1. An improved process for the production of Portland slag cement using of granulated blast furnace slag, the said process comprising the steps of:
(i) preparing cement clinker
(ii) ball-milling of cement clinker for a period ranging between 30-60 minutes under dry condition,
(iii) reducing size of granulated blast furnace slag to a size of ranging between 210 to 100 \u03bcm, for using as feed for attrition mill,
(iv) wet milling of granulated blast furnace slag for a period ranging between 5-15 minutes, in an attrition mill with granulated blast furnace slag to water ratio in the range of 1:1 to 1:2 and granulated blast furnace slag to grinding ball ratio in the range of 1:5 to 1:15 to obtain a slurry,
(v) removing water from the above said slurry after attrition milling followed by drying to obtain the attrition milled slag,
(vi) mixing intimately
attrition milled slag obtain in step (v) in the range of: 50 to 95% by weight,
ball-milled clinker obtain in step (ii) in the range of: 05 to 45% by weight,
and gypsum in the range of: 01 to 05% by weight,
for a period in the range of 15 to 30 minutes, to obtain the Portland slag cement.
2. An improved process as claimed in claim 1 wherein the granulated blast furnace slag has a following composition:
range: SiO2-20 to 40%, Al2O3-20 to 40%, Fe2O3-0 to 2%, CaO-20 to 40%, MgO-5 to 17%, MnO-0 to 5%, SO3-0 to 2% and glass content >85%.
3. An improved process as claimed in claim 1, wherein the cement clinker has a following composition range: SiO2-20 to 25%, Al2O3-3 to 8%, Fe2O3-2 to 4%, CaO-60 to 70%, MgO-0 to 6%, MnO-0 to 4%, SO3 <1.5%.
4. An improved process as claimed in claim 1, wherein the gypsum has a following composition range: CaO-25 to 40%, SO3-30 to 60%.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
I claim:
1. A method of collecting trash comprising the following steps,
picking up a trash apron, the trash apron having two sashes and a bag portion, the apron being made of flexible plastic, the bag portion being pleated and having and opening extending substantially from one sash to the other sash.
placing the sashes around a persons waist and securing the sashes to each other to hold the apron in place on the person.
expanding the pleats to increase the volume of the opening and the bag portions, and
collecting trash in the bag portion.