This invention relates to a process of manufacture of an abrasive from non-abrasive material -
Calcined bauxite, as such, cannot be used as an abrasive. It has to be furnaced at around 1800 deg.C
to form abrasive alumina, as is already known to the
/
art -
The process proposed herein. however, enables non-abrasive material„ such as, calcined bauxite, emery, f erro si 1 icon and other substances containing 407. alumina and above to be converted into abrasives without the need for furnacing at high temperatures, thereby resulting in substantial energy saving.
According to this invention the process of manufacture of an abrasive from non-abrasive material containing /40X alumina or mep*nc? „ comprises the steps of wetting the said material in grain form with phosphoric acid (up to 77. by weight of the said material ) ; preparing a blend -of aluminous compounds and of fine hard particles such as those selected from oxides of aluminium, chromium, titanium„ calcium, vanadium, magnesium, zirconium and

carbides of si 1 icon „ titanium;, tungsten in the proportion 30:70 to 70:30; and adding the said blend to the wetted material in the ratio 2:1 to 7:1 by weight of the said acid, before firing the same between 400 deg-C to 800 deg-C for up to 2 hours
Any type of phosphoric acid may be used.
The percentage of phosphoric acid added is up to 77. depending on the grain surface area available.
The blend of aluminous compounds and the said fine hard particles is in the proportion of 30:70 to 70:30, prefereably 40:60.
The mixing time for wetting ^nd for addition of the blend depend on factors such as quantity of acid, quantity of powder added and the type of mixer used.
The coated grains a.re loaded in trays Bnd fired at 400 deg.C to 800 deg.C preferably at 650 deg.C for 2

hours - After firing,the grains ar& sieved through coarse mesh to break up lumps, if any- The grains arB now ready for use -
EXAMPLE I
Calcined bauxite graded in accordance with FEPA 36 grit was wetted by 5% of posphoric acid for 10 minutes in a
mixer. A blend consisting of calcined alumina
>
SiC fines <800 grit) in the ratio 40:60 was prepared. This blend was added to the wetted grain and mixed* The grains were then 1oaded in saggars and fired at 650 deg.C for 2 hours- A ratio of blend:acid of 5:1 was used■
The SiC coated calcined bauxite was used as an abrasive in a standard formulation to form a vitrified wheel -Wo processing problems were encountered - These wheels were evaluated for grinding performance and compared with uncoated calcined bauxite as wel1 as with standard aloxide grain wheel -


While calcined bauxite, as such, could not perform any cuttinq action, after coatinq with SiC it could perform up to 85% of that of a standard whee1 made of brown alumina. This establishes that a non-abrasive whee1 has been converted into an abrasive without fusinq at h iqh temperatures•
The abrasives so prepared find applicat ion in the production of vitrified, resinoid and rubber bonded and coated abrasive articles.
The terms and expressions in this specif icat ion are of description and not of limi tat ion, there beinq no intention in the use of such terms and expressions of

excluding any equivalents of the features i1lustrated and described, but it is understood that various other modes of carrying out the process proposed herein are possible without departing from the scope and ambit of this invention.

We Claim:
l.A process of manufacture of an abrasive from non-
abrasive material containing /407. alumina
comprising the steps of wetting the said material in grain form with phosphoric acid (up to 77. by weight of the said material); preparing a blend of aluminous compounds and of fine hard particles such as those selected from oxides of aluminium ., chromium „ titanium „ calicum, vanadium, magnesium and zirconium and carbides of silicon titanium, tungsten in the proportion 3(3:70 to 70:30; and adding the said blend to the wetted material in the ratio 2:1 to 7:1 by weight of the said acid, before firing the same between 400 deg.C to 800 deg.C for up to 2 hours.
2-A process of manufacture of an abrasive from non-abrasive material substantially as herein described and illustrated by the Example-

We Claim:
l.A process of manufacture of an abrasive from non-
abrasive material containing /407. alumina
comprising the steps of wetting the said material in grain form with phosphoric acid (up to 77. by weight of the said material); preparing a blend of aluminous compounds and of fine hard particles such as those selected from oxides of aluminium ., chromium „ titanium „ calicum, vanadium, magnesium and zirconium and carbides of silicon titanium, tungsten in the proportion 3(3:70 to 70:30; and adding the said blend to the wetted material in the ratio 2:1 to 7:1 by weight of the said acid, before firing the same between 400 deg.C to 800 deg.C for up to 2 hours.
2-A process of manufacture of an abrasive from non-abrasive material substantially as herein described and illustrated by the Example-