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Ovaj rad prikazuje rezultate terenskog mjerenja energije drobljenja na eksploatacijskom polju „Očura“. Hipoteza rada je da smanjenjem veličine čestica raste energija potrebna za njihovo sitnjenje. Na separacijskom postrojenju eksploatacijskog polja „Očura“ uzorci su drobljeni u čeljusnoj (primarnoj), konusnoj (sekundarnoj) i udarnoj (tercijarnoj) drobilici. Pomoću mjernog sustava mjerena je potrošnja električne energije elektromotora prilikom drobljenja u pojedinim drobilicama. U čeljusnoj drobilici izdrobljeno je 16 pojedinačnih uzoraka te je određivana njihova specifična energija. U konusnoj i udarnoj drobilici izdrobljen je materijal iz čeljusne drobilice, ali odjednom. Uspoređivana je specifična energija drobljenja u čeljusnoj, konusnoj i udarnoj drobilici. Statističkom analizom utvrđivana je ovisnost između mase uzorka, specifičnoj energiji drobljenja, prosječnoj snazi drobljenja i maksimalnoj snazi tijekom drobljenja., This thesis shows the results of crushing energy measurements on the field on „Očura“ surface mine. The hypothesis of the thesis is that lowering the particle size raises the energy needed for their comminution. Samples of rock were crushed in jaw (primary), cone (secondary) and impact (tertiary) crushers on the „Očura“ processing plant. Electrical energy consumption of the crushers motor was measured with the measuring system during sample crushing. In the jaw crusher, 16 individual samples were crushed and their specific crushing energy was calculated. In the cone and impact crushers the material form the jaw crusher was crushed all at once. Specific crushing energy of jaw, cone and impact crushers was compared. Dependence between samples mass, specific crushing energy, average crushing power and maximum crushing power was determined by statiscial data processing.

Cilj ovog rada bio je usitniti uzorak zeolita klinoptilolita do veličina manjih od mikrometra. Mikroniziranjem zeolita povećava mu se specifična površina, a time i adsorpcijski kapacitet i kapacitet ionske izmjene. Usitnjavanje je provedeno u planetarnom kugličnom mlinu pri različitim brojevima okretaja (300, 400 i 500 o/min) u vremenskim periodima od 10, 20, 30 i 60 minuta. Eksperimenti su provedeni u dvije različite posude mlina pri 500 o/min. Raspodjela veličina čestica određena je metodom laserske difrakcije. Prema dobivenim rezultatima vidljivo je da je usitnjavanjem pri većem broju okretaja i u dužem vremenskom periodu dobiven veći udio manjih čestica. Raspodjela veličina čestica izražena je Sauterovim promjerom. Specifična površina određena je snimanjem adsorpcijsko-desorpcijskih izotermi dušika. Povećavanjem vremena usitnjavanja specifična površina se smanjila zbog narušavanja mikroporozne strukture zeolita. The aim of this work was comminution of the zeolite clinoptilolite to sizes smaller than a micrometer. Micronization increases specific surface area, adsorption capacity and ion exchange capacity of zeolite. Comminution was performed in planetary ball mill at different rotation speed (300, 400 and 500 rpm) at intervals of 10, 20, 30 and 60 minutes. The experiment was conducted in two different grinding pots at 500 rpm. The particle size distribution was determined with laser diffraction method. The results show that the comminution at high rotation speed and over a longer period obtained higher proportion of smaller particles. Particle size distribution was expressed with Sauter diameter. The specific surface area was calculated from the adsorption-desorption isotherms of nitrogen. Specific surface area is reduced increasing the time of comminution, due to the disruption of microporous structure of the zeolite.

