A mixture contains two or more substances
which have not reacted chemically with each other. A mixture is made of little bits of each substance mixed together. A mixture can be separated by physical methods, a compound can not.
Since they are a mixture, they can be separated by simple physical methods. Using a magnet (of any kind), the black or dark grey iron, can be separated from the yellow coloured sulphur. This is because, a mixture of iron filings and sulphur can be separated by using a magnet to attract the iron. Iron is a magnetic material but sulphur is not.