ПОРІВНЯННЯ АМІНІВ ЯК ГАЗОУТВОРЮВАЧІВ ВОГНЕЗАХИСНИХ КОМПОЗИЦІЙ ІНТУМЕСЦЕНТНОГО ТИПУ

Purpose. Study of influence of blowing agents amines structure on the construction processes of thermal insulating char layer of intumescent system ammonium polyphosphate/pentaerythritol/amine and fire protection efficiency of this system at high temperatures. Methodology. A fire retardant mixture of ammonium polyphosphate/pentaerythritol/amine was chosen as a model intumescent system. Dispersion of vinyl acetate copolymer with vinyl ether of versatic acid was used as a polymeric component. A step-by-step study of the characteristics of the char layer of the intumescent composition was applied in the study, consisting in the analysis of the characteristics of the char formed after keeping the intumescent composition samples at a certain temperature between 100 and 800 °C, char residue mass (m, %), structure and density of the formed char layer. The method of infrared spectroscopy was used for identification of products of thermolysis of intumescent systems. Determination of fire protection efficiency of intumescent coatings was carried out in a mini-oven under standard fire conditions. Findings. The influence of the structure of amines blowing agents on the formation of char layer of intumescent system ammonium polyphosphate/pentaerythritol/amine was studied. Physico-chemical parameters of char layer formed during high temperature swelling of intumescent system components with varying amine: urea, melamine, dicyandiamide, guanidine, thiocarbamide, formylthiosemicarbazide, thiosemicarbazide, phenylethylcarbamide have been determined. In the temperature range 200–400 oC for systems with linear amines (urea, thiocarbamide, thiosemicarbazide), there is a rapid formation of insulating layer with intense outgassing (high intumescent coefficients K) and the same rapid its destruction with significant losses of char residue mass (Δm). The presence of melamine, dicyandiamide and guanidine in intumescent system provides constancy of intumescent coefficient at minimal mass loss. Chemical transformations of intumescent systems were studied by the method of infrared spectroscopy when the investigated amines were varied. It was found that linear diamines do not form stable spatially branched phosphamide compounds with phosphates as the basis of a thermostable heat-insulating frame. At the same time in IR spectra of char residue systems with melamine, dicyandiamide and guanidine the absorption bands of P-N-C bonds (1070–1050 cm-1) and P-N (980–950 cm-1) up to 600–700 oC are observed. Fire tests proved that melamine, dicyandiamide and guanidine are blowing agents providing maximum protection of metal against fire and can be used for composition of fire retardants for steel constructions.Originality. It has been proved that amines in intumescent polyphosphate system perform at least two functions: blowing agents by means of thermal destruction to incombustible gases and nucleophilic compound that takes part in char layer formation by aminolysis of electrophilic substrates.Practical value. The optimum amine blowing agents for developing formulations of intumescent coatings with enhanced flame retardant properties have been established.

Optimization of Microwave Reductive Roasting Process of Bauxite Residue

In this study, microwave-assisted heating is presented as a suitable method to transform the hematite and goethite contained in bauxite residue into magnetite, wüstite, and metallic iron, with a short processing time. The final target was the production of a sinter with strong magnetic properties, allowing the magnetic separation of Fe from the residue. The influence of microwave energy on the sample, the effect of irradiation time, and the carbon/bauxite residue mass ratio (C/BR) were the parameters that have been analyzed to optimize the process. Their optimized combination allowed transforming 79% of the iron present in the sinter into metallic iron. However, hercynite was also formed, and the presence of this mineralogical phase could be considered a possible drawback for its magnetic properties.

