scholarly journals Configuration of flowsheet and reagent dosage for gilsonite flotation towards the ultra-low-ash concentrate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ataallah Bahrami ◽  
Fatemeh Kazemi ◽  
Mirsaleh Mirmohammadi ◽  
Yousef Ghorbani ◽  
Saghar Farajzadeh
Keyword(s):  
Sulfuric Acid ◽  
Sodium Silicate ◽  
Tannic Acid ◽  
Size Fraction ◽  
Sodium Cyanide ◽  
Ash Content ◽  
Drilling Fluids ◽  
Gas Oil ◽  
Size Fractions ◽  
Process Mineralogy

AbstractGilsonite has a wide variety of applications in the industry, including the manufacture of electrodes, paints and resins, as well as the production of asphalt and roof-waterproofing material. Gilsonite ash is a determining parameter for its application in some industries (e.g., gilsonite with ash content < 5% used as an additive in drilling fluids, resins). Due to the shortage of high grade (low ash) gilsonite reserves, the aim of this study is to develop a processing flowsheet for the production of ultra-low-ash gilsonite (< 5%), based on process mineralogy studies and processing tests. For this purpose, mineralogical studies and flotation tests have been performed on a sample of gilsonite with an average ash content of 15%. According to mineralogical studies, carbonates and clay minerals are the main associated impurities (more than 90 vol.%). Furthermore, sulfur was observed in two forms of mineral (pyrite and marcasite) and organic in the structure of gilsonite. Most of these impurities are interlocked with gilsonite in size fractions smaller than 105 µm. The size fraction of + 105 − 420 µm has a higher pure gilsonite (approximately 90%) than other size fractions. By specifying the gangue minerals with gilsonite and the manner and extent of their interlocking with gilsonite, + 75 − 420 µm size fraction selected to perform flotation tests. Flotation tests were performed using different reagents including collector (Gas oil, Kerosene and Pine oil), frother (MIBC) and depressant (sodium silicate, tannic acid, sulfuric acid and sodium cyanide) in different dosages. Based on the results, the use of kerosene collector, MIBC frother and a mixture of sodium silicate, tannic acid, sulfuric acid and sodium cyanide depressant had the most favorable results in gilsonite flotation in the rougher stage. Cleaner and recleaner flotation stages for the rougher flotation concentrate resulted in a product with an ash content of 4.89%. Due to the interlocking of gilsonite with impurities in size fractions − 105 µm, it is better to re-grinding the concentrate of the rougher stage beforehand flotation in the cleaner and recleaner stages. Finally, based on the results of mineralogical studies and processing tests, a processing flowsheet including crushing and initial granulation of gilsonite, flotation in rougher, cleaner and recleaner stages has been proposed to produce gilsonite concentrate with < 5% ash content.

scholarly journals Configuration of Flowsheet and Reagent Dosage for Gilsonite Flotation Towards the Ultra-Low-Ash Concentrate

2021 ◽  
Author(s):  
Ataallah Bahrami ◽  
Fatemeh Kazemi ◽  
Mirsaleh Mirmohammadi ◽  
Yousef Ghorbani ◽  
Saghar Farajzadeh
Keyword(s):  
Sulfuric Acid ◽  
Organic Compounds ◽  
Sodium Silicate ◽  
Complex Structure ◽  
Sodium Cyanide ◽  
Ash Content ◽  
Drilling Fluids ◽  
Natural Occurrence ◽  
Size Fractions ◽  
Process Mineralogy

