Figure 01. Reactions calculation tool - Choose Phases.
On this page you can select up to 20 mineral phases made from the 12 oxide components (SiO2, TiO2, Al2O3, Fe2O3, FeO, MnO, MgO, CaO, Na2O, K2O, H2O, CO2) and calculate a list of the mathematically posible chemical reactions among those phases, and subgroups of those phases. To begin, use the pulldown lists to select minerals one at a time. The minerals on these lists are mineral end-members with fixed compositions. After each selection, click on the "Add to List" button and the mineral should appear on the List of Selected Minerals along with its chemical composition, both as a formula and in terms of oxide components.
When your list of phases is complete, press the "Remove Unused Components" button to remove any of the components not used. Next press the "Calculate Reactions" button to display a list of possible chemical reactions among your selected phases. The algorithm should also find the reactions for subgroup combinations of your phases. In most cases, not all the reactions found will be mathematically independent. The number of independent reactions is reported below the reaction list. Note: the Gauss reduction algorithm used here will calculate reactions only if there are more phases than chemcal components. So in some cases you may have to add one or more addtional phases to see some reactions. For example, add Qz to And, Ky, and Sil if you want to see the aluminosilicate reactions. Similarly, should you use elements, rather than oxides, as components, the code will identify more reactions if you add O2 as a phase. Also, if more than 50 reactions are found, you will need to repeat your querry with a smaller number or different group of phases.
If you would like to see the approximate equilibrium positions of the identified reactions on a T-P diagram, click on the "Plot Selected Reactions" button.
If you wish to balance reactions for minerals or compositions or components not on the lists, you may upload your own minerals, compositions, and components using Figure 02.
This reaction calculation tool is inspired by program REACTION, written by Larry Finger (Finger and Burt, 1972). The javascript code used to find the reactions uses a Gaussian Elimination procedure that is similar to that used by Larry Finger to write his FORTRAN program. This tool also incorporates features similar to those added by Frank Spear in the 1990's when he revised Larry's program to run in MacOS.
