A method for producing a poultry litter-based fertilizer by a) supplying poultry litter to a rotating rotary drum, b) adding acid or a source of acid to the rotating rotary drum, wherein acid reacts with the poultry litter to form an acidified mixture, c) adding ammonia or a source of ammonia to the rotating rotary drum, d) drying and cooling the ammoniated product by evaporation of water to form a dried, cooled product in a free-flowing semi-solid or solid form, repeating the steps b) through d) until a desired nitrogen content is reached in the dried, cooled product.

A method for producing a poultry litter-based fertilizer by a) supplying poultry litter to a rotating rotary drum, b) adding acid or a source of acid to the rotating rotary drum, wherein acid reacts with the poultry litter to form an acidified mixture, c) adding ammonia or a source of ammonia to the rotating rotary drum, d) drying and cooling the ammoniated product by evaporation of water to form a dried, cooled product in a free-flowing semi-solid or solid form, repeating the steps b) through d) until a desired nitrogen content is reached in the dried, cooled product.

A method for producing a poultry litter-based fertilizer by a) supplying poultry litter to a rotating rotary drum, b) adding acid or a source of acid to the rotating rotary drum, wherein acid reacts with the poultry litter to form an acidified mixture, c) adding ammonia or a source of ammonia to the rotating rotary drum, d) drying and cooling the ammoniated product by evaporation of water to form a dried, cooled product in a free-flowing semi-solid or solid form, repeating the steps b) through d) until a desired nitrogen content is reached in the dried, cooled product.

A method for producing a poultry litter-based fertilizer by a) supplying poultry litter to a rotating rotary drum, b) adding acid or a source of acid to the rotating rotary drum, wherein acid reacts with the poultry litter to form an acidified mixture, c) adding ammonia or a source of ammonia to the rotating rotary drum, d) drying and cooling the ammoniated product by evaporation of water to form a dried, cooled product in a free-flowing semi-solid or solid form, repeating the steps b) through d) until a desired nitrogen content is reached in the dried, cooled product.

A composition, in the form of an aqueous suspension. The composition comprises at least one form of attapulgite present in a solid weight fraction (SWF) amount ranging from 0.065% to 0.30%. The composition comprises kaolin present in a percent solids by weight (w/w %) amount ranging from 0.80% to 2.80%. The composition comprises one or more main plant nutrients or major animal mineral nutrient supplements. In the composition, the total percent solids by weight (w/w %) amount in the composition ranges from 45% to 90%. Although usable for other purposes, the composition is usable as a fertilizer. Although makeable in other ways, the composition is makeable by mixing the ingredients with agitation sufficient enough to form an aqueous suspension.

A composition, in the form of an aqueous suspension. The composition comprises at least one form of attapulgite present in a solid weight fraction (SWF) amount ranging from 0.065% to 0.30%. The composition comprises kaolin present in a percent solids by weight (w/w %) amount ranging from 0.80% to 2.80%. The composition comprises one or more main plant nutrients or major animal mineral nutrient supplements. In the composition, the total percent solids by weight (w/w %) amount in the composition ranges from 45% to 90%. Although usable for other purposes, the composition is usable as a fertilizer. Although makeable in other ways, the composition is makeable by mixing the ingredients with agitation sufficient enough to form an aqueous suspension.

A method for chemical processing of sewage sludge ash comprises dissolving a start material, emanating from sewage sludge ash, in an acid comprising hydrochloric acid. The start material comprising at least silicon and iron compounds. Undissolved residues are separated, whereby a leachate remains. The amount of colloidal silica in the dissolved sewage sludge ash is controlled. At least one of iron and phosphorus is extracted from the leachate by liquid-liquid extraction with an organic solvent. At least a part of a raffinate at least partly depleted in at least one of iron and phosphorus originating from the step of extracting at least one of iron and phosphorus is recirculated for dissolving the start material, emanating from sewage sludge ash. The recirculated part of the raffinate at least partly depleted in at least one of iron and phosphorus comprises chloride ions.

The invention relates to the field of slow/controlled release fertilizer, in particular to a urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer and a preparation method thereof. The urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer comprises ammonium polyphosphate, inorganic silica gel and urea-formaldehyde, wherein the phosphorus-oxygen double bond of ammonium polyphosphate can at least form hydrogen bond linkage with a urea-formaldehyde molecule chain, the hydroxyl group of the inorganic silica gel can at least form hydrogen bond linkage with the urea-formaldehyde molecular chain, and ammonium polyphosphate, inorganic silica gel and urea-formaldehyde together form a hydrogen bond associated polymer network structure. The invention can prepare a urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer comprising a strong hydrogen bond network structure by using a conventional aqueous solution polymerization in combination with a normal temperature extrusion granulation process, avoiding the coating process in the latter stage of the preparation of a coated fertilizer, achieving a simple and effective preparation process, and saving a lot of manpower and material resources. The urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer provided by the invention can stably and continuously release nitrogen nutrient throughout the release period, thereby making up for the shortcoming of excessively long nutrient release period of the existing urea-formaldehyde fertilizers.

The invention relates to the field of slow/controlled release fertilizer, in particular to a urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer and a preparation method thereof. The urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer comprises ammonium polyphosphate, inorganic silica gel and urea-formaldehyde, wherein the phosphorus-oxygen double bond of ammonium polyphosphate can at least form hydrogen bond linkage with a urea-formaldehyde molecule chain, the hydroxyl group of the inorganic silica gel can at least form hydrogen bond linkage with the urea-formaldehyde molecular chain, and ammonium polyphosphate, inorganic silica gel and urea-formaldehyde together form a hydrogen bond associated polymer network structure. The invention can prepare a urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer comprising a strong hydrogen bond network structure by using a conventional aqueous solution polymerization in combination with a normal temperature extrusion granulation process, avoiding the coating process in the latter stage of the preparation of a coated fertilizer, achieving a simple and effective preparation process, and saving a lot of manpower and material resources. The urea-formaldehyde-based multi-nutrient slow/controlled release fertilizer provided by the invention can stably and continuously release nitrogen nutrient throughout the release period, thereby making up for the shortcoming of excessively long nutrient release period of the existing urea-formaldehyde fertilizers.

A method of calcination includes providing a raw material including whitlockite Ca.sub.9(Mg,Fe.sup.2+)[PO.sub.3(OH)|(PO.sub.4).sub.6], and/or iron phosphate FePO.sub.4, and/or aluminum phosphate AlPO.sub.4 and/or fluorapatite Ca.sub.5(PO.sub.4).sub.3F; providing an alkaline-sulfuric compound as an additive; and calcining a mixture of the raw material with the additive to obtain a product, including a citrate soluble phosphate compound.