Title of Invention

A PROCESS FOR THE MANUFACTURE OF FLY ASH BASED SOIL CONDITIONER CUM FERTILIZER.

Abstract

This invention relates to a process for the manufacture of fly ash based soil conditioner cum fertilizer. The soil conditioner is based on fly ash, a waste material. The soil conditioner cum fertilizer essentially consists of fly ash, rock phosphate,potassium chloride (muirate of potash), urea, humic acid and bio-fertilizers. The bio-fertilizer used is Rhizobium, Azotobacter and Phosphobacterium either singly or in a mixture. This soil conditioner cum fertilizer is suitable for all types of soils and can be used under normal conditions for effecting improvement in crop productivity.

Full Text

The present invention relates to a process for the manufacture of fly ash based soil conditioner cum fertilizer. This invention finds its usage in agricultural sector as an effective fertilizer. It also improves the texture and fertility status of waste/degraded land for agricultural and forestry purposes. Coal combustion results in a residue consisting of the inorganic mineral constituents in the coal and some organic matter, which is not wholly burned. The inorganic mineral constituents, whose residue is ash, make up from 10 to 40 percent of the coal. During combustion, this ash is distributed into two parts: bottom ash, collected from the bottom of the boiler unit and fly ash, most of which, is collected by electrostatic precipitator from the flue. The distribution of ash between the bottom and fly ash fraction is a function of the boiler type, coal type, operating condition, and whether or not a wet or dry bottom furnace is utilised. Fly ash makes up to 90% of the coal ash residue and occurs as spherical particles, usually ranging in diameter from 0.5 to 100 microns. The bottom ash, composed primarily of coarser, heavier particles than the fly ash, ranges from gray to black in colour and is generally angular with porous surface. If it is collected as a slag, these particles generally are black, angular and have a glass-like appearance. Petrographic analysis has shown that glass is the primary component of ash. Other components of the ash include magnetite, haematite, carbon, mullite and quartz. The major chemical constituents of ash are primarily silica, alumina, iron oxide and calcium oxides. Minor elements present include magnesium, titanium, sodium, potassium, sulphur and phosphorous. They comprise from 0.5% to 3.5% by weight of the ash. Ash also contains trace concentrations of from 20 to 50 different elements including antimony, arsenic, barium, beryllium, boron, chromium, copper, fluorine, lead, manganese, mercury, molybdenum, nickel, selenium, tellurium, thallium, tin, uranium, vanadium, cobalt and zinc. If we compare the list of elements found in coal ash residues with the list of elements required for plant nutrition, we find considerable overlap. Carbon, hydrogen, oxygen, nitrogen, phosphorous and sulphur are the elements of which proteins, hence, protoplasm, are composed. In addition to these six, there are fourteen other elements, such as calcium, magnesium, potassium, iron, manganese, molybdenum, copper, boron, zinc, chlorine, sodium, cobalt, vanadium and silicone, which are essential for the growth of most of the plants. While all are not required for all plants, all have been found to be essential to some extent. These mineral elements, in addition to phosphorous and sulphur, usually constitute what is known as the plant ash, or the minerals remaining after the burning off of carbon, hydrogen, oxygen and nitrogen. Each of the 20 elements plays a role in the growth and development of plants, and when present in insufficient quantities, can reduce growth and yield. When comparing the elements of coal ash residues and the required elements for plant growth, it is amazing to find that only sufficient quantities of nitrogen, phosphorous and chlorine are not available in fly ash residues and perhaps sufficient potassium also depending on the origin of the coal ash. Considering the great diversity of elements found in nature, overlap between coal ash residues and what is required for effective growth of plants is remarkable. By suitable chemical modifications to introduce larger quantities of nitrogen and phosphorous and small amount of chlorine, if required, these chemically modified coal ash residues will make excellent stimulators at very low cost because unlike commercial stimulators, they contain all the necessary elements for the plant growth. To achieve an effective plant growth stimulator, it is necessary to transform some of the elements found in coal ash residues into a desirable chemical moieties. The major elements of a plant growth stimulator are the following: ammonium sulphate, anhydrous ammonia, ammonium chloride, ammonium nitrate, ammonium nitrate with lime, ammoniated super-phosphate, mono-ammonium phosphate, diammonium phosphate, ammonium phosphate-sulphate, calcium nitrate, calcium cyanamide, potassium nitrate, sodium nitrate, urea, urea-sulphur, urea-phosphate, sulphur coated urea, urea-formaldehyde, metal-ammonium phosphates, i.e. magnesium ammonium phosphate, oxamide, crotonylidene diurea, isobutylidine diurea, dicyanadiamide and thiourea. The second major element is phosphorous. There are two types of phosphorous, an organic type and an inorganic type. The organic types are: