Modern Mining September 2019

PRODUCT News

Pumps for filter presses require careful selection being pumped into the press to low-flow and high-pressure when full.”

can often lead to issues in the plant, when valuable product is lost through leakage. “An expeller seal is not usually recom- mended, as the pressure it generates to seal the pump is generally not sufficient in a filter press application,” he says. The stuffing box option can be used under certain conditions. However, the pressure of the surface water needs to be higher than the pressure inside the pump. This means that it would usually be suitable on a low-pressure pump for a low-pressure filter press. “When the filter press requires a higher pressure, then the plant will have to pro- vide a water line with a higher pressure to feed the gland, or it will not seal properly,” he says. The preferred sealing option is a mechanical seal. While more costly, the mechanical seal can offer the customer substantial savings by preventing product being lost and downtime being incurred. “While the benefits of a mechanical seal far outweigh its cost, it must be properly installed by a specialist,” he warns. “It is a unique piece of equipment and we see plenty that fail due to incorrect installation.” A further consideration is the level of corrosive aspects of trace elements in the slurry. This can lead to rapid corrosion of mild steel pumps, and many applications

As a mission-critical system in the mineral concentration process, the filter press demands a carefully selected pump to ensure optimal performance and uptime. According to Marnus Koorts, product manager for slurry pumps at Weir Minerals Africa, the role of a filter press in recovering valuable saleable product is an important consideration for a mine operator. The high pressures associated with operating a fil- ter press, however, often lead the pump to underperform. “The operation of a filter press involves a wide spectrum of pressure and flow con- ditions within each cycle,” Koorts points out. “This ranges from high-flow, low- pressure conditions when slurry is initially

extended service life and low maintenance requirements, can be customised to suit exact customer requirements.” Popular units in the Dezzi range are the 1200 LP (low-profile) loaders, designed for efficient loading of various materials, includ- ing coal and mill scale. Dezzi shunting haulers and tractors are used at harbours and terminals for towing trailers that haul containers, cargo and any specialised commodity handled at the port. These tractors are also used at the harbour to tow and shunt rail cars. Included in the range of Dezzi trailers are quick-turn and tip-dump trailers, designed for various materials handling applications inmin- ing, construction and general engineering. BLT WORLD, in close association with Desmond Equipment, supports Dezzi equip- ment with a technical advisory and service facility throughout the country. BLT WORLD, website: www.bltworld.com He emphasises that it is not enough to simply specify a pump for the average of this range of conditions. Rather, it is vital to establish the minimum and maximum values on the spectrum and to specify accordingly. “Filter presses in the market can demand pressures of up to 45 bar,” he says. “In many cases, therefore, the appli- cation requires high-pressure pumps such as the Warman AHPP high pressure range. Where lower pressure requirements are present, the newer technology of the Warman WBH could be used as it is gener- ally a more efficient pump with longer wear life of spare parts.” Failure of the pump to deliver enough pressure to the filter results in the solid- liquid separation process being inefficient. The selection of the right size of pump is therefore an important starting point in ensuring optimal operation. With decades of experience in this field, Weir Minerals Africa has developed the expertise to advise on the best selection. It also offers a wide range of pumps suitable for application with filter presses. The next key aspect of the customer’s selection, Koorts says, is the choice of seal- ing arrangement. This aspect of the pump

Pressure tests are conducted on slurry and dewatering pumps to ensure the quality of Weir Minerals’ locally manufactured products.

require stainless steel options. Weir Minerals Africa, website: www.minerals.weir

Index to advertisers

KZN companies celebrate 10 years of partnership Two leading KwaZulu-Natal materials han- dling specialist companies – BLT WORLD and Desmond Equipment – are marking 10 years of their association this year.

AEL Mining Services Allied Crane Hire

2 7

ASPASA Babcock

53 28 15 55 IBC

Belaz Africa

“BLT WORLD, which was appointed by Desmond Equipment to supply and support the Dezzi range of bulk handling equipment in 2009, is proud to celebrate this important milestone,” says Ken Mouritzen, MD, BLT WORLD. “The locally-designed and manu- factured range of Dezzi machines comprises front-end loaders, articulated dump trucks, graders and tractor-trailer combinations, including hauler tractors. “These units can be seen hard at work throughout the country in all sectors, par- ticularly in the shipping, sugar, timber and agricultural sectors. “What’s important for users is Dezzi machines have robust features to cope efficiently in difficult operating conditions. This range, which offers high productivity,

CDE South Africa CMS Cepcor

Condra ContiTech Flexicon Geobrugg

OBC

12

9

40 32 24 21 44 36 49

Joburg Indaba Komatsu Mining Master Drilling Multotec Group Maptek

Murray & Roberts Cementation

Pilot Crushtec

IFC 52

SKF

Transcor Truck Hire Vega Instruments

5

51 37

Wearcheck

Weba Chute Systems

11

Weir Minerals

OFC

Worley

17 25

Zest WEG Group

56  MODERN MINING  September 2019