Outotec Larox CC filters installed at the Angas Zinc Mine located in South Australia have helped the mine exceed all expectations for zinc and lead concentrate production.
The Angas Zinc Mine, situated only 60 kilometres from Adelaide is 100% owned and operated by Terramin Australia Ltd. The mine exceeded all production start-up expectations by using the latest filter technology from Outotec Larox CC filters, which dries higher than expected grades of zinc and lead concentrate.
Following commissioning in July 2008, the site was brought into full production six months early in January 2009.
In its first year, the low-cost mine with a resource of 2.4 million tonnes has produced nearly 23,000 tonnes of high-grade lead and zinc concentrate by the end of its second quarter.
The excellent production performance is due in part to an advanced filtering and drying system installed at the mine. Two Outotec Larox CC filters (formerly Larox Ceramec capillary action disc filters) fitted in the mine’s zinc and lead concentrators are fed by two Larox Flowsys peristaltic pumps.
The feed pumps employ a single, bearing-mounted eccentric roller design that compresses each hose once during a 360° operating cycle, reducing the hose compression requirement by 50%.
Outotec filters in action
The two Outotec Larox CC filters use capillary action within ceramic disks to dewater the lead and zinc concentrates. The extracted filtrates are very high in clarity while the dried filter cakes meet required transport moisture limits (TMLs) for their ore grades.
The process involves pumping the coarse lead and zinc concentrates into their respective filtering systems after slurry thickening. The concentrates coat the ceramic disk segments during immersion in slurry baths and dewatering starts immediately via capillary action. Extracted filtrate passes through the micro-porous structure in each disk before being transferred away by a small 2.2 kW vacuum pump. The dried filter cake that remains is continuously scraped off as the disks rotate.
When lead grades rose higher than expected soon after installation at the mine, the filters were quickly upgraded, providing Angas with a 30% increase in filtration capacity and allowing the handling of higher lead concentrates.
The upgrade allows the lead filter to efficiently handle higher lead head grade ore and increase production while still producing filter cake under the required TML.
The high performing filter with new ultrasonic positioning between the disks is currently being utilised by Angas at rates of 75% to 90% over a 24-hour period, depending on the ore grade being received.
Key benefits of Outotec Larox CC filters and Larox Flowsys peristaltic pumps
- Plug-and-play design
- No downtime is required for maintaining filter disks
- Only monthly maintenance checks required for filter ultrasonics and seals
- Filter backwashing is automatic
- Feed pump hose leaks can be easily detected
- Revolution counters can record pump hose life
- Processing noise levels can be kept to a minimum