Abstract: Method for determining chemical constituents in an electrolysis cell for the production of metal, in particular aluminum, involving the use of light spectroscopy such as Raman spectroscopy that analyses the light emitted from the cell constituents and represents the light as a spectrum, wherein the analysis is performed directly in the cell while the cell is in its production mode, whereby the spectrum is analysed on the basis of reference spectrums based on known compositions, to determine chemical constituents in the cell. Also provided is an apparatus for performing this method.

Abstract: Air reactivity, CO.sub.2 and soot index of a carbon product is determined. The air reactivity and CO.sub.2 reactivity of a sample of a carbon product are determined on the basis of the same test of the same sample. Air reactivity is analyzed first and, when such analysis is finished, CO.sub.2 reactivity is automatically analyzed on the same sample. The soot index is determined by collecting and weighing soot dust. A vertical tube furnace includes an inlet for the introduction of gas, and a sample holder which is freely suspended from a weighing device and extends down into the tube furnace. The sample holder is provided with one or more thermocouples for registering temperature of a carbon product.

Abstract: An apparatus for the analysis of carbon products enables air reactivity, CO.sub.2 reactivity, soot index and coefficient of thermal expansion of the carbon products to be determined in one analysis operation. The apparatus includes vertical and/or horizontal tube furnaces, each of which is provided with devices for weighing, temperature registration and/or registration dilation. Introduction of gas takes place via one end of each of the tube furnaces. Each of the furnaces is connected to a joint processing unit which checks the various instruments and registers the various instruments and registers and processes the analytical data.