• Table of Contents
• Introduction
• Plant Data
• Electrolyte Properties
• Concentration Converter
• Cell Voltage
• Alumina Feeding
• Anode Table Layout

• Table of Contents
• Introduction
• How to Use AlPrg
• Plant Data
• Alumina Feeding
• Electrolyte Properties
• Cell Voltage

• Table of Contents
• Introduction
• ATab Version 2
• Layout-View
• Evaluation-View
• 3D-View
• Floating Windows
• Optimization Window
• Examples
• Downloads

• Table of Contents
• Principles Hall-Héroult
• Mass Balance
• Electrolyte Properties
• Cell Voltage
• Energy Balance

• Current Efficiency

• Raw Materials

• Cell Operation

• Measurements

• Environment, Emissions
• Examples, Exercises
• Literature

• News and Events
• Name Index
• Subject Index
• Sitemap
• Recreation

If you want to conceive a new anode numbering schema and anode change cycle schedule or you want compare different layouts you need values to evaluate and classify these arrangement. Since there are quite a lot of possibilities to arrange an anode table its evaluation properties should be represented by a set of few values. ATab uses for this task the distance to the next anode to be changed, the anode mass distribution as well as the anode height and anode surface differences.
On this Evaluation View ATab gives a detail account how it determines the key result values i.e. you find here the start values, intermediate data and final results. The Layout History Floating Window lists for each layout a summary of the evaluation results. On the Examples page you find an overview about anode table layout evaluations methods found in the literature.

Average Anode Distance and Anode Change Paths.

The distance from one anode to the next anode to be changed indicates how much the anode change process will influence the local properties of the anode table. ATab calculates an average value with standard deviation of these anode distances. Furthermore ATab draws the so called Anode Change Paths where arrows indicate the anode changing sequence (next figure).

Evaluation-View with Anode Distance and Anode Change Paths.

ATab draws arrows on the top view of the anode table to indicate the anode change sequence. The green circle indicates the anode that starts the anode change cycle. The yellow arrow closes the anode change cycle pointing from the last anode to be changed (red circle) to the first one.

By using the time slider you may draw dynamically these anode change paths. According to the time slider the anode changing sequence starts with anode 10 (green circle on the upper right corner anode ) to continue with anode 2, 19, etc. and finishes with anode 11 (red circle on the lower left corner anode).With the time slider you draw dynamically intermediate anode change paths. When you drag the time slider bar to day 8 of the anode change cycle period ATab draws the corresponding shortened anode change path (next figure A). The drawing of figure B shows the anode change path at day 21.

Intermediate Anode Change Paths.

When you drag the time slider bar to anode change cycle day 8 ATab draws the corresponding intermediate anode change path (A). Figure B shows the anode change path of day 21.

Changing Several Anodes.

ATab allows you to change two anodes simultaneously i.e. during one day. ATab considers two cases: two adjacent anodes (anodes 9 and 10 in the next figure) or two anodes separated by at least one anode (anodes 3 and 17 in the next figure). ATab treats adjacent double anodes especially for the permutation calculation as a single anode. In the Anode Distances diagram the double anodes are connected by a transparent rectangle and the position circle for the the distance arrow is placed between the anodes. ATab treats the separated double anodes as normal anodes however they are connected by a grey arrow to indicate that the are changed the same day.

Changing Two Anodes Per Day.

Two anodes namely 9-10 and 3-17 are changes on the same day namely day 10 and 17 respectively. ATab treats the adjacent double anodes (9-10) as a single anode indicated by the grey transparent connecting rectangle and the position circle between the anodes. ATab connects the separated double anodes (3-17) with a grey arrow to indicate that they are changed the same day but otherwise ATab considers them as normal anodes.

The next figure shows as an example the formation of the anode change path for an electrolytic cell with twenty double anodes according to Knizhnik et al. (see Examples). The picture shows the 5^th, 10^th, 15^th and 20^th day of the anode change cycle period.

Development of the Anode Change Path.

This figure represents the development of the anode change path of an electrolytic cell with 20 double anodes according to Knizhnik et al. (see Examples). The path is shown for day 5, 10, 15 and 20 of the anode change cycle period.

Anode Mass Differences.

ATab divides the anode table into four quarters and determines the sum of the anode masses (m in the next figure) for each quarter and the their differences (L-R: left minus right). ATab calculates these values for each day of the anode cycle period (Daily Values) and determines also the average values with its standard deviation for the whole cycle period (Cycle Period Averages). For the special case of anode masses ATab list also the maximum difference as value and percent of new anodes (max).

Anode Mass Differences.

ATab determines the sum of anode masses for the four quarters of the anode table (m in the upper figure) and the differences of this sum (L-R: left minus right). On the upper figure you find the daily values and on the lower figure the averages with standard deviations calculated for the anode cycle period. Furthermore you see also the maximum mass difference and its percentage deviation from the new anodes is given.

Anode Height Differences.

ATab determines the differences between adjacent anodes (Δh(between)) and at the center of the electrolytic cell (Δh(at center)). The next upper figure shows daily values, daily differences, daily averages and the lower figure the corresponding cycle period averages with their standard deviations.

Anode Height Differences.

The upper figure shows daily values, daily differences Δh(between) adjacent anodes and Δh(at center) of the electrolytic cell and the daily average value with standard deviation.The lower figure depicts the corresponding averages and their standard deviation over the anode cycle period.

Anode Surface Differences.

As for the height differences ATab determines the similar values for the anode surface differences ΔA(between) adjacent anodes and ΔA(at center) of the electrolytic cell and shows daily and anode cycle averages.

Anode Surface Differences.

As for the height differences the upper figure shows the daily values and the lower figure the corresponding anode cycle averages.

Auxiliary Diagrams.

ATab draws a couple of diagrams that you can verify even more the data and calculated values. As an example the next figure shows the daily start data that ATab uses for the evaluation calculations.

Auxiliary Diagrams.

With the goal that you can verify even more the data and the results of the calculation ATab draws several auxiliary diagrams, for instance, showing the daily start data.