Please review my IELTS task 1

The two figures illustrate the processes by which cement and concrete are manufactured as well as the essential components of facilities employing for these productions.

In the cement fabrication, limestone and clay exploited from natural resources are introduced to a crushing roller to smash it into fine powder. Next, the powder is collected and transported via a closed channel called mixer. At this level, it passed the continously-rotating heater so that the mixed materials are transformed into a unique grayish substance. In the last phase, such a newly hot product goes through the grinder system, cools down to become final cement ready to be packed in bags for distribution.

When making the concrete, three materials consisting of cement, sand, and small stones (gravel) as proportion as 15%, 25%, and 50%, respectively are put into a rotating cylinder-shaped tank called mixer. An amount of water calibrated at 10% of total volume is also poured in the tank. After a couple of time rolling in the mixer, all solid substances are blended to be a sticky mixture. That is ready-to-use concrete.