Pure Rhodium

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arthur kierski
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Pure Rhodium

Post by arthur kierski » October 13th, 2018, 7:01 pm

I need pure rhodium to make plating solutioons--- i obtain rh from copper wires plated with gold and rh over it-or plated with silver and rh over it-----when i obtain these rh flakes mixed with gold flakes,i put these flakes in ar---the gold goes to solution and the rh flakes stay as rh----the gold solution is not transparent,and i suspected ,that lead chloride was present---i added h2so4 to the gold solution and it became translucid ,with lead sulphate precipitated(yellow powder)--then the usual metabisulfite to precipitate the gold----Where this lead impurity appeared from??>the rh plated with silver underneath,i add hcl,and precipitate silver chloride --then i clean the rh flakes with hot water and or nh4oh to clean for lead,and nh40h to dissolve any silver chloride left behind in the flakes----is there another way to separate rhe gold from rhodium? is there another way to separate the silver (as a chloride ,from the rh? i think that i do a good work,but i suspect that is not so good---and from where the lead appears in the rh plated wires? i do the first attacck on the wire with nitric acid(sometimes,twice nitric acid----- please ,pardom me if you did not understand this thread----my english is not native----but the idea,is what i wrote------In resume,how to obtain pure rhodium from rh plated wires?
Arthur

nickvc
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Re: Pure Rhodium

Post by nickvc » October 14th, 2018, 4:46 am

Arthur after you have removed the copper with nitric could you then rinse the remainder off and then dissolve the gold using cyanide, if there’s any copper remaining it should dissolve that as well , it should work well as it’s only thinly plated I’m guessing and the cyanide won’t affect the rhodium so hopefully leaving pure rhodium to work with.

Platdigger
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Re: Pure Rhodium

Post by Platdigger » October 14th, 2018, 7:03 am

I thought lead sulfate was white.

arthur kierski
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Joined: February 10th, 2008, 8:04 am
Location: são paulo---brazil

Re: Pure Rhodium

Post by arthur kierski » October 14th, 2018, 8:19 am

Platdigger,i was missing you in my threads ,welcome back----you sent me a private message but cancelled it,before i read it--------Well,the use of cianide to eliminate the gold is a great idea----but the gold issue and the silver issue is not so important,because as i wrote : and after the nitric,i add hcl,and if silver is present ,forms silver chloride which is filtrated out--the gold is eliminated by ar----my problem is seeing in the ar,lead(which i eliminate with h2so4)---i filtrate this lead ,which i suppose is lead chloride,after the addition of h2so4,becomes insoluble lead sulphate ----strange but it is a yellow powder-----now ,what really preocupies me is the rh flakes---i suspect that after dissolving the rh plated wire,with nitric---metals as lead,copper and perhaps others metals,remains inside(embedded) in the flakes-----And when i use the rh to make rh plating solutions,these metallics affects the quality of my plating soltution----after ,writing the first thread,and waiting for replies,a though came into my mind---incinerate the rh flakes and then use hcl to dissolve the metals oxides out------thanks for your ideas and sugestions----your friend
Arthur Kierski

Platdigger
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Re: Pure Rhodium

Post by Platdigger » October 14th, 2018, 8:30 am

Once you have these flakes, if need be, there are ways to purify the rh.

arthur kierski
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Posts: 1036
Joined: February 10th, 2008, 8:04 am
Location: são paulo---brazil

Re: Pure Rhodium

Post by arthur kierski » October 14th, 2018, 11:31 am

please remind me of some ways----i stopped working for five yearas now ,and needs to be reminded---i reminded myself of some Harolds advise on incinerations---

Arthur Kierski


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