Q&A Ash2Phos

Here we have answered the most common questions about our Ash2Phos process. Do you have a question that you want to be answered? Please email info@easymining.se

What are the recovery rates of the products from the Ash2Phos process?

 

Ash2Phos typical recovery
Phosphorus 90-95 %
Aluminium 60-80 %
Iron 10-20 %
Calcium 80-90 %

These values reflect, that we have optimized the recovery for P (90% at moderate acid consumption) in clean and commercial form, the key purpose of Ash2Phos. More Fe can be recovered depending on the local/regional demand and price levels for i.e. FeCl3 and also for the sand color required. 

How efficient is the detoxification of Ash2Phos; what are the reduction of heavy metals?


The Ash2Phos process can reduce more than 96% of the heavy metals. The figure below show the compilation of the reduction rate (mg/kg PCP) of heavy metals from the Ahs2Phos process.

    Recovered P Ash % Reduction
As mg/kg 1,5 34,6 96
Cd mg/kg 0,1 5,5 98
Co mg/kg 0,7 32,4 98
Cr mg/kg 1,7 232 99
Cu mg/kg 5,5 1756 100
Fe mg/kg 1340 202826 99
Hg mg/kg - 0,0526 100
Pb mg/kg 3,6 344 99
Zn mg/kg 45,9 6780 99
Ni mg/kg 2,6 164,6 98

 

Which market is there at the moment for these products?


The potential markets for the recovered P product are as fertilizer for conventional farming, organic farming or as feed raw material. The main benefits are the purity (e.g. less than 0.1 mg/kg Cd, very low fluorine, very low heavy metals) and the low CO2 emissions compared to virgin products. 

The PCP can today be used directly as fertilizer. It is not fully water soluble but has the same solubility in citric acid compared to commercial mono-calcium phosphate. It can be used directly  as a slow release fertilizer or as feed phosphate. It is a versatile raw material and can be used by the existing fertilizer or feed phosphate industries for production of any kind of phosphorus product.

The legislation for feed is still linear (not circular), i.e. focusing on origin instead of quality. So even if the PCP is cleaner and have the same digestibility level as MCP (see Table 1), we still have legal barriers within the EU. The question is already on the EU commissions table to make the feed legislation circular, but it is unclear when and if this route will be open for recovered nutrients. 

Digestibility of P in citric acid PCP (EasyMining) Precipitated Calcium Phosphate MCP (Customer A) Mono-Calcium Phosphate MCP (Customer B) Mono-Calcium Phosphate
Test 1 86,4% 85,1% 84,3%
Test 2 87,4% 86,7%  
Test 3 95,0% 85,5%  
Average 89,6% 85,8% 84,3%

The figure show a compilation of results from citric acid digestibility tests with Ash2Phos PCP, benchmarked with two different MCPs. Digestibility of P in citric acid indicates how easy the Phosphorus is dissolved in mono-gastric (chicken, pigs) animal’s stomach. The higher the % the higher is the available Phosphorus for animals. The test is the most accepted test for Phosphorus availability besides real tests on animals.

The Silica sand has potential to be used as cement replacement see our webinar on the webpage to learn more.

The Fe and Al- products are of high quality and can e.g. be recycled to the WWTP plants.

How much primary resources are “replaced” by these products, what is the “gain” in terms of CO2?


The advantage for our PCP is the direct applicability in existing fertilizer and feed production without technical adaptions. The silica sand has potential to be used in construction replacing sand or cement.

The Swedish Environmental Research Institute (IVL) has conducted a LCA study for an Ash2Phos plant located in Helsingborg with supply and valorization routes fitting that geography (~ 30 000 ton ash / y plant, only available in Swedish).

The results show that the recovery products from Ash2Phos will save significant amounts of CO2 emissions compared to using virgin products. Additionally, the decontamination of the products are very efficient in the Ash2Phos process.