In many areas of industry, a wide variety of residual materials are produced which, from a global perspective, are sent to landfill for reasons of cost or effort. On the part of politicians and other stakeholders, however, there is a growing interest in a closed raw material cycle. This offers not only a reduction in landfill capacity, but also a saving in CO2 and the conservation of primary resources. The refractory industry produces, among other things, heat-resistant linings for several types of furnaces. The largest customers are metal, as well as cement and glass industry. After the application of refractory materials in different furnaces, kiln breakout with a wide range of elements accumulates. The further process, especially in third world countries, is the simple dumping of these spent products. However, since the composition of these products is known, little to hardly contaminated stones can partially substitute primary raw materials, as is already the state of the art in many industrialized nations. However, stones that are heavily infiltrated with melt and slag turn out to be a major problem. These contain metallic, but also oxidic components that interfere with recycling, either through a reduction in quality or environmental pollution. Therefore, this outcrop cannot be recycled by simple mechanical processing methods and addition to the primary production of refractory bricks. Therefore, the search for alternative recycling methods for the refractory industries is prioritized to meet the "Circular Economy". The aim of this work is the examination of spent refractory bricks from the copper industry, provided by RHI magnesita GmbH. With the help of hydrometallurgy, more precisely a leaching with sulfuric acid, of the previously crushed material, an attempt is to be made to separate out harmful elements so that limit values can be observed. In the first step, ideal process parameters must be found based on a heavily infiltrated stone, which can then be applied to the remaining products to be investigated. Filtrate and residue can be separated by a subsequent filtration, which will be examined and analyzed by an atomic emission spectrometer with microwave-induced plasma on the one hand and by a scanning electron microscope on the other hand. Thus, the presence of the individual elements can be determined and the effectiveness of this series of experiments is shown.