Just last month, the Global Tailings Review released the Global Industry Standard on Tailings Management in response to recent tailings dam failures. This Standard seeks to improve the diligence on tailings management solutions in order to have the lowest managed risk. Specifically for new facilities, Operators are required to review various technologies and methods to achieve the same. Tailings have traditionally been stored as a slurry in a Tailings Storage Facility. However, other techniques, such as paste thickening or dewatering the tailings, are becoming more popular in that they reduce the risk factor.
Dry stacking is a method of dewatering the tailings stream such that the liquid component is mostly removed allowing the resulting cake to be stored in piles. This method eliminates the risk of liquefaction, significantly reduces the volume of the tailings and recovers process water. The equipment typically used for dewatering tailings are filter presses. The solution has often been perceived as costly, complicated and ill-suited for large capacity applications, but technology advancements have altered this perception.
"Diemme Filtration's GHT-F Filter Press is a system designed in particular for dewatering of fast filtration tailings and, due to its features and benefits, is rapidly becoming the standard" says Andrea Pezzi, Sales Director N. America & UK. "There are currently many GHT-F filter presses in operation dewatering various tailings all over the World with our largest multi-filter installation dewatering more than 25.000 mtpd of material."
The GHT-F filter press is our proven "fast" filter press. The heart of the filter utilizes an electrically-driven moving head to open the filter plate package like an accordion discharging the filter cake in about one minute. This system considerably reduces both the cake discharge time and the entire opening-closing sequence of the filter. The result is a fast cycling filter press which allows increased throughput per unit area of the filter.
The "fast" filter, however, wouldn't be fast if the rest of the filter cycle were slow. So, we have designed the filter plates to fill quickly using two large feed ports and multiple filtrate outlets to provide free and unrestricted filtrate flow. The result is a filter plate with high dewatering efficiency.
A major feature of our GHT-F is the integrated high-pressure cloth washing system. The onboard cloth wash system uses 50 bar water pressure to regenerate and extend the life of the cloth while the cloths are installed on the press. The frequency of the cloth washing is adjustable by setting the parameter on the PLC; in this way the client can optimize the system for their process conditions. Since the system is entirely automatic, it is guaranteed that the cloths will be periodically washed. The benefits of this system are fewer cloth changeouts, less downtime, less maintenance costs, improved filtration efficiency of the cloth and extended cloth life.
When it is time to replace the cloth, it can be done easily and safely. With the GHT-F design, filter cloths are "hanging" on the top of the filter plate and are easily accessed using the integrated platforms. To replace a cloth, it simple needs to be lifted out of the filter press; there are no snaps, zippers, ties or other fastening hardware to remove or install. Furthermore, multiple cloths can be removed at once using a provided cloth removal tool. This reduces the time needed for cloth changing meaning more on-line time dewatering slurry.
Up until now, the GHT-F was available in two filter plate sizes, 1500x1500mm and 2500x2500mm. But with the current and forecasted demand for even-larger throughputs of future tailings applications, we are releasing our GHT5000F (nominal plate size 5000x5000 mm). This huge, next-generation filter press will have more than 3,000 m2 of filtration area making it the largest in the World. Depending on the nature of the tailings to be dewatered, one GHT5000F can exceed capacities of 12,000 mtpd of solids throughput.
Built upon the successful GHT-F platform, this game-changing technology was years in the making overcoming design obstacles such as manufacturing and transportation limitations. The filter plate design itself results from our experiences coupled with computational fluid dynamic modeling and material engineering. The filter plate then went through extensive testing to further optimize the final design. The body of the filter plate is manufactured by injection molding and consequently a new plate mold had to be created.
The filter press itself is massive. To reduce the amount of weight and steel utilized, finite elemental analysis was done over the entire structure. In addition, a topological optimization was performed resulting in increased mechanical performance with less material.
Lastly, the GHT5000F, as well as our other GHT-F filters, will have upgraded control systems using advanced machine intelligence and control. Tablet-based human machine interface and data acquisition and trending will allow full optimization of the system.
The first unit will be delivered in 2021 to an Operator in South America for tailings dewatering. We are excited for this milestone in filter press manufacturing.
We are also planning to launch this unit through a virtual event on line.
We will be providing updates and more information through our several media.
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