Refined Iron Sand is one of the key crafting materials that you will get to acquire in Black Myth Wukong. Upgrading weapons through each tier of rarity requires new materials as you progress through the narrative, and to finally unlock the epic rarity you will need to acquire Refined Sand.
You will start acquiring it once you reach the Pagoda Realm, however, the resource is still going to be quite scarce at this point in the action-adventure. So if you are looking to get your hands on a lot of Refined Sand as soon as possible, here is a guide that tackles just that.
How to get Refined Iron Sand in Black Myth Wukong

Here are some of the ways of acquiring Refined Iron Sand in Black Myth Wukong:
1) Defeat Yaoguai Chiefs in the Pagoda Realm
One of the simplest ways of acquiring the crafting resource as soon as you enter the new area is to defeat the Yaoguai Chiefs. You will obtain the resource as a drop after beating the bosses.
To reach the Pagoda Realm you will need to beat the dragon on the lake in Chapter 3 the area is one of the hardest regions to explore in Black Myth Wukong.
2) Opening rare chests in the Pagoda Realm
Before you reach the Captain Wise-Voice boss encounter you will find atleast three rare wooden chests in the Pagoda Realm that do not need you to open the cells to access them. These will contain Refined Iron Sand.
Additionally, after opening all the cells, you will gain access to more wooden trunk chests that contain the resource as well. However, you will need to open the purple prison doors to gain access to them.

3) Purchase from the Keeper’s Shrine shop
Refined Iron Sand will be much more readily available as you reach the later stages of the game. Especially once you complete a big chunk of Chapter 4, the drop rate for it will go up significantly.
However, another reliable way of getting it will be to purchase it from the Keeper’s Shrine Shop. As soon as you complete the Pagoda Realm you are likely going to find Refined Iron Sand as one of the purchasable resources in Black Myth Wukong.
So if you are running low on the resource you can use some will to purchase it.