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

Analysis of Advantages of Single Layer Vs Double Layer Anastomosis of Bowel

INTRODUCTION: In the modern day surgical practice, we come across situations in abdominal surgery, where we require resection and anastomosis of bowel. In small bowel resection and anastomosis, conventionally, two layer suturing technique i.e., inner layer with absorbable suture material in continuous fashion and outer layer with non absorbable suture material in a continuous or interrupted fashion, was considered secure. Recently, it has been advocated that anastomosis of small bowel with a single layer suturing using a non absorbable monofilament suture material in a continuous fashion has the same outcome when compared to double layer suturing technique. AIMS AND OBJECTIVES: 1. Complications of Single layer technique and the Double layer technique in emergency and elective surgeries. 2. Time consumption for performing single layer anastomosis as well as double layer anastomosis. 3. Cost effectiveness of single layer anastomosis. MATERIALS & METHODS: All adult patients requiring intestinal anastomosis at Govt. Rajaji Hospital from July 2008 to June 2010 were considered eligible. Totally 60 patients were included in our study. 30 patients under went single layer anastomosis and 30 patients underwent double layer anastomosis. Patients who underwent elective or emergency surgery were included in our study. Based on a careful history and meticulous physical examination, combined with adjunctive investigations, a decision to operate urgently or electively was taken. Baseline laboratory parameters like blood urea, blood sugar, serum creatinine, serum electrolytes, blood grouping and typing were done in all the cases, to rule out co morbid conditions. Evaluation of patients with Acute abdomen: Immediately after receiving the patient, primary survey was done, which included resuscitation secondary survey included definitive management. DISCUSSION: Our study assessed the efficacy and safety of single and double layer anastomosis after intestinal resection, in emergency and elective situations. Generally, conventional two layered technique is being practised. But this causes excessive mucosal inversion, causing narrowing of lumen and may lead to ischaemia of anastomotic site. To overcome this problem little mucosal and complete serosal continuous suturing technique was tried. It has the advantage of good opposition of serosal surfaces, no luminal narrowing and less damage to submucosal vascular plexus. In our study, anastomotic leakage in single layer group was 3.3% which is consistent with the other studies which showed leakage in the range of 1.3 to 7.7%. In emergency situations the anastomotic leak rate in single layer group is 5% The double layer group shows anastomotic leakage around 3.3% again which is consistent with the other studies. In emergency situations the anastomotic leak rate in double layer group 5%. CONCLUSION: Among the two methods of small intestinal bowel anastomosis which we have studied, our observations are ; 1. There is no much difference in the development of the complication in both the methods. However the development of complications in emergency situation is more marked in both the methods. 2. The time required to construct a single layer anastomosis is lesser than that of the double layer anastomosis. 3. Narrowing of the lumen of the bowel is lesser in single layer anastomosis when compared to double layer anastomosis. 4. Bowel movements recovered early in single layer anastomosis when compared to double layer anastomosis. 5. Finally, construction of single layer anastomosis of small bowel is cost effective when compared to that of double layer anastomosis

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

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

Processing of Tungsten Alloy Scrap for the Recovery of Tungsten Metal

Penetrators usedfordefence purposes are prepared by po wder metallurgical technique. The material contains 90% tungsten along with other minor constituents such as iron, nickel, cobalt, chromium, aluminium etc. During the manufacturing process, three forms of scraps are generated whichare, powder, turnings and defective solid. Since the major constituents of the scrap is the costly tungsten metal, attempts were made to recover the metal by four different methods which are described in this paper. Electro-leaching of turnings in a diaphragm cell using chloride electrolyte bath was tried to remove minor elements. The purity of tungsten achieved in thisprocess was 99.9%. In the soda roasting - leaching process of powderliurning scraps, sodium tungstate of 99.85% purity was obtained with 90% yield. Attempt was also made to remove the impurities by acid leaching. 99.8% pure tungsten with 99% yield was achieved by acid leaching. Fine gravity separation and high intensity magnetic separation techniques were also adopted to enhance the tungsten value from the powder scrap, which produced the concentrate containing 96.2% tungsten

Autonomic regulation therapy to enhance myocardial function in heart failure patients: the ANTHEM-HFpEF study.

BackgroundApproximately half of the patients presenting with new-onset heart failure (HF) have HF with preserved left ventricular ejection fraction (HFpEF) and HF with mid-range left ventricular ejection fraction (HFmrEF). These patients have neurohormonal activation like that of HF with reduced ejection fraction; however, beta-blockers and angiotensin-converting enzyme inhibitors have not been shown to improve their outcomes, and current treatment for these patients is symptom based and empiric. Sympathoinhibition using parasympathetic stimulation has been shown to improve central and peripheral aspects of the cardiac nervous system, reflex control, induce myocyte cardioprotection, and can lead to regression of left ventricular hypertrophy. Beneficial effects of autonomic regulation therapy (ART) using vagus nerve stimulation (VNS) have also been observed in several animal models of HFpEF, suggesting a potential role for ART in patients with this disease.MethodsThe Autonomic Neural Regulation Therapy to Enhance Myocardial Function in Patients with Heart Failure and Preserved Ejection Fraction (ANTHEM-HFpEF) study is designed to evaluate the feasibility, tolerability, and safety of ART using right cervical VNS in patients with chronic, stable HFpEF and HFmrEF. Patients with symptomatic HF and HFpEF or HFmrEF fulfilling the enrolment criteria will receive chronic ART with a subcutaneous VNS system attached to the right cervical vagus nerve. Safety parameters will be continuously monitored, and cardiac function and HF symptoms will be assessed every 3 months during a post-titration follow-up period of at least 12 months.ConclusionsThe ANTHEM-HFpEF study is likely to provide valuable information intended to expand our understanding of the potential role of ART in patients with chronic symptomatic HFpEF and HFmrEF

Seperation & Recovery of Copper & Nickel from Copper Bleed Stream by Solvent Extraction Route

Bleed stream from electro r(fining step of copper slnelter was processed to recover the metals as high value products such as copper and nickel powders or salts. The process consists of partial decopperisation of the bleed stream followed by crystallisation of a ,nixed salt of copper and nickel sulphate, leaching of the mixed salt, removal of iron, solvent extraction separation of copper and nickel and winning the solution to produce metal powders. With the partially decopperised bleed stream, the composite crystal was obtained by crystallisation which contained 8.4 -12.5 % Cu and 13.7-14.38 % Ni with 1-2pptn Fe as impurity. This mixed salt was leached with water and was treated for iron precipitation. The purified solution was subjected to solvent extraction using LIX 84 and CYANI X 272, A 20% LIX 84 in kerosene extracted 99.88% copper acrd 0,059% nickel (if ct p1I of 2.5 and 5% C}'ANEX 272 in kerosene extracted 98,06% copper and 0.511, nickel at a p!I of 4.85. 1,L1' 84 was usec! for metal separation in the ,fixer-seiller unit. The pure solutions of copper and nickel sulphates obtained from stripping circuit were electrolysed to produce pure copper (99.9%) and nickel (99.8) powders; alternatively pure sulphate salts could also be crystallised