Footsteps for Enhancing Data Bank on Bauxite, Hydrate, Alumina & Alumina Chemicals

Hi Friends,

In present post, we have put forward our aggressive steps to enhance the inventory of technical data bank pertaining to bauxite, hydrate, alumina and alumina chemicals covering all spheres of activities for all friends of our professional fraternity.

It's my natural temperament to exchange ideas particularly on technical topics. It is also the truth that blessings of my superiors and best wishes of my friends have attributed in enriching my knowledge base which further encouraged me to move forward with accelerated pace in exchanging ideas and opinions. I do not believe in diary culture in hiding information unnecessarily in my desk. I know, I have very limited data / information with me compared to many others in the World. My this approach has given me more than 2500 trust-worthy friends who are directly or indirectly associated with bauxite, hydrate, alumina and aluminium including specialty chemicals. As such, I have faced many road blocks in my career path so is impossible for me to forget the blessings of society and almighty God. Majority of my life, I have enjoyed with smile. What ever work I do, I get immense pleasure in contributing to my fullest satisfaction.  

During early days of my professional careers, I faced acute problems in learning technical things as limited people had the desire to exchange their fresh or outdated perceived ideas as they used to keep those data as very confidential just like keeping the personal property in the Bank lockers. Those days i.e in early eighties, internet in India was available to defense people only. You can imagine the extent of difficulties faced by me in learning the basics and design aspects of process, calculations, equipment, capex, opex and profitability aspects. Truly, it was hard time for me when I recall. I struggled a lot for finding even tiny technical information. You will be astonished to know that people were reluctant to tell even the basic process and operating parameters of Alumina refinery. Can you think of doing process design engineering calculations using scientific calculators and preparation of drawings using Mini Drafters on the Drawing boards. For the first time in 1984, I got opportunity to work on computer that to with 640 kb RAM. Those days, Word star and Lotus-123 were the basic software for  word processing and calculations respectively. In 1990, I got the computer with MS-Excel on which I initiated to take up the assignment for developing a mathematical model for Design of Alumina Refinery during extra hours. I was fortunate to be awarded for development of that mathematical model sometime in 1995. I kept on updating the mathematical model considering it as my person achievement. If I see the model today, I am surprised on myself for completing this unique and wonderful developmental work alone. The outcome of this model has been well tested with the results provided by other leading technology suppliers in the World. This mathematical model has been developed on MS-Excel platform and requires only 150  basic input data and it gives detailed process calculations like material balance, thermal energy balance, water balance, caustic soda balance, alumina balance etc and sizing calculations for all major technological equipment, tailor made equipment and requirement of utilities and services within no time. Utmost accuracy in outcome is the essence of this mathematical model. Since this Mathematical model has been awarded by Internationally reputed Engineering & Consultancy Organization and they are using the same even today for design of Alumina refinery. Thus, I consider it as their asset but as an originator, I keep on updating the Mathematical model incorporating advancements in process technology. 

To summarize the facts of my professional life, I had to face a lot of difficulties which can not be expressed in words. All of us know the fact of our life that we are not going to remain alive on this earth for more than 200 years under any circumstance. Thus, it would be a wiser decision to dissipate the knowledge and expertise acquired by all of us. Though our first forefathers were monkeys, but we can not behave like monkeys today in keeping intact the assimilated information with us as the World has become very small because of advancements in communication technology. I feel proud of myself as I initiated this move of exchanging the ideas of public domain nature among my friends about a decade back which was appreciated by almost all across the globe. Now, I have observed that my friends are contributing much more than what I could and what I am. I have always advised one and all to share the information of public domain nature and never disclose any data, information and drawings of proprietary and confidential nature. My interest  has remained at the same level among the global team but I am contributing little less because of paucity of time due to other pressing assignments.Till date, I have published 283 technical articles on this specialized subject and could present few papers in national and International seminars covering all aspects starting from concept to commissioning of Alumina Refinery.

No matter, I am always (24x7) available for serving the community around and specifically to bauxite, hydrate, alumina, aluminium and alumina chemical fraternity on techno-commercial issues across the globe even during odd hours.

If any individual particularly the young professionals / Entrepreneurs has any question with regard design, engineering, execution, commissioning, process calculations and costing (such as bauxite mining cost, alumina production cost, specific capital cost etc.) related to Bauxite, mining, Hydrate, Alumina and Specialty grades of hydrates and aluminas including Alumina chemicals, please feel free to ask any information / clarification clearly indicating your e.mail ID for receiving your reply. Our team of Experts will definitely put efforts for reply to you. Sometimes, you may be required to wait a while for the reply. Simplicity in our language and authenticity in information are major strength. 

We wish to have your opinion / comments / remarks on our new move on the very specialized subject like alumina. We will welcome your suggestions.

Kunwar Rajendra
rajendra@ceti.co.in
www.ceti.co.in

Major Cost Component in Manufacture of Calcined Alumina

Hi Friends,

We covered a variety of techno-commercial  issues with regard to production of calcined alumina. In present post, we will discuss the major cost components and their optimum level to control manufacture cost of alumina.

