would you mind if evaluate my writing task1

[alirester]

the attached picture is about writing task 1 and here is my writing task 1:

Two flow charts illustrate the processes cement and concrete are produced. there are some stages that cement is made from limestone and clay and after that can be used to make concrete.
Cement is one of most important materials that is used in building industry. Its two main ingredients are limestone and clay. As it can be seen, they are crushed together, then mixed into a mixer and conveyed toward a rotating heater. after they hit up, by conveyor belt get into grinder to get smaller. in this stage cement is ready to be packed and used for building purposes.
Preparing concrete from cement has a few stages. first, cement should be mixed with water, sand and small stones in special ratio, as the cement ratio should be 15% and other ingredients respectively are 10%, 25% and 5%. at the last stage, all of them are mixed together in a rotating large bowl is named concrete mixer so that concrete becomes ready.
finally prepared concrete can be transported for end users in builing industry.