Recycling Of Auriferous Ore Flotation Tailings In Slag-alkaline Cement

Research analysis aimed at stabilizing processes in industrial waste and other, similar hazardous ion containing materials, shows that these materials can be successfully stabilized, if they are bound as a mineral component in cement. Considering that auriferous ore flotation waste contains heavy metals that are useless for any production and accumulated in dumps, storages and sumps, this impairs the ecology of the country. This is why current study is conducted on recycling of auriferous ore flotation tailings by binding it as a cement component, which is also can be one of its effective applications. For heavy metal bonds stability evaluation in the composition of the cement matrix, the method of leaching elements by atomic spectroscopy was applied.According to the research it was found that application of slag-alkaline viscid systems for recycling of auriferous ore dump flotation tailings provides considerable advantages over traditional Portland cement systems based on PC I-500. It was shown that along with the physical blocking in the artificial stone matrix, based on slag-alkaline viscid systems, elements of heavy metals were also bound chemically as a part of structure-forming compounds. In this regard use of auriferous ore dump flotation tailings (10…30 %) in the compound of slag-alkaline cement results in the prolonged solidification and provides the same level of cement stone durability as the check sample compound

Аналіз ефективності використання пороутворювачів для газобетону з різними фізико-механічними і структурними характеристиками

The development of the market of gas-forming agents takes place in a market economy amid increasing demands on the quality, safety, environmental friendliness and cost-effectiveness of their use. The main blowing agent used at cellular concrete production facilities is pigmented aluminum powders and aluminum pastes.The article provides a comparative description of various types of blowing agents in accordance with specific production conditions.The quality of cellular concrete products largely depends on the reactivity of the used aluminum and on how much it corresponds to the production process, depending on the reactivity of the raw materials.A very important parameter is the stability of the technical characteristics of aluminum pastes over time. This characteristic is very important for ensuring the storage of the paste, its safety during transportation and storage in the warehouse.Depending on the required structure of aerated concrete, coarser or finer powder is used in production. The higher the average density of the product, the coarser the powder should be used. If necessary, you can make powder with any time the start of the reaction of gas formation.The stability of the technological process for the production of cellular concrete products and, as a consequence, the minimization of the amount of substandard products depend to a large extent on the reactivity of the used aluminum and on how much it corresponds to the production process depending on the reactivity of the raw materials. The reactivity of aluminum powder depends on the particle size of aluminum, the structural characteristics of its surface and the properties of the protective film.During the experimental studies, a study was made of the characteristics of aluminum powder of the Ukrainian manufacturer PAP-1 and aluminum paste ALBApor308B (Romania).Based on the analysis of the influence of the considered technical characteristics of aluminum pastes on the course of the technological process and the complex of technical and environmental factors (the cost of the paste, the effectiveness of its use, environmental factors), preference is given to aluminum paste made in Romania by «Alba» companyРозвиток ринку газоутворювачів відбувається в умовах ринкової економіки на тлі підвищення вимог до якості, безпеки, екологічності та економічності їх використання. Основним газоутворювачем, що застосовується на підприємствах з виробництва ніздрюватого бетону, є пігментні алюмінієві пудри та алюмінієві пасти.В статті наведена порівняльна характеристика різних видів пороутворювачів у відповідності з конкретними умовами виробництва. Якість продукції з пористого бетону в значній мірі залежить від реакційної здатності використаного алюмінію і від того, наскільки він відповідає виробничому процесу в залежності від реакційної здатності сировинних компонентів.Дуже важливий параметр – стабільність технічних характеристик алюмінієвих  паст в часі . Ця характеристика дуже важлива для забезпечення зберігання пасти, її безпеки при транспортуванні і зберіганні на складі.Залежно від необхідної структури газобетону на виробництві використовують більш грубу або тонку пудру. Чим вище середня густина виробу, тим грубіше пудра повинна використовуватися. При необхідності, можна виготовити пудру з будь-яким часом початку реакції газоутворення. Стабільність проходження технологічного процесу виробництва виробів з ніздрюватого бетону і як наслідок мінімізація кількості некондиційної продукції в значній мірі залежать від реакційної здатності використаного алюмінію і від того, на скільки він відповідає виробничому процесу в залежності від реакційної здатності сировинних компонентів. Реакційна здатність алюмінієвої пудри залежить від розмірів частинок алюмінію, структурної характеристики її поверхні і властивостей захисної плівки.При проведенні експериментальних досліджень виконано дослідження характеристик алюмінієвої пудри українського виробника марки «ПАП-1» і алюмінієвої пасти «ALBApor308B» (Румунія). На основі проведеного аналізу впливу розглянутих технічних характеристик алюмінієвих паст на хід технологічного процесу та комплекс техніко-економічних факторів (вартість пасти, ефективність її застосування, екологічні чинники) перевагу віддано алюмінієвій пасті румунського виробництва фірми «ALBA»

