Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
151 words
A method of measuring temperature of a hot mineral material which comprises: doping a calcareous mineral material containing CaCO 3 with a sufficient amount of a lanthanide group rare earth metal compound, in which the rare earth metal has an atomic number between 58 and 71; calcining the mineral material in a kiln at a sufficient temperature and for a sufficient time to convert at least a major part of the CaCO.sub. 3 into CaO and incorporate the rare earth metal into the crystal lattice of the CaO to form a phosphor; exciting the hot CaO-based phosphor with laser light energy while it is still within or as it is discharged from the kiln wherein the exciting wavelength is shorter than the wavelength of the major fluorescence peaks of the phosphor; measuring the fluorescence emitted by the excited hot phosphor and relating the measured fluorescence to the temperature of the material.
Claim 2
Independent Claim
151 words
A method of measuring temperature of a hot mineral material which comprises: doping a calcareous mineral material containing CaCO 3 with a sufficient amount of a lanthanide group rare earth metal compound, in which the rare earth metal has an atomic number between 58 and 71; calcining the mineral material in a kiln at a sufficient temperature and for a sufficient time to convert at least a major part of the CaCO.sub. 3 into CaO and incorporate the rare earth metal into the crystal lattice of the CaO to form a phosphor; exciting the hot CaO-based phosphor with laser light energy while it is still within or as it is discharged from the kiln wherein the exciting wavelength is shorter than the wavelength of the major fluorescence peaks of the phosphor; measuring the fluorescence emitted by the excited hot phosphor and relating the measured fluorescence to the temperature of the material.
Claim 3
Dependent Claim
29 words
The method of claim 1 in which the laser light is pulsed to induce fluorescence and the decay time of the induced fluorescence is measured and related to temperature.
Claim 4
Dependent Claim
29 words
The method of claim 1 in which the fluorescence is measured at two wavelength peaks and the ratio of fluorescence intensity at the two wavelengths is related to temperature.
Claim 5
Dependent Claim
19 words
The method of claim 1 in which the mineral material calcined at a temperature of at least 800° C.
Claim 6
Dependent Claim
16 words
The method of claim 1 in which the calcareous mineral material also contains an argillaceous mineral.
Claim 7
Dependent Claim
54 words
The method of claim 1 in which the calcareous mineral is limestone and the calcined material is reconverted to CaCO.sub. 3 in a downstream process, the reconverted material being recycled to the calcining step without the further addition of calcareous mineral and rare earth compound other than that required to make up process losses.
Claim 8
Dependent Claim
17 words
The method of claim 6 in which the downstream process is the recausticizing of kraft pulping liquor.
Claim 9
Dependent Claim
25 words
The method of claim 1 in which the rear earth metal is selected from the group consisting of praseodymium, samarium, europium, gadolinium, terbium, and dysprosium.
Claim 10
Dependent Claim
22 words
The method of claim 1 in which the rare earth metal is present in an amount of at least 0.001 mol %.
Claim 11
Dependent Claim
22 words
The method of claim 1 in which the rare earth metal is present in an amount of at least 0.01 mol %.
Claim 12
Dependent Claim
19 words
The method of claim 1 in which the laser excitation wavelength is at a wavelength of about 355 nm.
Claim 13
Dependent Claim
35 words
The method of claim 1 in which the rare earth metal is selected from praseodymium, samarium, europium, terbium, and dysprosium, and the excitation is at the third harmonic wavelength of a neodymium doped YAG laser.
Claim 14
Dependent Claim
13 words
The method of claim 12 in which the rare earth, metal is praseodymium.
Claim 15
Dependent Claim
28 words
The method of claim 1 in which the rare earth metal is gadolinium and the excitation is at the fourth harmonic wavelength of a neodymium doped YAG laser.