Raw Material Blending and Batching in the Production of Calcium Aluminate cements

Sustainable utilization of Bauxite Residue (BR) is currently one of the greatest challenges being tackled by the alumina industry, due to its high production rates and limited reuse options. The present work is concerned with the use of BR as a candidate metallurgical raw material for iron (Fe) production and aluminum (Al) extraction. In more detail, at first, BR undergoes reductive smelting to extract its Fe content and produce a slag of mainly calcium aluminate composition. In a second step, Al contained in the calcium aluminate phases is extracted hydrometallurgically by leaching with a Na2CO3 aqueous solution. The focus of the current study is the optimization of this leaching process, and it was performed in two stages. The first was a laboratory scale investigation on the main parameters affecting the extraction rate of Al. The second stage was performed in pilot scale and incorporated observations and suggestions based on the laboratory scale investigation. Laboratory work showed that more than 50% of aluminum could be easily extracted in less than 1 h, in 5% S/L, at 70 °C and with an 20% excess of Na2CO3. Pilot scale work, by successfully applying the suggestions derived from laboratory scale work, achieved an average Al extraction of 68% from a 10% S/L pulp, with a slag of optimized composition in relation to the one used in the laboratory scale.

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An HREM study of superstructures in Ca4Al6SO16

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010017846x ◽

1990 ◽

Vol 48 (4) ◽

pp. 1066-1067

Author(s):

Y.G. Wang ◽

H.Q. Ye ◽

K.H. Kuo

Keyword(s):

Calcium Aluminate ◽

Structural Model ◽

Bright Spot ◽

Sulphur Atom ◽

Synthetic Compound ◽

Space Group ◽

Lattice Images ◽

Cubic Structure ◽

Good Agreement

A synthetic compound Ca4Al6SO16 (usually abbreviated as C4A3S) obtained by mixing CaO, A12O3 and CaSO4 powders and finally sintered at 1380°C is a cement with excellent hydraulicity and greatly expanding in application. It is hydralysed rapidly by water to form predominatly calcium aluminate hydrates and therefore unlikly to occur naturally, although structurally it may be regarded as an end member of the sodalite-hauynite series of naturally occuring minerals. C4A3S has a cubic structure with ao=9.19Å and space group . Fig.1 is the projection viewed down axis, in which there are two sets of 8C position in , namely CaI and CaII, occupied by the calcium atoms, respectively, and the ratio of occupations in these two sets of positions is about 3:1. This suggests that the calcium atoms can freely occupy these sites in various degrees and usually they almost locates on the CaI positions. A through-focus series of the lattice images were found in good agreement with the simulated ones. Each bright spot in the image taken at Scherzer defocus correspounds to a colunm of sulphur atom in the structural model (Fig.1).

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Mental representation of economic crisis in Italian and Swiss samples 1The authors would like to thank Maurizio Mistri for his help in the construction of items. This research was supported by a grant from the Italian Murst (ex 40%).

Swiss Journal of Psychology ◽

10.1024//1421-0185.60.1.11 ◽

2001 ◽

Vol 60 (1) ◽

pp. 11-14 ◽

Cited By ~ 10

Author(s):

Lucia Savadori ◽

Eraldo Nicotra ◽

Rino Rumiati ◽

Roberto Tamborini

Keyword(s):

Economic Crisis ◽

Mental Representation ◽

Mental Representations ◽

Social Contexts ◽

Raw Material ◽

National Context ◽

Cluster Procedure ◽

Total N ◽

Two Samples ◽

Important Symptom

The content and structure of mental representation of economic crises were studied and the flexibility of the structure in different social contexts was tested. Italian and Swiss samples (Total N = 98) were compared with respect to their judgments as to how a series of concrete examples of events representing abstract indicators were relevant symptoms of economic crisis. Mental representations were derived using a cluster procedure. Results showed that the relevance of the indicators varied as a function of national context. The growth of unemployment was judged to be by far the most important symptom of an economic crisis but the Swiss sample judged bankruptcies as more symptomatic than Italians who considered inflation, raw material prices and external accounts to be more relevant. A different clustering structure was found for the two samples: the locations of unemployment and gross domestic production indicators were the main differences in representations.

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Raw material mix optimization system for sintering plant and blast furnace at CST

Revue de Métallurgie ◽

10.1051/metal:2006157 ◽

2006 ◽

Vol 103 (2) ◽

pp. 76-81

Author(s):

C. Perin Filho ◽

D. Tassinari Miranda ◽

E. Medeiros Milanez ◽

E. Luiz Massanori Harano ◽

E. Torres Bispo dos Santos ◽

...

