Please give me feedback for my IELTS Task 1: Process

Topic: The diagram shows how plate glass and bottle glass are made.

Paragraph:

The diagram shows the processes by which plate glass and bottle glass are manufactured.

Overall, there are three stages in each process to produce two glass products. Especially, the initial stages of both processes are the same, which means both bottles and plates are made from the same material.

At the first stage of the plate glass process, three types of raw materials, including limestone, sand, and soda, are melted together in a furnace at 1700⁰C until they form molten glass. After that, this mixture flows through piping to a tank. At the bottom of this tank, there is a valve which the molten glass mixture comes out of and then goes through rollers. These rollers perform a function of straightening the glass.

For producing bottles, the molten glass flows into the removable moulds. At the same time, compressed air is pumped into those moulds to force the glass onto the inside walls of the moulds, leaving the rest of it empty. After a cooling process, the mould can be opened, and the final product-the bottle can be taken out.