He dismembered her body, included cutting off her hands and nipples, before he put the pieces in garbage bags and dumped them on a rural property on the NSW south coast.
Justice McCullum expressed her sympathy to the parents of Ms Grant, whose twin sister was murdered in Brisbane in 1991.
The judge found Richardson was partly motivated to cut up the body to remove evidence of injuries inflicted by him.
She noted the jury rejected his claim that Ms Grant, a prostitute who was a heavy user of drugs and alcohol, died when she hit her head on a coffee table after falling during a fight.
Ms Grant died the day before she was due to give evidence against Richardson, who had initially been refused bail after being charged with assaulting her in October 2009.
“The existence of the charge and the impending hearing is relevant to an assessment of the offender’s likely state of mind on the night he killed Ms Grant,” the judge said.
On the night she died, Ms Grant borrowed a mobile phone from a neighbour to call her bank to order a new card as she had lost her purse.
“The recordings of those telephone calls are chilling,” the judge said.
“They reveal that Ms Grant was at times incoherent, angry, frustrated and distressed.
“The offender, by contrast, was calm, politely providing the information required by the bank.”
The judge was satisfied Ms Grant rang the bank under threat from Richardson and “that she was in grave fear of harm at his hands at that time”.
She found Richardson had formed the intention to kill Ms Grant and was forcing her to make the calls so he would have access to her bank account after her death.
The judge set a maximum term of 28 years.