The process of producing concrete for construction purposes begins with making cement. The first step is the mixing together of limestone and clay which is then crushed by a special machine which produces a fine powder as a result. This then passes through a mixer and a heating tube which rotates as the powder passes through it. This powder is then processed by a grinder which emits very fine powdered cement; it is then bagged.
Concrete is made from a mixture of this fine cement, water, sand and gravel in the ratio of 15%, 10%, 25% and 50% respectively. This combination is mixed together in a concrete mixer and the final product is concrete ready to use in construction.
Cement production requires fewer ingredients than concrete, but more equipment and there are various different stages to the process whereas concrete is a simpler process involving only the mixing of cement with three other elements.