Gold will not be dissolved in nitric acid alone, nitric acid will not hold gold, gold will dissolve in an acidic solution of hydrochloric acid and nitric acid, forming gold chloride, gold chloride will stay in a solution of nitric and an chloride solution, until the nitric is removed from the gold chloride solution, and some other chemical reaction is used to precipitate or replace the gold from solution.
To learn to recover and refine gold there is no need for a $500-dollar kit of fertilizer sold as a proprietary chemical, the solutionto your problem is free and only takes a little studying.
Hoke's book, and reading the forum, you will learn more than the folks who sell that kit of fertilizer to uneducated people trying to get gold,.
You will learn secrets unrevealed to people before this forum was formed.
Taking cnbarr's advice will get you started in the right direction.
You have some work to do in educating yourself before trying to use acids to recover and refine valuable metals, like protecting your health, and the health of others, understanding proper procedures for the materials you are working with, how to deal with the toxic waste you generate safely, getting an understanding of the reactions involved, so that you are not just wasting your time dissolving and losing your valuable metals.
Welcome to the forum