Papers by Keyword: Mineralizer

Abstract: In order to achieve the goal of absorption of environmental pollutants, poly-component materials based on magnesium and calcium silicates - metal cations mineralizers – have been synthesized. The study of the processes of mineralization was carried out using model solutions containing soluble sulphates of copper, zinc, manganese and iron. The studies carried out have shown that the synthesized mineralizer based on calcium and magnesium silicates has a multicomponent structure with active electrochemically inhomogeneous centres on its surface as a result of breaking the Ca-O-Si, Mg-O-Si bonds, hydration and leaching of the Ca²⁺ and Mg²⁺ ions. In an acidic environment, the leaching reaction is activated due to H⁺ adsorption and the weakening of the bond between Ca²⁺ and O^2-, thus making the transition of Ca²⁺ into the liquid phase more advantageous. As a result, a negatively charged ≡Si-O-layer enriched with silicon is formed, which is able to interact chemically with heavy metal ions present in the electrolyte solution.

Abstract: The aim of the present study is to evaluate the properties of cements produced from clinkers co-processed with unreacted ore waste (UOW), that is a waste generated in TiO₂ production. A commercial CP V ARI RS cement and four different cements produced in the laboratory were characterized. The cements produced in the laboratory were made from raw mixes with a Lime Saturation Factor (LSF) fixed in 98% and varying the incorporation content of TiO₂ in 0% (reference); 0.5%; 1.0% and 2.0% from the incorporation of UOW, by weight. The raw mixes were calcined at 1340°C and the resulting clinkers were mixed and interground with gypsum, thus resulting in the laboratory cements. These cements were characterized physically and mineralogically, besides tests of loss on ignition, expansibility (Le Chatelier’s needle) and compressive strength at 1, 3, 7, 28 and 91 days. It was observed that the incorporation of the UOW enhanced the formation of alite, due to the mineralizing effect of the titanium, and cement with 0.5% TiO₂ (1.3% of UOW) presented the highest strength.

Abstract: The article presents the results of work on manufacturing paving clinker based on carbonate-argillaceous opokas belonging to the group of siliceous opal-cristobalite rocks. General characteristics of these rocks are given. Their composition, properties and spread patterns are shown. It has been shown that the introduction of strong minerals up to 1% allows creating products with water absorption of less than 2.5% at burning temperatures of 1050-1100 ° C. The resulting products are yellow and fully meet the requirements of regulatory documents. The main technological factors in the production of paving clinker are as follows: the grain composition of the crushed raw materials, burning temperature of the products and the amount of mineralizer. The production of paving clinker based on carbonate-argillaceous opokas can be organized either by extrusion molding or by compression molding.

Abstract: Currently building sector requires the use of new technologies and innovative materials. Realization of mentioned requirements allow ensuring rate of performed works, reducing labour building constructions costs and improving building performance. In current work, loose fill material from hemp shives and binding material are analysed. The mixture of hemp shives and binder may be used in frame constructions as blown or poured loose fill material for thermal insulation or structural use. Hardened composite is characterized by high strength and excellent thermal conductivity when it is used in building partitions and enclosures. In our work hemp shives are mineralized with different amount of liquid sodium silicate and mixed with cementitious binder. Macro-and microstructures of hardened composite are analysed, influence of amount of mineralizer on the strength and thermal conductivity of composite is evaluated.

Abstract: In this paper, the ZnO crystal was synthesized using hydrothermal method through 24 hours reaction with 35 % filling factor at 430°C. When the mineralizer concentration is rather low (eg. lmol/L NaOH), only ZnO microcrystal is produced. The mineralizer concentration increases, the larger crystal was present. When 5 mol/L NaOH served as mineralizer, the extent of the synthesized crystal was nearly 500m. The ZnO cryslals with length of 1500m were present when 3ml/L KOH served as mineralizer. Respectively when 3mol/L NaOH and lmol/L KBr were used as mineralizer, the extent of the synthesized crystal was nearly 700m , the diameter was 200m and the exposed faces m { 100}, p { 101 } was complete , so we obtained the higher quality crystals. Besides the larger crystal, a great deal of microcrystal and nanocrystallites cluster was also present in the product.

