or centrifugation where the precipitating agent is the chloride i e co nh 3 6 cl 3 or cr nh 3 6 cl 3 the bismuth will precipitate as co nh 3 6 bicl 6 and cr nh 3 6 bicl 6 the precipitate may then be washed preferably with an aqueous acidic chloride solution so as to reduce solubility losses and treated with a water soluble base or salt to decompose the precipitate to the corresponding water insoluble bismuth product and the water soluble m nh 3 6 3 salt wherein m is co or cr this decomposition is generally conducted at a temperature of about 20 u00b0 130 u00b0 c preferably 60 u00b0 80 u00b0 c when the decomposition is effected using a water soluble base the washed precipitate e g co nh 3 6 bicl 6 is slurried in water and treated with lime caustic soda ammonia or any other soluble base capable of effecting the conversions alternatively the decomposition of the precipitate may be effected using other water soluble salts such as carbonates phosphates silicates or borates capable of decomposing co nh 3 6 bi salts and cr nh 3 6 bi salts to an insoluble bismuth product and soluble co nh 3 6 3 salts and or cr nh 3 6 3 salts respectively if copper is present in the insoluble bismuth product obtained after decomposition the copper can be dissolved by adding ammonium hydroxide the following examples are included to further illustrate the present invention one liter of chloride leach solution containing in g l cu 25 fe 90 zn 2.