Low molecular weight thymic factor inhibits histamine release from basophils

Low molecular weight thymic factor stimulates the suppressor function of T-lymphocytes, increases cAMP content (but not cGMP) in lymphocytes and inhibits histamine release from sensitized basophils. The mechanisms of LTF action are discussed

ПОМ’ЯКШЕННЯ УПРАВЛЯЮЧОГО УХИЛУ В КРИВИХ НА ПРОМИСЛОВОМУ ТРАНСПОРТІ

Influencing of decline of coefficient of rolling friction is examined in curves on the size of softening of leadingslope.Рассматривается влияние снижения коэффициента сцепления в кривых на величену смягчения руководящего уклона.Розглядається вплив зниження коефіцієнта зчеплення в кривих на величену пом’якшення керівного ухилу

Development of Solutions Concerning Regulation of Proper Deformations in Alkali-activated Cements

The essence of the problem related to proper deformations in alkali-activated cements (AAC) complicated with high content of gel-like hydrate formations was analyzed. Cement types diametrically opposite in their compositions and, accordingly, in the content of gel phases during hydration, that is, the alkali-activated portland cement (AAPC) and alkali-activated slag cement (AASC) were taken for consideration. Approaches to formation of an effective structure of artificial stone counteracting shrinkage deformation by means of interference in structure formation when using complexes of mineral and organic compounds were proposed. Such compounds in composition of complex organo-mineral admixtures jointly influence intensification of crystallization processes and formation of an effective pore structure and morphology of hydrate phases while reducing water content in artificial stone. Salt electrolytes of various anionic types and anion-active surface-active substances were considered as ingredients of the proposed complex modifying admixtures.It has been found that the "salt electrolyte–surfactant" system is the most effective for AAPC modification. It was shown that modification of AAPC with this complex admixture based on NaNO3 reduced shrinkage from 0.406 to 0.017 mm/m. Instead, the use of Na2SO4 provided AAC of this type with a capacity of expansion up to 0.062 mm/m. It was shown that the effect of compensated shrinkage of modified AAPC is associated with a higher crystallization of low-basicity hydrosilicates (CSH(B)) and calcium hydroaluminates (CaO∙Al2O3∙10H2O). An additional effect is associated with formation of sulfate-containing sodium-calcium hydroaluminate (for the Na2SO4-based system) and crystalline calcium hydronitroaluminate (for the NaNO3-based system) with a corresponding microstructure stress.For further development, a complex admixture of "Portland cement clinker–salt electrolyte–surfactant" system was proposed for AASC modification. It provided shrinkage reduction from 0.984 mm/m to 0.683 mm/m. Minimization of the modified AASC shrinkage was explained by formation of sodium hydroalumosilicate of gmelinite type ((Na2Ca)∙Al2∙Si4∙O12∙6H2O) with a high degree of crystallization along with low-basicity calcium hydrosilicates. It was noted that the cement stone structure is characterized by high density, uniformity, and consolidation of hydrate formation

Development of Solutions Concerning Regulation of Proper Deformations in Alkali-activated Cements

The essence of the problem related to proper deformations in alkali-activated cements (AAC) complicated with high content of gel-like hydrate formations was analyzed. Cement types diametrically opposite in their compositions and, accordingly, in the content of gel phases during hydration, that is, the alkali-activated portland cement (AAPC) and alkali-activated slag cement (AASC) were taken for consideration. Approaches to formation of an effective structure of artificial stone counteracting shrinkage deformation by means of interference in structure formation when using complexes of mineral and organic compounds were proposed. Such compounds in composition of complex organo-mineral admixtures jointly influence intensification of crystallization processes and formation of an effective pore structure and morphology of hydrate phases while reducing water content in artificial stone. Salt electrolytes of various anionic types and anion-active surface-active substances were considered as ingredients of the proposed complex modifying admixtures.It has been found that the "salt electrolyte–surfactant" system is the most effective for AAPC modification. It was shown that modification of AAPC with this complex admixture based on NaNO3 reduced shrinkage from 0.406 to 0.017 mm/m. Instead, the use of Na2SO4 provided AAC of this type with a capacity of expansion up to 0.062 mm/m. It was shown that the effect of compensated shrinkage of modified AAPC is associated with a higher crystallization of low-basicity hydrosilicates (CSH(B)) and calcium hydroaluminates (CaO∙Al2O3∙10H2O). An additional effect is associated with formation of sulfate-containing sodium-calcium hydroaluminate (for the Na2SO4-based system) and crystalline calcium hydronitroaluminate (for the NaNO3-based system) with a corresponding microstructure stress.For further development, a complex admixture of "Portland cement clinker–salt electrolyte–surfactant" system was proposed for AASC modification. It provided shrinkage reduction from 0.984 mm/m to 0.683 mm/m. Minimization of the modified AASC shrinkage was explained by formation of sodium hydroalumosilicate of gmelinite type ((Na2Ca)∙Al2∙Si4∙O12∙6H2O) with a high degree of crystallization along with low-basicity calcium hydrosilicates. It was noted that the cement stone structure is characterized by high density, uniformity, and consolidation of hydrate formation