Abstract: Silica is used for lining of the upper parts of glass furnaces and their regenerators and for lining of the lids of arc furnaces and for the coke oven batteries construction. Silica bricks represent 60% of refractory material used for a coke battery construction. Coke ovens are generally the largest oven aggregates, where silica material is used. The whole coke oven battery may reach the length up to 80 m due to the chamber sizes. A single coke oven battery contains up to 50.000 tons of refractories [1]. From the material science point of view, the durability of silica bricks depends on numerous parameters including first of all porosity and mineral composition. Microstructure of silica bricks changes during their application due to the heat load, repeated heating and cooling, and direct contact with the oven atmosphere. The paper discusses the possibility of reducing the apparent porosity and increasing of bulk density of coke oven silica bricks. It describes the effects of an iron dust, microsilica and influence of the compaction pressure on the coke oven silica microstructure. Functional characteristics of the material prepared according to the new standard recipes are compared with the properties of standard silica products.

Abstract: In ( OH ) ₃, InOOH and In₂O₃ crystals were synthesized by hydrothermal method, using pure water, 1mol/L KOH and 5mol/L KOH as mineralizer, the fill factor of 35%, reacted at the temperature of 200°C, 250°C and 350°C respectively, and time of 24 h. The phase transformation rule of In ( OH ) ₃, InOOH and In₂O₃ was studied in different temperatures and mineralizer, and their morphology have been analyzed. When pure water was used, temperature was 200°C , the results showed that In ( OH )₃ crystalline phase was no obvious transformation and secondary crystallization, the crystal had nonspecific morphology. While temperature was 250°C and 350°C, the In ( OH ) ₃ crystal transformed into InOOH. When 1 mol/L KOH and 5 mol/L KOH was used, temperature was 200°C , the In ( OH ) ₃ crystal had secondary crystallization. In particular, the largest-scale crystal was about 20 μm, the smallest crystal was less than 200 nm when 5 mol/L KOH was used. InOOH crystal and a small amount of In₂O₃ were obtained in 250°C. When temperature reached 350°C , the In₂O₃ with cubic bixbyite structure was obtained, exposing the faces { 001}, { 010}, { 100} and { 101}, and the length of crystal side was more than 50 μm.

Abstract: Zn_1-xCo_xO crystals were synthesized by hydrothermal method with 3mol/L KOH as mineralizer. The fill factor was 35%, reaction temperature, 430°C and reaction time, 24 hours. When the Zn ( OH )₂ doped with CoCl₂ 6H₂O was used as precursor, many different shapes of Zn_1-x Co_x O crystals were obtained in the hydrothermal synthesis products. The Co concentration in the crystal was determined by electron probe, the atomic percentage of Co in the crystal increased as the concentration o f CoCl₂ 6H₂O in precursor increased. The measurement of magnetism was carried out by using a superconducting quantum interference device ( SQU ID ). It is found that the magnetization varies unobviously as the temperature rises below the room temperature. The hysteresis loop of Zn_1-x Co_xO crystals was obtained at 300K and shows the ferromagnetism at the room temperature.

Abstract: In this paper, the ZnO crystal was synthesized using hydrothermal method through 24 hours reaction with 35 % filling factor at 430°C. When the mineralizer concentration is rather low (eg. lmol/L NaOH), only ZnO microcrystal is produced. The mineralizer concentration increases, the larger crystal was present. When 5 mol/L NaOH served as mineralizer, the extent of the synthesized crystal was nearly 500m. The ZnO cryslals with length of 1500m were present when 3ml/L KOH served as mineralizer. Respectively when 3mol/L NaOH and lmol/L KBr were used as mineralizer, the extent of the synthesized crystal was nearly 700m , the diameter was 200m and the exposed faces m { 100}, p { 101 } was complete , so we obtained the higher quality crystals. Besides the larger crystal, a great deal of microcrystal and nanocrystallites cluster was also present in the product.

Abstract: A comparative study worked on crystal morphology and luminescence characteristic by hydrothermal method with mineralizer of 3 mol /L KOH, fill factor of 35%, under the condition of three kinds of mineralizers which included 3 mol /L KOH in sample 1, 3 mol /L KOH and 1 mol /L LiOH in sample 2, 3 mol /L KOH and CaO: Zn ( OH) 2 = 2% (amount of substance percentage). Nonpolar ZnO crystals were synthesized by adding proper proportion of CaO or LiOH,the speed of growth along c-axic was weakened obviously. The obtained ZnO crystals exposed more areas on the positive polar face c { 0001}. meanwhile,it exposed negative polar-c {000},positive pyramidal face + p { 101},negative pyramidal face-p {10} and hexagonal faces m {1010}. Only KOH or LiOH auxiliarily added,the emission spectrum was only visible light,no UV light from band edge transition, indicating that the crystal defects luminous center are numerous. A strong UV band emitting from band edge transition was in luminescent spectrumn of the prepared crystals by adding CaO,which indicated a decrease in defects luminous center.