CA3069 works with an RTD and directly drives a triac in ZVC mode. You set the input level with an analogue voltage generated by your 8052.

But an RTD isn't going to work well at 650 deg C, you need to use a thermocouple (type K will work), then use one of the Analog devices TC chips to drive a 3069.

Not an 8052 job, unless you need to see the temperature somehow.
Steve