Elkem Asa

Elkem As

Elkem A/s and Den Norske Stats Oljeselskap A.s.

Eldar O Dingsoyr

Magne Dastol

Halvard Tveit

Svein Harsaker

Bjorn Vassoye

Per J Svenkerud

Cor Oldenziel

Per Ronning

Bjorn Vassoy

Nils Blomberg

The present invention relates to a slurry containing water, amorphous silica panicles having a particle size less than 1 micron and silica flour with a particle size between 2-200 microns. In order to stablize the slurry, the slurry contains a polysaccharide. The invention further relates to a method for the production of a slurry containing water, amorphous silica having a particle size below 1 micron, and silica flour with a particle size between 2-200 microns, where a polysaccharide is added to a slurry of water and amorphous silica, whereafter the silica flour is mixed into the slurry of amorphous silica.

Silicon oxide slurry and method for producing such slurry

The present invention relates to a method for producing microsilica having a reflectivity between 65 and 90% in a smelting furnace for production of ferrosilicon or silicon by using a charge comprising an SiO source and a solid carbonaceous reduction agent, where microsilica is recovered from the off-gases from the smelting furnace, wherein the solid reduction agent supplied to the furnace contains an amount of volatile matters of less than 1.25 kg per kg produced microsilica and that the temperature in the gas atmosphere in the furnace above the charge is kept above 500&deg; C.

Method for production of white microsilica

The cement slurry of the present invention is gas tight, very low strength retrogression at high temperature, and substantially no tendency to settle or segregate. The cement slurry is made with a hydraulic cement, 5-85% microsilica based on the weight of the cement, 5-250% of a high density filler material based on the weight of the cement, 0-5% of a retarder (dry weight) based on the weight of the cement, 0-12% of a thinner (dry weight) based on the weight of the cement, 0-8% of a fluid loss additive (dry weight) based on the weight of the cement, 0-30% silica flour and/or silica sand based on the weight of the cement and water in such an amount that the cement slurry has a density between 1.95 and 2.40 g/cm.sup.3.

Hydraulic cement slurry

Hydraulic cement slurry for use in cementation of oil wells containing hydraulic cement, 5-100% microsilica based on the weight of cement, 2-200% light weight aggregate with a real particle density between 0.1 and 1.5 g/cm.sup.3 based on the weight of the cement, 0-5% thinner (dry weight) based on the weight of the cement, 0-10% fluid loss additive (dry weight) based on the weight of the cement, and water in such an amount that the cement slurry has a density between 0.8 and 2.0 g/cm.sup.3. The cement slurry according to the present invention is gas tight and can thereby be used for cementation of oil well in fields having gas containing formations.

Growing community of inventors

Sogne, Norway

Eldar O Dingsoyr