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|Fertilisers (24/02/22 20:12:52)||Reply|
The phosphate is sourced from various sources, at least one of which is politically contentious (Western Sahara).
Potassium is sourced from Belarus,which is an increasing problem.
Well. Phosphate and potassium, in the form that are used, are limited resources. Much of it endsin sewage and goes into the ocean, with minimal attempts at recovery.
I'll see if I can research the topic more thoroughly.
|Re: Fertilisers (25/02/22 10:25:39)||Reply|
|Re: Re: Fertilisers (25/02/22 10:27:36)||Reply|
"Support domestic farmers"...
|Re: Re: Re: Fertilisers (25/02/22 16:15:38)||Reply|
1 ammonium nitrate requires 6 hydrogens for synthesis (three for each nitrogen atom), so, ideally, each ammonium nitrate requires 1.5 methane (CH4).
Ammonium nitrate: 2xN=28; 3xO=48, 4xH=4 makes 80.
Methane: 4xH + C = 16. 1.5 methane makes 24.
So 1 million tons ammonium nitrate translates into 300 000 tons natural gas. At least.
|Re: Re: Re: Re: Fertilisers (25/02/22 21:12:35)||Reply|
|Phosphorus (25/02/22 18:14:22)||Reply|
"More than 70 full-scale P recovery plants are currently operating in Europe, North America, and East Asia. Basically, the P recovery technologies are (i) chemical Pi leaching from incinerated sludge ash, (ii) Pi salts precipitation, and (iii) struvite crystallization after anaerobic sludge digestion. Incinerated sludge ash having the high content of P is also used as a raw material for the manufacture of phosphoric acid in a wet acid process.
P recovery practices are now expanding not only to the wastewater treatment sector but also to the manufacturing sector. In the manufacturing sector, Pi must be removed from wastewater to meet stringent effluent regulation in areas vulnerable to eutrophication. The recycling of recovered P products as a fertilizing material can save the costs of sludge disposal and leads to the significant reduction of plant operating expenses. P recovery is also practiced from solid waste streams such as animal manure and steelmaking slag. In East Asian countries, including China, Korea and Japan, steelmaking slag is one of the most important secondary P resources. Recovering P from steelmaking slag allows the rest to be reused as raw materials in blast furnaces. This has the enormous potential to improve the resource efficiency of steelmaking process.
|Phospho Rus (25/02/22 21:15:26)||Reply|
|Phosphorous fertilisers and cadmium (16/05/22 20:14:47)||Reply|
"The main effect of Cd on human health is kidney disease, and although other adverse effects have been reported (e.g. pulmonary, cardiovascular, and musculoskeletal systems), controversy exists regarding their effects. The only known case of Cd toxicity (i.e. itai-itai disease) occurred with subsistence farmers in Japan growing rice on soils contaminated with industrial wastes. Cadmium behaviour in soil and its accumulation by crops is complicated. Numerous factors (e.g. soil pH, organic matter content, salinity, macro and micronutrient fertilizers, crops species and cultivar, and tillage) influence the bioavailability and uptake of Cd by crops. Because fertilization increases the risk of Cd transfer to the food chain, some governments have imposed limits restricting the Cd content of P fertilizers. However, scientific risk assessments have shown that P fertilizer containing Cd is safe and does not pose risk to human health."
"Fertilizers made from phosphate rock naturally contain cadmium that can accumulate in the soil; they are to blame for more than half of the heavy metal present in some agricultural soils. On average across Europe today, fertilizer contains about 32 milligrams of cadmium per kilogram (mg Cd/kg) of phosphorus, but the level can be as high as 200 mg Cd/kg, depending on where the phosphate rock is mined. Sedimentary phosphate rock found in northern Africa has naturally high cadmium levels, whereas so-called igneous rock found in Russian phosphate mines has much lower levels.
Humans can get exposed to cadmium by ingesting crops that have taken up the metal from the soil. That doesn't appear to be a major problem in Europe; an EU-wide study published in 2015, for instance, showed that only 0.6% of 1271 nonsmoking women had an exposure higher than the "no-effect threshold.""
|Potassium: Reversible binding of ions (07/03/22 18:46:09)||Reply|
"Zeolites have a porous structure that can accommodate a wide variety of cations, such as Na+, K+, Ca2+, Mg2+ and others. These positive ions are rather loosely held and can readily be exchanged for others in a contact solution. Some of the more common mineral zeolites are analcime, chabazite, clinoptilolite, heulandite, natrolite, phillipsite, and stilbite. An example of the mineral formula of a zeolite is: Na2Al2Si3O10·2H2O, the formula for natrolite. Cation exchanged zeolites possess different acidity and catalyse different reactions.[non-primary source needed]
Natural zeolites form where volcanic rocks and ash layers react with alkaline groundwater. Zeolites also crystallize in post-depositional environments over periods ranging from thousands to millions of years in shallow marine basins. Naturally occurring zeolites are rarely pure and are contaminated to varying degrees by other minerals, metals, quartz, or other zeolites. For this reason, naturally occurring zeolites are excluded from many important commercial applications where uniformity and purity are essential."
So zeolites are candidates for potassium recovery from sewage and seawater. But from there wehave a long and thorny road in technology development: How is recovery of the salt to be done? How is the concentrated solution going to be made in an energy-responsible way? How is fouling of the absorbent by algae andbacteria to be avoided? What is to be done with end-of-useful-life-material? Landfill is not an option.
|Sustainability of a private economy (09/03/22 19:32:00)||Reply|
So - with agriculture: Today's mineral fertiliser use is unsustainable because it relies on tapping fossil nonrenewable resources of phosphate and potassium. Nitrogen is another matter - but we now see that the Oslo fjord is dying, presumably because of too high availability of nitrogen.
And what do we know of the environmental consequences of metformin
for a world population steadily getting fatter?
|If the economy is unbalanced, it is unsustainable. (09/03/22 21:20:32)||Reply|
But will recycling and seawater be able to sustain all those billion people?Or must we simply overrun the religious reactionaries who are banning contraceptives and killing to hinder abortions?
|Population planning and family planning and food (12/03/22 09:13:30)||Reply|
So - how much recycled or sustainably acquired fertilizer minerals can we produce? So far it is only manure, which was insufficient even 150 years ago.
So better get started - either with phosphate and potassium recovery - or with worldwide contraception efforts. Ideally both.
|Cycling of crops as a method of nitrogen enrichment of soil: Yes. What more? (12/05/22 07:31:15)||Reply|
So we have protein foodstuffs that do not need nitrogen fertiliser. To me that is sensational.
A teaser (2015):
|Food for the belly - and food for thought (16/05/22 19:33:48)||Reply|
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