Thank you for asking a very important question. By definition, goods such as iron ore, natural gas, coal etc. are 'Primary' goods. When iron ore is purified in a furnace by burning gas and inputting coke and some other elements and is heated to 1600*C, it becomes steel, a secondary product.
When this steel is again re-heated to produce plates, round or deformed bars, channels, angles etc., these are called tertiary products. Tertiary products require additional labour inputs. So, an economist would say that more values are added to the primary product to make a secondary or tertiary product.
Same can be said of fertilizer. It is a secondary product and natural gas is the primary product. But, the tertiary product is food. If fertilizer is applied to a farmland, so-far without it, the land will produce 5 tons of more food when 1 ton fertilizer is applied under optimum conditions. You have to check the value of 1 ton fertilizer against that of 5 ton of rice. The value will rise by many folds.
So, the govt of BD must find ways to retain the secondary goods for use inside BD. It will greatly enhance our economic strength.