BEIJING, Sept 24 (Reuters) - China's benchmark iron ore futures gained for the second straight session on Friday, rising more than 4% following gains in spot market, though demand for the steelmaking ingredient is expected to stay cool amid environment-related curbs.

The most-traded iron ore futures on the Dalian Commodity Exchange, for January delivery, gained as much as 4.2% to 696 yuan ($107.74) per tonne in morning session. They closed up 2.5% on Friday and gained 8.8% this week.

Spot prices of iron ore with 62% iron content for delivery to China increased $4 to $109 per tonne on Thursday, according to SteelHome consultancy.

However, analysts expect the rebound will not last as iron ore demand is still dampened by production cuts at mills.

"Affected by the autumn-winter environmental protection measures and winter Olympic games, domestic iron ore consumption is hard to increase in short term," analysts with Huatai Futures wrote in a note.

Dalian coking coal futures fell 6.24% to 2,800 yuan per tonne and coke prices plunged 7.6% to 3,198 yuan a tonne.

Steel prices on the Shanghai Futures Exchange also declined.

Construction used rebar slipped 2.8% to 5,468 yuan a tonne.

Hot rolled coils, used in cars and home appliances, fell 2.9% to 5,511 yuan per tonne.

Stainless steel futures, for October delivery, dived 4.7% to 20,945 yuan a tonne.

($1 = 6.4601 Chinese yuan renminbi) (Reporting by Min Zhang and Shivani Singh; Editing by Rashmi Aich)