This study evaluates radiative heat transfer in a mixture of gases and \( \text {Al}_{2}\text {O}_{3} \) particles, considering both emission and absorption by gases and particles, and scattering by particles. The effects of both uniform and non-uniform particle clouds on particle properties and the influence of particle volume fraction on radiative heat flux are calculated. The Spectral properties of the particles are derived using Lorenz-Mie theory, and absorption coefficients for \( \text {H}_2\text {O} \) and \( \text {CO}_2 \) gases are obtained from the HITEMP database. Further, the spectral absorption and scattering coefficients of \( \text {Al}_{2}\text {O}_{3} \) particles are evaluated for four uniform particle sizes, as well as a Gaussian size distribution is used to account for non-uniform particle sizes. The impact of anisotropic scattering is estimated using the Henyey–Greenstein approximation. The Finite Angle Method (FAM) is employed to solve the spectral radiative transfer equation, and the Line-by-Line (LBL) method accounts for the spectral variation. Larger particles exhibit pronounced forward scattering, forming lobes predominantly in the forward direction. The inclusion of \( \text {Al}_{2}\text {O}_{3} \) particles significantly amplifies radiative heat flux. While isotropic scattering tends to reduce flux variations with particle size, anisotropic scattering more accurately captures these changes, emphasizing the importance of considering directional scattering in radiative heat transfer calculations. The Henyey–Greenstein method improves computational efficiency by addressing rapid oscillations in scattering phase functions. Additionally, increasing the particle volume fraction enhances radiative heat flux due to higher particle concentrations.