First from the copper slag, not necessarily pure copper, anything, as long as the copper.
Because it is not copper that melts in the copper water and burns. In order to reach the boiling temperature of copper water, workers in factories pumped extremely high pressure oxygen into the boiler.
Melted copper water (containing some impurities) into the mold. The mold is then cooled to a machinable temperature.
After cooling, the molded die is sent to a giant electrolytic bath to remove impurities. The finished product is such a much cleaner copper.
To make a wire, the copper will be sent to a new workshop and melted again. Melted pure copper water was cooled and pulled into thicker copper strips. Thicker copper strips, when stretched, become thicker lines that meet the requirements.