Processing of polymetallic sea nodules: An overview

Polymetallic sea nodules are the potential sources of copper, nickel, cobalt and manganese. As the land based resources of these metals are depleting very fast, a considerable R&D effort have been made all over the world to extract the metals from the sea nodules during the past four decades. The paper summarises the processes developed by various R&D organisations and metallurgical consortia for the extraction of metal values from the sea nodules. Since the copper, nickel and cobalt in the sea nodules are in oxide Forms and they associate in the lattices of iron and manganese minerals, for extraction of these metals the lattices are broken either by hydrometallurgical reduction or by reductive pyre-treatment. Based on this criteria, processing methods have been broadly divided into two categories : (i) pyrometallurgical treatment followed by hydrometallurgical processing and (ii) purely hydrometallurgical processing. Processes developed under these two categories have been discussed highlighting their merits and demerits. Pilot plant studies carried out by various metallurgical consortia like Knnecott Copper Corporation, Deep Sea Ventures, Metallurgie Hoboken - Overpelt, International Nickel Company are also given. The R&D efforts made in India in the processing of sea nodules during last one decade and the future programme are also discussed

Processing of dust materials from Indian copper plants

In the pyrometallurgical processing of copper are, there is considerable amount of copper losses in the form of dust from the roaster, smelter and converter. Most of this dust is simply charged back into the smelting cir¬cuit, thereby reducing the capacity offresh charge processing. In the present paper separate processing of copper dust sample by sulphuric acid leaching method has been examined with the idea that the resulting leached cop¬per sulphate solution can be used as electrolyte in the copper electro¬refining section of the plant. The copper dust sample from Khetri Copper Complex, Rajsthan contained about 22% copper. The XRD analysis of the sample revealed that copper was mainly present in the forms of ox¬ides, sulphates and sulphides. Simple water leaching of the dust sample dissolved copper to the tune of 30%. This implied that about 30% of cop¬per was present in the sulphate form and rest of the copper was in the oxide and sulphide forms for which acid leaching process might be suit¬able. Sulphuric acid leaching at various concentration and at varied solid : liquid ratio, time and temperature were carried out at atmospheric pressure. The maximum recovery of copper obtained in these experiments was found to be about 52%. Since the sulphuric acid leaching at atmospheric presssure did not yield good results, the dust sample was leached at higher pressure in an autoclave on 200 g scale and the recovery of copper improved to 80%

Reduction of Emission from Aluminium Industries and Cleaner Technology

Aluminium metal is produced by electrolytic reduction of alumina in cells lined with carbon blocks. During the process of smelting different gaseous emissions like PFC (per flurocarbon).HF PAH (poly aromatic hydrocarbon), CO2, SO„ particulate matters etc. occur in to the atmosphere. The concentration of emission from a cell depends upon the type of cell, bath chemistry, scrubbing system and gas cleaning equipment used. These emissions cause severe environmental damages such as global warming and disease like fluorosis, cancer, asthma, emphysema, bronchitis etc. Through the development of newer technologies like, intro-duction of prebake technology, use of non-consumable (inert) anode, use of computer controlled and point feeding of alumina to the cell to control the frequency and duration of anode effects, use of low carbon pitch to replace tar, use of pollution monitoring and control equipment etc., there is a significant reduction in the emission levels. This paper deals with the factors infl-uencing the generation of these emissions and its reduction through the development of various cleaner technologies. Use of pollution control equipment and other remedial mea-sures to minimise the environmental pollution are also discussed

Neural net implementation of steam properties on FPGA

Real time applications like model predictive control, monitoring and data reconciliation of power plants and industrial processes employ nonlinear mathematical models and require thermodynamic properties and their derivatives of working fluids. Applications like super heater temperature control based on energy balance and real time data reconciliation, require an efficient and a compact method for simultaneous estimation of thermodynamic properties, and their partial derivatives suitable for implementation in field-programmable gate array (FPGA). However, the complex mathematical formulations of these properties prohibit direct implementations in FPGAs. Single artificial neural network (ANN) architecture is used to replace the entire code in higher level languages, running into a few thousand lines. FPGA implementation of a compact neural network for the entire range of thermodynamic properties is presented. Large arguments in sigmoid function are factored into a product of integer and a fractional part which is represented using series approximation with five terms only and the integers are represented in look up table (LUT). This ensures optimum storage and computational burden for the above applications. The ANN is implemented in IEEE 754 floating point with synthesis in Xilinx ISE design suite using Verilog HDL. The results are presented for a typical pressure versus saturation temperature

Security Enhancing based on Node Authentication and Trusted Routing in Mobile Ad Hoc Network (MANET)

