First fluo-solid Roaster in India-design and Operation

THE fluo-solid roaster is a modern device which has passed on to the hands of metallurgists from the oil industry where it was used for the first time by Houndry in 1936, for catalytic cracking of petroleum and since then it has been improved and perfected. It is now in common application for sulphide roasting recover gas for acid manufacture and calcines from which metal constituents are extracted. It can also he used for partial oxidation and sulph- atation roasting of concentrates and matte to render them suitable for extractive treatments. Fluid bed operation gives precise control of temperature without any hot spot and feed material to air ratio. These facts are advantageously used in sulphide roasting. The feed is intimately and rapidly mixed with the air or gas introduced from the bottom of the roaster

Effect and Control of Impurities in Electrolytic Zinc Production

THE commercial application of hydrometallurgy and elec-trolytic zinc production has been of recent development when compared to its strong competitor, namely , pyro-metallurgy and zinc distillation. The zinc produced by pyrometallurgical methods has its own disadvantages due to ( i) large losses of metal and valuable impurities,( ii) fume handling problems, (iii) limitations to equip ment size, (iv ) heavy repair and maintenance charges, (v) high labour costs and ( vi) low quality of zinc

Characteristics of electrolytic cells

THE electrolysis section of zinc smelter, at Debari, is designed for a low current density process taking into consideration the ambient temperature of the region. The cells are made of reinforced concrete with lead lining and contain 2 5 anodes of lead (alloyed with 0.5--I'0°o silver) and 27 cathodes of high purity aluminium sheet. Current density is maintained around 300 ampslm2 and the cells are oper- ated between 9 000 and 10 000 amperes per hour per cell. There are 240 cells distributed in 20 cascades of 12 cells each. Each cascade has two rows of six cells. The temperature in cells is maintained by removing excess heat with the help of lead cooling coils. The normal working temperature varies between 38 and 45 C. Purified zinc sulphate solution, termed neutral solution, is fed to individual cells through a small feeder pipe With provision for regulating the flow. The rated capacity of the plant is 555 tons of zinc cathodes per day

Paper Fluo-Solid Roaster in India Design and Operation

Fluo-solid roaster is now in common application for sulphide roasting to recover gas for acid manufacture and calcines from which metal constitutents are extracted. It can also be used for partial oxidation and sulphatation roasting of concentrates and matte to render them suitable for extractive treatment. Fluid bed operation: gives precise control of temper- ature without any hot spot and feed material to ratio. These facts are advantageously used in sulphide roasting. The feed is intimately and rapidly mixed with the air or gas introduced from the bottom side of the roaster

Tinnitus and tinnitus disorder: Theoretical and operational definitions (an international multidisciplinary proposal)

As for hypertension, chronic pain, epilepsy and other disorders with particular symptoms, a commonly accepted and unambiguous definition provides a common ground for researchers and clinicians to study and treat the problem. The WHO's ICD11 definition only mentions tinnitus as a nonspecific symptom of a hearing disorder, but not as a clinical entity in its own right, and the American Psychiatric Association's DSM-V doesn't mention tinnitus at all. Here we propose that the tinnitus without and with associated suffering should be differentiated by distinct terms: “Tinnitus” for the former and “Tinnitus Disorder” for the latter. The proposed definition then becomes “Tinnitus is the conscious awareness of a tonal or composite noise for which there is no identifiable corresponding external acoustic source, which becomes Tinnitus Disorder “when associated with emotional distress, cognitive dysfunction, and/or autonomic arousal, leading to behavioural changes and functional disability.”. In other words “Tinnitus” describes the auditory or sensory component, whereas “Tinnitus Disorder” reflects the auditory component and the associated suffering. Whereas acute tinnitus may be a symptom secondary to a trauma or disease, chronic tinnitus may be considered a primary disorder in its own right. If adopted, this will advance the recognition of tinnitus disorder as a primary health condition in its own right. The capacity to measure the incidence, prevalence, and impact will help in identification of human, financial, and educational needs required to address acute tinnitus as a symptom but chronic tinnitus as a disorder. © 2021 Elsevier B.V