Which of the following techniques can extend the working time of a zinc phosphate cement?

Control of Setting Time: Manufacturing process Sintering temperature: Higher the temperature, the more slowly the cement sets. Particle size: Finer particles react more quickly as a greater surface area is exposed to the liquid. Water content of liquid: Presence of excess water accelerates, whereas insufficient water retards the reaction. Buffering agents: When added, slows down the reaction. Factors under control of operator Temperature: Higher temperatures accelerate the reaction. Cooling the mixing slab is an effective way of slowing the reaction and prolonging the working time. Powder-liquid ratio: More the liquid, slower the reaction.  Rate of addition of powder to liquid: The reaction is slower, if the powder is incorporated slowly. Mixing time: Longer the mixing time (within practical limits), the slower is the rate of reaction. Ref: Manappalil P: 90