Keyword(s):

Blast Furnace ◽

Raw Material ◽

Optimization System ◽

Raw Material Mix ◽

Sintering Plant

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Hydrostatic Fiber Optic Liquid Level Sensor with position sensitive detector

Metrologiya ◽

10.32446/0132-4713.2020-4-38-51 ◽

2020 ◽

pp. 38-51

Author(s):

V. N. Astapov ◽

I. N. Kozlova

Keyword(s):

Fiber Optic ◽

Effective Area ◽

Raw Material ◽

Position Sensitive Detector ◽

Fiber Optic Sensor ◽

Liquid Level ◽

Problem Solution ◽

Sensitive Detector ◽

Position Sensitive ◽

Triangulation Sensor

This article presents the rationale and methodology for developing an intrinsically safe device, namely, a hydrostatic fiber optic sensor with a position-sensitive detector for monitoring the level of oil products in large-capacity tanks at oil depots and during pumping in a raw material warehouses. This device suitable for continuous monitoring of the liquid level, based on the measurement of a hydrostatic column of liquid with automatic offset of changes in the density of the liquid. Offset is carried out by means of a displacer (a fully submerged float), inside which a housing with a position-sensitive detector (PSD) is integrated. Theoretical validation of the bellows suspension usage for a displacer is given. During filling a container with a liquid whose level is measured, liquid bellows, the movement of which is recorded by an optical triangulation sensor using the reflected infrared ray incident on the bottom of the bellows. The principle of the triangulation sensor operation is based on the geometric properties of the triangles. The pulses of infrared radiation come through a fiber optic cable. In order to measure the movement of the surface (the bottom of the bellows) by measuring the movement of the reflected beam, a position-sensitive detector is used, which is located in a remote controller. In this device for the intrinsic safety problem solution, optical inputs of a fiber optic flat cable are located in the active zone of the sensor, which is connected to the optical inputs of a position-sensitive detector, operated on the principles of photoelectric effect. The light spot moving along the sensitive zone and converted by the detector into a one-dimensional signal proportional to the distance to the object. hydrostatically applies pressure over the entire effective area of the measuring

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Problems Facing the Arab Pharmaceutical Industry: A Case Study from Yemen

Research in Pharmacy and Health Sciences ◽

10.32463/rphs.2016.v02i04.45 ◽

2016 ◽

Vol 2 (4) ◽

pp. 234-241

Author(s):

Mohammed Al-Shakka ◽

Ebtesam Abood ◽

Adel Al-Dhubhany ◽

Sami Abdo Radman Aldubai ◽

Khaled Said ◽

...

Keyword(s):

Pharmaceutical Industry ◽

Low Income ◽

Well Being ◽

Pharmaceutical Products ◽

Domestic Market ◽

Raw Material ◽

Political Crisis ◽

Pharmaceutical Manufacturer ◽

University Graduates ◽

Pharmaceutical Drugs

Because of the almost-instant connection with the welfare and well-being of individuals, pharmaceutical industry stands prominently as a very important factor for the improvement and progress of a healthy productive nation. These days, pharmaceutical industry thrives as one of the largest and exponentially expanding global industries. Nonetheless, millions of people in low income developing countries, have to suffer from the fatal consequences of the inaccessibility and non-availability of essential drugs. This is also happening in Yemen, where the pharmaceutical manufacturers sector have to face up to many challenges. The Yemen Drug Company (YEDCO) was founded in 1964 by the Yemeni government as it collaborated with private investors. It was endorsed as a company with the expertise in the medicinal drug marketing. YEDCO started its work by taking in drugs from foreign companies and then locally marketing and distributing them. In 1982, YEDCO built the first medicinal factory for drugs in Sana’a. Since then, seven companies were set up to manufacture medicines in Yemen. The expanding population has led to the need to have more pharmaceutical products. It may be understandable that pharmaceutical manufacturer companies are also hit by the political crisis in the country. Inadequate amount of fuel and raw material as well as low security status were some of the underlying factors behind these ill-effects in Yemen. Imported drugs make up about nearly 90% % of the pharmaceutical market compared to 10% drugs from the domestic market. This situation has led to an additional burden being shouldered by the national economy, where Yemen spends about US$263 million annually on pharmaceutical drugs, in reference to the national Supreme Drugs Authority. Although there is a very quick growth in the population and drugs consumption, the pharmaceutical industry has not been very active, where global pharmaceutical products play their role dominantly on the domestic market. The pharmaceutical production necessitates skilled human resources like university graduates. By contrast, the government and the private sector should also motivate the pharmaceutical industry and make use of the local employment

