$\begin{cases}MgCO_3:x mol \\ MgSO_3:y mol\\CaCO_3:z mol\\CaSO_3:t mol\\84x+104y+100z+120t=43,67\\x+y+z+t=\frac{9,856}{22,4} \\\frac{44(x+z)+64(y+t)}{x+y+z+t}=2.26,901\\111(z+t)=22,2\end{cases}\Rightarrow x+y=0,24 mol$$\Rightarrow m_{MgCl_2}=0,24.95=22,8 gam$