Ny industriell prosess for resirkulering av HF New industrial process for recycling of HF

The activity in 2013 was focused around finding possible process routes that would be feasible from an economic, environmental and safety, logistics and process engineering perspective. We ended up with four possible process routs that we wanted to look into. One of these processes were excluded early in 2014 and we were looking at all aspects of the three remaining to be able to assess which of the three we should go ahead with in detail. The entire 2014 was used to conduct intensive laboratory work to confirm if all the steps in the 3 remaining processes were practical. The work led to the first decision point in Q3 2014 where the most promising process was chosen. Q3 and Q4 2014 was then used to clarify some details in this process route and preliminary discussions with a potential partner was taking place. We considered then to have done proof of concept in laboratory scale of all unit operations. They should all be feasible and possible to scale up to industrial scale. In parallel with this project, there has been a major project in the company with the goal to optimize the acid leach process. It has been shown that it is possible to reduce acid consumption significantly and that it is also possible to use a mixture of H2SiF6 and HF in the process. It is therefore not necessary to recycle 100% of the used acid back to HF. Meanwhile, this BIA project has attempted to purify the used acid by distillation before precipitating silica to form the purest possible silica as a byproduct. In this process, we see that it is possible to form an azeotrope consisting of 5% HF, 42% H2SiF6 and 53% water. After the development work done in the company, we now see that it should be possible to use this azeotrope in acid leach process. Through the work done in Q1 2015 we saw that the distillation route has a better potential than the sulfuric acid route that was selected in 2014. It was therefore decided to investigate the distillation route further in order to make a decision whether to build a pilot plant. This is a more flexible process route where we are not dependent on new raw materials or production of by-products other than the precipitated silica which fits naturally in the existing business area. After further investigations from Q2-Q4 2015 the steering committee decided that the process looked promising and wanted to start planning a pilot phase. During Q1-Q2 2016 a bench scale unit has been designed, constructed and experiments has now started in to be able to obtain industrially relevant data. This is carried out, and the project is now in the final phase where documentation is beeing prepares for the comapny for application of the research results in which a 3 step approach to the realization of innovation is recommended.

Prosjektets overordnede idé er å utvikle en ny prosess for resirkulering av flussyre som er gjenvunnet fra fluorkiselsyre. Den nye prosessen skal kunne implementeres i søkers, the Quartz Corp AS (TQC), eksisterende produksjonsanlegg. Resirkulering av HF i prosessen vil ha en betydelige økonomisk gevinst og søkers evne til å realisere innovasjonen er dokumentert. Den planlagte forskningen inkluderer state-of-the-art eksperimentelle- og modelleringsaktiviteter, teknisk-økonomisk analyse, og en demonstrasjon på pilotskala. Prosjektpartnere er TQC og SINTEF.