US4758406A — Molybdenum addition agent and process for its pro…

Claim 1

Independent Claim 122 words

A molybdenum-containing addition agent for incorporating molybdenum in a molten metal bath maintained at a temperature of at least about 1500° C., said addition agent consisting essentially of polymolybdenum oxide composition derived from the roasting of MoS 2 at an elevated temperature sufficient to provide a roasted product in which the oxygen content of said composition exceeds the stoichiometric oxygen content of MoO 2 and is less than the stoichiometric oxygen content of MoO 3 , said oxygen content, excluding gangue material, ranging from about 26% to 32.5% by weight, with the sulfur content less than about 2%, by weight, said polymolybdenum oxide composition having an equivalent MoO 3 content in excess of 5% and ranging up to about 15% by weight.

Claim 2

Dependent Claim 122 words

A molybdenum-containing addition agent for incorporating molybdenum in a molten metal bath maintained at a temperature of at least about 1500° C., said addition agent consisting essentially of polymolybdenum oxide composition derived from the roasting of MoS 2 at an elevated temperature sufficient to provide a roasted product in which the oxygen content of said composition exceeds the stoichiometric oxygen content of MoO 2 and is less than the stoichiometric oxygen content of MoO 3 , said oxygen content, excluding gangue material, ranging from about 26% to 32.5% by weight, with the sulfur content less than about 2%, by weight, said polymolybdenum oxide composition having an equivalent MoO 3 content in excess of 5% and ranging up to about 15% by weight.

Claim 3

Dependent Claim 66 words

The molybdenum-containing addition agent of claim 1, wherein said polymolybdenum oxide composition is derived from roasting MoS 2 at a temperature in the range of about 500° C. to 700° C., wherein the oxygen content thereof ranges from about 27% to 31.5% and the sulfur content is less than about 0.7%, and wherein the equivalent MoO 3 content ranges from about 10% to 15% by weight.

Claim 4

Dependent Claim 142 words

A process for introducing molybdenum into a molten metal bath having a temperature of at least about 1500° C. which comprises: introducing said molybdenum as an addition agent in the form of a polymolybdenum oxide composition derived from the roasting of MoS 2 at an elevated temperature sufficient to provide a roasted product in which the oxygen content of said composition exceeds the stoichiometric oxygen content of MoO 2 and is less than the stoichiometric oxygen content of MoO 3 , said oxygen content, excluding gangue material, ranging from about 26% to 32.5% by weight, with the sulfur content less than about 2%, by weight, said polymolybdenum oxide composition having an equivalent MoO 3 content in excess of 5% and ranging up to about 15% by weight, said polymolybdenum oxide composition entering said molten metal bath efficiently and with substantially reduced volatization.

Claim 5

Dependent Claim 142 words

A process for introducing molybdenum into a molten metal bath having a temperature of at least about 1500° C. which comprises: introducing said molybdenum as an addition agent in the form of a polymolybdenum oxide composition derived from the roasting of MoS 2 at an elevated temperature sufficient to provide a roasted product in which the oxygen content of said composition exceeds the stoichiometric oxygen content of MoO 2 and is less than the stoichiometric oxygen content of MoO 3 , said oxygen content, excluding gangue material, ranging from about 26% to 32.5% by weight, with the sulfur content less than about 2%, by weight, said polymolybdenum oxide composition having an equivalent MoO 3 content in excess of 5% and ranging up to about 15% by weight, said polymolybdenum oxide composition entering said molten metal bath efficiently and with substantially reduced volatization.

Claim 6

Dependent Claim 71 words

The process as defined in claim 3, wherein said polymolybdenum oxide composition introduced in said molten bath is derived from roasting MoS 2 at a temperature in the range of about 500° C. to 700° C., wherein the oxygen content thereof ranges from about 27% to 31.5% and the sulfur content is less than about 0.7%, and wherein the equivalent MoO 3 content ranges from about 10% to 15% by weight.

Claim 7

Dependent Claim 30 words

The process of claim 3, wherein said molybdenum-containing addition agent is added to said molten metal bath in a form selected from the group consisting of powder, pellets or briquettes.

Claim 8

Dependent Claim 191 words

A process for producing a molybdenum-containing addition agent for use in molten metal baths which comprises: roasting MoS 2 concentrate in a multiple hearth roaster comprising a first and second hearth and a plurality of hearths thereafter in which the temperature of each of said plurality of hearths is controlled at a temperature of about 500° C. to 700° C., controlling the air supply for each hearth at a rate less than that required to convert the molybdenum sulfide concentrate completely to MoO 3 , and thereby produce a polymolybdenum oxide composition at a rate of about 20% to 60% higher per area of hearth surface as compared to the production of MoO 3 per se, said polymolybdenum oxide composition characterized in that the oxygen content thereof exceeds the stoichiometric oxygen content of MoO 2 and is less than the stoichiometric oxygen content of MoO 3 , said oxygen content, excluding gangue material, ranging from about 26% to 32.5% by weight with the sulfur content less than about 2% by weight, the MoO 3 equivalent content thereof being in excess of about 5% and ranging up to about 15% by weight.

Claim 9

Dependent Claim 191 words

A process for producing a molybdenum-containing addition agent for use in molten metal baths which comprises: roasting MoS 2 concentrate in a multiple hearth roaster comprising a first and second hearth and a plurality of hearths thereafter in which the temperature of each of said plurality of hearths is controlled at a temperature of about 500° C. to 700° C., controlling the air supply for each hearth at a rate less than that required to convert the molybdenum sulfide concentrate completely to MoO 3 , and thereby produce a polymolybdenum oxide composition at a rate of about 20% to 60% higher per area of hearth surface as compared to the production of MoO 3 per se, said polymolybdenum oxide composition characterized in that the oxygen content thereof exceeds the stoichiometric oxygen content of MoO 2 and is less than the stoichiometric oxygen content of MoO 3 , said oxygen content, excluding gangue material, ranging from about 26% to 32.5% by weight with the sulfur content less than about 2% by weight, the MoO 3 equivalent content thereof being in excess of about 5% and ranging up to about 15% by weight.

Claim 10

Dependent Claim 63 words

The process of claim 6, wherein said multiple hearth furnace is a Herreshoff type roaster and wherein said roasting is carried out through a series of at least seven hearths, the polymolybdenum oxide composition produced thereby containing about 27% to 31.5% with the sulfur content less than about 0.7%, the MoO 3 equivalent content thereof ranging from about 10% to 15% by weight.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1991-07-19	1992-01-18	1992-07-19	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1995-07-19	1996-01-18	1996-07-19	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1999-07-19	2000-01-18	2000-07-19	$7700.00	Window Closed / Lapsed

Molybdenum addition agent and process for its production

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