Hindustan Zinc said it has raised Rs 3,520 crore through issuance of non-convertible debentures (NCDs).”The issuer approved the allotment of 35,200 rated, listed, unsecured, redeemable, NCDs bearing a face value of Rs 10,00,000 each, aggregating to Rs 35,20,00,00,000 on private placement basis (’Issue’) by Hindustan Zinc,” the company said in a filing to BSE.