FLOTATION TECHNOLOGY
Metso Outotec ' s cPlant flotation solution is based on pre-fabricated and functionally tested modules inside container-sized steel frames that can be easily transported and installed , and quickly connected to the process
decreased energy consumption with Outotec cells ( 40 %). Minimised sanding increased flotation circuit availability , leading to increase production and overall there was improved flotation performance and recovery of both copper and gold .
In China , at Jinchuan Group ’ s Ni-Cu facility in Jinchang , Outotec in 2017 upgraded five non-Outotec 150 m 3 flotation cells in the low grade circuit with
FloatForce , automatic air feed controls , an ACT frothspeed control system , pulp level sensors and FrothSense cameras . The FloatForce upgrade improved the metallurgical performance and energy efficiency , whilst reducing operating costs with a new generation mixing mechanism . By improving flotation hydrodynamics and pumping performance at high airdispersion rates , the FloatForce enhanced particle recovery in the flotation cell while at the same time reducing power consumption and the risk of sanding . The energy savings were measured at an 8 % saving per cell with an extended rotor wear life . A comparison study revealed a significant improvement measuring a 1.9 % higher recovery of nickel and 2.1 % increase in copper without affecting the grade , amongst other benefits .
Looking at trends in cell sizes , Sohlberg says the trend to go bigger continues – “ we have over 50 units of the 500 to 630 m 3 TankCells already installed with another 40 or so in the process of being delivered or commissioned . Customers have seen extremely good results , with the Metso Outotec TankCell being renowned for its reliability in these larger sizes . Many of these projects are copper or copper-moly mines using very large cells for rougher duty for a number of reasons , but top being cost efficiency versus smaller cells . and we see not only this part of the market going this way . For other duties , smaller cells will continue to play an important role , although large cells can offer very good performance also in cleaner duties .”
Examples of large cell success include Grupo
Mexico ’ s Buenavista del Cobre ( BVC ) concentrator in Northern Mexico where two Metso Outotec TankCell e630 ’ s brought an increase of more than 3 % in overall recovery as well as producing higher Cu grade in the concentrate ( 24 % Cu ), which can be sent directly to the Cu-Mo separation plant . The motors of the cells are connected to a Variable Speed Drive allowing the rotational speed control of the flotation mechanism . The air flow rate and froth height are controlled locally from a CellStation ® control panel . Flotation air requirement is provided by dedicated centrifugal air blowers .
Elsewhere , Baikal Mining will also apply e630 TankCells at its Udokan copper project in Russia , with the cells in the process of being delivered . In addition to the projects named by Sohlberg , in Chile , Los Andes Copper in its latest project presentation from September 2020 ( see https :// www . losandescopper . com / site / assets / files / 3522 / los _ andes _ corp _ presentat ion _ 2020-09-23 . pdf ) has specified the use of 18 e500 TankCells at its Vizcachitas project ( rougher duty , two banks of nine cells ).
In the TankCell line generally Sohlberg said the real focus of late has been on optimising plant performance with froth management as well as working with customers on plant expansions and scale-ups and on how to achieve the best capex and opex without compromising metallurgical performance . An important part of the optimisation work is applying the Metso Outotec ACT platform to flotation , which forced air technology is very well suited to . ACT consists of three main components : ACT Designer , ACT Engine , and the ACT User Interface . ACT Designer is a graphical design environment used to configure and implement all aspects of the advanced process control solution . ACT Engine executes multiple ACT applications and interfaces with the plant control system . The ACT User Interface is used to monitor and control the status of the ACT solution .
It isn ’ t all about the big cells either . Innovation wise , two new solutions that Outotec had introduced and which are now part of Metso Outotec are focussed not on the very high throughput and low grade gold , copper and copper-moly operations , but more agile , higher grade , lower tonnage operations .
One is the cPlant Flotation concept , offering “ a costeffective , flexible solution for tackling challenges with project budget or tight project schedule , constantly changing capacity needs , or operations in remote locations .” The plant is based on pre-fabricated and functionally tested modules inside container-sized steel frames that can be easily transported and installed , and quickly connected to the process . cPlant offers reduced EPC project costs compared to a conventional flotation plant ; up to 20 % lower capital investment and 30 % less labour resources with 95 % of installation & pre-commissioning done prior to delivery and minimal civil engineering work required . The plant has been developed for projects handling up to three million tons of ore per year , with cell capacities of 1.5 , 3.6 , or 11 m 3 . Additionally , the plant provides a solution for bigger sites as cleaning cells or for selective flotation .
Sohlberg comments : “ cPlant would allow you to build up a flotation plant quickly and easily on-site , almost like building blocks . This is ideal for projects where you might need a temporary flotation solution or where modularity represents the best option based on the capacity or where the site is very remote and difficult to access . There is even the option to move the plant to another location – a possibility where you have satellite pits and don ’ t want to have to truck the ore a long distance to the existing plant . We have delivered a few cPlant projects already for example in Saudi Arabia for the Al Amar gold processing plant , owned by Ma ’ aden .”
Another new innovation that has focussed on the smaller to mid-sized mines , a part of the market that wants less complex and more standardised units , is the s-Series of TankCell flotation cells , which are easy to operate , allow a flexible layout , and are designed to enable gains in throughput , grade , and recovery , while improving the sustainability and minimising the environmental impact of a customer ’ s process . Metso Outotec says because they are standardised and delivered preconfigured , the s-Series units offer an even more cost-effective solution . Based on in-depth test work , it can design a tailor-made flotation circuit , based on the s-Series , for a plant that will deliver optimised cell volume and residence time . Units are available in sizes from 5 to 30 m 3 . “ Standardised products offer a great solution to customers looking for a quick time to market for their metals and commodities and a cost effective option ,” said Sohlberg .
Lastly looking at flash flotation and SkimAir , which is used for flash flotation and flash roughing . It enables mines to minimise overgrinding and improve overall mill throughput , recovery and dewatering . The SkimAir unit also provides help with achieving a more stable feed and better overall plant recovery . Introduced back in the 1980s , it has seen a lot of take up recently , notably in Russian gold ( for more detail see attached Polyus case study ). But Sohlberg says it also has very satisfied customers outside Russia for SkimAir including major copper mines in Peru , Chile ,
26 International Mining | NOVEMBER / DECEMBER 2020