Multinutrient phosphate-based fertilizers from seawater bitterns
Seawater bittern, a by-product from seawater solar halite plants is rich, among other chemical elements in Mg, K and B. The potential advantages of low solubility Mg-K-PO4 fertilizers for use in acidic tropical soils has been recognized. The salt can supply Mg, K and P over long periods of time since it has a low solubility, about 0.02g per 100g of water. A novel method is presented for the recovery of the these elements from seawater bittern as a Mg-K-PO4 salt also containing some B. The method consists, essentially, in mixing the NaH2PO4 with seawater bittern, followed by neutralization with NaOH solution to precipitate the multinutrient salt which is separated from the mother liquor by filtration, washed and dried. Under appropriate reaction conditions of pH 10 and 15ºC, for 60min, bittern density of 1.250g/ml, bittern dilution with water of 100% and stirring speed of 350rpm, it is possible to produce a salt with 54% PO4, 18% Mg, 5% K and 0.05% B. The recovery efficiencies were about 100% for PO4, Mg and K, and 90% for B. X-ray powder diffraction analysis showed the product to be mainly MgKPO4·3H2O and Mg3(PO4)2·4H2O. Some MgNaPO4·3H2O was also present. SEM photographs of the crystalline product showed a uniform crystal grain of orthorhombic shape and size of 20-75µm.
| Main Authors: | , |
|---|---|
| Format: | Digital revista |
| Language: | English |
| Published: |
ASOCIACIÓN INTERCIENCIA
2002
|
| Online Access: | http://ve.scielo.org/scielo.php?script=sci_arttext&pid=S0378-18442002000900009 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|