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Abstract
Under dry grinding procedures, the immersion heat of the unit surface of talc stays as a constant close to 0.2 J/m2 and reveals a weak hydrophilic behaviour. Chlorite crude mineral is more hydrophilic than talc, mainly due to inter-layered swelling sheets, but when ground it behaves according to two different mechanisms, leading to a strong decrease of the immersion heat. One mechanism involves the production of external surface with an immersion heat close to 0,23 j/m2 that does not significantly differ from the talc one but dilutes the internal surface contribution. An other mechanism, involved in the early stages of comminution, could be the collapse of the internal surface due to mechanical effects, this collapse disappear when fineness increases, due to mechanical relax. The main conclusion is that the apparent hydrophilic behaviour of the crude chlorite mineral is mainly due to foreign swelling sheets with an average cross section area of 16Å2 per exchangeable site, and decreases when grinding, up to reach the talc behaviour.
Abstract
Effect of fifteen variables on hydrophobic floc flotation characteristics of ultra fine (-10 μm) siliceous manganese ore in mechanical flotation cell has been studied. Linear orthogonal saturated design was selected to study the main effect of 15 variables. The regression model was developed to quantify
the effects of variables and attempt was made to optimize grade and recovery of beneficiation of low-grade siliceous manganese ore. The effect of independent variables on response has been explained wherever possible. The maximum grade obtained was 42.3 % Mn at 38.2 % Mn recovery. The maximum Mn recovery was 78.1 % at 34.9 % Mn grade from the feed having 27.8% Mn.
Abstract
This paper summarized under the title: “Operating technique of mills in the process of micronization milling of alumina” is occupied with micronization of alumina and its influences on change of alumina crystal structure; the research is based on existing scientific and technical-technological findings
and experiences in the field of development and application of processes of the materials.
In short, this research task involves:
– investigation of initial material effects on kinetics and mechanism of the particle formation together with the phase transformations occurring in the process,
– characterization of materials,
– consideration of close relations between theoretical principles of operation of high-energy mills, such as vibrational and planetary mills during the micronized of alumina which obeyed the certain laws, with their dependance on selected experimental conditions,
– detailed investigation of the possibility to obtain high-grade αAl2O3 alumina in the form of micronic, nonagglomerated particles by the method of dry micronized combined with heat treatment, and starting from the γAl2O3 alumina modification after the Bayern process.
The elements that are necessary for determination of operation of mills, particularly vibrational and planetary ones, were determined by detailed investigation of the alumina micronized; also, conditions required to define the both technological and production parameters of micronization are
fulfilled, too.
Based on investigated parameters and theoretical consideration of the alumina micronized, together with its influences on change of the alumina crystal structure by usage of mills with advanced construction and contemporary instrumental techniques used in determination and observation of the most important physical, chemical and thermic characteristics, kinetic model which is the basis for a quick and efficient determination of above parameters in order to optimize and automize micronization processes was developed.
Abstract
The possibility of preconcentration of scheelit and sulphide minerals from mine “Rudnik” polymetallic ore, using the gravity concentration process was investigated in this paper. Because of wolfram minerals occurrence in some parts of mine, the aim of this investigation was the processing of the ore at the shaking table. With this process, the preconcentrat of heavy minerals (sulphide and scheelite) was obtained. That preconcentrate will be the starting material for flotation, and about 60% mass of waste material will be remove.
Abstract
The paper deals with the results of industrial investigation of fly ash preparation, transport and disposal, in the form of high-density hydromixture, at Thermal Power Plant Nikola Tesla B. This technology enables transport and disposal of high-density fly ash hydromixture, at water to solids ratio 1:1 (50 % of solids), implementing completely different approach in regard to the conventional technology, which is based on low-density hydromixture at water to solids ratio 1:10-1:13 (7-9 % of solids). The novel technology has demonstrated the significant advantages concerning the improved stability of disposal area, increased quantity of fly ash to be disposed at the same site, reduced air pollution as well as considerably decreased quantity of excess water drained from disposal site, together with reduced emission of harmful elements into the underground water and, finally, complete elimination of the necessity to discharge the free water into the ground water streams.
Abstract
In this work is given a scheme of the results of determining the conditions under which the waste material from plant for flotation “Feldspar” Bujanovac can become the start as row material for the ceramic industry. In the frame of this researches are issued the examines of possibilities of
thickening and filtering the sample of the waste on class -0.063 mm, after the magnetic separation in laboratory conditions.
Abstract
Laboratory researches of possibilities of getting coated limestone which is using like filler and producing PVC products was in two phases:
– first phase is getting coated limestone
– second phase is checking the degree of coating
Like a start row material was used the limestone from the deposit “Vencac”- Arandjelovac. The results of the experimental researches showed very successfully coating the surfaces of the particles by stearic acid (content 3 %) is making in vibration mill with rings, during which is releasing the
degree of coating min 95 %.
Checking the degree of coating is made by microscope way and immersion method (immersion of waters).
Abstract
Possibility for valorization of molybdenum from copper ore, which is excavating in RBB Bor (Copper Mines Bor), was analyzed several times. The most serious analyze was done in 1982nd, during the preparations for starting exploitation in “Veliki Krivelj” mine. That was the time when Copper Institute
in Bor made “Techno-economical study of possibility for producing and treatment of molybdenum concentrates”, and the facility for extraction of molybdenum from copper-molybdenum concentrates in flotation plant “Veliki Krivelj” was built. Production of molybdenum in this facility has never started
because of the various justified and unjustified reasons. Second, not so serious, analyze of possibility for valorization of molybdenum was done in 2005th, when “RIVS” institute from St. Petersburg, Russia, showed, in its “Study of technological processes for enrichment of smelter slag and underground pit ore in flotation plant “Bor” and copper ore in flotation plant “Veliki Krivelj” “, that it would be interesting to discuss again economical justification of valorization molybdenum in “Veliki Krivelj” mine. However, that statement was based on wrong conclusions from the data of molybdenum con-
centrations in ore, more then twice greater then real. On the other hand, they did not see or comment very high concentration of molybdenum in slag. Because of that, but also several other inconsistencies, that study showed many weaknesses. Therefore, that is why the need for taking more serious analyzes of possibility for valorization of molybdenum in RBB Bor, and to show its potentiality, appeared.
