Fang Chen has been trying to focus on repairing the damaged spirit weapon. He has been trying to successfully refine a newly formed ore but he was unsuccessful because the beast core required for the spirit weapon was lot harder to control so the 1st attempt was unsuccessful.
It was good that he didn't use the spirit weapon otherwise it would have been destroyed like the beast core and ore has been destroyed. Since he has same type of core and so he can try once again from the beginning.
He was able to purify the ore with the hammer technique and now it was time to use the beast core to purify the ore so after the heating the purified ore he started to temper the ore with the beast core this time he was moving very meticulously and slowly so each step was very very harder.