When producing lime on a lime kiln, there exists the possibility of overburning the original limestone and producing the so-called dead-burnt lime, with a much lower reactivity than quicklime.
Some informal source states that dead-burnt lime is just sintered quicklime: if this is the case, how does sintering affect reactivity, provided the product is milled to the desired granulometry after production?
After calcium carbonate (lime rock) is heated in a kiln to form calcium oxide, it must be slaked (mixed with water) to form calcium hydroxide. This may occur right away in a sugar processing plant, or later for premix concrete. Note that the mined lime rock is never perfectly pure and contains impurities such as silica (the primary component of common beach sand). If the kiln temperature gets above 1300C, impurities in the lime rock such as silica sinter or vitrify and become glass. The glass is intermixed in the structure and greatly reduces the rate at which the calcium oxide can dissolve in water and consequently the over heated lime is termed "dead burnt lime" or "overburned lime". Grinding will certainly help by increasing the surface area and improve the acceptable range of overheating, but the impurities are intermixed at a molecular level and will still reduce the rate of the reaction.
