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UTILIZATION OF FINE LATERITIC ORES AND FILTERS DUSTS IN THE PRODUCTION OF FERRONICKEL

Objective

The object of the project is to improve the economical and environmental conditions of ferronickel production.
Research was carried out into the production of ferronickel from Greek nickel ores in order to establish:
a new procedure for a more economic, energy saving, and environmentally favourable method for dust treatment;
a technique for a direct treatment of the ore fines.

Residue agglomeration by sintering technology was studied and the fluidized bed reduction technique was investigated for the direct treatment of nickeliferous fine particles.

Work carried out on sintering technology included:
studies on and prediction of the influence of the raw materials on the main process parameters;
briquetting tests;
studies of the process variables in laboratory sintering tests;
pilot scale tests in a sinterband installation;
studies of the smelting behaviour of sinter lumps in a laboratory scale electric reduction furnace.

Work on the fluidized bed reduction included:
analysis of the raw materials and comparison to other ores;
investigation of the decomposition and reduction behaviour of the material;
briquetting tests.

It has been shown that sintering is a feasible agglomeration and recycling process for ferronickel production from nickeliferous waste raw material. The feasibility of reduction of fine nickeliferous ores in a fluidized bed reactor has been confirmed.
The project structure is as follows.

Part A involves the agglomeration and prereduction of: dust and sludges produced daily by the treatment of nickeliferous ore in rotary kilns (400 tons/day); and 1 000 000 tons of already stockpiled dust and sludges. The sintered material will be recycled in the electric furnaces.

Part B involves reduction of lateritic ferronickel ore, in the presence of fine grained carbon, in a fluidized bed as an alternative to the rotary kiln furnace to avoid dust emission and to reduce energy consumption.

Part A involves the following:
dismantling of the sintering plant in Frankfurt, transport and installation at Larymna plant and commissioning of the pilot plant;
sinter production with pilot sintering plant in 3 periods of experiments by using different mixtures of ore and dust;
meltdown tests with product sinter in the electric reduction furnace in one set of experiments;
and results interpretation and conclusion, feasibility study.

Part B involves the following stages.
Transport of the ferronickel ore and carbon to Aachen.
Analysis, scientific description of the burden material, test planning and examination of the reduction process.
Design of experiments for reduction of lateritic ferronickel ores in a fluidized bed plant. Reequipping of the present plant, visual fluidized bed in a Technikum (large laboratory) scale. Experiments for approaching and performing the production of prereduced ferronickel to burden it into the electric reduction furnace(ERF) Technikum scale, analysis of the products. Experiments are also planned in a fluidized bed by LURGI for one week to collect some data on an industrial scale.
Design of a test programme for the melting down of prereduced ferronickel from the fluidized bed in the electric reduction furnace, reequipping of an existing electric reduction furnace on a technical scale. Milestones and test results: production of metallic ferronickel from lateritic ferronickel fine grained ore by prereduction in the fluidized bed and melting down in the electric reduction furnace.
Scientific preparation of the know how obtained, devising of feasibility studies, planning of more far reaching test programmes.

Coordinator

General Mining and Metallurgical Company SA 'Larco'
Address
20,Amalias Avenue
10557 Athens
Greece

Participants (3)

LURGI METALLURGIE GMBH
Germany
Address
Lurgi Allee 5
60439 Frankfurt-am-main
Rheinisch-Westfälische Technische Hochschule Aachen (RWTH)
Germany
Address
Intzestraße 1
52072 Aachen
University of Patras
Greece
Address

26110 Patras