FY13 annual report describing the calculations and results associated with the data and dissolution rate contained in "Chlorite Kinetic Dissolution Data and Rate" (linked below).

Spreadsheets provides measured chlorite rate data from 100 to 300 degrees C at elevated CO2. Spreadsheet includes derived rate equation.

Chemical reactions pose an important but poorly understood threat to EGS long-term success because of their impact on fracture permeability. This report summarizes the dissolution rate equations for layered silicates where data were lacking for geothermal systems. Here we report updated rate laws for chlorite (Carroll and Smith 2013), biotite (Carroll and Smith, 2015), illite (Carroll and Smith, 2014), and for muscovite. Also included is a spreadsheet with rate data and rate equations for use in reactive transport simulators.

Chlorite dissolution kinetics were measured under far from equilibrium conditions using a mixed-flow reactor over temperatures of 100-275 degrees C at pH values of 3.0-5.7 in a background solution matrix of 0.05 m NaCl. Over this temperature range, magnesium was released congruently with respect to silica. The effect of variable pCO2 levels representative of engineered geothermal systems with CO2 as a heat-exchanging fluid (CO2-EGS) was explored by reacting chlorite with solutions containing a range of dissolved CO2 concentrations (0.1-0.5 M).

This document provides results of experiments aimed at removing silica from geothermal brines. All experiments were conducted with simulated brines. The data presented shows the effect of iron addition, kinetics, temperature, pH and brine concentration.