Abstract Gilsonite is a natural occurrence of bitumen and consists of a complex structure of organic compounds. Gilsonite has a wide variety of applications in the industry, including the manufacture of electrodes, paints and resins, as well as the production of asphalt and roof-waterproofing material. Ash content of gilsonite is a determining parameter for its application in some industries (e.g., ash content <5% as an additive in drilling fluids, Resins). In this study, a process mineralogy approach used in order to design an optimal flotation circuit for the production of gilsonite concentrate with ultra-low ash content (<5%) from gilsonite ore with an average ash content of 15%. According to mineralogical studies, carbonates and clay minerals are the main associated impurities (more than 90 vol.%). Furthermore, sulfur was observed in two forms of mineral (pyrite and marcasite) and organic in the structure of gilsonite. Most of these impurities are interlocked with gilsonite in size fractions smaller than 105 µm. In addition, the size of +105 µm to 420 µm has a higher pure gilsonite (approximately 90%) than other size fractions. The effect of different reagent regime on the production of low ash content concentration in gilsonite flotation are investigated. Based on the results, 400 g/ton of kerosene collector led to the production of a concentrate with the lowest amount of ash (6.36%) in the rougher stage. In addition, the highest amount of recovery (80.83%) were obtained in gilsonite flotation with kerosene collector. The use of depressants in the rougher stage increased the gilsonite recovery by 3.5% and slightly reduced the ash content (less than 0.20%) of gilsonite concentrate. In general, gilsonite flotation with 400 g/ton kerosene collector, 100 g/ton from a mixture of sodium silicate, tannic acid, sulfuric acid and sodium cyanide depressants, and the use of 100 g/ton MIBC resulted in the production of a concentrate with the lowest amount of ash (6.36%) in the rougher flotation stage. Cleaner and recleaner flotation for the rougher flotation concentrate resulted in a product with an ash content of 4.89% and recovery of 86.75%. Due to the interlocking of gilsonite with impurities in size fractions smaller than 105 µm, it is better to re-grinding the concentrate of rougher stage then flotation done in the cleaner and recleaner stages. Finally, flowsheet has been proposed to produce gilsonite with the least ash.

Can We Estimate the True Weight of Zooplankton Samples after Chemical Preservation?

1989 ◽  
Vol 46 (3) ◽  
pp. 522-527 ◽  
Author(s):  
Louis A. Giguère ◽  
J.-F. St-Pierre ◽  
B. Bernier ◽  
A. Vézina ◽  
j.-G. Rondeau
Keyword(s):  
Weight Loss ◽  
Body Length ◽  
Freeze Drying ◽  
Size Fraction ◽  
Dry Weight ◽  
Ash Content ◽  
Caloric Content ◽  
Size Fractions ◽  
Size Dependent ◽  
Weight Losses

Zooplankton are collected and sorted into two size fractions from which samples are randomly alloted to a battery of commonly used preservation techniques. We determine dry weight, ash content, and caloric content. We compute organic and inorganic losses of the samples to examine potential causes of variation in dry weight estimates. Treatments are: no preservation, preservation with one of three chemicals (75% ethanol, 5% or 10% buffered formaldehyde), preservation for 1 or 66 wk, and oven- or freeze-drying. Overall dry weight losses are independent of preservation methods. Chemical preservation reduces dry weight by 37 to 43%. Organic and inorganic losses range from 25 to 33% and 73 to 82%, respectively. Because inorganic losses are large, chemical preservation increases the caloric content of samples by 13 – 27%. Dry weight losses are somewhat size-dependent (37 versus 43% for the large and small size fraction respectively, after 66 wk of preservation). A regression of percent dry weight losses on body length (in millimetres) is obtained for our data, and published reports where formaldehyde is used as a preservative. It is: In[dry weight loss] = 4.149 − 0.576 length0.333. This relationship can be used to adjust the weight of zooplankton samples which have been preserved chemically. A survey of studies published in 1983 indicates that most authors did not adjust for dry weight losses due to preservation.

scholarly journals Reduction of Ash Content in Raw Coal Using Acids and Alkali

2010 ◽  
Vol 7 (4) ◽  
pp. 1254-1257 ◽  
Author(s):  
K. H. Shivaprasad ◽  
M. M. Nagabhushana ◽  
C. Venkataiah
Keyword(s):  
Sulfuric Acid ◽  
Hydrochloric Acid ◽  
Coal Sample ◽  
Toxic Elements ◽  
Thermal Power ◽  
Calorific Value ◽  
Ash Content ◽  
Subsequent Removal ◽  
Inorganic Matter ◽  
Leaching Experiments

Ash, an inorganic matter present in coal is amenable for dissolution using suitable reagents. Thus the dissolution of ash and its subsequent removal reduces the release of many toxic elements into the environment by coal based industries. Removal of ash also enhances the calorific value. In the present investigation an attempt has been made to reduce the ash content of raw coal obtained from nearest thermal power by using hydrochloric acid, sulfuric acid and sodium hydroxide. A series of leaching experiments were conducted on coal of different size fractions by varying the parameters like concentration, temperature and time of leaching. The results indicate that it is possible to remove nearly 75% of ash from coal sample by leaching.