phospholipids, nucleic acids, and inositol phosphates; inorganic types are collectively called orthophosphates; these are phosphoric acid, super phosphoric acid, calcium orthophosphates, ammonium phospahtes, nitric phosphates, potassium phosphates, dicalcium phosphates and calcium metaphosphates and the so called polyphosphates. With respect to the third major element, potassium, which is slowly available, and these include potassium tied up with various clay soils or we can have water soluble potassium compounds present as potassium halides, nitrates, sulphates or double salts containing potassium compounds. It has been found that functional fertilisers derived from coal ash residues can be classified into two types. The first type is where various nitrogen, phosphorous and sulphur (organic and inorganic) compounds are simply added to the coal ash, thus these fertilisers can be considered admixtures. Secondly, various compounds, either organic or inorganic can be made to react with certain chemical constituents in coal ash to form products, which are very effective fertilisers. Some examples of nitrogen containing compounds which are fertilisers that yield very quickly available nutrients are ammonium nitrate, ammonium nitrate with lime, ammonium nitrate-sulpahte which is a double salt, ammonium sulpahte, ammonium dihydrogen phosphate, diammonium monohydrogen phosphate, ammonium chloride, urea, a urea-sulphur compound, a urea phosphate compound or any of the soluble nitrates. Slowly available nitrogen compounds are sulphur coated urea, urea carbonyl compounds where the latter is formaldehyde or other aldehydes, metal ammonium phosphates such as magnesium ammonium phosphate, oxamide or calcium cyanamide or thiourea of dicyanamide. The nitrogen compounds, which will form salts with the various cations readily available in coal ash, such as calcium, magnesium, sodium, potassium and aluminum, are Bronsted and /or Lewis acids. Some examples are sulphamic, amidosulphonic, imidosulphonic, nitrilosulphonic, hyponitrous, nitrous and nitric acids. Many other nitrogen containing Bronsted and /or Lewis acids are also useful. Reference may be made to US Patent No:5451240 wherein activated humic acid bearing ores are combined with coal ash to provide a composition with plant growth stimulator abilities. However, it consists of several complex steps using several chemicals. First the fly ash is hydrated by water spraying onto the ash in a large mixer. While water is added, the mixture is stirred for about 20-30 minutes. After the ash and the water have been thoroughly mixed, the mixture is transferred to a holding unit, where heat is generated. The mixture is then allowed to cool down. The entire hydration process takes about 24 hours. It is at this point where the activated leonardite ore and the hydrated fly ash are preferably combined. However, the heat of hydration then must be dissipated without allowing an excess temperature rise in the leonardite ore, which would negatively affect the proper formation of a prill. Preferably, the activated ore and the hydrated ash are combined in a 50:50 weight to weight ratio. Then the dry mixture of activated leonardite ore and hydrated fly ash are binded through a liquid binding agent. The binder is a solution of potassium hydroxide and aqueous ammonia. Reference may be made to US Patent No: 5482528 wherein solid waste such as sewage sludge containing fecal matter is processed to reduce pathogens and converted to a useful product such as an amendment to agricultural land by combining the waste with an acid such as concentrated sulphuric acid and a base such as fly ash which exothermically react and thermally pasteurize the waste and add mineral value to the product. Pazzolanic materials, such as fly ash agglomerate the product and after grinding, the particles can aerate soil. The calcium oxide in fly ash reacts with sulphuric acid to form calcium sulphate dihydrate, a soil amendment. This invention relates to combining sludge or other waste with heat generating treatment chemicals that pasteurize the waste and convert to a soil amendment or fertiliser. Reference may also be made to US Patent No: 5468276 wherein a process for producing a fertiliser which incorporates fly ash with an organic fertilising component comprising manure. The fly ash and manure are mixed with the resulting mixture compressed by passing the mixture through a roller press thereby forming a sheet and fracturing the sheet into chips or other particulate form. The water content of the mixture is controlled in an effort to produce particulates having high dry strength. The drawbacks of the above processes are that the nutrients present in fly ash are mostly in insoluble form; hence are unutilised. The main object of the present invention is to provide a process for the manufacture of a fly ash based soil conditioner cum fetiliser, wherein fly ash, a waste product is used as one of the main ingredients. Another object of the present invention is to provide a soil conditioner which can improve the texture and fertility status of agricultural land. Yet another object is to provide an economical soil conditioner cum fertilizer composition which will effectively improve crop productivity. Still another object of the present invention is to improve the texture and fertility of waste/degraded land for agricultural and forestry