Mineral concentrate is the concentrated mineral nutrients solution obtained from separation process (e.g. membrane filtration or evaporation) of waste streams that concentrates the mineral nutrients in the end-product compared to the input.
Mineral concentrates predominantly consist of ammonium-nitrogen and soluble potassium. The main driver for the production of mineral concentates is to prevent transport of liquid streams with low nutrient contents or to tailor the ratios of nutrients (nitrogen, potassium and sulphur) in the fertilisers to meet the requirements of crops. Analysis across ten pilot plants in the Netherlands showed that the mineral concentrates produced from reverse osmosis (RO) concentration process contains on average 90% of the total nitrogen in the form of NH4 -N. The ingoing liquid fraction contains some organic matter which is present in mineral concentrates (1.3% organic matter or 0.6% organic carbon). Compared to pig slurry the ratio between NH4-N to Total N increased from 66% to 90%.
Examples for mineral concentrate products available on the NUTRIMAN Farmer Platform
- ID520: https://nutriman.net/farmer-platform/product/id_520 (Netherlands)
- ID593: https://nutriman.net/farmer-platform/product/id_593 (Netherlands)
- ID1504: https://nutriman.net/farmer-platform/product/id_1504 (Netherlands)
- ID1528: https://nutriman.net/farmer-platform/product/id_1528 (Netherlands)
Typical nutrient content and availability for plants
The mineral concentrate from RO process usually contains N 5-9.5, P2O5 0-0.1 and K2O 6-11 kg/ton (ID:520-593-1504) and even 65 kg/ton K2O after further evaporation (ID:1528).
Fields of application in agriculture:
The mineral concentrate can be used in conventional farming, covering fresh vegetables, root crops and plants, grain maize and corn-cob, permanent grassland and dry pulses and protein crops. The recomended application dose depends on the crop needs and soil analyses. Currently the max is 170 kg N/ha as livestock manure (230-250 kg N/ha for derogation dairy farms). In The Netherlands it is accepted as pilot RENURE fertilizer defined as the processed manure fractions that can replace chemical fertilizers. Application can be done using regular liquid manure injection systems. Low emission application techniques are compulsory to prevent ammonia volatilization. The mineral concentrate can be mixed with manure/slurry and/or diluted with water prior to application on grassland.
Benefits for farmers:
The N and K in mineral concentrate from RO process (ID:520-593-1504-1528) are mostly plant available, which shows higher nutrient value compared to unprocessed manure. The N and K recovery from manue contributes to closing agricultural nutrient cycles. The product is locally produced for local farmers. Agronomic effectivity of mineral concentrates has been tested under controlled conditions in pot experiments and in field experiments on arable land and grassland. Potassium is equally effective as mineral potassium fertilisers. The fertiliser value of the reference chemical fertiliser is set at 100% although this does not mean that chemical fertilisers are for 100% effective. To prevent ammonia volatilisation, mineral concentrates require shallow placement or need to be injected into the soil. The nitrogen fertilizer replacement value (NRFV) is determined by comparing with chemical fertiliser as reference. Under controlled conditions (pot experiments) mineral concentrates are almost comparable with calcium ammonium nitrate (NFRV is approaching a full replacement value of 100%). In the field situation attention still has to be given to the application technique (surface broadcast or injection). The environmental performance of mineral concentrates was tested by looking at their effect on nitrate accumulation in soil, nitrate accumulation in groundwater, ammonia volatilisation and emission of greenhouse gasses. There is no evidence that mineral concentrates increase nitrate concentration in groundwater. In fact relatively low values are measured compared to the application of calcium ammonium nitrate (CAN) and pig and cattle slurry. This is also the case for nitrate accumulation in the soil where mineral concentrates show the lowest levels of concentration. To prevent ammonia volatilisation, mineral concentrates need to be incorporated into the soil. N2O emission caused by mineral concentrates is higher compared to CAN but lower when compared with the chemical fertiliser urea. Overall agronomic and environmental performances of mineral concentrates is in line with chemical nitrogen fertilisers.
For more information:
- ID520: https://nutriman.net/farmer-platform/product/id_520
- ID593: https://nutriman.net/farmer-platform/product/id_593
- ID1504: https://nutriman.net/farmer-platform/product/id_1504
- ID1528: https://nutriman.net/farmer-platform/product/id_1528
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