Yes, you can make rice flour in a blender.
While a grain mill is suggested if you are going to produce rice flour in large quantities, a blender can be used effectively for smaller batches. The process involves blending uncooked rice until it reaches a fine, flour-like consistency. Keep in mind that the type of blender and the quantity of rice you are trying to process at once can affect the outcome, so you might need to do it in smaller batches and sift the result for a finer flour.