This study presents morphological and structural variations of K-Feldspar mineral after acid treatment. Both organic and inorganic acids such as C

2

H

2

O

4

HCl

HNO

3

and H

2

SO

4

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 H

2

SO

4

and HNO

3

treated sample disappeared. However

HCl and C

2

H

2

O

4

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 cha

nge for C

2

H

2

O

4

leached sample. Whiteness index of 91% was obtained for C

2

H

2

O

4

leached sample with the pH of 2.5 to 3 at temperature of 50℃ and during 1 h.