Patent ID: 6852641

Claim:
A method of spiking a mixed acid liquid in a reactor by using a computer to control a concentration of the mixed acid liquid, the concentration of the mixed acid liquid being controlled at a target level under a based-on-charge mode, a based-on-time mode, or a based-on-time-and-charge mode, the based-on-charge mode control comprising: providing a charge list including a plurality of lot numbers of product and a plurality of spiking amounts of a first acid liquid corresponding lot numbers of product; and introducing the spiking amounts of the first acid into the reactor in an order corresponding to the lot numbers of product; the based-on-time mode control comprising: providing a timing list including a plurality of timing points and a plurality of spiking amounts of a second acid liquid corresponding to the timing points; and introducing the spiking amounts of the second acid liquid into the reactor at the corresponding timing points; and the based-on-time-and-charge mode control comprising: providing a charge/timing list including spiking amounts and spike timing points; and introducing the spiking amounts of the first acid into the reactor based on the lot numbers of product and the spike timing points.