I need to know a few online marketplaces where businesses can sell industrial goods.
There are quite some marketplaces online like industrykart or Tolexo. Also I believe Indiamart also have a section of Industry goods. You may try exploring them. Depending on what you buy or sell you may try some relevant blogs and try doing affiliate programs with them via hosting the products on your own website, if you are able to crack this, you may create a marketplace of your own!