In this study, the specific rates of breakage (S-i) and the primary breakage distribution (B-i,B-j) values of Na-feldspar were determined for four mono-sized feed fractions; -0.106+0.090 mm, -0.090+0.075 mm, 0.075 vertical bar 0.063 mm, and -0.063 vertical bar 0.045 mm. Batch dry grinding tests were carried out for 0.25 and 0.50 minutes of grinding time by using labratory grinding mill having cylpebs with 10 mm diameter. And then the kinetic model parameters (S-i, a(T), a, gamma and square(J)) were calculated and presented in a comparative manner for different grinding times.