Assaying at 90 grams per kilo is very good material, that converts to 1.3 ounces per pound here in the US. Back in the day when all of the jewelry manufacturing was here in the US that kind of assay was considered very high yield material.
The difference between light soda ash and dense soda ash is the density of actual sodium carbonate per unit of volume. The dense, as the name implies, is more dense so a scoop of dense contains more sodium carbonate than the same size scoop of light soda ash. Using weight in your flux makeup will make both the same in the end. Like they used to say "What weighs more a pound of lead or a pound of feathers?"
The extra 4.6% of the gold you did not recover as per your assay will likely come out by remelting the slags. All refiners using this process have a slag remelt day.
It is interesting to read that Harold used water to make his sweep flux mixture into bricks and then waited for them to dry. The flame hitting directly on the charge does blow off any loose fines and wetting them is a unique way of preventing this. Harold has posted a picture of his reverberatory furnace and it is a beautiful thing I might add.
I also melted large quantities of sweeps but prevented the dust by pelletizing the material in a pellet press after the flux and charge were mixed but I melted larger quantities and the furnace rotated as it heated. But we were adding the equivalent of 2, 55 gallon drums of sweeps flux mixture per day to keep up with the sweeps we had to process.
Legend in Sparks Nevada may ship you a bag of flourspar http://www.lmine.com/product/17120-50.html you should check. I cannot say it too often, it is a necessary component for recovery.
The difference between light soda ash and dense soda ash is the density of actual sodium carbonate per unit of volume. The dense, as the name implies, is more dense so a scoop of dense contains more sodium carbonate than the same size scoop of light soda ash. Using weight in your flux makeup will make both the same in the end. Like they used to say "What weighs more a pound of lead or a pound of feathers?"
The extra 4.6% of the gold you did not recover as per your assay will likely come out by remelting the slags. All refiners using this process have a slag remelt day.
It is interesting to read that Harold used water to make his sweep flux mixture into bricks and then waited for them to dry. The flame hitting directly on the charge does blow off any loose fines and wetting them is a unique way of preventing this. Harold has posted a picture of his reverberatory furnace and it is a beautiful thing I might add.
I also melted large quantities of sweeps but prevented the dust by pelletizing the material in a pellet press after the flux and charge were mixed but I melted larger quantities and the furnace rotated as it heated. But we were adding the equivalent of 2, 55 gallon drums of sweeps flux mixture per day to keep up with the sweeps we had to process.
Legend in Sparks Nevada may ship you a bag of flourspar http://www.lmine.com/product/17120-50.html you should check. I cannot say it too often, it is a necessary component for recovery.
