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(11) Patent Number: KE 000193

(45) Date of grant: 11/03/2005

(12) PATENT 

(51) Int.C1.7:C 04B 7/24

(21) Application Number: 2003/ 000394

(22) Filing Date: 11/09/2003

(30) Priority data:  

(73) Owner: WATHIONG'0, JOSEPH KARANJA, DR.,

P.0 Box 74862-00200, City Square,

Nairobi

(72) Inventor:WATHIONG'0, JOSEPH KARANJA, DR.

(74) Agent/address for correspondence:  

(54) Title: POZZOLANA BASED CEMENT FROM INDUSTRIAL AND AGRICULTURAL WASTE MATERIALS 

(57) Abstract:

Novel methods and uses of environmentally nuisance waste materials from industrial and agricultural sources are reported. Pozzolanic Cement was made from Spent Bleaching Earth, Rice Husks, Broken Bricks and Acetylene Lime Sludge. Pozzolana was made by mixing Spent Bleaching Earth, Rice Husks, and Broken Bricks in different proportions and burning in a Fixed Bed Kiln under controlled temperature conditions. The pomolana was mixed with dried acetylene lime sludge in specified proportions and milled to obtain pozzolanic cement. By use of acetylene lime sludge in the stack, acidic gases were scrubbed before the exhaust release to the atmosphere. The heat dissipated from the kiln was used to dry the acetylene lime sludge. The invention is a breakthrough in dealing with environmentally nuisance and potentially dangerous materials in a safe and profitable manner. The invention leads to a low cost cement that should go a long way in addressing housing problems in the rural areas especially in the developing world. In the Spent Bleaching Earth was found significant amounts of oil whose calorific value was utilizable in cookers, warmers and cement clinker manufacture. The material would be fed in a similar manner to coal or with the raw mix in the clinker manufacture. The material had significant amounts of silica, iron oxide and alumina that are valuable in the clinker manufacture.

Abstract

Title: "POZZOLANA BASED CEMENT FROM INDUSTRIAL AND

AGRICULTURAL WASTE MATERIALS"

`Novel methods and uses of environmentally nuisance waste materials from industrial and agricultural sources are reported. Pozzolanic Cement was made from Spent Bleaching Earth, Rice Husks, Broken Bricks and Acetylene Lime Sludge. Pozzolana was made by mixing Spent Bleaching Earth, Rice Husks, and Broken Bricks in different proportions and burning in a Fixed Bed Kiln under controlled temperature conditions. Thepozzolana was mixed with dried acetylene lime sludge in specified proportions and milled to obtain pozzolanic cement. By use of acetylene lime sludge in the stack, acidic gases were scrubbed before the exhaust release to the atmosphere. The heat dissipated from the kiln was used to dry the acetylene lime sludge. The invention is a breakthrough in dealing with environmentally nuisance and potentially dangerous materials in a safe and profitable manner. The invention leads to a low cost cement that should go a long way in addressing housing problems in the rural areas especially in the developing world. In the Spent Bleaching Earth was found significant amounts of oil whose calorific value was utilizable in cookers, warmers and cement clinker manufacture. The material would be fed in a similar manner to coal or with the raw mix in the clinker manufacture. The material had significant amounts of silica, iron oxide and alumina that are valuable in the clinker manufacture.

 

DESCRIPTION

"POZZOLANA BASED CEMENT FROM INDUSTRIAL AND AGRICULTURAL 

WASTE MATERIALS"

FIELD OF THE INVENTION

The following invention relates to tackling the problem of wastes from industries manufacturing and/or processing, among others:

-Vegetable oils

- Clay bricks and similar products

-Acetylene gas

- Rice

The wastes covered by the invention include:

-Spent bleaching earth

-Broken bricks or other fired clay products

-Acetylene lime sludge or other lime based wastes

-Rice husks

-Similar materials

OBJECT OF THE INVENTION

It is the object of the invention to deal with obnoxious solid wastes from the oil, agricultural and other similar processing industries. It will also deal with wastes from clay, brick and ceramic industries. The invention will find application in the manufacture of Portland cement, Pozzolanic Portland cement, and pozzolana as well as provision of energy. The invention will find use in dealing with acidic gases from boilers, kilns, incinerators and other industrial stacks. Following on these applications, the invention is expected to impact significantly and positively on cement and concrete industry and industrial environmental issues. The invention is expected to address global housing infrastructure, and environmental issues especially in the developing world.

DISCLOSURE OF THE INVENTION 

Characterization of materials under investigation

Investigation of Spent bleaching earth found the following characteristics among others:

PropertyValue

Calorific value14-16J/g

Oil content   32-39 %wt

Ignition temperatureApprox.240°C

Maximum self Combustion temperature   475-1000 °C

Ash content52-59% wt

 

 

Table 1.1 Some Properties of Spent Bleaching Earth (SBE) 

 

 

The burning process of cement represents 40-60% of the production cost snaking the calorific value of the material, (40% of the heavy fuel oil) significant if used for cement manufacture.

Other materials investigated on included, broken bricks (BB), rice husk ash (RHA) and a volcanic tuff (Ptuff) used for blending ordinary Portland cement to make Portland Pozzolanic cement. The materials were activated at approximately 550° C and analyzed, to check on the pozzolanicity potential. Results of some physical and chemical investigations were

Sample 90 µm% retention     212 µm% retention

BB7.31-7.92   1.40-1.42

RHA7.19   1.40

SBE  Approx. 6.987   1.34-1.38

Ptuff 7.01   1.40

Combined mix   7.18   1.42

 

 

Table 1.2: Percentage sieve retention of milled samples

Compound SBE BBPtuff RHA

% by wt.% by wt.          % by wt.    % by wt.