In theMobile Ad HocNetwork, identifying trusted nodes for secure communication is a key challenge. Node compromises a service and leads to ambiguity in the behaviour of a node in the network. Node authentication and trust level calculation will enhance the security aspect of MANETs. Thispaper proposes enhancing security based onthe "Node Authentication and Trusted Routingapproach (NATR)".  NATR aims to avoid abnormal node interference in MANET. There through improved security and output data delivery. NATR calculates the predictability of the node by evaluating the three most common actions performed by a node in the connection process. Node licensing is a key aspect of evaluating custom network security. In this method, we monitor the Success rate of RREQ, Success rate of RREP, and Data Success rate node trust. The reliability of data delivery is measured bythe successfuldelivery of packets and theloss or drop of packets. The experimental results showthere is a 25% increase in package delivery and a 40% decrease in overhead for routing. NATR is compared with SAR TMS, and AODV to assess efficiency in Adhoc network

AN INTELLIGENT HYBRID SCHEDULING ALGORITHM FOR COMPUTER AIDED PROCESS CONTROL OF MANUFACTURING SYSTEM

In recent times, maintaining stable and efficient operation, industrial automation and control systems that quickly respond to change is become a tedious task. Although the purpose of process scheduling is different according to the classes of process, the conventional methods have scheduled every process equivalently because they do not know the classes of process. To overcome this limitation, intelligent process scheduling method has to be developed to help the complexity associated with industries. In this paper, an intelligent algorithm is developed to do process scheduling of manufacturing system. Here, the proposed method utilizes a recent soft computing algorithm called, cuckoo search and traditional algorithm, called genetic algorithm.  These two algorithms are effectively combined to do intelligent process scheduling. Initially, solutions are encoded effectively by considering the sequential order, set up selection and machine selection. Solution is nothing but the order of process to be carried out sequentially by considering machine availability, set up condition and predefined order of machine ordering. Then, the fitness of the solution are found out using the fitness that considers machine cost of doing task, set up cost and machine change cost. After designing the solution coding and fitness function, the intelligent scheduling will be done with the help of HCGA algorithm which is developed by combining cuckoo search and genetic algorithm. The experimental results showed that, the proposed approach gives fitness rate of 0.82 and which helps to achieve the scheduling in limited time, listed as 22000 sec on an average.

Hepatoprotective activity of ethanol extract of Pavetta Indica Linn leaves

Background: Traditionally, the bark of Pavetta Indica Linn., in decoction or pulverized, is administered, especially to children, to correct visceral obstructions. The decocted leaves are used externally to alleviate the pains caused by hemorrhoids. The root, pulverized and mixed with the ginger and rice-water, is given in dropsy. A local fomentation with the leaves is useful in relieving the pain of piles. Paracetamol (PCM) toxicity generates free radicals and raised serum enzyme levels-SGPT, SGOT, Alkaline Phosphatase and S. Albumin. It causes necrosis, congested vessels, multifocal area of fatty changes nuclear disintegration, sinusoidal dilation, kuffer cell hyperplasia. The reverse is considered as the index of hepatoprotective activity. The present study is being taken up to screen hepatoprotective action of P. Indica Linn.Methods: The acute liver damage in albino rats was induced by per oral administration of a single dose of 2000mg/kg b.w. PCM suspension in 0.5% Carboxy methyl cellulose (CMC) and chronic liver damage by giving the same dose of PCM on the 7th day. The hepatoprotective activity was monitored biochemically by estimating S. transaminase, S. bilirubin and S. Protein on the 8th day of experiment.Results: Ethanol extract of P. Indica inhibited PCM induced liver toxicity in albino rats at 100mg/kg and 200mg/kg b.w as assessed by the biochemical values.Conclusions: Ethanol extract of “P. Indica” exhibited significant hepatoprotective activity

Role of impurities in solvent extraction-electrowinning of copper and nickel for the processing of sea nodules

During the leaching of roasted nodules from Indian Ocean the soluble amine species of iron, manganese and zinc along with valuable metals such as Cu, Ni and Co enter the ammoniacal solution. Even after the purification step, the metal impurities in small amounts remained in the leach solution. In metal separation using LIX 64N, iron and manganese found their way in the nickel and copper electrolytes. Depending on the feed pH of the nickel spent electrolyte, the selective nickel stripping could be achieved with minimum contamination of copper. A flow sheet based on co-extraction-selective stripping has been developed to process the ammoniacal leach liquor of Indian Ocean nodules. While running the continuous SX-EW circuit, the build-up of metallics (Fe and Mn) and organic impurities in the nickel electrolyte was observed which affected the deposition. The cut-off impurity level in electrolyte for nickel winning was determined as : 0.175 Kg/m(3) Mn, 0.010 Kg/m(3) Fe and 20 ppm organic reagent. A purification scheme for nickel bleed stream was developed to recycle the electrolyte back to SE-EW circuit. Copper being a more noble metal than nickel can usually tolerate higher level of impurities. Organic levels of less than 100 ppm in the copper electrolyte produced good sheet deposit. The results showed the possibility of producing electrolytic grade copper and nickel metals of 99.94% and 99.8% purity