The primary problem with industry in a desert environment is that of resources. Obviously, there are many valuable ores that can be harvested, some as simply as shovelling up a wagonload of sand, others may require some pickwork before the shovelling can start. However, that is the least part of the problem.
The primary problem is maintaining a sufficiently large workforce. We have an environment with precious little food or water, so much of these would have to be either carefully husbanded, or imported. Fortunately, there are all these valuable ores lying around, and hopefully, trading partners. This kingdom would most likely be trading metal ingots, or preferably value-added metal goods (this is very important! Never sell off your ores when you can sell jewellery instead, unlike some idiot nations that I wont mention but live in - have a mass-based export duty) that can bring in more money and employ more people, for foodstuffs and livestock.
The secondary problem is energy. Transporting and processing ores requires energy. Much of it could be muscle power (human or animal), fuelled by food, but heat will be required. While often hot, no desert is that hot, so some other heat source may be required. Since a solar furnace is probably out of the question, we would require some sort of fuel. Fortunately, there may be carbon/coal sands that could come to the rescue (those being capable of being described as an ore), so they could be burned for fuel as well as being an oxygen sink in a process such as iron ore refining.
The third problem is building materials. While you may have lots of metals, they can be expensive to work, and stone and wood - if you have it - is easier to work. Expect a lot of stone or brick buildings, since wood would be rare and expensive, and usually imported too.
However, given all these ores lying (or blowing) about, waiting to be picked up, with a bit of ingenuity and effort, a very tidy profit could be made, even with the necessity for imports. I would expect the inhabitants of this region to be very conscious of making the best use of whatever they have (since they have so many scarcities), and they would likely not sell raw metals to outsiders when they could sell finished goods instead. These would likely be clever, disciplined people (since those who were otherwise would be sick or dead from metal toxicity) who would be highly protective of their families and their nation, and would bargain hard at every opportunity.
I can also see that the temptation to be a slave-owning culture would be very strong. Mining some of these ores would be downright dangerous, and the miners might have short lifespans. Criminals and the indigent could be rounded up and made to do these nasty jobs that a decently industrious person would not want to do themselves, which could lead to defeated invaders being enslaved and sent to the mines, and eventually to slaves being imported. In such a case, there would be no beggars. Anyone who could work would work voluntarily, or would be made to work, or if not capable of working and lacking in resources, would starve in short order to the general approval of the populace. There would need to be a fairly powerful cultural counter-pressure to prevent this.