Excerpt from Quantitative Metallurgical Analysis: Selected Methods for Chemical Analysis of Ores, Slags, Coal, Pig Iron and Steel

(c) Add sodium carbonate till a permanent precipitate occurs and then acetic acid until the precipitate dissolves, and heat the solution to boiling. Free mineral acids decompose the iodide of potatssium, therefore no free acid stronger than acetic should be present. The condition is attained by any one of the above methods. Cool the solution to the ordinary temperature, and dilute with water to about 50 c.c. Add 3 grams of potassium iodide and shake gently until the salt dissolves. Titrate the solution immediately with the thiosulphate until the brown color is nearly destroyed. Add 1 or 2 c.c. of starch solution, and continue the titration until the blue color disappears. Calculate the strength of the thioslilphate solution in terms of copper.

Process - Treat one gram of the pulverized ore in a covered casserole, under a hood, with 7 c.c. of concentrated nitric acid and gently heat for a few moments; add five c.c. of concentrated hydrochloric acid and again heat for a short time. Then add five c.c. of concentrated sulphuric acid and evaporate until dense fumes of sulphuric anhydride are evolved. Cool; add 50 c.c. of water and heat until the sulphates of copper, iron, etc., have dissolved. Filter into a small beaker, wash with a little hot water and endeavor to keep the volume of the filtrate down to about 50 or 60 c.c.

Place in the beaker two pieces of aluminium about 1 1/2 inches square, 1/16 inch thick, with the four corners bent for 1/4 inch alternately up and down at right angles. Add five c.c. of concentrated sulphuric acid, cover the beaker and heat to boiling. Boil for eight or ten minutes. Unless the bulk of the solution is excessive, this will generally be sufficient to precipitate all of the copper. Transfer the solution to a flask of 200 to 300 c.c. capacity, rinsing in with hot water, as much of the copper as possible. Allow the copper in the flask to settle and decant the liquid through a filter, wash the copper two or three times, retaining it as completely as possible in the flask. Pour upon the aluminium in the beaker five c.c. of dilute nitric acid (sp. gr. 1.2) warm gently until the copper is dissolved. Then pour the solution through the filter, receiving the filtrate in the flask containing the main portion of the copper.

About the Publisher

Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com

This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works. Это и многое другое вы найдете в книге Quantitative Metallurgical Analysis (Charles Frederick Sidener)