I believe mixing phosphoric acid and Hydrochloric acid, I believe would weaken your HCl, as the phosphoric is a very weak acid compared to HCl, and phosphates are fairly strong bases, both of these acids would remain in solution and both would react with metals involved, although the reaction of these two acids on metals is very different, and I cannot predict what products you would form when both of these are mixed, metal salts would include phosphates and chlorides, the phosphates could become dangerous to breath the fumes if metals were melted later, basically this is not a good idea for what we do.
Do not take chances, get Hoke’s book study it, and study the forum, otherwise your not only wasting your time and values but also others time here on the forum.
quit trying to mix a chemical you have no knowledge about with metals, or mixing two chemicals together if you do not understand what they will do, forget about trying to refine or recover metals until you have done your study, and have an understanding of what you are doing, otherwise it is just careless and foolishness that will get you or others around you hurt or killed, this is not something for some kid to pick up read a post or two and start experimenting, and most young people would be smarter than to try something like that, they would know that chemistry can be dangerous and would have the common sense to know they would need to understand before mixing chemicals that could form deadly gases or explosives without understanding what they are doing, they would know to study and y reaction before trying it studying the dangers and what would form and why, and what dangers the compound or gases formed, what safety equipment they would need to protect themselves and others, and how to properly deal with the solutions or wastes they had made or generated.
Do not be a fool:
Study Hoke's book and the forum before trying anything you do not completely understand.
You need to have patience, study first before trying to recover or refine, otherwise your just wasting your time, values, and your health and others health.