Two BoVac Disc filters M176 are operated for dewatering of zinc tailings from a copper and zinc mine in Australia, Qld. Start of operation was in 2014. Each filter has a filter area of 176 m² and consists of 8 filter discs with a diameter of 4.1 m. Four filter discs each are connected to one control head. The tailings slurry mainly consists of silicates.

The two BoVac Disc filters replaced two disc filters of older design (with a solids performance of 120 t/h each) to meet the total plant capacity of 350 t/h of tailings. This is an almost 50 % capacity increase on basically the same filtration area. It was essential that the two BoVac Disc filters fit into the existing filter floor space with minimum of modification work.

The two disc filters are operated in a fully automatic way i.e. filter start up, filter operation and filter shut down are carried out automatically. An automatic filter operation control adapts filter performance to changing slurry and process conditions and avoids emergencies.  Depending on the slurry feed charge it can occur that the discharged filter cake is too dry for downstream processing in the mixer. This can be prevented by adjusting the pressure difference in the dewatering vacuum line by throttling which effects higher moisture in the filter cake. Experiences gained from filter commissioning and filter operation led to the following recommendations to ensure safe and reliable filter operation:

  • an exact mounting and fixation of the filter bags onto the filter segments prevents solids from penetrating into the filtrate piping
  • routine inspections by a well trained operator and maintenance team
    • to detect defective filter bags which have to be replaced as prompt as possible
    • to detect initiating damages through the abrasiveness of the slurry in an early stage.

BoVac Disc Filter M176

Units installed

[–]

2

Filter area per unit

[ m² ]

176

Material of construction

 

S 235 JR

Power of filter drive

[ kW ]

7.5

Foot print incl. receiver & tank

[ m ]

9 x 7  per unit

Year of commissioning

 

2014

 

Process and Operation Data

Solids throughput

[ t DS/h ]

> 175 up to 210 (max. peek)

Solids content in feed

[ wt.- % ]

60–65

Cake moisture content

[ wt.- % ]

17–20

 

Product Data

Product

 

zinc tailings
consists mainly of silicates

Medium particle size

[ µm ]

50

Flocculant dosage

[ g /t DS ]

0 –  50

depending on feed charge

 

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