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. III. Distribution and kinetics of soil organic carbon in particle size fractions

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 293 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Size Fraction ◽  
Organic C ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Clay Size Fraction ◽  
Sand Size

Distribution of soil organic carbon in sand-, silt- and clay-size fractions during cultivation for periods ranging from 20 to 70 years was studied in six major soils used for cereal cropping in southern Queensland. Particle-size fractions were obtained by dispersion in water using cation exchange resin, sieving and sedimentation. In the soils' virgin state no single particle-size fraction was found to be consistently enriched as compared to the whole soil in organic C in all six soils, although the largest proportion (48%) of organic C was in the clay-size fraction; silt and sand-size fractions contained remaining organic C in equal amounts. Upon cultivation, the amounts of organic C declined from all particle-size fractions in most soils, although the loss rates differed considerably among different fractions and from the whole soil. The proportion of the sand-size fraction declined rapidly (from 26% to 12% overall), whereas that of the clay-size fraction increased from 48% to 61% overall. The proportion of silt-size organic C was least affected by cultivation in most soils. It was inferred, therefore, that the sand-size organic matter is rapidly lost from soil, through mineralization as well as disintegration into silt-size and clay-size fractions, and that the clay fraction provides protection for the soil organic matter against microbial and enzymic degradation.

THERMAL NEUTRALIZATION OF CARBON-CONTAINING SLUDGE

2021 ◽  
Vol 3 (1) ◽  
pp. 118-123
Author(s):  
D. YU. UMANSKY ◽  
◽  
M. V. VASINA ◽  
Keyword(s):  
Sulfuric Acid ◽  
Aromatic Hydrocarbons ◽  
Petroleum Products ◽  
Oil Refinery ◽  
Gas Oil ◽  
Hazard Class ◽  
Resinous Substance ◽  
Oil Fractions ◽  
Petroleum Distillates

Acid tar is a resinous substance, which in most cases has a viscous structure. They are obtained as a result of sulfuric acid purification of petroleum distillates, oil residues, in the production of sulfonate additives, in the sulfonation and purification of oils, paraffins, kerosene and gas oil fractions and other petroleum products from aromatic hydrocarbons. Until recently, this type of waste was temporarily accumulated in specially designated areas - acid tar storage ponds, which were located near the oil refinery, which had a significant impact on the environment. The paper considers the process of formation of acid tar on the example of the production of sulfonate additives. The composition of the mixture of acid tar and sulfonate sludge was evaluated, and the hazard class of this type of waste was determined. Methods of utilization of acid tar are studied and a method of utilization of acid tar for the considered production is proposed.

The Influence of Heat and Two Stages Precipitation in the Process of Natural Polymer Purification from the Byproduct of Bioethanol Process Base on Empty Palm Fruit Bunch

2015 ◽  
Vol 1123 ◽  
pp. 177-181
Author(s):  
Achmad Hanafi ◽  
Harry Budiman ◽  
Fauzan Aulia
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Room Temperature ◽  
Black Liquor ◽  
Ash Content ◽  
Natural Polymer ◽  
Palm Fruit ◽  
Second Stage ◽  
Direct Precipitation ◽  
Two Stages

The biopolymer material, lignin, was recovered from the black liquor by acidification of the black liquor using sulfuric acid. Several purification techniques were carried out to produce the high purity of lignin such as gradual precipitation of lignin from black liquor (first stage: precipitation at pH 7, second stage: precipitation at pH 2) and the diluting of crude lignin by sodium hydroxide then followed by re-precipitation at different temperature. Subsequently, the impurities of lignin product resulted from each purification techniques was determined as ash content that analyzed using temperature program furnace; and the content of lignin was investigated using spectrophotometer UV-Vis. The result showed that the content of lignin of material produced from gradual precipitation was approximately 77.6%. It was higher than the content of lignin about 3.4% of material produced from direct precipitation to pH 2. In addition, the elevating of temperature from 40 to 60°C was no considerably affect to the content of lignin in precipitate produced from re-precipitation of crude lignin solution in sodium hydroxide. Nonetheless, the content of lignin of precipitate improved 15% when the temperature of re-precipitation of crude lignin solution in sodium hydroxide was raised from room temperature to 40-60°C.

