Slurry gets a stir

Sand and gravel processor Aggregate Industries has reported major efficiency and maintenance benefits following the installation of a new Linatex pump for use in abrasive slurry applications.

In a trial, the Markfield, Leicestershire-based company replaced a conventional eight-inch, 75HP pump with an eight-inch, 60HP Linatex G4 rubber pump in a coarse sand application. For another test nvolving fine sand, a standard six-inch, 30HP pump was replaced with a six-inch, 25HP version of the G4 pump.

Over its nine-month evaluation, Aggregate Industries noted power-consumption savings of 18% when processing coarse sand and 44% for fine sand applications compared with the previous pumps. This performance equated to annual savings of up to £2,000 and £1,500, respectively.
The results are linked to the casing liner volute and impeller on the G4 pump, which have been designed to improve the flow dynamics of slurry.
The main selling point of the G4, however, relates to design features (see image below) that allow a 30-minute service, versus three hours for equivalent rival offerings. The pump can be fully serviced, and the impeller and gland pack removed, without the need to disconnect or remove discharge pipework.

Rotating connecting flanges also allow easier pipework alignment, while a large-diameter suction door component can be rotated to equalise wear. This has been confirmed by Aggregate Industries, the company reporting significantly reduced maintenance issues with the pump.
“The levels of wear to date have been impressive compared to the old-style pump,” said its quarry operations manager Duncan McIntosh. “These pumps are so much easier and safer to work on.”

The wear resistance of the rubber derives from the inherently high abrasion resistance of Linatex natural rubber (NR), which has up to three times the wear life of most rubbers.

The NR material is produced via a unique cold latex process. This avoids the mastication processes conventionally used to break up the polyisoprene molecular chains, making the rubber easier to process but impairing physical properties such as abrasion resistance.

The G4 launch is part of Linatex’s aim to significantly increase its share of the $800-million slurry pump market, said Bruce Cooke, general manager of Linatex Europe. The company, he noted, is a major player in the sand and gravel production industry but a minor player in other markets.

According to Cooke, the limited range of pump sizes and types in its portfolio - particularly the lack of metal pumps - meant Linatex could not offer the complete contract bids, as required increasingly by end-users. Metal pumps, he added, represent around 75% of the slurry pumps market.

In response, the company started a collaboration with a small UK company to market its hard metal pumps within the Linatex product range. The G4 rubber pump was then developed to complement the hard metal unit, with both offerings utilising a shared drive frame.
Slurry pump applications can be divided into two main groups of mineral extraction. Those that are found particularly in hard rock mining, and which are major users of spares, and industrial processes, which are highly fragmented with numerous applications and with sales generally handled through distributors.

Mineral extraction and treatment applications

• Aggregates
• Metals - milling, beneficiation, tailings disposal
• Coal washing
• China clay refining
• Potash
• Brines

Industrial applications

• Ceramics - clay slips
• Coal power generation - ash handling
• Building block manufacture
• Vegetable washing
• Aggregate recycling
• Scrap metal separation
• Flue gas desulphurisation
• Sugar