To give an idea of the size of the merged entity, it had combined sales of €3.9 ($A6.3) billion. Add in Metso's recently acquisition of Canadian mobile screening and crushing maker McCloskey and that goes up to €4.2 billion.

The combined Metso Outotec business will have 15,630 employees representing 100 nationalities.

It will have the ability to provide an end-to-end offering in minerals processing with breadth across minerals, metals and aggregates, geography and application.

The company will have a portfolio of products in community, beneficiation and metals refining as well and aggregates.

It should also have a stronger research and development capability.

Arguably the group's largest competitor FLSmidth reported sales of €2.5 billion for 2018.

Metso's Flow Control business will become a listed entity called Neles.

The deal is expected to be completed in the second quarter of 2020.

Metso Outotec is expected to achieve annual pre-tax cost synergies of €100 million and run-rate annual synergies of €150 million.

The company will be headquartered in Helsinki, Finland and Metso CEO Pekka Vauramo will become CEO of Metso Outotec.

Outotec chairman Matti Alahuhta called the deal an industry-shaping combination.

"It builds on Outotec's leading technology competencies and Metso's excellent service capabilities," he said.

"Metso Outotec's global operating network, scale, wide technology and service offerings, and sustainable development principles will unlock significant benefits for all stakeholders."

On the Neles spinoff, Metso chairman Mikael Lilius said he believed it was the right time to create a focused standalone flow control company.

He said Neles was expected to trade in line with its flow control peers.