scholarly journals Atmospheric trace metals measured at a regional background site (Welgegund) in South Africa

2017 ◽  
Vol 17 (6) ◽  
pp. 4251-4263 ◽  
Author(s):  
Andrew D. Venter ◽  
Pieter G. van Zyl ◽  
Johan P. Beukes ◽  
Micky Josipovic ◽  
Johan Hendriks ◽  
...  
Keyword(s):  
South Africa ◽  
Trace Metals ◽  
Trace Metal ◽  
Size Fraction ◽  
Abundant Species ◽  
Metal Species ◽  
Metal Concentrations ◽  
Igneous Complex ◽  
Size Fractions ◽  
Bushveld Igneous Complex

Abstract. Atmospheric trace metals can cause a variety of health-related and environmental problems. Only a few studies on atmospheric trace metal concentrations have been conducted in South Africa. Therefore the aim of this study was to determine trace metal concentrations in aerosols collected at a regional background site, i.e. Welgegund, South Africa. PM1, PM1–2. 5 and PM2. 5–10 samples were collected for 13 months, and 31 atmospheric trace metal species were detected. Atmospheric iron (Fe) had the highest concentrations in all three size fractions, while calcium (Ca) was the second-most-abundant species. Chromium (Cr) and sodium (Na) concentrations were the third- and fourth-most-abundant species, respectively. The concentrations of the trace metal species in all three size ranges were similar, with the exception of Fe, which had higher concentrations in the PM1 size fraction. With the exception of titanium (Ti), aluminium (Al) and manganese (Mg), 70 % or more of the trace metal species detected were in the smaller size fractions, which indicated the influence of industrial activities. However, the large influence of wind-blown dust was reflected by 30 % or more of trace metals being present in the PM2. 5–10 size fraction. Comparison of trace metals determined at Welgegund to those in the western Bushveld Igneous Complex indicated that at both locations similar species were observed, with Fe being the most abundant. However, concentrations of these trace metal species were significantly higher in the western Bushveld Igneous Complex. Fe concentrations at the Vaal Triangle were similar to levels thereof at Welgegund, while concentrations of species associated with pyrometallurgical smelting were lower. Annual average Ni was 4 times higher, and annual average As was marginally higher than their respective European standard values, which could be attributed to regional influence of pyrometallurgical industries in the western Bushveld Igneous Complex. All three size fractions indicated elevated trace metal concentrations coinciding with the end of the dry season, which could partially be attributed to decreased wet removal and increases in wind generation of particulates. Principal component factor analysis (PCFA) revealed four meaningful factors in the PM1 size fraction, i.e. crustal, pyrometallurgical-related and Au slimes dams. No meaningful factors were determined for the PM1–2. 5 and PM2. 5–10 size fractions, which was attributed to the large influence of wind-blown dust on atmospheric trace metals determined at Welgegund. Pollution roses confirmed the influence of wind-blown dust on trace metal concentrations measured at Welgegund, while the impact of industrial activities was also substantiated.

scholarly journals Pooling size sorted malaise trap fractions to maximise taxon recovery with metabarcoding

2020 ◽  
Author(s):  
Vasco Elbrecht ◽  
Sarah J. Bourlat ◽  
Thomas Hörren ◽  
Angie Lindner ◽  
Adriana Mordente ◽  
...  
Keyword(s):  
Size Fraction ◽  
Sequencing Depth ◽  
List Type ◽  
Malaise Trap ◽  
Size Fractions ◽  
Size Classes ◽  
Size Sorting ◽  
The Individual ◽  
Size Heterogeneity ◽  
Wet Sieving

