Agronomic potential of four rock powders, pure or mixed, as soil remineralizers

Detailed knowledge of chemical, petrographic and mineralogical compositions as well as the effects of applying rock powder on soil chemical properties and plant production are required for classifying these materials as soil remineralizers (SR), as according to Brazilian legislation in force. This study aimed to evaluate the potential of rock powders siltstone, tephrite and olivine melilitite, pure or mixed, on improving the fertility of a Cambisol and a Nitisol as well as the yield of soybean and barley crops grown in succession inside a greenhouse. For that purpose, these products were characterized as their granulometry, chemical, mineralogical and petrographic compositions. Based on the results, it was verified which products met the requirements for registration as SR established by the Normative Instruction Number 5 (NI5) from MAPA. Elemental chemical and grain size analyses indicated that all tested products met the NI5 requirements for their registration as SR. The mineral composition identified through petrographic analyses was confirmed by analyses performed via X-ray diffractometry techniques. Olivine melilitite rock, pure or mixed with siltstone, had the highest agronomic potential when compared to other powders, thus acknowledged as a SR. Although tephrite had little agronomic response on evaluated soils and crops, it also meets the SR requirements. Siltstone fulfilled most of NI5 criteria, except for exceeding the maximum content of free silica (quartz); therefore, it likely does not meet the requirements for its admittance as a SR.

Characteristics of Agricultural Dust Emissions from Harvesting Operations: Case Study of a Whole-Feed Peanut Combine

The rapid development of peanut mechanization has increased the amount of dust expelled from peanut mechanized operations, which degrades the air quality and endangers the health of agricultural workers. Therefore, the purpose of this study is to figure out the characteristics of dust emission from mechanized peanut harvesting. To this end, the particulate matters of diameters ≤ 2.5 μm and ≤ 10 μm and the total suspended particles were sampled in real time during peanut harvesting in Henan Province, China, and the airborne particle concentrations and particle size distributions were measured. The dust particles discharged during the mechanized peanut harvesting were concentrated within the 2~30 µm size range. When the wind speed was reduced below the settling velocity of the largest particles, the more massive particles were carried in the downwind. The amount of free silica in the dust samples was determined by X-ray diffraction analysis. Both the total dust and free silica concentrations exceeded the occupational exposure and threshold limits. To improve the characteristics of dust emission, the microstructure and dispersion of the dust were also investigated. Reducing the agricultural operations during periods of high wind speed, low crop-moisture content, and low air humidity is recommended for reducing the dust exposure of workers. The results will provide guidance and technical support for reducing the dust emissions of mechanized harvesting operations, improving air quality, and reducing the health hazards to operators.

Life cycle assessment of crushed glass abrasive manufacturing from recycled glass

Sustainable Development Goals (SDGs) are the key motivation factors to determine the characteristics of green abrasives, contributing to carbon emissions reduction, reduce waste generation and build up a recycling-based sustainable blasting industry. Such aim can be evaluated through life cycle assessment as a structured basis for evaluating the performance of environmental impacts and benefits of green abrasives application in blasting industry. Crushed glass is one of zero free silica content abrasives from recycled glass, and it is widely used due to inert and safe characteristics. Database of life cycle inventory (LCI) are obtained through literature review. Production of 1 ton/year of crushed glass abrasives has been modelled at gate-to-gate boundary where the human health appears as the major impact potentials (0.71 DALY, disability-adjusted life year) at the production stage. The selection of 100% recycled glass as the raw materials in the supply chain has led to insignificant impact potentials of resources scarcity and ecosystem damages per unit production of 1 ton of crushed glass at USD 4.79 and 0.06 species. year, respectively.

Sustainability-Based Characteristics of Abrasives in Blasting Industry

The abrasive blasting industry is identified as the most unsafe operation in terms of potential exposure to airborne crystalline silica. This is due to the free silica content in the common abrasives that are used for blasting activities. This paper will identify a sustainability-based or green blasting media to replace free silica content abrasives for blasting activities. The characteristics of sustainability-based abrasives are determined based on systematic review procedure. The combination keywords of “Abrasive blasting”, “Garnet’’, “Free Silica Media”, “Sustainable blasting”, “Eco-friendly blasting”, “Glass Bead blasting” and “Green blasting” were used to collect the existing studies on abrasive blasting operations. Six characteristics of green abrasives were identified: (1) zero content of free silica, (2) high efficiency and productivity, (3) low consumption media (4) low amount of waste generation and emission potentials (5) high recyclability and (6) environmentally friendly in line with sustainable development goals SDG3, SDG12, SDG13, SDG14 and SDG15. The application of green abrasives as substitution to free silica media is therefore important not only for safety and health reasons, but also for the environmental protection and sustainable business operations.

