When a hero goes to the market, should be the deck shuffled each time?

I do not know how must I say it in english, **** it... We put the cards on the bottom of the deck when we discard a treasure, or when we do not purchase any treasure of the market, ... And we never shuffle the deck.

Are we playing correctly?

The treasure deck is shuffled at the end of each game week, so sold or discarded or destroyed treasures are not available in the current week, but again in the next one.

Thank you. Could you tell me where is the answer in the book?

EDIT: I found it.

So, when a hero lose a weapon, is it discarded and sent back to the deck? Or should it be removed until the next week?

It goes to the discard pile and is shuffled back in the deck in the next week.