The industrial importance of Iron Sulphate and Lead Chromate?

Question

Why are they important for industry and how are they produced in industry, this is part of my science coursework, any explanation or useful sites will be really helpful, thanks

Answer 1

iron sulfate:
http://en.wikipedia.org/wiki/Iron(II)_sulfate
lead chromate-apparently used in pigments. also coatings (plating) for steel. Found a lot of links to studies of carcinogenic properties.Can be produced by electrochemical methods: http://www.springerlink.com/content/k8q5k574q200t638/