The Effect of Resin and NH4OH Addition in The Making of Ammonium Silica Fertilizer from Geothermal Sludge

Geothermal sludge is a waste product from geothermal where it contains SiO2 which can be used as fertilizer. In this study, the making of silica ammonium fertilizer was carried out by taking salicy acid from geothermal sludge by extracting and adding resin which was then modified with NH4OH addition. Extraction was done using 1000 ml of KOH 1 N to dissolve 60 grams of Geothermal Sludge. Resins are added with variations in resin weight, namely, 5, 10, 20, 30, and 40 grams. NH4OH was added with variations in concentrations namely 3, 6, 9, 12 and 15% with a ratio of filtrate and NH4OH solution of 1: 1. The resulting ammonium silica inorganic liquid fertilizer products were analyzed for free silica and ammonia levels. The results of this study indicate that the levels of free silica and ammonia are influenced by the weight of the resin used and the concentration of ammonium hydroxide mixed. From the results of the research, it was found that inorganic silica liquid fertilizer with the highest SiO2 content in ammonium silica liquid fertilizer occurred when adding 20 grams of resin with the addition of NH4OH with a concentration of 15% which was 1,831.87 mg / L while the highest NH3 content in fertilizer liquid ammonium silica occurs when adding 40 grams of resin with the addition of NH4OH with a concentration of 15% which is equal to 252,312.80 mg / L.

A rare free silica-bearing micrometeorite

<p>Extraterrestrial dust that reaches the Earth’s surface has shown to represent the diverse types of samples from different precursors, namely, asteroid complexes and cometary bodies from the solar system. A substantial amount of this dust that strikes the upper atmosphere is believed to have been lost due to frictional heating with air molecules. Cosmic spherules that are melted particles are some of the widely recognized micrometeorites that survived this catastrophic entry process; however, their primordial characteristics are altered from their precursors making it difficult to identify the precursors. An individual peculiar spherule MS-I35-P204 recovered from the Antarctica blue ice has been identified. The spherule has been segregated using magnetic separation method, mounted in epoxy, and examined using SEM, subsequently analysed under electron microprobe. It is surrounded by a thin magnetite rim, and also holds a single kamacite bead that protrudes out at its top. The interior mineralogy mostly constitutes of a bulk pyroxene normative glass (MnO>2wt%) with several vesicles. The rare mineral phase is a skeletal aggregate of free silica, bearing Fe nuggets embedded in a glass. An isolated narrow lath of forsterite appears to be chondritic and is observed as relict grain that is associated with an anomalous low Ca pyroxene (MnO ~1.3 wt%, FeO~13 wt%). Earlier, free silica has been reported in some chondritic meteorites particularly the Enstatite and Ordinary group, and also in some carbonaceous chondrites such as CM, CR, CH, and K. It profoundly forms a pod that encloses the ferromagnesian silicate in silica-bearing chondrules. The unusual mineral assemblage seen in this spherule thereby appears to constrain probably the unique type of its contributor which need to be studied.</p>

Effect of Particle Size and Sintering Temperature on the Formation of Mullite from Kyanite and Aluminum Mixtures

The effect of particle size and sintering temperature of the mixtures of kyanite and metallic aluminum related to the thermal transformation of kyanite into primary mullite and free silica was studied. In addition, the reaction between α-Al2O3 (in situ produced by aluminum oxidation) and the silica was obtained in cristobalite structure from kyanite to obtain secondary mullite. The kyanite powders were milled by 0.5, 3, 6, and 12 hours and then were mixed with aluminum powder, which were previously milled by 3 hours. After that, the powders were characterized by X-ray diffraction technique (XRD), scanning electronic microscopy (SEM), differential thermal analysis (DTA), and thermogravimetric analysis (TGA), and the particle size was determined in a centrifugal analyzer particle size Shimadzu model SA-CP4. The mixed powders were pressed uniaxially into cylindrical samples (compacts), and then sintering was conducted at 1100, 1200, 1300, 1400, 1500, and 1600°C; these samples were characterized by XRD, SEM, and thermodilatometry analysis (TD); density and open porosity measurements were performed by the Archimedes method. The samples were thermally etched to observe the microstructure, which consisted of mullite equiaxial grains contained in a glassy phase. It was observed that the nonmilled kyanite mineral becomes into mullite plus silica at temperatures between 1400 and 1500°C. When the particle size was reduced at sizes less than 1 µm, the transformation temperature was low until 200°C; the X-ray patterns of the sintered samples at 1400°C, ground for 6 hours, showed mullite peaks with small reflections of cristobalite and α-Al2O3, and these samples exhibited high density and low open porosity.

Effect of beneficiation of Harin-Hamza Futuk bentonite for drilling fluid formulation

This research focused on beneficiation and characterization of raw Garin Hamza Futuk (GHF) Bentonite for oil and gas drilling fluid formulation. The FTIR results confirmed that GHF bentonitic clay is rich in montmorillonite mineral noticed at approximately 3620-3630cm-1 stretching band in the higher frequency level. In the lower frequency region, montmorillonite had a strong band at 1024.24 and 1028.09 cm-1 for Sivibration of layered silicates.The X-ray fluorescence (XRF) results showed slight reduction in free silica (Quartz) by about 1%. The SEM images of the beneficiated samples were more dispersed than the raw sample with some large flocs structure confirming their montmorillonitic nature. The optimum amount of poly anionic cellulose (PAC)used for instant drilling fluid formulation was found to be at 2.0 g, while the aged formulation was achieved at 0.8g PAC when compared with the API grade. Hence, GHF bentonite can be used for drilling fluid formulation.