Cement Production

The question

How to approach this process diagram question

A process diagram shows how something is made or how a cycle works. Describe the stages in order, using sequence language and the passive voice.

1. Say what process the diagram shows and how many stages it has.
2. Overview: the number of stages, where it starts and ends, and whether it is a cycle or a straight line.
3. Describe every stage in order (First, Next, After that, Finally) mostly in the passive: the grain is crushed.
4. Do not add opinions or explain why; describe what happens.

How to plan this answer

Structure

1. Overview: state that cement is produced in eight stages, starting with quarrying and ending with packing, and note the two-row layout.
2. Paragraph 2: describe the first four stages in order (quarrying, crushing, mixing and grinding), with the excavator and the crusher as the physical actions.
3. Paragraph 3: describe the remaining four stages (kiln, cooling, final grinding and packing), including the move from the top row to the bottom row.
4. Do not add an opinion or a conclusion paragraph; a closing sentence restating the start and end is enough.

Key features to spot

• Stage 1 is a quarry, where an excavator digs raw material from a rock face, so the process begins with extraction rather than manufacturing.
• Stage 2 uses a crusher with two large rollers to break the rock into smaller pieces, which are then dropped onto a conveyor or pile.
• Stage 3 is mixing, shown as a tall silo that holds two different powdered materials, which are combined inside it.
• Stage 4 is grinding in a rotating drum mill, and stage 5 is a long, inclined kiln heated by a fire at one end.
• Stage 6 is cooling on a bed with upward airflow, and stage 7 is a second, smaller grinding drum that produces the final powder.
• The process ends with stage 8, where the cement is poured into a hopper and filled into sacks on a conveyor belt.

Useful vocabulary

• is extracted from: The raw rock is extracted from a quarry before it is crushed.
• is fed into: The crushed material is fed into a mixing silo.
• is subsequently ground: The mixture is subsequently ground in a rotating drum.
• is heated in: The powder is heated in a long rotating kiln.
• is left to cool: After heating, the material is left to cool on a bed of grates.
• is then ground again: The cooled material is then ground again to a fine powder.
• is filled into sacks: The finished cement is filled into sacks at the packing stage.
• is followed by: Crushing is followed by mixing, which takes place in a silo.
• once ... has been: Once the rock has been crushed, it is moved to the mixing silo.
• the final stage involves: The final stage involves filling and sealing the bags for transport.

Common mistakes

• Describing the process as starting at the mixing silo because it is the first large object seen in the top row; the diagram starts at the quarry.
• Confusing the two grinding stages and describing only one of them, so the final grinding step is missing from the account.
• Treating the two rows as separate processes instead of one sequence that continues from stage 4 down to stage 5.
• Using the active voice throughout (for example, the workers crush the rock), when the task asks for passive forms where suitable.
• Adding a view on the environmental impact of cement production, which the task explicitly forbids.

Examiner tip: Name the first and last stages in your overview and check that the eight stages appear in the same order as the numbers in the diagram.