TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: In the process, the chemical conditioning, step (b), to prevent the oxidation of the cakes and/or sludges recovered by filtration or centrifugal agglomeration of silicon kerfs, is performed at pH -0.5-5.5, more preferably 3-5, using a non-oxidizing acid such as a mineral acid, mono carboxylic and dicarboxylic organic acids. The step (b) is performed with an organic solvent not acid sensitive, such as, acetone, ether, ethanol, propanol, iso-propanol, methanol, or butanol. The step (b) is performed in two steps: first a conditioning in an organic solvent not acid sensitive, such as, acetone, ether, ethanol, propanol, iso-propanol, methanol, or butanol followed by a conditioning in a non-oxidizing acid such as a mineral acid, organic acid, such organic acid can be monocarboxylic or dicarboxylic. The treatment with hydrofluoric acid, step (c), is performed in a way where the ratio Si and HF is 1:0.01-1 by weight. The treatment step (d) is performed in a way where the ratios Si:HCl:H2O2 are 1:0.05-0.5:0.05-0.2 by weight. The treatment step (d) is performed in a way where the ratios Si:HF:H2O2 are 1:0.01- 0.1:0.05-0.5 by weight. The treatment step (e) is performed in a way where the ratio Si:HF is 1:0.05-0.15. The treatment step (f) is performed under inert gases or vacuum and the temperature is raised up to 100 degrees C. The treatment step (f) is performed by washing the silicon cake with an organic solvent such as ethanol, isopropanol, butanol, methanol, and/or ether. The compaction step (g) is performed in a mold, where the mold can be a crucible made of silica, and the mold can have inner mold that could be removed, the mold can be inflatable, or the mold can be water soluble and/or ethanol soluble and/or acetone soluble. The mold has a melting point lower than 150 degrees C. The treatment step (g) is performed following the steps listed: i) dried silicon powder is added inside an industrial standard casting crucible that is maintained under nitrogen environment; ii) the crucible filled with the silicon dry powder is put under vacuum, until the vacuum reaches the values 20-60 kPa; and iii) by using a nitrogen flow at room temperature, the vacuum of the environment containing the crucible filled with the silicon powder is released and the pressure is raised to the value of about 1 bar; in its path through the silicon particles, nitrogen creates a drag effect on the silicon particles, yielding a consistent compaction of the silicon powder. The step (g) is performed by tabletting or pelletizing the dried silicon powder. EXAMPLE - No suitable example given.