Mag drive pumps solve problems at smelter refinery

Copper is one of the most in-demand minerals in Australia. There are different ways you can extract copper from the mineral ore. The normal way is to break and crush the ore and then finely grind it along with a floatation process.

This concentrate will contain from 25 to 57 per cent copper and is then sent to the smelter for more processing.

Smelting converts the concentrate into a copper metal which involves melting down the concentrate with fluxes in a smelter furnace to create a copper matte.

This is a mix of iron and copper sulphides and other impurities that have up to 70 per cent copper. The molten matte is then sent to a converter and other fluxes are added to create a copper blister which is almost 100 per cent pure. This blister copper is even further refined by electrolysis processes.

The smelting increases the amount of copper in the concentrate which is finally obtained in a pure form in the end process.    

Lots of impurities and particles are contained within the concentrate that comes to the smelter - they need to be pumped to move it from one process to the next.

The pumps usually only pump clean fluids so if there's undissolved solids left in such fluid, it creates a few problems.

The pump can fail and this can mean major downtime for the plant and heavy company losses.

Pumping problem faced by the smelter refinery in Australia

There are a few copper smelting refinery industries in Australia; one had to pump the concentrate that contained the copper sulphate slurry for final production of copper.

These are the strange features of this slurry that the smelter needed to manage:

• There were traces of solids including salt, lead, silica and arsenic.
• The entire solution is very acidic and has the potential to corrode the pump's vital parts. eg the impeller, seals, volute, etc.
• The slurry heats to a temperature between 60 to 80°C.
• The smelter company originally used standard magnetic drive pumps for pumping this very aggressive solution. But a few problems arose including:
• Scales forming on the pump's inside surfaces. The slurry's chemical components had the inherent property to form scales on all the wet parts of the pump including the impeller, volute and critical bearing surfaces.

Because of these formations, the pumps had to be cleaned each week. This extra maintenance problem was costly as it took a couple of hours to de-commission, disassemble, perform the necessary cleaning and parts replacement, reassemble and re-commission.

Sometimes the pumps would seize on the shafts and this would result in a costly, major failure of the pump.

Searching for a solution

The smelter refinery's maintenance manager met with the engineering team to talk about the scale problem in the magnetic drive pumps.

Several pumps were looked at and it was decided to trial some alternative pumps. Unfortunately, none of them were able to stop the scales from forming. The problem with the expensive maintenance and replacement of pumps, parts and labour continued.

The company's maintenance personnel were introduced to the Techniflo magnetic drive pumps which are sold and serviced by Global Pumps in Australia.

These pumps are leak free centrifugal pumps that are designed to transport any hazardous or corrosive liquid, including dirty, aggressive and solid-laden liquids.

The pumps are also equipped with non-metallic parts that are highly resistant to corrosion. They never leak because they don't have mechanical seals or gland packing.

Implementation of the solution

The refining smelter company discussed this situation with Global Pumps' engineers. Based on this problem, they suggested that the Techniflo magnetic drive pumps were the best solution because they're designed to manage over 30 per cent slurries without the normal problems of pump failure due to wear and scale.

Here are the findings after these specialised pumps were installed:

• All maintenance issues have been decreased dramatically. The pumps' internal parts are such that scale accumulation happens over a much slower period.
• Previously, the maintenance crew had to clean the pumps each week to get rid of the scale build-up but after installing the Techniflo pump, continuous, efficient operation for up to a period of three months was achieved before any amount of cleaning was needed.  
• The plant operators were pleased with the performance of the Techniflo magnetic drive pumps because there's a decrease in the amount of maintenance downtime.
• The operators reported the pumping capacity of the new pumps on a daily basis and have noted that there has been very little change in performance in that time. This consistent feature enables the company to plan production and maintenance of the plant with better accuracy.