I have no knowledge in chemistry. I am looking for information about etching circuit boards with citric acid instead of hydrochloric acid because it seems it could be a safer, easier way as citric acid is way safer to handle and not that toxic and harmful.
I am struggling to find much information online about the process since it is not as popular as other etchants.
It seems to work really well if I mix 100ml of 3% hydrogen peroxide solution in water with quite a lot of citric acid powder(4-6 teaspoons) and a bit of salt(around 1 teaspoon), heat everything in a microwave oven to a warmer temperature(not boiling, around 70-80° C) so everything dissolves and then while it's still warm I put the copper clad in it and this seems to work just as good as hydrochloric acid and hydrogen peroxide in room temperature - etches 10x15cm PCB in 15-20 minutes.
I have done it a few times in well ventilated room, but I have no knowledge about what exactly happens in the reaction and if it is dangerous in any way, so I would like some insight into what exactly might be happening, what materials are produced and how safe/toxic they are.