Comprimo Sulfur Solutions

Spent Acid Treatment

Chemetics has developed a number of processes to purify and concentrate Sulfuric and/or Nitric Acid from a variety of sources. Our processes focus on concentrating the acid, recover valuable by-products, and minimize effluents and energy consumption. In many cases, several process options are combined to provide a tailor-made process.

Chemetics’ spent acid plants and equipment solutions are specifically custom designed to each clients’ individual needs. Chemetics capabilities range from engineering studies to complete turnkey projects.

The following are examples of our process options. Please Contact Us if your application is not listed, and we can discuss further the development of a process that fits your needs:

Sulfuric Acid Denitration
Spent sulfuric acid from nitration processes (e.g. Di-Nitro Toluene/Tri-Nitro Toluene production) or from the production of concentrated Nitric Acid contains various amounts of NOx, Nitrous Acid and Nitric acid. Our Sulfuric Acid Denitration process removes these components and recovers the impurities as weak Nitric Acid which can be re-used.

Sulfuric Acid Stripping
Sulfuric Acid StrippingSome spent sulfuric acids contain impurities that can be removed by air or steam stripping. Common examples are Mono-Nitro Toluene, Di-Nitro Toluene, Methanol, Methyl Chloride and Chlorine. Our process can incorporate additional equipment to separate and concentrate valuable byproducts.

Sulfuric Acid Pre-concentration
Some spent sulfuric acids contain impurities (e.g. Ammonium Sulphate) that cannot be removed and prevent the re-use of the spent acid. Common examples are spent acid from Methyl/Methacrylate and Acrylonitrile production. Our pre-concentration system removes a substantial amount of water from the spent acid before it is thermally decomposed in a Sulfuric Acid Regeneration furnace. This can reduce the SAR plant size or lower energy requirements.

Sulfuric Acid Concentration (SAC)
Sulfuric acid is concentrated using a vacuum evaporation process. The SAC process can be designed to produce sulfuric acid up to 98 wt%. Large capacities are obtained by using multiple stages in series. For dilute sulfuric acid it is also possible to use a multiple effect process to minimize energy consumption.

Nitric Acid Denitration
Spent Nitric Acid from the hydroxylamine production process contains Nitrous Acid. Our Nitric Acid Denitration process removes the Nitrous Acid as NOx, which can then be returned to the originating process or recovered as Weak Nitric Acid.

Weak Nitric Acid Concentration (<67 wt%)
Dilute Nitric acid can be concentrated using a single or multiple effect distillation process to commercial concentrations of 65-67wt%. Our process is designed to minimize nitric acid decomposition and produces a water white product.

Strong Nitric Acid Concentration (>67 wt%)
Weak Nitric acid can be concentrated using an extractive distillation process to any desired concentration. Our process utilizes either sulfuric Acid or Magnesium Nitrate to manipulate the nitric acid/water azeotrope. Depending on the application the process can also include a bleaching step to remove NOx and provide a water white product.