FLSmidth delivers breakthrough technology in thickeners to iron ore project in Western Australia

The first of its kind in Western Australia, the Sino Iron project is a large-scale magnetite iron ore mining and processing operation. Considered highly-technical and requiring significant processing and transport infrastructure, the project will, under full operating conditions, produce some 27 million tonnes of magnetite pellets and concentrate per year.

The eight thickeners, designed by solids/liquid separation specialists FLSmidth Minerals, have been developed to accommodate the unique requirements of magnetite processing. Additionally, the four tailings thickeners are introducing a new feed delivery system which will enhance mixing and markedly improve the quality of output.

The design and delivery of the eight thickeners is a joint venture between FLSmidth offices in Australia and China. The company’s Western Australian office will supply the drive, lift and hydraulics for each cell with the mechanism, bridge and feed system coming from China.

New technology within the feed system
The overall operational plan for the project includes two concentrate thickeners (delivering 72% solids) and two high-rate tailings thickeners (64% solids) at the on-site processing plant, two high-density tailings thickeners (72% solids) at the disposal site and, at the port processing facility, twenty-five kilometres away, two more concentrate thickeners (delivering 72% solids).

The four 90m diameter tailings thickeners – each processing some 25,000m3 per hour – will be equal to the largest diameter thickeners ever built in Australia. They are based on the proven FLSmidth owned Eimco thickener and E-Duc feed system but include new technology in the feed system to maximise the mixing potential of the slurry and flocculant to deliver greater efficiency for output processing downstream.

High productivity and smaller footprint
Developed by FLSmidth design engineers in Australia following extensive CFD (Computational Fluid Dynamics) modelling of low aspect ratio feed wells by the CSIRO (Commonwealth Scientific & Industrial Research Organisation), the revolutionary feed system ‘barrel rolls’ the combined slurry/flocculant feed as it is introduced into the thickener tank to enhance mixing and retention in the feed well.

Engineered for high productivity, the giant tailings thickeners are fitted with four rake arms and feature 4.5m high walls to aid compression. When fully operational, they will each process some 4,300 tph (tonnes per hour).

At both the mine site and the port facility, the concentrate thickeners have been elevated to meet site and environmental requirements. Apart from a considerably smaller footprint than tanks of a similar size installed at ground level, elevated tanks will improve access to the underflow pumps and associated equipment. With a ground level tank, such equipment would be housed in and accessed through a series of tunnels and trenches.

These ‘bridge’ type concentrate thickeners are fitted with industry-proven FLSmidth owned Eimco gearboxes and the bridge structures have been designed to accommodate a range of extra services including lighting and pipe work.