purposes. In the process of the present invention the fly ash based soil conditioner cum fertilizer essentially consists of fly ash ground phosphatic rock, commercial grade potassium chloride (muirate of potash), urea, humic acid, and bio-fertilizers, such as Rhizobium, Azotobacter, Phosphobacterium and water to make a workable mixture. In order to have a better understanding of this invention, it is important to understand how each of the major nutrient elements for plant functions. Nitrogen is absorbed by plants primarily in the form of nitrates, although smaller amounts of the ammonium ion and urea can also be absorbed. An adequate supply of nitrogen is associated with vigorous vegetable growth and a deep green colour. When plants are deficient in nitrogen, they become stunted and yellow in appearance. Phosphorous is generally absorbed as the primary orthophosphates and smaller amounts of the secondary orthophosphate. Other forms of phosphorous can be assimilated into a plant, among which are pyrophosphates and metaphosphates. They are absorbed by plant roots. These latter materials are polyphosphates hydrolysed slowly. Phosphorous is associated with increased root growth and hastens plant maturity. Potassium is generally absorbed as the potassium ion. The requirement for potassium in plants is quite high. Potassium deficiencies greatly reduce crop yields and decrease the resistance to certain plant diseases. Photosynthesis is decreased, thus carbohydrates are less available. Calcium is also required by plants and is absorbed principally as the calcium ion. Deficiency results in failure of the terminal buds of the plants to develop. Magnesium is responsible for the production of chlorophyll. The chlorophyll molecule contains a coordinated magnesium ion needed for photosynthesis. Sulphur is absorbed by plant roots as the sulphate ion, it is almost exclusively reduced to disulphide and the mercapto group. The deficiency of sulphur has a pronounced retarding effect on the plant growth. Boron is generally absorbed in the ionic oxygenated form, while iron is utilised from complex organic materials. With respect to phosphorous plant nutrients, the various ortho-phosphates such as calcium, ammonium, potassium can be added directly to increase the content of phosphorous, or phosphoric acid or superphosphoric acid can be added to the coal ash residue which reacts with the cations available, the major one of which is calcium. Thus calcium oxide would react with phosphoric acid to form the various calcium orthophosphates. Thermal treatment of this reaction mixture would form metaphosphates, pyrophosphates and polyphosphates depending on the actual reaction conditions. With respect to potassium, many coal ash residues contain up to 4% potassium expressed as potassium oxide. If additional potassium is needed, any of the soluble potassium salts could be added. Various organic type potassium compounds could also be added, such as potassium derivatives of various polyfunctional carboxylic acids. Once the basic requirements of nitrogen, phosphorous and potassium are satisfied by simple addition of compounds as an admixture comprising inorganic, organic and/or the addition of compounds containing these elements, which react with the coal ash, it can be noticed that the remaining major and minor nutrients are already present. Accordingly the present invention provides a process for the manufacture of fly ash based soil conditioner cum fertilizer which comprises mixing of fly ash in the range of 80 to 95 wt % with grounded phosphatic rock in the range of 3 to 10 wt % and potassium chloride in the range of 0.5 to 4.0 wt% with water under constant shaking to form a workable mixture; adding to the said workable mixture urea in the range of 0.5 to 5.0 wt % and humic acid in the range of 0.3 to 1.0 wt %, to obtain urea- hurnic acid slow release type formulation; subjecting the resulting mixture to room temperature and adding bio fertilizer in the range of 0.15 to 0.35 wt %, under constant stirring for around 10 minutes after each addition and discharging the resulting mixture at room temperature to obtain fly ash based soil conditioner cum fertilizer. In an embodiment of the present invention, any type of fly ash, irrespective of particle size and characteristics can be used. In another embodiment of the present invention, the potassium chloride used is of commercial grade such as muirate of potash. In yet another embodiment of the present invention, during mixing of fly ash, ground phosphatic rock and potassium chloride, the temperature is maintained below 50°C, preferably at room temperature, by constant shaking in a rotary mechanical shaker. In still another embodiment of the present invention the urea and humic area used are of commercial grade. In a further embodiment of the present invention the bio-fertilizer used is such as Rhizobium, Azotobacter, Phosphobacterium or mixture thereof. In the process of the present invention fly ash is added to grounded phosphatic rock and commercial grade potassium chloride (muirate of potash) in a rotary mechanical shaker with minimum amount of water to form a workable mixture. The temperature generated due to exothermic reaction is controlled to this slurry urea and humic acid (both commercial grade) are added. The urea and humic acid under these acidic conditions forms urea-humic acid slow release