Hydrocyclone boosts coal plant performance

A colliery in Mpumalanga is said to have achieved improved yields and production throughput with the installation of a new hydrocyclone.

The opencast coal mine was looking to improve the performance of its dense media separation (DMS) circuit in its wash plant 1. The existing 610 mm cyclone, installed during the mine’s initial design phase, had an operational life of only six months between refurbishments and a site audit revealed that the existing cyclone was operating inefficiently.

A wash-ability analysis showed that an improved yield could be achieved using new hydrocyclone technology on the DMS circuit. The customer specified that product was required to offer improved separation efficiency, increase wear life and match the existing cyclone footprint.

Following a proposal that included dense media (DM) hydrocyclone simulations, a Cavex 500CVXT20 DM hydrocyclone was installed at Yoctolux Collieries in Mpumalanga in August 2017. To date, the hydrocyclone is said to have achieved higher separation efficiency through an average 15% yield increase. It has achieved an overall average of 75% yield for both of the mine’s coal types – grains and peas. This compares favourably to the 65% achieved previously by the competitor’s cyclone.

Manufactured from mild steel, the hydrocyclone from Weir Minerals Africa is lined with 25 mm slip-casted radius ceramic tiles manufactured with 92% alumina content.

The mine reports a 49% throughput increase in production tonnage, from 78 t/h to 116 t/h as a result of the reduced turbulence in the hydrocyclone’s design. An improvement in wear life has also been noted, with the new hydrocyclone requiring only a spigot replacement after nine months.

The colliery placed an order for an additional Cavex 500CVXT20 DM hydrocyclone in May 2018, to replace the existing cyclone on wash plant 2.