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Phosphogypsum

ameliorant for agriculture (TU 24.1-31980517-002:2005)

Name of indicators Norm
Physical state, appearance, smell. Moist, crumbly product is white or light gray to dark gray or brown
Mass fraction of calcium sulfate (CaSO4*2H2O), calculated on the dry dihydrate,%, not less 80
Mass fraction of hygroscopic moisture,%, max 26
Water-soluble fluoride (Na2SiF6, Ka2SiF6, etc.) in terms of Fv.r.,%, max 0,6
Mass fraction of total phosphate (P2O5 gen.)%, Not more. 2

Agrochemical characteristics

The need for the country's agriculture in phosphogypsum to eliminate alkalinity and salinity of 2.5-3.2 million tons. Natural gypsum is used for this purpose in a small amount (4%). Especially effective is the use of gypsum on soils with a high concentration of sodium. The increase of sodium ions leads to disruption of soil structure and its bonding. On the surface of the soil in this case a waterproof crust. With the introduction of finely grind gypsum sodium ions are displaced from the soil composition of calcium ions, the resulting sodium sulfate susceptible to leaching, alkalinity of the soil decreases and recovers its permeability. Phosphogypsum effect on the soil more effectively than natural gypsum, as is more soluble in the soil compositions. Phosphogypsum into the soil (once every few years), high doses (5-20 t / ha). Gypsum provides a significant yield increase, not only by improving soil structure, phosphogypsum is also a source of calcium and sulfur components for power plants. Purification of phosphogypsum is not needed, phosphorus in its composition is absorbed by plants.

I n the United States investigated the level of radiation plants grown under conditions of intensive cultivation phosphogypsum. Found that in the soil and plant radiation levels well below the allowable.

Phosphogypsum for agriculture shipped from dumps. Humidity in the phosphogypsum dumps is 12-16%. This phosphogypsum can be put to agriculture second grade. Humidity can dig phosphogypsum reduced by its perelopachivaniya and outdoor weathering.

Successfully tested a mixture of wet phosphogypsum or phospho-hemihydrate with limestone flour, intended for gypsum and liming of soils. Such mixtures have sufficient flowability. Mixing of phospho-hemihydrate with limestone flour makes it suitable for rassolonchakovyvaniya soil. A mixture of phospho-hemihydrate with limestone flour does not harden and form a solid structure under the influence of moisture for several months. Limestone can be replaced by digging shale ash.

Preparation of mixtures of limestone-gypsum for agricultural fertilizer plants or thermal drying of phosphogypsum involve significant costs, primarily phosphogypsum comes to agriculture vehicles to consumers directly from the factory dumps after the pre-weathering product on special grounds.

At the rate of introduction of the order of 10 tons of phosphogypsum per hectare to the soil receives 110-130 kg P2O5 in a digestible form, which largely compensates the cost of agriculture to transportation and the introduction of phosphogypsum.

Phosphogypsum can be used in agriculture, not only as ameliorant soil, but also for slowly dissolving fertilizer of prolonged action. For example, U.S. patent describes the preparation of a modifier of the soil with a slow acting nitrogen fertilizer phosphogypsum interaction with urea at a temperature. 95 +160 ° C.

Written communication of urea, ammonium nitrate, phosphogypsum, and urea formaldehyde and phosphogypsum to produce fertilizer of prolonged action. The ability of urea to form complexes with phosphogypsum used for granulation of simple superphosphate without drying. Vnostitsya phosphogypsum to the soil in two stages: before and after plowing it under cultivation. The dose to make phosphogypsum shall be determined by the amount of sodium in the root soil layer, which is necessary to replace the calcium and ranges from 3-4 to 10-15 t / ha. The highest dose of phosphogypsum for making soda solonetz.


The use of phosphogypsum in agriculture:

  • For the amelioration of solonetzes (desalinization of the soil).
  • M ixed with lime for reclamation of acidic soils.
  • A s fertilizing reclamation (1 tons of phosphogypsum contains about 10 kg of phosphorites).
  • Composting of organic fertilizers and biological products.

Delivery of phosphogypsum

Phosphogypsum supplied in bulk by road or rail, is stored in piles at the consumer in vivo.