An essential aspect of the physical and chemical theory of the processes of magmatic petrogenesis is the comparison of data on the material composition of rocks - members of natural associations - and experimental data on the composition of products of evolution and crystallization of melts in model silicate systems.

The name of Academician A.N. Zavaritsky, one of the greatest scientists of our country, is associated with a significant stage in the development of Soviet petrography and geology of ore deposits.

The general principles of selecting selectively acting solvents, setting up tests and interpreting their results for the technical and economic assessment of mineral leaching processes have long been known and described in detail in many hydrometallurgy courses. With regard to the specific problems of selectivity of dissolution in phase chemical analysis, these issues are also covered quite fully ...

The dependences linking the degree of decomposition of a solid substance with the initial amount and concentration of a solvent through an equilibrium constant are described more simply if the equation of the chemical dissolution reaction, accompanied by the formation of complex or difficult-to-dissolve products, is attributed to one mole of solvent. The equilibrium constant of such a reaction ...

Studies on the kinetics of apatite dissolution in sulfuric acid have shown that the formation of films of insoluble compounds on the surface of the solid phase makes it difficult for solvent to access it and leads to a slowdown and even complete cessation of the dissolution process. In the concentration range of 16-25 n. H2SO4, the dissolution reaction slows down sharply. At concentrations above 25 n., apatite dissolves quickly. This is due to the different physical structure of the calcium sulfate film, which depends on the concentration of the solvent...

Molybdenum and tungsten can be extracted with alkylamines from acidic solutions obtained during the chemical refinement of scheelite concentrate at the Tyrnyauz Processing Plant. These solutions contain 5-8 g/l of molybdenum and tungsten. Each is present in both oxidized and reduced forms. The solution also contains significant amounts of phosphorus and silicon. Apparently, molybdenum and tungsten are found in these solutions in the form of phosphoric and silicic heteropoly acids, since these metals are excellently extracted by solutions of amines in nonpolar diluents. To determine the state of molybdenum and tungsten in these solutions, the behavior of metals during extraction by their amines from hydrochloric acid solutions in the presence of phosphorus and silicon in a wide range of hydrochloric acid concentrations was studied...

The flotation capacity of a mineral is influenced by the electrical characteristic of the boundary layer in the mineral-solution system. Therefore, it is important to correctly determine the zero charge point, which characterizes the absence of a double electric layer. It can be found by measuring the capacity of this layer ...

The Snider Nunataks are located at coordinates 107°41' E and 66°03' S on the Knox Coast in East Antarctica. They are several rocky outcrops among the mainland ice, located in an area of about 0.15 km^2. The sizes of nunataks vary from 10-15 to 120-150 m across. Nunataks are located 200-250 m from the coastal barrier of the ice sheet.

The year 1962 marked the 75th anniversary of the completion of the works of I. G. Bogusky, which laid the foundation for the study of the kinetics of solid-liquid dissolution. The question of the dissolution rate was raised by Wenzel and then by some French scientists in the middle and even at the beginning of the XIX century. However, the first systematic studies of the regularities of the dissolution process of a solid were the works of I. G. Bogusky, one of the pupils of D. I. Mendeleev. Bogusky found that the dissolution rate is proportional to the concentration of the solvent and the size of the solid surface. Subsequent work by Shpring and other researchers on a variety of objects confirmed the conclusions of I. G. Bogusky, but did not give exhaustive results that would allow to express the observed regularities in the form of mathematical formulations.

The developed symbolism makes it possible to solve the problem in the same way and simply in the most general case: given (using a model, drawing or other way) a regular system of points or a combination of several regular systems of points forming a crystal lattice; it is required to find the space symmetry group of this set. We will not present a systematic approach to solving this problem here; we will only point out that the matter comes down to writing the group symbol. To avoid possible errors in choosing orientation and correctly selecting the generating element of symmetry among the set of parallel elements of symmetry of a given direction, a simple “determinant” of space groups has been compiled. Using this determinant, it is possible to determine a group, even if the found group symbol does not correspond to the accepted one for this group. The compilation of such a determinant and a systematic presentation of the progress in solving the problem posed above is the work of the author that has already been completed. The second significant consequence of the proposed symbolism is the ability to carry out a new simple and systematic derivation of 230 space groups.

As we know, in the angular ratio, tetragaric crystals are characterized by only one crystallographic constant. No matter how simple the given formulas are, to simplify and facilitate calculations, V. M. Goldshmidt, O. M. Ansheles, V. V. Dolivo-Dobrovol'skii, G. V. Barker, as well as other crystallographers-calculators, resorted to special ones, once and forever compiled tables, wholly or partly replacing logarithm by simply finding answers from tables. Massive crystallographic calculations carried out while working on the Determinant of Crystals forced its compilers to use these tables. However, in addition to these ready-made tables of Goldschmidt, Ansheles, Dolivo-Dobrovol'skii and Barker, for the speed of calculations, the authors of this article compiled some more tables, which, together with the first ones, should finally simplify all crystallographic calculations of tetragyr crystals. The ease of working with the compiled tables makes it rational to publish them for general use.

The classification of 32 types (or groups) of crystal symmetry, i.e., the basis for dividing them into systems, or systems, can be based on various principles. Of these principles, the following two are the main and most natural. It is possible to classify the types (or groups) of symmetry, i.e., certain spatial collections of symmetry elements as such, by themselves, without relation to the complexes of possible faces and edges of the crystal to which these types of symmetry are characteristic. Let us call such classifications “purely geometric”. It is possible to classify the types of symmetry, taking into account the properties of those complexes of possible faces and edges of the crystal, in other words, those spatial lattices to which these types (groups) of symmetry are characteristic. Let us call such classifications “crystallographic”. The proposed classification, nomenclature and symbolism are closely linked by a single principle and are entirely based on a genetic trait — on the generative elements of symmetry.

(Report read on March 11, 1933 at a meeting of the departments of petrographic-mineralogical cycle of sciences, dedicated to the 50th anniversary of the death of Karl Marx). The history of crystallography, its main trends and recent achievements are presented in a brief and reference form. This base serves for the study of crystallographic problems that are largely solved according to industrial requirements. Modern period and tasks of crystallography (see article). We can distinguish groups of problems: a group of physical problems connecting the physics of phenomena with their geometry; group of chemical problems; a group of problems related to physical and chemical phenomena."

It is no coincidence that the author did not title this article as a new method for determining symbols. Being a combination of two already known methods, this method cannot be called new. It turns out that two methods - the method of Prof. O. M. Anshelis and a slightly modified method of belts with their joint application make the process of determining symbols simpler than when using each of these methods separately.However, the purpose of this article is not only to show a method for such a joint application of these methods, but also to give a simple and independent conclusion and proof of the proposed combined method. The author considers it necessary to give such an independent conclusion in order to make this method quite accessible, both practically and theoretically, even to persons unfamiliar with the methods on which the proposed method is based, from which the proposed method originated.