Aggressive Sludge Treatment

Aggressive gold sludge: special pump technology delivers long service life without the addition of water

Global demand for gold and silver remains as high as ever. Precious metals are not only sought after by investors, but are indispensable materials in modern industry.       

 

Look behind the scenes

The mixture must first be condensed and concentrated, therefore the water content of the gold slurry should ideally not exceed 40 percent. In the past, centrifugal pumps were typically used in the mining industry for this conveying step, although centrifugal pumps are in fact designed for fluids and therefore require a medium that contains at least 50 percent water. Additional water was hence injected to operate these pumps, accepting the drawback that the added water made subsequent extraction more difficult and costly.

 

Challenge accepted

In search of alternatives, a pump from another producer was installed in a mining region on a trial basis. However, the pump housing was completely destroyed within just two days. The high abrasiveness of the gold sludge was to blame. The stone particles in the sludge behave like sandpaper, particularly at high speeds, and wear away all surfaces extremely quickly – until the system fails completely.    

 

Excellently solved

This effect can only be reduced by particularly smooth pumping at an economically viable volume, as further tests with a NEMO® progressing cavity pump demonstrated. To achieve a system with as long a service life as possible, despite heavy wear, the designers at NETZSCH selected tungsten carbide for the rotor. Tungsten carbide, with a scratch hardness of 9.5 on the Mohs scale, is almost as hard as diamond and is therefore scarcely affected by the grinding of the crushed stone. SBE, a nitrile material, was used for the stator. It is similarly extremely wear resistant, but also soft enough to prevent the points of contact with the rotor from wearing out too quickly. The progressing cavity pumps are also low power consumers and are easy to clean and maintain, which in turn reduces operating and maintenance costs. However, it is the durability of the pumps which is decisive when it comes to conveying gold. In the first test, the pump ran for three months without damage to the stator or rotor. The mine operator has since installed further three NEMO® pumps with an average service life of approximately 3.5 months. The service life exceeds the life cycle of earlier centrifugal pumps, which were completely worn out after three months, despite the addition of water.

Technical Data

Building Materials

To meet the needs of the construction materials production industry, NEMO® Progressing Cavity Pumps and be customized to your individual application – from plain water, to highly viscous spackling compounds with solid content. NEMO® Pumps and TORNADO® Rotary Lobe Pumps are already widespread in this industry because they are capable of efficiently handling a wide range of substances with precise metering.

You’ve got the application – NETZSCH has the optimal solution.

NEMO® SY conveying coal slurry with solid content

Products

NEMO® SY Industrial Construction in Bearing Housing Design with Free Shaft Extension

The NEMO® SY Progressing Cavity Pump is used for demanding applications in every branch of industry worldwide. Bearing block with free shaft extension design pump can be run with any type of drive, such as servo motors, diesel motors or hydraulic drives.

NEMO® BY

NEMO® BY Progressing Cavity Pumps can be used in industrial markets where a great variety of substances must be pumped or very precisely metered.

NEMO® C.Pro®

The NEMO® C.Pro® Metering Pump is a fully synthetic pump for the precise metering of a great variety of chemicals in environmental and chemical industries. Its synthetic construction makes it perfectly suited for the gentle and low-pulsation handling and metering of aggressive or non-aggressive chemicals.

TORNADO® Industrial Rotary Lobe Pumps T2

NETZSCH TORNADO® industrial rotary lobe pumps are versatile stand-alone equipment. Used primarily in environmental technology and the chemical industry, these pumps handle almost any substance continuously and gently while metering in proportion to rotation speed.


Literature