Pengaruh Medan Elektromagnetik terhadap Densitas dan Vikositas pada Vacuum Residue

This study tested the effect of electromagnetic field on density and viscosity of vacuum residue from PT. PERTAMINA Refinery Unit III Plaju. The study was conducted using a batch reactor equipped with electromagnetic. The fixed variable in this study is the vacuum residue mass and cracking time, while the variables which are varied are reaction temperature and electromagnetic field. The study was conducted to see the effect of temperatures ranging from 100, 200, 300 and 400oC, and the use of electromagnets with electric currents of 0A, 5A, 10A, 15A and 20A on the density and viscosity of vacuum residue. The experiment compared the effect of the process with electromagnetic field and without electromagnetic field on the density and viscosity of vacuum residue. The results showed that the lowest density (0.874 g/cm3) and viscosity (0.481 cP) were obtained by using 20A electric current electromagnetic field at a temperature of 400oC.A B S T R A KPenelitian ini dilakukan untuk menguji pengaruh medan elektomagnetik terhadap densitas dan viskositas vakum residu petroleum dari PT. PERTAMINA Unit Pengolahan III Plaju. Pengujian dilakukan dalam reaktor-batch yang dilengkapi dengan elektromagnetik. Variabel tetap dalam penelitian ini adalah massa vakum residu dan waktu cracking, sedangkan variabel yang divariasi adalah suhu cracking dan kuat arus listrik elektromagnetik. Studi dilakukan untuk melihat pengaruh suhu mulai dari 100, 200, 300, dan 400oC, serta penggunaan elektromagnet dengan arus listrik sebesar 0A, 5A, 10A, 15A dan 20A terhadap perubahan densitas dan viskositas dari vakum residu. Eksperimen yang dilakukan membandingkan pengaruh proses dengan medan elektromagnetik dan tanpa medan elektromagnet terhadap densitas dan viskositas vacuum residue. Hasil penelitian menunjukkan bahwa nilai densitas dan viskositas vakum residu terendah diperoleh pada penggunaan medan elektromagnetik dengan arus listrik 20A pada suhu 400oC yaitu pada nilai denitas sebesar 0,874 g/cm3 dan nilai viskositas sebesar 0,481 cP.

Dynamics of Sulfentrazone Applied to Sugarcane Crop Residues

The sulfentrazone is regularly applied to sugarcane crop harvest residue for PRE control of weedy species, especially in the dry season during the year, but little is known about how rainfall timing or crop residue mass affect the release of sulfentrazone into the soil and its subsequent effectiveness. Two experiments were conducted to examine the effects of sugarcane residue mass (5, 10, 15, and 20 t ha−1) and rainfall timing (1, 30, and 60 d after herbicide application) on sulfentrazone retention. Rainfall volumes were simulated at 2.5, 5, 10, 20, 35, 50, and 100 mm. A 20-mm rainfall volume was simulated at 7 and 14 d after the first simulated event. The water passing through the straw was collected after each rainfall simulation. The concentration of sulfentrazone was measured by liquid chromatography and mass spectrometry. The initial 20 mm of rain released the maximum mass of sulfentrazone from the sugarcane residue. The mass of sugarcane residue affected the amount of sulfentrazone recovered. The amount of sulfentrazone released from the residue was significantly reduced by the persistence on the residue surface for long periods before the occurrence of rain. During periods of low rainfall, recommendations for sulfentrazone rate must take into account losses that occur when applied over the harvest residues to design a weed-management plan that does not compromise efficacy and duration of the residual effects.

One-Step Pyrolysis Process for Recover Zinc and Mercury from Spent Zinc-Manganese Batteries

In this paper, One-step pyrolysis process for the recovery of mercury and zinc from spent zinc–manganese batteries is proposed. Laboratory tests were performed to remove mercury and zinc from spent batteries and recover them. Correctitude test were used to analyze the effect of three factors: temperature, weight and time on the removing and recovery efficiency of zinc. In this research, temperature is dominant factor, weight and time are subordinate. After removing mercury, higher temperature could assure the removing efficiency of mercury above 99.9% at the same time of removing zinc. Under 0.02 MPa, efficiency of removing and recycling of zinc were investigated. The removing efficiency is 94.2% at 950 °C and 96.2% at 1000 °C. When the heated time is 1.5 h, the removing efficiency is 95.6%, which reach the aim 95.0%. With the increase of sample weight, the necessary heated time could be kept within 2.5 h without the loss of removing efficiency. The recycling efficiency of zinc could approach 75%. The content of zinc is above 99.0% in condensed zinc product. After being treated, the residue mass is about 40% of sample.