Nickel is absorbed mainly through the lungs and gastrointestinal tract. Once in the body it enters the bloodstream, where it binds to albumin, L-histidine, and _2-macroglobulin. Nickel tends to accumulate in the lungs, thyroid, kidney, heart, and liver. Absorbed nickel is excreted in the urine, wherease unabsorbed nickel is excreted in the faeces. (L41)
Nickel is known to substitute for other essential elements in certain enzmes, such as calcineurin. It is genotoxic, and some nickel compounds have been shown to promote cell proliferation. Nickel has a high affinity for chromatin proteins, particularly histones and protamines. The complexing of nickel ions with heterochromatin results in a number of alterations including condensation, DNA hypermethylation, gene silencing, and inhibition of histone acetylation, which have been shown to disturb gene expression. Nickel has also been shown to alter several transcription factors, including hypoxia-inducible transcription factor, activating transcription factor, and NF-KB transcription factor. There is also evidence that nickel ions inhibit DNA repair, either by directly inhibiting DNA repair enzymes or competing with zinc ions for binding to zinc-finger DNA binding proteins, resulting in structural changes in DNA that prevent repair enzymes from binding. Nickel ions can also complex with a number of cellular ligands including amino acids, peptides, and proteins resulting in the generation of oxygen radicals, which induce base damage, DNA strand breaks, and DNA protein crosslinks. (L41, A40)
The most common harmful health effect of nickel in humans is an allergic reaction. This usually manifests as a skin rash, although some people experience asthma attacks. Long term inhahation of nickel causes chronic bronchitis and reduced lung function, as well as damage to the naval cavity. Ingestion of excess nickel results in damage to the stomach, blood, liver, kidneys, and immune system, as well as having adverse effects on reproduction and development. (L41)
Symptoms of nickel poisoning include headache, nausea, vomiting, dizziness, irritability, and difficulty sleeping, followed by chest pains, sweating, rapid heart beat, and a dry cough. Nickel tetracarbonyl poisoning is characterized by a two-stage illness. The first consists of headaches and chest pain lasting a few hours, usually followed by a short remission. The second phase is a chemical pneumonitis which starts after typically 16 hours with symptoms of cough, breathlessness and extreme fatigue. These reach greatest severity after four days, possibly resulting in death from cardiorespiratory or renal failure. Convalescence is often extremely protracted, often complicated by exhaustion, depression and dyspnea on exertion. (L42, L508)
Process for producing nickel carbonyl, nickel powder and use thereof
申请人：——
公开号：US20040109810A1
公开（公告）日：2004-06-10
A process for producing Ni(CO)
4
from carbon monoxide and a source of nickel selected from the group consisting of elemental nickel, a nickel compound or mixtures thereof, provided the nickel compound is not nickel chloride per se or in admixture with a nickel carbonate ore, in an amount greater than 50% W/W nickel chloride; which process comprises (a) treating the nickel source with hydrogen at a pressure of at least atmospheric pressure and an effective temperature, in the presence of chloride anion or an in situ generator thereof precursor, to produce a resultant nickel; (b) reacting the carbon monoxide with the resultant nickel to produce the Ni(CO)
4
; and collecting the Ni(CO)
4
. The process offers the production of Ni(CO)
4
at atmospheric pressure and at a sufficiently high rate for direct use in subsequent deposition processes without the need for storage facilities.
Production of active nickel powder and transformation thereof into nickel carbonyl
申请人：Collins Michael
公开号：US20070034053A1
公开（公告）日：2007-02-15
Active nickel powder is produced by reducing a feed material, containing one or more reducible nickel salts, such that when nickel chloride is present, the weight ratio of chloride to total nickel is greater than 0.1 and the reducible nickel salts have a surface area in excess of 1 m
2
/g, with a reducing gas containing preferably at least 20 volume per cent hydrogen, at a temperature preferably between 300° C. and 600° C., and when nickel chloride is not present, by adding hydrogen chloride directly to the reducing gas. The resulting active nickel powder can be rapidly converted into nickel carbonyl by reaction with a gas containing carbon monoxide preferably at atmospheric or super-atmospheric pressure, in the absence of conventional carbonylation catalysts.
A process for the production of methane comprising reacting at least part of a feed gas containing carbon monoxide and hydrogen in an internally cooled methanation reactor containing a nickel comprising methanation catalyst to produce a product gas containing methane, cooling the internally cooled methanation reactor with water, wherein the water enters the internally cooled methanation reactor at a temperature in the range from 20-120° C. below its boiling temperature.
A process for the production of methane comprising reacting at least part of a feed gas containing carbon monoxide and hydrogen in an internally cooled methanation reactor containing a nickel comprising methanation catalyst to produce a product gas containing methane, cooling the internally cooled methanation reactor with water, wherein the water enters the internally cooled methanation reactor at a temperature in the range from 20-120° C. below its boiling temperature.
