Purchasing chrome ore, chrome concentrate

We would like to purchase chromium ore and concentrate.
Our company is buying from the European Union countries (Poland, Czech Republic, Romania and possibly Ukraine).
Interested to start by buying small quantities of chromium concentrate in Big Bags by road freight.
The amount of silicon oxide and the amount of chromium oxide in the concentrate is important to us.
Please indicate detailed quality characteristics of the goods, current quality certificates and prices on delivery terms «Ex Works» (“EXW” - from the seller’s warehouse).