Iron ore when found containing high levels of phosphorus element becomes detrimental to the manufacture of steel due to the increase of its hardness making it brittle and fractures. In this sense the process of acid leaching of iron ore is seen in the literature as favorable, providing its desfosforização. However, depending on the way the element phosphorus is present in the iron ore application structure becomes additional power required for its release. Thus this work, the acid leaching process with the aim of reducing the phosphorus content in iron ore as well as the application of heating the particles of iron ore by using microwave energy. By using Termocalc® software to parse the different structures formed having different levels of phosphorus element. By scanning electron microscopy technique (SEM) was possible to observe the structure of the iron ore particles after treatment with microwave energy. Through the use of statistical design factor with central and axial points was possible to determine the optimal conditions used in the acid leaching process, the following values are found: 19.25 g mass ore, leaching time 20 min, leaching temperature of 65 °C, agitation speed of 620 rpm, average grain size of 28 mm size, having a 3-minute contact time with the microwave energy. Under these conditions the reduction of phosphorus content in iron ore sample reached a value of 52.47% was possible to demonstrate the positive effect of the sample heating process of iron ore and may therefore be regarded as increasing the acid leaching technique to reduction of the phosphorus content.