Mechanical Technology May 2016

⎪ Materials handling and minerals processing ⎪

polyvinyl chloride pipe launders have proved their worth in these arduous ap- plications for many years, significantly outperforming their steel rubber-lined counterparts. Now, chrome producers are taking note of their benefits. This includes Nor tham Chrome Producers, the first chrome miner to put Multotec’s pipe launders to the test, and Multotec’s Graeme Smith reports that the company will shortly be supplying an additional 400 running metres to another undisclosed chrome producer. The pipe launders were supplied as part of a spiral retrofit project at Northam Chrome Producers’ recovery plant. A total of 72 of Multotec’s HX5 and HX3 spirals were designed, manufactured and installed, boosting the plant’s recoveries by as much as 6.0%. The plant was using conventional steel rubber-lined pipe launders that had been designed for the previously installed spirals that were also due for replacement. Smith says that Multotec’s Technology Division discussed the many advantages offered by its pipe launders with the plant’s management team. “We detailed the pro- Siebtechnik Conturbex centrifuge is an important feature, which enables inde- pendent adjustment of the scroll and drum speed. This allows adjustment where extreme process conditions exist and this flexibility enables performance to be optimised. The centrifuge is engineered in such a manner so as to enable easy mainte- nance and one of the features relevant to this is the single bearing overhang design, which allows easy access to the internal rotating components. This saves time, leading to greater cost effectiveness during planned maintenance activities. Another important time saving feature is that cleaning nozzles, strategically positioned within the machine, facilitate cleaning-in-place (CIP) during scheduled maintenance shutdowns. Pointing to applications where Conturbex centrifuges are operating successfully, du Plessis says that in the petrochemical sector these centrifuges replaced pusher centrifuges as part of a de-bottle necking project with the added benefit of less frequent washing requirements. Also in the petrochemical industry, Conturbex centrifuges are used

Two Conturbex centrifuge installations dewatering glaubersalt and mixed salts produced using a ZLD process.

to produce a sodium sulphate by-product from a sulphur effluent stream. Du Plessis says that there are defi- nitely applications where the features of pusher centrifuges will outweigh those of the Conturbex centrifuge, however the ZLD process is not one of these. “We manufacture all types of centrifuges, including pusher centrifuges, and will recommend the correct type of centri-

fuge for the application at hand. Pusher centrifuges are suitable for applications where the need for crystalline purification is essential.” Conturbex centrifuges are also used for water treatment and de-watering of mixed salts, including sodium sulphate in a colliery plant, and in a crystalliser plant de-watering mixed salts at a platinum operation. q

Pipe launders make their way to chrome M ultotec’s pipe launders are well known in the mineral sands and iron-ore mining industries. The posed layout of the launder solutions, and the team really liked our idea of ensuring a more durable and tidier installation that would also be safer and easier to maintain over time,” says Smith.

a smaller outside diameter, Multotec pipe launders are easier to handle and can be installed by two men without the need for any lifting or hanging equipment. The launder pipes supplied to chrome producers have an outside diameter of 200, 255 and 400 mm. Every pipe launder, installed from the collection point leading down to the sump, had to be specially designed and manufactured to fit into the existing footprint of the plant. It may just be that more chrome miners will come to experience and appreciate the benefits of a better pipe launder system, thanks to Multotec. q

One of the biggest benefits offered by the company’s pipe launders is their durability. Smith says some of the company’s instal- lations in the mineral sands production environment have lasted for up to nine years in highly corrosive coastal environments. What is more, they are easy to maintain. Their design incorporates a replaceable polyurethane boot inside the pipe that

endures wear and protects the inside of the pipe. “In arduous ap- plications, such as those found in min- eral sands and iron ore mining, the boots would have to be re- placed about every two to three years,” he says, adding that the boot can be replaced within five minutes. Manufactured from a much lighter material than steel and having

The cleaner concentrate, rougher concentrate and tail pipe launder arrangement, together with Multotec distributors.

Mechanical Technology — May 2016

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