The Multotec HM12 spiral concentrator is engineered to essentially provide multi-stage separation of the slurry feed within a compact footprint that reduces space and ancillary equipment requirements.

Process equipment specialist Multotec has introduced its first 12-turn spiral concentrator.

According to Christina Ramotsabi, general manager-process engineering at Multotec, the HM12 spiral was designed and tested in-house, evolving from the company’s popular NHM heavy minerals spiral. The first order has been manufactured and shipped to an international customer.

“The customer required higher recoveries from their mineral sands plant, while also achieving optimal grades,” said Ramotsabi. “Our HM12 spiral concentrator will deliver these increased recoveries while still maintaining a limited footprint in the plant.”

Conventional spirals generally feature seven or eight turns, she noted. Two stages of these spirals would be required to achieve similar recoveries with one 12-turn spiral. The use of the 12-turn setup reduces footprint requirements as well as the use of additional equipment such as pumps, distributors, and piping. 

The new model, said Multotec, was developed through collaboration between its R&D, process, and engineering teams. Kgabo Mashita, applications engineer at Multotec, said the initial phase of testing used a conventional spiral to generate benchmark results. In the next phases, the feed box was redesigned and evaluated, and re-pulpers were introduced.

“The length of the spiral made it necessary for us to introduce more energy to the slurry mix at certain stages, to renew the separation process,” said Mashita. “We placed re-pulpers strategically on each spiral, to receive and re-energize the slurry, essentially creating a multi-stage separation process.”

He emphasized the critical role of the feed box in optimizing the functioning of the spiral. The improved presentation of the slurry feed allows even and consistent distribution as it enters the spiral. This ensures that more residence time is spent on separation. 

The first units were ordered through Multotec International’s Eurasian division and have been shipped to the customer. A technical team from South Africa will assist in the commissioning and optimization of the equipment.