The diagrams below show the stages and equipment used in the cement making process, and how cement is used to produce concrete for building purposes. Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

The diagrams show how

cement

and concrete are produced.

Overall

, there are five stages in the production of

cement

,

while

the procedure for producing concrete from

cement

and a few other simple ingredients

involves

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involve

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a single stage.

Cement

production begins when the initial raw materials, namely limestone and clay, are crushed using two rotating drums to make a fine powder which is

then

mixed in a cylindrical mixer. The next stage involves a tube-like rotating heater with a blowtorch mounted at its bottom opening. The mixed powder is fed from the top and simultaneously heated and blended, after which it is transferred to a grinder using a conveyor belt. There, it is milled to yield the final

cement

product which is eventually packed in bags.

This

cement

is used as raw material in the production of concrete in a second process. An initial mixture comprising 15%

cement

, 10% water, one-quarter

sand

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of sand

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and half

gravel

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of gravel

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is

Correct subject-verb agreement

are

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fed into a rotating concrete mixer where they are stirred until the concrete mix is ready for construction purposes.