AbstractSmall and rare specimens can remain undetected when metabarcoding bulk samples with a high size heterogeneity of specimens. This is especially critical for malaise trap samples, where most of the biodiversity is often contributed by small specimens. How to size sort and in which proportions to pool these samples has not been widely explored. We set out to find a size sorting strategy that maximizes taxonomic recovery but remains highly scalable and time efficient.Three 3 malaise trap samples where size sorted into 4 size classes using dry sieving. Each fraction was homogenized and lysed. The corresponding lysates were pooled to simulate samples never sorted, pooled in equal proportions and in 4 different proportions favoring the small size fractions. DNA from the pooled fractions as well as the individual size classes were extracted and metabarcoded using the FwhF2 and Fol-degen-rev primer set. Additionally wet sieving strategies were explored.The small size fractions harbored the highest diversity, and were best represented when pooling in favor of small specimens. Not size sorting a sample leads to a 45-77% decrease in taxon recovery compared to size sorted samples. A size separation into only 2 fractions (below 4 mm and above) can already double taxon recovery compared to not sorting. However, increasing the sequencing depth 3-4 fold can also increase taxon recovery to comparable levels, but remains biased toward biomass rich taxa in the sample.We demonstrate that size fractionizing bulk malaise samples can increase taxon recovery. The most practical approach is wet sieving into two size fractions, and proportional pooling of the lysates in favor of the small size fraction (80-90% volume). However, in large projects with time constraints, increasing sequencing depth can also be an alternative solution.

scholarly journals The Effect of the Characteristics of the Partition Plate Unit on the Separating Process of −6 mm Fine Coal in the Compound Dry Separator

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 215 ◽  
Author(s):  
Chen ◽  
Wang ◽  
Luo ◽  
Zhao ◽  
Lv ◽  
...  
Keyword(s):  
Density Distribution ◽  
Size Fraction ◽  
Industrial Applications ◽  
Average Density ◽  
Ash Content ◽  
Separation Process ◽  
Contour Map ◽  
Separation Technology ◽  
Fine Coal ◽  
Separation Results

Although compound dry separation technology has been applied to industrial applications for +6 mm size fraction of coal separation, the technology has not been widely applied in the separation of fine coal (−6 mm). In this study, the effect of the partition plate unit characteristics on both the average density of particles in the bed uniformly and the final separation results in a fine coal separation process were studied. According to the results, the standard deviations of the corresponding density distribution were 0.08, 0.14, and 0.07 when the height of the partition plate was 2.5 cm, the partition plate angle was 35°, and the distance from the apex of partition plate on the backplane, was 12 cm, respectively, which were the lowest values at the same level. These results showed that the average density of particles in the bed was uniformly, and its corresponding density distribution contour map was more regular. When the amplitude was 2.8 mm, the frequency was 29 Hz, the height of the partition plate was 2.5 cm, the partition plate angle was 35°, and the distance from the apex of the partition plate to the backplane was 12 cm; as a result, the E value was 0.115 g/cm3, the yield of the concentrate was 69.24%, the ash content was 12.52%, and the separation effect was better. The characteristics of the partition plate unit have an important effect on the separating process of −6 mm fine coal in the compound dry separator.

scholarly journals Improved Dynamic Light Scattering using an adaptive and statistically driven time resolved treatment of correlation data

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexander V. Malm ◽  
Jason C. W. Corbett
Keyword(s):  
Steady State ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Size Fraction ◽  
Power Relationship ◽  
Time Resolved ◽  
Size Fractions ◽  
Use Of Data ◽  
Primary Advantage ◽  
State Size

Abstract Dynamic Light Scattering (DLS) is a ubiquitous and non-invasive measurement for the characterization of nano- and micro-scale particles in dispersion. The sixth power relationship between scattered intensity and particle radius is simultaneously a primary advantage whilst rendering the technique sensitive to unwanted size fractions from unclean lab-ware, dust and aggregated & dynamically aggregating sample, for example. This can make sample preparation iterative, challenging and time consuming and often requires the use of data filtering methods that leave an inaccurate estimate of the steady state size fraction and may provide no knowledge to the user of the presence of the transient fractions. A revolutionary new approach to DLS measurement and data analysis is presented whereby the statistical variance of a series of individually analysed, extremely short sub-measurements is used to classify data as steady-state or transient. Crucially, all sub-measurements are reported, and no data are rejected, providing a precise and accurate measurement of both the steady state and transient size fractions. We demonstrate that this approach deals intrinsically and seamlessly with the transition from a stable dispersion to the partially- and fully-aggregated cases and results in an attendant improvement in DLS precision due to the shorter sub measurement length and the classification process used.

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