"使结晶为砂糖" can be translated into English as "to crystallize into sugar" or, more specifically in a chemical or industrial context, "to cause crystallization to form sugar (sucrose crystals)".
The first phrase is a more general and concise way of expressing the idea, while the second provides additional clarity about the type of sugar (sucrose, which is commonly referred to as "sugar" or "table sugar" in everyday contexts). Depending on the context in which you're using this phrase, you may choose one over the other.