| Abstract [eng] |
The topic of Master's thesis – „Mineral Feed Additives Preparation and Properties”. In this work we used a natural mineral - dolomite, which is a sedimentary carbonate rock composed of the mineral (CaMg(CO3)2) having the same name, and a small number of other mineral impurities - calcite, sometimes plaster, clay minerals and iron oxides. The paper investigates the chemical interaction of heated dolomite with phosphoric acid, by assessing the suitability of the obtained product for granulation process and the proposed technological recommendations of the use of natural dolomite for the production of forage phosphates. Granulation of calcium magnesium phosphate was carried out by drum and fluidized bed granulator. In addition, the IR spectrum, atomic absorption spectrum and X-ray diffraction analyses were carried out, as well as the concentrations of phosphorus pentoxide, calcium oxide and magnesium oxide were determined. Granulometric composition of calcium magnesium phosphate depends on the chosen method of granulation and on the starting moisture content of granulated material. Reduction of moisture leads to the decrease in the quantity of the largest (> 5 mm) fraction, and to the increase of other fractions: in order to produce the highest amount (56,35 %) of the product fraction (1 – 3 mm) by using drum granulator, the optimal moisture of raw material is between 22% and 26%; while granulating in a fluidized bed granulator, in order to obtain the highest amount (78.32%) of the product fraction (0.5 - 2 mm), the optimal moisture content of raw materials is from 2 % to 10 %. It can be stated that there is a direct relationship between the particle size and their strength, i.e., the smaller the grain size decreases, the lower the strength of the granules. Mixing of calcium magnesium phosphate with K2SO4 as well as with the sulfates of microelements (Fe, Zn, Cu, Se) during the granulation process, does not cause a chemical reaction to occur, therefore new chemical compounds are not formed. Addition of these components changes granular properties little. |
