This study presents morphological and structural variations of K-Feldspar mineral after acid treatment.Both organic and inorganic acids such as C2H2O4,HCl,HNO3 and H2SO4 were employed for this purpose.Another aim of this study was to find an optimum experimental condition for iron(Fe)removal with a minimum damage on the structure of K-Feldspar in which high whiteness index is obtained.The effect of different parameters such as concentration,pH and temperature on the final structure of this mineral was investigated.To find out the chemical composition of powder,XRF was utilized.FTIR,XRD and SEM were employed to study the structure of mineral.Spectrophotometry was chosen to analyze whiteness index of powder after acid treatment.It was found that O—Al—O bond at 647 cm-1 for H2SO4 and HNO3 treated sample disappeared.However,HCl and C2H2O4 were ineffective at this band.In addition,the results revealed an increase in K-Feldspar content,a decrease in Fe content,an increase in whiteness index and no significant structural change for C2H2O4 leached sample.Whiteness index of 91％was obtained for C2H2O4 leached sample with the pH of 2.5 to 3 at temperature of 50℃ and during 1 h.