Production cost of calcined alumina is directly impacted by process efficiency figures due to higher consumption of input materials. Requirement of energy and consumption of Caustic soda are the main challenges for the process engineers to monitor on continuous basis so as to minimize the manufacture cost of calcined alumina. Total cost component of energy and caustic soda is estimated at around 70% of manufacture cost of alumina. Energy requirement for bauxite mining ranges from 0.40 US$ to 0.50 US$ per tonne of ROM Bauxite which is purely dependent on stripping ratio (meters of overburden : meters of Bauxite) and haulage (distance between Bauxite deposit to point of loading for despatch to Alumina refinery). Land area used for mining Bauxite ranges from 50 to 60 m2 per 1000 tonnes of ROM Bauxite or 5 to 6 hectares land per million tonnes of ROM Bauxite.

In Alumina refinery, energy is used in three forms- (i) Solid / liquid / gaseous fuel for raising  saturated steam to be used in digestion and evaporation stages and (ii) Liquid / gaseous fuel for Calcination and (iii) Electrical power for running the rotating equipment. Though the electrical power consumption is equivalent to about 1.0 GJ per tonne of calcined alumina which accounts for about 10% of total energy consumption for production of alumina. Various methods for controlling the energy consumption have already been elaborated in previous posts.


The other main challenge is to minimize caustic soda consumption. Presence of high reactive silica in Bauxite, lower alumina recovery, poor washing efficiency figures of residue and hydrate are the main reasons for higher caustic soda consumption. Thus steady plant operation with optimum temperature profile of the process circuit attributes in reducing the caustic soda consumption. 


All information presented here are the personal views of the author and thus advised not to act upon these data / information without taking professional advice from experts as it  is essential to take care of consequences on other efficiency figures.


Please put your views / remarks / comments, if any.
Regards.


Kunwar Rajendra 
www.bauxite2aluminium.blogspot.com

Energy Requirement for Gibbsitic Bauxite Based Efficient Alumina Refinery

Hi Friends,

In earlier posts, we have discussed various critical issues pertaining to design, engineering and operational aspects wherein we have observed that consumption of thermal energy and caustic soda are the major cash components in production cost of calcined alumina. Thus process experts, technologists and equipment manufacturers are continuously striving to develop energy efficient Alumina refinery so as to improve profitability of the plant. In present post, we will discuss in detail with break up of thermal energy consumption for various unit operation and unit processes of gibbsitic bauxite based Alumina refinery to arrive at a realistic figure as a bench mark for comparison purposes.

Here, we would like to discuss the energy consumption in Alumina refineries processing gibbsitic bauxite which may be taken as guiding tool to develop similar figures for other types of bauxitic and and non-bauxitic ores, if so desired. Thus our purview of discussion will remain within the limits of energy requirement for Alumina refineries adopting Medium pressure digestion with two stage continuous precipitation followed by stationary calciners for production of smelter grade calcined alumina. We are aware that thermal energy in Alumina refinery is used in two forms as outlined below-

1. Saturated steam for heating the process streams in Pre-desilication, Digestion and Evaporation areas. Minor steam is also required for miscellaneous purposes in the plant.
2. Natural gas or Fuel oil (HFO / LSHS) in calciners for calcination of hydrate for converting to desired product.

Our calculation is based on pressure of saturated steam at 12 bar to be used in medium pressure digestion at 145 degree Centigrade as well as evaporation and HFO as the fuel oil for calcination. The break up of steam consumption and fuel oil consumption along with respective heat value have been tabulated below-

 

The above presented data clearly reveal that total thermal energy consumption  for alumina production works out to around 8.14 GJ per tonne of calcined alumina. If we take 5% additional energy to compensate for unforeseen inefficiencies and losses, even then total thermal energy consumption in efficient Alumina refinery processing gibbsitic bauxite should not exceed 8.50 GJ/t of calcined alumina. Hence, specific energy consumption figure of 8.5 GJ per tonne of calcined alumina is the International benchmark for efficient Alumina refineries in the World.

On the process and energy audit of efficient Alumina refineries in various part of the globe, it has been observed that if one refinery is energy efficient in digestion area because of efficient heat recovery system then the same plant is lagging in operating the evaporators efficiently and reverse order as well. All the operative plants can become energy efficient provided they implement modifications in equipment and operating practices by exchanging the merits and shortcomings with one another. Such things are rarely happening today and every body has the feeling that he has the best plant. But, with comparison of any two Alumina refineries, you will find that  many changes can be incorporated immediately without any investment which may attribute in reducing the production cost substantially. 

The indicated figures are realistic figures which can be achieved with a little efforts and  constant vigil on design, equipment, process control and operational aspects of Alumina refinery. Hope, all experienced people of bauxite-alumina-aluminium fraternity will agree with my above indicated observations and analysis in reducing the thermal energy consumption drastically for alumina production. Request to kindly put your views / suggestions / remarks / comments, if any.

If you like this article, then please press your rating as  +1  .
Thanks and regards.

Kunwar Rajendra