Dear Benito, At Salt Water ...
Published by Matthew Brannock, Technical Director at Salt Water & AqMB Software
Dear Benito,
At Salt Water we specialise in evaluating the feasibility (chemistry, technology & economics) of salt/mineral/resource recovery from brines. We undertake this via speciation/thermodynamic modelling, process modelling, bench-scale trials, pilot trials, market evaluation and design review. The key questions are:
- What is the composition of your brine? This determines what salts/minerals you can recover.
- What is the volume of the brine? This influences the economies of scale, process complexity etc.
- What is the location of the brine? This affects the product transport costs, process type/complexity, footprint availability etc.
Feel free to contact me if you have any further questions.
Cheers,
Matt.
1 Comment
Hello Matt,as a reply for your questions, the salts mainly caso4 and Na2so4 and location egypt and quantity about 22 tons per day.
looking for your reply soon
Published by Tamer ramzy Abd-Elsadek, Employee at Oregon Environmental Engineering, LLC
1 Comment
Hi Tamer,
[Apologies for the formatting below. There appears to be no option to improve it. Please send me an email if it is too difficult to read.]
Fortunately CaSO4 (and it's different hydrate forms) is considerably less soluble than Na2SO4 at practically all temperatures. Also, as the CaSO4 hydrate form moves from monohydrate (gypsum) to anhydrous as temperature increases the solubility starts to decrease significantly at around 50C.
Therefore a potential treatment process might entail ambient temperature or 60C solids contact clarification and then a seeded brine concentrator (CaSO4 is often seeded in evaporators to prevent fouling of HTX surfaces) to produce a CaSO4 rich stream. You may be able to replace the brine concentrator step with solar evaporation (luckily Na2CO3 solubility is at it's highest at about 40C). There may also be membrane process that could help. CaSO4 is commonly used for agricultural purposes for pH adjustment or amendment of irrigation water to prevent clay swelling (i.e. to adjust the sodium adsorption ratio). The purity requirements should not be too high for most of its uses (depending on heavy metal contaminanty you may have).
The next step in the process would be to take the brine and crystallise it either via thermal crystallisaton (preferred for purity reasons) or pond crystallisation to produce Na2SO4. Na2SO4 is typically used for detergents. I know of a site which separates Na2SO4 from their acid battery waste and sells it on the market.
Note that there are many other technologies which may assist. The above technologies are the most commonly used for salt crystallization but may not necessarily the best for particular scenario.
Economics wise, CaSO4 is a cheap commodity product whereas Na2SO4 can get a reasonable price (3x sodium chloride). Other factors which will affect your economics include:- tonnages - the amount of salt you're producing is rather small- waste disposal costs - you need to compare a salt recovery option against the option where you dispose of it as waste- capital/operating costs - thermal equipment is relatively expensive but ponds (depending on the location and regulations) are cheaper. Do you have good quality waste heat?- footprint - ponds will need significant footprint- composition/impurities - What amount of the 22 tonnes is Na2SO4? What impurities are present? - location/transport options - how close is your site to the markets of the two salts? What type of transport is available and how much does it cost?- reliability- project life- etc
I hope this helps. If you need any more assistance please do not hesitate to contact me.
Cheers,
Matt.
www.saltwatersolutions.com.au
Published by Matthew Brannock, Technical Director at Salt Water & AqMB Software