The two companies have signed a memorandum of understanding to build together "a large-scale maritime mining and phosphate downstream manufacturing business," ICL said in a statement.
LLNP, a Namibian subsidiary of the Leviev Group owned by Israeli diamond dealer Lev Leviev, holds permits and exploration rights to mine phosphate deposits that are estimated to total about one billion tonnes.
Over the next several months, ICL said they would "finalize the technology development required to produce phosphate downstream products from marine deposits, including the establishment of a local industrial pilot plant."
Once complete, the partners will prepare a feasibility study to secure financing for the project.
The plan is to build the plant on Namibia's Atlantic shore, not far from the marine mining site, ICL said.
A nearby port will be used to export goods to North and South America, and a railway line will help reach high-demand areas in Southern and West Africa.
Wealthy backers made up of Omani billionaire Mohammed Al Barwani who has a 85 percent stake in Namibia Marine Phosphate, and Israeli billionaire Lev Leviev , who owns LL Namibia Phosphates, have been lobbying hard for mining permits to be issued.
Leviev's firm according to media reports claims it will invest some N$13.6 billion off Lüderitz to develop phosphate mining, if Namibia's government gives its permission.
The Namibian government issued a moratorium on planned marine phosphate mining off the country's coastal waters until an environmental impact study has shown that mining will not destroy the fishing industry.
LL Namibia Phosphates was granted a license to build a N$289 million demonstration plant in 2013 to prove its case on phosphate mining.
No other country in the world conducts marine phosphate mining.-reuters/observer