DIFFERENTIAL THERMAL ANALYSIS OF HYDROUS FERRIC OXIDE FORMED BY DIRECT NEUTRALIZATION OF FERRIC CHLORIDE SOLUTION

Differential thermal investigation was made of amorphous hydrous ferric oxides, precipitated on neutralization of ferric chloride solution under different laboratory conditions, ranging from DOC to 85°C in temperature, and from 3 to 12 in pH. Each of the differential thermal curves obtained shows an endothermic peak due to the release of adsorbed water, followed by a exothermic peak due to crystallization of anhydrous ferric oxide to hematite. The temperature corresponding to the exothermic peak varies in the range from 240°C to 460°C accrding to the temperatures and pH values of the solution from which the hydrous ferric oxide is precipitated.