Industrial Solutions and Services
New flotation cell from Siemens: higher material yield with lower costs
Erlangen, Jul 12, 2007
In the framework of a joint pilot project with the Minera Los Pelambres copper mine, the Siemens Industrial Solutions and Services Group (I&S) and Siemens S.A. Chile have commissioned a newly developed flotation cell for separating ores into their metal and rock components. The intention is that, compared to conventional flotation cells, the new system should feature the special floatability of very fine particulate materials, the possibility of substantially higher concentration, low gas requirements and low power consumption. The flotation cell can be used in cascaded design for separating different metal components in an ore, and in stand-alone mode for increasing the concentration of a specific metal component. With the new method, operating costs and the amount of space needed can be reduced considerably.
Flotation cells are used in open-cast mines to extract the metal components from finely crushed ore which has been made into rock slurry. Together with the Minera Los Pelambres mining company, Siemens is currently testing the flotation cell in the Los Pelambres open-cast mine, which is around 360 kilometers to the north of Santiago de Chile. The cell is being used successfully as an upstream separation unit for the separation of copper and molybdenum in the molybdenum extraction plant.
The Siemens solution combines a so-called pneumatic spray-in principle with a column method. An agitating apparatus as used in conventional cells is not needed. Nitrogen is added to the ore slurry (pulp) in mixing chambers before it goes into the cell. This considerably improves the frequency of contact between the gas bubbles and very fine molybdenum particles as well as the ability of the particles to stick to these bubbles. The resulting mixture is sprayed into the flotation cell. The nitrogen blown in through an internal column in the second stage ensures that the molybdenum particles which were not “captured” in the first stage stick to the gas bubbles and are transported to the surface. The foam concentrate thus produced is taken off over the edge of the flotation tank and drained off. The rock, which still contains a lot of copper, then falls to the floor (as tailings) and is pumped into the copper extraction process.
In contrast to the agitating cells which are usually arranged one after the other in a cascade, the innovative flotation cell consists during the pilot project only of a single cell. In the test phase, in which the Siemens cell is upstream of rough flotation (separation of copper and molybdenum), the objective is to illustrate particularly its ability to turn very fine particles of molybdenum into the target product. In the previous process, this was not done sufficiently. As a result, Minera Los Pelambres can substantially improve the total yield from very fine particles. Moreover, the Siemens flotation cell produces a one to four times higher concentration of molybdenum in the foam product than the existing rough flotation stage, as a result of which the subsequent fine flotation process can be shortened by at least one stage. The Siemens system, which has a nominal capacity margin of 100 to 400 cubic meters per hour of pulp supply with a solid component of up to 48 per cent, is operated with only three pumps and without an agitator. It therefore needs up to 70 per cent less current compared to conventional systems of comparable capacities. Around 60 to 100 cubic meters of nitrogen an hour are needed to operate the cell. This is considerably below the hourly consumption rate of 1000 to 1400 cubic meters associated with conventional systems.
Further information at: http://www.siemens.com/mining
Further information and downloads at: http://www.industry.siemens.com
The Siemens Industrial Solutions and Services Group (I&S) is the integrator of systems and solutions for industrial and infrastructure facilities and global service provider for the plant and projects business covering planning, installation, operation and the entire life cycle. I&S uses its own products and systems and process technologies in order to enhance productivity and improve competitiveness of companies in the sectors of metallurgy, water treatment, pulp and paper, oil and gas, marine engineering, open-cast mining, airport logistics, postal automation, intelligent traffic systems and industrial services. In fiscal 2006 (to September 30) I&S employed a total of 36,200 people worldwide and achieved total sales of EUR 8.819 billion, according to U.S. GAAP.
Reference Number: I&S 0607.6262 e