Na tržištu tehničkog kamena najtraženije su klase veličine zrna 4/8, 2/4, -4, -2 mm, čiji maseni udio prevladava u agregatima za izradu betona i asfalta. Međutim proizvodnja tih klasa nije uvijek jednostavna. Pored zahtjeva za količinom, redovito se traži određeni grano-sastav i oblik zrna kamenog agregata, te minimalan udio čestica veličine -0,09 mm. Do prije desetak godina, najčešće su se za proizvodnju navedenih klasa koristile udarne drobilice i čekićare, dok se danas u tu svrhu sve češće koriste vertikalne udarne drobilice. Vertikalne udarne drobilice predstavljaju izvjestan tehnološki napredak koji se prvenstveno očituje u većem udjelu zrna kubičnog oblika u izlaznom materijalu i manjem habanju udarnih elemenata i obloge u odnosu na prije spomenute drobilice. U članku su opisane osnovne konstrukcijske značajke i princip rada vertikalnih udarnih drobilica, te je analizirana njihova učinkovitost (grano-sastav proizvoda, udio zrna povoljnog oblika, udio čestica -0,09 mm u ovisnosti o utjecaju pojedinih tehnoloških parametara., In the technical stone market, the most demanded grain size classes are 4/8, 2/4, -4, -2 mm, which weight portion being predominant in aggregates for production of concrete and asphalt. However, the production of these classes is not always simple. In adition to quantity requirements, the specific grain size distribution and grain shape of stone aggregate, as well as a minimal portion of the particles -0,09 mm are regurarly demanded. Until about ten years ago, impact and hammer crushers were most often used for the production of the above mentioned classes, while nowdays vertical impact crushers are being used with increasing frequency for this purpose. Compared to the first-mentioned crushers, vertical impact crushers represent a certain technological progress manifested primarily in a greater content of cubic shaped graines in output material and reduced wear of crusher lining and impact elements. The paper descibes the basic construction features and the operating principle of vertical impact crusher and analyzes their efficiency (grain size distribution of the crushed product, content of favourably shaped grains, filler content) as a function of the particular technological parameters.

Sitnjenje je proces u kojem pod djelovanjem mehaničkih sila mije¬njamo disperzno stanju čvrstih tvari. Disperzno stanje jednoznačno je određeno granulometrijskim sastavom. Do sitnjenja dalazi uslijed de¬formacije zrna, pri čemu deformacija ovisi o načinu nanošenja sile, njezinoj brzini i veličini. Drobljenje pojedinačnog zrna najučinkovitija je metoda sitnjenja, jer su gubici energije uslijed trenja i neproduktiv¬nog naprezanja u trenutku drobljenja izbjegnuti. Najveći gubici ener¬gije su u mlinovima s kuglama i to uslijed trenja između novostvorenih zrna i tih zrna s kuglama i oblogom mlina. Nove spoznaje dovele su do boljeg razumijevanja sitnjenja. u realnim uvjetima, te inovacijskih zahvata s kojima je povećana učinkovitost pojedinih uređaja i to kako u pogledu grano-sastava i raščina zrna tako i u pagledu utroška ener¬gije. Konstruirano je nekoliko novih drobilica od kojih se u praksi najčešće spominju visokotlačna drobilica s valjcima i inercijske konus¬ne drobi lice., Comminution is the process in which by activity of mechanical forces the dispersion state of solid material is being changed. The dispersion state is definitely determined by the granulometric compo¬sition particle (size distribution). The comminution is a consequence of the particle deformation, in what this deformation is dependent on the force offering mode, its velocity and size. The breaking of individual particles is the most efficient comminution method because the energy losses owing to friction and unproductive tension in the instant of breakage are avoided. The greatest energy losses occur in ball mills and that because of the friction between the newly-formed particles and of these particles and the balls and the mill lining. New insights have led to a better understanding of comminution in real conditions and to innovative interventions which increased the efficacity of the individual devices, and that with regard to particle size distribution and particle dislocation degree as well as to energy consumption. Some new kinds of crushers have been invented, of whose most mentioned are the high pressure roll crusher and the inertial cone crusher.