Study of the technological properties of Karelian rocks as raw material for production of mineral wool

A technological study of basic and ultrabasic Karelian rocks as mineral wool raw material was conducted. It was found that ultrabasic rocks with a ratio of CaO: MgO ≥ 0.5 are the optimum raw material for production of mineral wool by the cupola method. Promising sections of these types of rocks for development are identified.     

A new method for modifying the elemental-phase composition of gabbro-basalt raw materials

A method for the complex modification of raw material compositions based on the process of gravitational differentiation of melts has been developed using new possibilities of the method of physicochemical modeling.     

Use of chemical and metallurgical methods for processing of gabbro-basalt raw material

The recovery of silica and the mixture of iron and aluminum oxides, as well as associated valuable elements, from hydrochloric acid solutions obtained after the desalination of the products of the sintering of wastes of gabbro-basalt raw material with soda by hydrochloric acid has been experimentally studied. A scheme of the integrated utilization of gabbro-basalt raw material involving chemical and metallurgical methods has been suggested.     

Some technological laws and properties for highly porous ceramic concretes

Conclusions Using ceramic concrete made from zirconia as an example we formulated conditions and established the main technological laws for obtaining highly porous ceramic concretes.We analyzed the composition and microstructure of the ceramic concrete from the point of view of the existence in the system of noncompensated shrinkage. It is shown that for ceramic concrete with a high bond shrinkage during drying and heat treatment, with the purpose of reducing the shrinkage stresses in the system, it is necessary to use multifraction (coarse, medium, and fine) fillers.We show the effectiveness of using, as one of the filler components, removable poreforming additive, based on foamed polystyrol.The optimum region of the grain-size distribution of the components was established; this comes within the true specific volumes in the structure of the shaped ceramic concrete and amounts to 20–30% bond, 20–25% fine (0.1–0.4 mm) and 25–40% coarse (5–10 mm) filler made from waste zirconia foamed ceramics, and 20–25% foamed polystrol (0.63–1.6 mm).We studied certain properties of the resulting materials with a porosity of 60–75% and a compressive strength of 5–20 MPa.Compared with other highly porous materials, for example, foamed ceramics, the highly porous ceramic concretes have technological advantages (much lower water capacity of the shaping system, reduced shrinkage in drying and firing) and also improved operating characteristics, for instance, thermal conductivity, thermal-shock resistance and volume constancy.Translated from Ogneupory, No. 2, pp. 20–25, February, 1984.     

Numerical and technological properties of bubble column bioreactors for aerobic processes

This paper describes the method of modelling and numerical simulation of bubble column bioreactors in which the process of aerobic biodegradation of carbonaceous substrate occurs. Such bioreactors belong to systems with distributed state variables. Determining steady states of such objects results in solving non-linear boundary-value problems.The bioreactors with axial dispersion and piston flow with biomass recirculation were analysed. The effectiveness of selected algorithms used to determine the steady states of such bioreactors were compared; the numerical properties of mathematical models of analysed bioreactors were specified, the branches of steady states in bioreactors with axial dispersion and piston flow were determined and the application areas of such bioreactors were defined.     

Analytical methods in assessing coke properties

Dynamic calculations of coke disintegration are considered. The change in mean piece size (geometric and harmonic means) corresponds to the coke quality. The relative ease of crushing (or erosion) shows how one coke compares to another. These characteristics provide improved ability to distinguish between batches of coke and are readily interpreted.     

A two-permeability approach for assessing flow properties in metal foam

One of the key properties for understanding the fluid flow and pressure drop in metal foam is the permeability. This paper investigates a non-traditional approach for evaluating this critical transport property by considering the physics of energy dissipation, i.e., the viscous dissipation and form drag and the fact that they are linked. The current work emphasizes the necessary initial step of clearly distinguishing between different flow regimes prior to evaluating the permeability. This distinction is usually either absent or overlooked in several previous studies, which may lead to significant errors. The approach presented in this study is applied to wind-tunnel steady-state unidirectional pressure-drop measurements for airflow through isotropic open-cell aluminum foam samples having different pore densities. The results show that the porous medium exhibits two different permeabilities—one is calculated and only valid in the Darcy regime, while the other is calculated and only valid in the Forchheimer regime.     

锭模用耐火涂料的流变性质与其工艺性能的关系

研究了水基锭模耐火涂料的流变学性质与其工艺性能之间的关系。实验结果表明，使用性能良好的钨模耐火涂料在低剪切条件下，应具有较大的表现粘度与屈服应力，以及较小的塑性粘度和适当的触变性。     

挤出工艺参数对聚乙烯薄膜性能的影响

探讨了不同的挤出工艺参数对LLDPE薄膜性能的影响，其中，以吹胀比和口模间隙对薄膜的取向有重要影响，决定薄膜帛品的最终机械性能。     

Composition and technological properties of coals from Mongolian deposits

The main characteristics of the composition of coals from Mongolian deposits and their reactivity in thermal dissolution and coking processes were determined. The thermochemical conversion of coals into hydrocarbon products was studied. It was found that Tavantolgoi coal is characterized by high coking properties with the yield of carbon residue to 82.3%. The composition of semicoking tar was studied by chemical analysis and IR spectroscopy.     

The rheological and technological properties of silicon carbide suspensions

Refractories and Industrial Ceramics - An investigation was carried out of the rheological and technological properties of silicon carbide suspensions. The optimal linear pH range of silicon...