Ca03.02-3.12   0.44-4.08   2.07   1.38

Si0267.70-69.15   63.31-65.71   57.86   80.61

Al20312.15-12.37   17.66-20.47   12230.53

Fe2O3  3.96-4.04   6.70-7.89   10.02   0.47

SO32.84-2.990.22-0.39   0.11   0.01

MgO 4.05-4.18   1.95-2.32   1.45   2.39

K20 0.58-0.59   2.34-3.52   1.47   0.15

Na20  <0.01-0.30   1.02-1.55   2.270.20

LOI(Loss on Ignition)   4.12-6.72   0.57-0.90   14.62   3.49

SiO2+ Al203+ Fe2O3   84.11-85.16   87.67-94.07   80.11   81.61

 

 

Table 1.3: Chemical Constituents of resultant Pozzolanic Samples

From the results, it was noted that the materials met the criteria for pozzolanicity, as stipulated by the Kenya Standard KS 1263 of 1993, and were fine enough for pozzolanic reactions to take place

 

Acetylene lime sludge as obtained from the acetylene gas-manufacturing factory was a wet dense white mixture. At this state it contained 38.21 % water by mass. The material separated on standing and on drying the supernatant material, the resulting solid contained 96.33% by mass hydrated calcium hydroxide. The percent lime content was higher than that of a commercial hydrated lime (CHL) used as a standard.

FURTHER EXPERIMENTATION WITH THE MATERIALS

The materials were investigated further to assess their potential exploitation in the cement industry. The experiments were carried out on the activated materials singly and in combined form. The relevant standards were used to gauge the suitability of the materials. The 'combined' material was made by taking different amounts of the raw waste materials, activating the mixture followed by milling, while the ashed mixture was made by taking different amounts of the activated materials, mixing and milling. The potentially pozzolanic materials were then mixed with commercial or dried lime sludge in different proportions and subjected to pozzolana or cement technology tests. Commercial cements were blended with the materials and similarly tested. Some results are given below.

Compressive Strengths and Setting Times

The compressive strengths evaluation were carried out in accordance with the ASTM 593 part C, while the setting times were evaluated using the Kenya Standard KS 02 1263.

 

 

Material    Material Initial settingFinal setting7-day 28-days 

 

 

: CHL   time timeCompressive Compressive 

 

 

                                    (IST)/Minute   (FST)/Minute   strength/MPa   strength/MPa

 

SBE    2:1    123-127    311-320    9.86-9.94    10.07-10.92

SBE    1:1    128    315   7.57    7.91

SBE   3:1    110    268    6.67    6.82

BB    2:1    160-850    239-1702    6.27-12.97    6.28-13.2

    1:1    180-1002    266-1351    4.74-9.32    5.01-10.42

    3:1    175-645    253-1226    4.46-9.64    4.34-10.73

Ptuff    2:1    283    541    8.94    8.99

    1:1    320    545    7.47    7.51

    3:1         290                        527                      8.12                     8.00

RHA    2:1    351    482    5.48    5.60

    1:1   360    498    3.99    5.09

    3:1    323    445    3.75    3.83

Combined    2:1        290                        471                     8.37                      8.90

Ashed 

mixture    2:1    301    552    7.73    7.80

Table 1.4: Setting Times and Compressive Strengths 

 

CLAIMS

1. Use of Spent Bleaching Earth (hereinafter referred to as SBE) as a fuel in cooking jikos', Boilers, heaters, warmers and kilns on its own or with other materials such as saw dust, firewood, oil, coal, any other fuel.

2. In cement manufacture, use of SBE as a fuel, fed with the raw mill or pumped into the kiln on its own, or as a mixture with oil, coal, and tire’s, any other fuel or material.

3. Use of SBE or its ash as a raw material correction ingredient in cement and other clay based manufacturing industries.

4. Use of SBE or its ash as a source or raw material for making pozzolana or cement material.

5. Arising from claim number 4, use of SBE or its ash in conjunction with wastes or products from clay based products manufacturers of whichever nature to make pozzolana or cement materials.

6. Arising from claim number 4, use of SEE or its ash in conjunction with Rice Husks or Rice Husk Ash to make pozzolana or cement materials.

7. Arising from claim number 6, use of SBE or its ash in conjunction with agricultural wastes from produce similar to rice including wheat to make pozzolana and/or cement materials.

8. Arising from claim number 4, use of SBE or its ash in conjunction with Sea Weeds or other vegetation that grow or grown in a similar manner or similar ecological conditions to rice to make pozzolana or cement materials.

9. Arising from claims number 4, 5, 6, 7 and 8, use of SBE or its ash in conjunction with clay and vegetation based products, by-products or wastes to make pozzolana or cement.

10. Use of dried or wet acetylene lime sludge to make pozzolana or cement materials.

11. Use of dry or wet acetylene lime sludge as a scrubber in Fixed Bed Kiln stacks.

12. Arising from claim numbers 9 and 10, use of acetylene lime sludge with SBE or its ash, clay and agricultural-based products to make pozzolana or cement materials and products.

13. Arising from claim number 11, use of wet or dry acetylene lime sludge as a scrubber in stacks, chimneys or exhaust gas systems of engines, boiler, kiln, incinerator, burners and loaded exhaust systems of all types.

14. Arising from claim number 11, use of acetylene lime sludge as a scrubber in any manufacturing process.

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