Hi zerodark30, I'll let SG's own words answer your question:Tell...

Hi zerodark30, I'll let SG's own words answer your question:

Tell us about the Direct Nickel process.
“Direct Nickel (or DNi) was invented by a guy in the US who sold the licence to a former ASX-listed company called Direct Nickel,” Grocott says.“That company and the CSIRO spent ~$30m developing and piloting DNi. In 2011 they did something like 19 pilot plant runs [a smaller version of the real thing] in Perth at whopping great facility.
“I’ve never seen anything piloted so extensively.“They tried to commercialise it, and they got close, but it never went ahead.“The reason is because there was only really one market for nickel back then – stainless steel.“In the 2000s, China developed something called nickel pig iron (NPI) which remains the cheap way to get nickel into stainless steel. When poor old Direct Nickel were trying to commercialise their process, the only market was stainless steel effectively and they were competing with low cost NPI.“But timing is everything. Battery sector demand is now emerging, and to go from NPI to battery nickel is not economical.“NPI is 14 % nickel, 86% iron — if you want nickel for the battery market you need 99.995% purity nickel sulphate.“The advantage of HPAL and DNi is that you can go straight through to battery grade nickel sulphate. NPI can’t.“The market has changed, and we aren’t competing with NPI anymore.”

How does DNI compare with HPAL?
HPAL doesn’t have a very successful track record so far.“Only two of the dozen HPAL projects in the world have been successful. All of the others have been abject failures,” Grocott says.“HPAL is difficult to get right.“While HPAL plants use sulfuric acid, which is cheap, the plants are capital intensive, they are difficult to operate. And we can only build them as whopping great units.“DNi is easier to scale up.“It also uses nitric acid which is the far superior acid. DNi process recycles more than 98% of the nitric acid back, which would be too expensive to use otherwise.“And as a side effect of recovering all that nitric acid you produce all these by-products – high grade iron ore, magnesium and aluminium, which we will convert to high purity alumina.“Anything you don’t get out of the ore is silica, which is about 15% to 20% of the ore mass.“Everything else ends up as a saleable product as a by-product of the process.”

-Taken from a $t0ckhead interview.