Browsing by Subject "comminution"

Now showing 1 - 7 of 7

Access status: Open Access ,
Analiza porównawcza kruszarek w wielostadialnych układach rozdrabniania skał bazaltowych
(2006) Nowak, Alicja; Gawenda, Tomasz
Basalt rocks are valuable feed to production of broken aggregates for road and building industry. Grain composition and grains shapes, highly influencing on aggregates resistance, determine the aggregates quality. The contents of irregular grains in mineral aggregates depend mainly on material crushing method, i.e. on sort of applied comminuting devices, their construction and movement parameters, comminution level and number of crushing stages. The paper presents conditions and results of multiple stage comminution processes for two selected basalt aggregates production plants. The effects of comminution were investigated for various sorts of crushers. The dependence of grain fractions yields on ratio of grain size »d« and crusher gap size »e« was determined. The comminution levels given by following crushing stages were determined too, as well their correlations with maximum value of d/e. The irregular grains contents in individual grain fractions of produced aggregates and the dependence of crushing products shape coefficients on comminution level were shown. Also, changes of cone crushers capacity dependably on crusher gap size and comminution level, were given.
Access status: Open Access ,
Analysis of efficiency of grinding in ball and rod mills dependably on contents of fine particles in feed
(2012) Foszcz, Dariusz; Gawenda, Tomasz
W artykule przedstawiono analizę efektywności pracy młyna kulowego i prętowego w zależności od uziarnienia nadawy a w szczególności udziału klas drobnych. Analizę przeprowadzono na podstawie wyników badań laboratoryjnych oraz przemysłowych wykonanych w ramach prac badawczych dla O/ZWR KGHM PM SA. Efektywność procesu mielenia oceniano wskaźnikiem przyrostu określonych wybranych klas ziarnowych w wylewie młyna. Zagadnienie wydzielania drobnych klas ziarnowych przed operacjami rozdrabniania jest niezwykle istotne z punktu widzenia ekonomiki prowadzenia procesu przeróbki. Wydzielenie drobnych klas ziarnowych tzw. gotowych do dalszych operacji nie wymagających rozdrabniania na danym stadium wpływa na koszty rozdrabniania oraz oczekiwaną wydajność urządzeń rozdrabniających. Niezwykle istotne dla prawidłowego określenia schematu układów rozdrabniania jest wiec ustalenie efektywności operacji rozdrabniania w zależności od zawartości ziarn drobnych. Pozwala to określić oczekiwaną efektywność procesu klasyfikacji i umożliwia optymalizację kosztów inwestycyjnych związanych z zakupem urządzeń o określonej wydajności i operacyjnych związanych z energią elektryczną zużywaną przez zaprojektowany układ technologiczny.
Access status: Open Access ,
Główne aspekty rozdrabniania twardych surowców mineralnych w wysokociśnieniowych prasach walcowych
(Wydawnictwa AGH, 2009) Gawenda, Tomasz
The high pressure grinding rolls (HPGR) of third generation are ones of the most modern devices and are often applied in new designed mineral processing plants in the whole world. Furthermore, they replace older crushers working on secondary comminution stages and mills on first grinding stages, being the source of high profits, mainly by energy savings, lower exploitation costs and higher quality of products. Sometimes, they totally replace mills, both by production of mineral flours and ores directed to beneficiation process. In the introduction to the main part of the paper, the main problems relied to exploitation of older grinding rolls types, as well the signification and application of the new ones were presented. The second chapter contains the discussion over the construction, rule of working and course of the comminution process in HPGR and the third one shows the benefits occurring from their applications on the basis of certain technological systems.
Access status: Open Access ,
Młyny powietrzno-strumieniowe stosowane w przeróbce wybranych materiałów ziarnistych
(Wydawnictwa AGH, 2011) Zbroński, Daniel
The satisfaction of industrial demand on the fine-grained materials caused the dynamic development of air-jet technologies. The division of air-jet mills and description of chosen their types are presented in the paper. The difference between mills mainly depends from method realization of comminution process, used milling-classify system and producer of mill. The experimental results of chosen granular materials comminution in the several types of mills confirmed the possibility obtainment of required particle size distribution of product on the definite stage of mineral processing.
Access status: Open Access ,
Problematyka doboru maszyn kruszących w instalacjach produkcji kruszyw mineralnych
(Wydawnictwa AGH, 2010) Gawenda, Tomasz
Main issues connected with proper selection of crushing devices in aggregate production circuits were presented in the paper. The first and second section of the article concerns the basics of the comminution processes and the types of crushing devices applied on the European market. The third section treats the principles of crushers' selection on the stage of design and the comminution methodology. It appears that the way of operating the technological process - the number of crushing stages, the control of the material mass flow streams - influences the quality of obtained products. Problems of closed and open comminution circuits were presented in the section four. In summary the examples of technological circuits of aggregates production proposed by the Metso Minerals were shown. The model production of grifts in cone granulator with and without the fines recycle stream was also presented.
Access status: Open Access ,
Rozdrabnianie ziaren piasku kwarcowego na laboratoryjnym stanowisku młyna strumieniowo-tarczowego
(Wydawnictwa AGH, 2010) Górecka-Zbrońska, Aleksandra; Zbroński, Daniel
The experimental results of comminution process selected size fractions of quartz sand on the laboratory stand of target-jet mill are presented in the paper. Experiment stand makes possible to comminute grains accelerated by the air jet with a single impact, using stationary target. Determined particle size distribution of product makes possible to estimate of quality and efficiency of comminution process. On the basis of experimental results the probable explanation of comminution mechanism of grains in the target-jet mill is presented. The analysis showed that comminution in the mill takes place as a result of percussive cracking and superficial attrition of grains.
Access status: Open Access ,
Uwarunkowania produkcji drobnych frakcji ziarnowych w procesach rozdrabniania w wysokociśnieniowych prasach walcowych
(Wydawnictwa AGH, 2011) Saramak, Daniel
An influence of two basics adjustable parameters of the high-pressure grinding rolls: the operating pressure and speed of rolls on the finest particle generation in crushed products, were presented in the paper. Finest fractions in comminution products are generally undesirable, due to the over-grinding phenomenon, what decreases the flotation process efficiency and the overall process effectiveness. When there is an application of the roller press in technological circuit, the suitable control influences the finest particles generation, what leads to the control of the comminution process efficiency.