There is something wrong with your idea. Domestic zinc price and aluminum price; London zinc price, aluminum price. These four are all variable values. How can we be sure that the domestic zinc price is high?

Shanghai Zinc/Renxin >; Shanghai aluminum/Lun aluminum may be that the price of Shanghai zinc is higher than Shanghai aluminum, or that the price of Lun Xin is lower than Lun aluminum. Both numerator and denominator are not fixed values. I don't know how you can be sure of them. ...