Having thought about this overnight, I get the impression that you may not be the DIY type and you may prefer to buy manufactured equipment to do this type of work in. So let me speculate further.
A kilo of gold scrap to be refined needs to be melted and poured into shot to give you both a homogeneous mixture (to negate the effect of potentially higher Silver content on some pieces) and to provide more surface area. A kilo of gold alloy will dissolve in about 4.25 liters of aqua regia, this can safely be handled in a 10 liter beaker and give you plenty of room for a rise in the reaction to prevent spills.
This size processing can easily be carried out in off the shelf glassware. They do make 20 liter beakers as well which can handle close to 3 kilo's at a time but at that size, and the shape of a cylindrical beaker make it harder to handle for pouring and filtering.
There are companies like Italimpianti in Italy that make equipment to handle lots as small as 100 ounces or less but personally I think beakers are the best way to handle this type of processing. Plus there are reactors that can easily handle lots as large as 300 ounces which will integrate easily into a single or double hood arrangement and accommodate future growth. This
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is a photo of one of the smaller tumbler plants Italimpianti makes. It will not make 9999 gold in a single pass and I think it will limit your ability to handle special types of processing you will encounter.
The special lots I mentioned are processing dental scrap or chemical stone removal. You will accumulate in your purchases goods that have diamonds and precious gems in them. These are best handled in a beaker or small reactor. The last thing we want to do when setting you up is limit your capabilities down the road.
To give you a sampling of a professionally fabricated refinery doing essentially what you want to do, you can look at this
thread. He is also doing fire assays which, at this point, you are not looking to get into. You can also go the DIY route and there are threads in this search
which will help you decide on a fume scrubber and this
search which concentrates on hoods.
Getting a good exhaust hood and a decent vacuum are necessary for you to begin processing. Honestly, with karat gold we can walk you through that process step by step once you are set up to handle the material safely.
Do you expect to buy scrap from small buyers who host gold buying parties? If you do, you will need a capability to melt the goods they bring you and buy them outright based on your XRF. This has to figure in to your setup plans as well.