type formulation. To the resulting mixture, biofertilizers such as Rhizobium, Azotobacter and Phosphobacterium, either singly or a mixture thereof, are added under constant mixing for 10 minutes after each addition. The novelty of the present invention resides in the agricultural use of waste and polluting products such as fly ask In another feature of the novelty, not only the texture and fertility status of agricultural lands is improved but also waste, degraded land could be utilised for agricultural purposes by improving their texture and fertility status. The inventive steps comprise of mixing requisite materials, having different micro-nutrients useful for plant growth; thus resulting in a synergistic soil conditioner cum fertilizer, as demonstrated in the examples. The following examples are given by way of illustration of the present invention and should not be construed to limit the scope of the present invention. Example-1 50 Kg of fly ash was taken in Feeder Screen Trommel Mixer to which 3.0 kg grounded phosphatic rock and 0.8 Kg commercial grade potassium chloride (muirate of potash) were added. A little amount of water was added to make a workable mixture. Due to exothermic reaction, temperature rose to 40 degree Celsius. The mixture was cooled down to room temperature by constant shaking. To this mixture, 1 kg of commercial grade urea and 0.2 kg of humic acid were added. Under these acidic conditions, urea-humic acid slow release type formulation was formed. To the resulting mixture, 0.1 kg Azotobacter was added under constant mixing. The resultant mixture was discharged at room temperature. Table: 1 (Effect of the composition on biological activity of the soil) (Table Removed) Example-2 50 Kg of fly ash was taken in Feeder Screen Trommel Mixer to which 4.0 kg grounded phosphatic rock and 1.6 Kg commercial grade potassium chloride (muirate of potash) were added. A little amount of water was added to make a workable mixture. Due to exothermic reaction, temperature rose to 45 degree Celsius. The mixture was cooled down to room temperature by constant shaking. To this mixture, 2 kg of commercial grade urea and 0.35 kg of humic acid were added. Under these acidic conditions, urea-humic acid slow release type formulation was formed. To the resulting mixture, 0.15 kg Phosphobacterium was added under constant mixing. The resultant mixture was discharged at room temperature. Table-2 Available Major & Secondary Nutrients (ppm) (Table Removed) Example-3 50 Kg of fly ash was taken in Feeder Screen Trommel Mixer to which 5.5 kg grounded phosphatic rock, 2.2 Kg commercial grade potassium chloride (muirate of potash, commercial grade) were added. A little amount of water was added to make a workable mixture. Due to exothermic reaction, temperature has rose to 48 degree Celsius. The mixture was cooled down to room temperature by constant shaking. To this mixture, 2.5 kg of commercial grade urea and 0.4 kg of humic acid were added. Under these acidic conditions, urea-humic acid slow release type formulation was formed. To the resulting mixture, 0.18 kg Rhizobiwn was added under constant mixing. The resultant mixture was discharged at room temperature. Table: 3 Total Major & SecondaryJNutrients in Crop Produce (grain and straw) %. Grain Straw (Table Removed) The main advantages of the present invention are: 1. Can be used under normal conditions of cultivation and effective in improving in crop productivity. 2. Suitable for all types of soils. 3. There was significant enhancement in the microbial population in respect of ectomycorrhiza, nitrogen fixing bacteria, total bacterial count and Dehydrogenase activity in the soil after harvest of each crop as compared to corresponding values in the soil used as control comprising all the amendments except fly ash. 4. Productive use of fly ash, a waste material. We claim: 1. A process for the manufacture of fly ash based soil conditioner cum fertilizer which comprises mixing fly ash in the range of 80 to 95 wt % with grounded phosphatic rock in the range of 3 to 10 wt % and potassium chloride in the range of 0.5 to 4.0 wt% with water under constant shaking to form a workable mixture; adding to the said workable mixture urea in the range of 0.5 to 5.0 wt % and humic acid in the range of 0.3 to 1.0 wt % to obtain urea- humic acid slow release type formulation; subjecting the resulting mixture to room temperature and adding bio-fertilizer in the range of 0.15 to 0.35 wt %, under constant stirring for around 10 minutes after each addition and discharging the resulting mixture at room temperature to obtain fly ash based soil conditioner cum fertilizer. 2. A process as claimed in claim 1, wherein during mixture of fly ash, ground phosphate rock and potassium chloride, the temperature is maintained below 50°C, preferably at room temperature, by constant shaking. 3. A process as claimed in claims 1-2, wherein the bio-fertilizer used is such as Rhizobium,Azotobacter, Phosphobacterium or mixture thereof. 4. A process for the manufacture of fly ash based soil conditioner cum fertilizer substantially as herein described with reference to the examples.

Documents:

211-del-2002-abstract.pdf

211-del-2002-claims.pdf

211-del-2002-correspondence-others.pdf

211-del-2002-description (complete).pdf

211-del-2002-form-1.pdf

211-del-2002-form-18.pdf

211-del-2002-form-2.pdf

211-del-2002-form-3.pdf