has the product and experience to help you

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Ozone Control

Ozone Control Controlling a gaseous service via a butterfly valve with any degree of accuracy is 100% dependent on the positioning of that butterfly disc. On small valves sizes common in the ozone treatment process, the position accuracy is even further emphasized, and the slightest movement of a butterfly disc can result in significant flow changes. The positioning accuracy of REXA Linear and Rotary Actuators truly shines on this service, as the dead-band accuracy (as tight as 0.05%) can position butterfly valve discs in small enough increments to promote accurate flow control, improving the ozone treatment process efficiency.

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Raw Water Influent Flow Control

Raw Water Influent Flow Control Reliable control of  incoming flows is very important to starting the wastewater treatment process off on the right foot. Incoming flows are being modulated, any flow swings due to actuator hunting can cause upsets further along in the treatment processes. For this service, it is more important that the actuators are reliable, in order to avoid any possible disruption to the desired incoming flow rates. REXA has a history of offering both reliable and accurate flow control for this important service

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