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Pengaruh Manajemen Modal Kerja Terhadap Profitabilitas Dan Risiko

Liquidity ◽

10.32546/lq.v6i2.24 ◽

2017 ◽

Vol 6 (2) ◽

pp. 95-102

Author(s):

Sri Setia Ningsih

Keyword(s):

T Test ◽

Raw Material ◽

Risk Level ◽

Capital Management ◽

Working Capital ◽

Working Capital Management ◽

Trading Company ◽

Regression Correlation ◽

Descriptive Method

The purpose of this research is to know about working capital management applied, and its influence on profitability and risk. The research object is trading company moves in import & distribute chemical raw material. The research used analysis descriptive method, and the hypothesis was testing by simple linier regression, correlation, and determination. The result of the research shows that the effect of the implementation of working capital management on the change of the net working capital with tend to rise has a profitability level of 10.4% lower than the net working capital change with tend to go down of 46%, but instead on the risk level, the net working capital change with tend to rise has a risk level of 43.8% higher than the change in net working capital with tend to go down of 0.3%.Based on t test, the result shows that the net working capital change influence is not significant to profitability and risk.

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Environmental benefits of magnesium hydroxide-based peroxide bleaching of mechanical pulp – mill results

TAPPI Journal ◽

10.32964/tj12.6.9 ◽

2013 ◽

Vol 12 (6) ◽

pp. 9-15 ◽

Cited By ~ 1

Author(s):

TOMI HIETANEN ◽

JUHA TAMPER ◽

KAJ BACKFOLK

Keyword(s):

Sodium Hydroxide ◽

Magnesium Hydroxide ◽

Oxygen Demand ◽

Pulp Mill ◽

Transition Metal Ions ◽

Environmental Benefits ◽

Raw Material ◽

Paper Machine ◽

High Brightness ◽

Peroxide Bleaching

The use of a new, technical, high-purity magnesium hydroxide-based peroxide bleaching additive was evaluated in full mill-scale trial runs on two target brightness levels. Trial runs were conducted at a Finnish paper mill using Norwegian spruce (Picea abies) as the raw material in a conventional pressurized groundwood process, which includes a high-consistency peroxide bleaching stage. On high brightness grades, the use of sodium-based additives cause high environmental load from the peroxide bleaching stage. One proposed solution to this is to replace all or part of the sodium hydroxide with a weaker alkali, such as magnesium hydroxide. The replacement of traditional bleaching additives was carried out stepwise, ranging from 0% to 100%. Sodium silicate was dosed in proportion to sodium hydroxide, but with a minimum dose of 0.5% by weight on dry pulp. The environmental effluent load from bleaching of both low and high brightness pulps was significantly reduced. We observed a 35% to 48% reduction in total organic carbon (TOC), 37% to 40% reduction in chemical oxygen demand (COD), and 34% to 60% reduction in biological oxygen demand (BOD7) in the bleaching effluent. At the same time, the target brightness was attained with all replacement ratios. No interference from transition metal ions in the process was observed. The paper quality and paper machine runnability remained good during the trial. These benefits, in addition to the possibility of increasing production capacity, encourage the implementation of the magnesium hydroxide-based bleaching concept.

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Resource efficiency in deinked pulp production: a review

TAPPI Journal ◽

10.32964/tj13.11.37 ◽

2014 ◽

Vol 13 (11) ◽

pp. 37-43 ◽

Cited By ~ 4

Author(s):

LIISA KOTANEN ◽

MIKA KÖRKKÖ ◽

ARI ÄMMÄLÄ ◽

JOUKO NIINIMÄKI

Keyword(s):

Waste Disposal ◽

Resource Efficiency ◽

Raw Material ◽

Ecological Strategy ◽

Recycled Paper ◽

Paper Production ◽

Recycled Pulp ◽

Current State ◽

The Cost ◽

Pulp Production

The use of recovered paper as a raw material for paper production is by far the most economical and ecological strategy for the disposal of waste paper. However, paper production from recovered paper furnish generates a great amount of residues, and the higher the demand requirements for the end product, the higher the amount of rejected material. The reason for this is that the selectivity of the deinking process is limited; therefore, some valuable components are also lost in reject streams. The rejection of usable components affects the economics of recycled paper production. As the cost of waste disposal continues to increase, this issue is becoming more and more severe. This paper summarizes the current state of the resource efficiency in recycled pulp production and provides information on the volumes of rejected streams and the usable material within them. Various means to use these reject streams are also discussed, including the main findings of a recent thesis by the main author. This review summarizes current internal and external use of reject streams generated in the deinking operations.

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