Patent GB-355223-A (GB)
Title: Improved process and apparatus for the treatment of sea-weeds
IPC: C08B37/12
Filed: 1930-05-13
Abstract: <PICT:0355223/III/1> Alkali alginates and mineral matter are obtained simultaneously by extracting marine plants, without agitation, by a solution of alkali carbonate or other alkali on the counter-current principle, precipitating the alginates by alcohol, and extracting the mineral matter from the mother liquor.  Alcohol retained by the alginate is removed by a current of superheated alcohol vapour.  The sub-divided seaweed may be placed in receptacles 1, Fig. 2, which have perforated bottoms and are carried on wheels travelling on rails 5 above a row of tanks C, a siding being provided for loading and unloading.  Between each pair of tanks is a compartment connected therewith by submerged conduits 11, 12; a pump draws alkali solution from the compartment and sprays it over the receptacle 1 on one side of the compartment, the liquid travelling through the series oppositely to the receptacles.  In the final stage or stages water only is used, and receives concentrated alkali solution at an intermediate point.  In a modification, the liquid flows directly over a weir from one tank to the next, and the spraying liquid from each receptacle is drawn from the tank below it.  Instead of pumps, there may be used air injectors, or steam injectors which also heat the liquid.  A p  hypochlorite may be added during extraction, or, subsequently, for bleaching.  After cooling, concentration, or other treatment, the aqueous extract may be pumped from a storage tank 16, Fig. 4, into a baffle chamber 20 to which alcohol is pumped from a tank 19. The mixture passes into a rotary press 21 having perforated cylinders 22 through which the liquid escapes, and is distilled for recovery of the alcohol, while the precipitated alginate, after an addition of strong alcohol from a pipe 24, is again treated in a second press 23, the liquid from which is used in the first alcohol treatment.  A conveyer 38 propels the alginate into a tunnel 28 containing a conveyer band 27.  Alcohol vapour is circulated by a fan 29 through the tunnel, and through a steam heater 31, where its temperature may be raised to 110 DEG  C.  Excess of vapour passes to a condenser 33.  The dried alginate falls into a chamber 34 from which residual vapour can be exhausted into the condenser by a pump 37 before discharging the alginate.  Any loss of alcohol is made up by manufacture of alcohol from the cellulosic residues left after diffusion.  The liquid from the press 21, after dealcoholization, can be used for the production of iodides and chlorides, for instance, by fractional crystallization, the sodium carbonate being also recovered for re-use; or the liquid may be used several times in the diffusion treatment before crystallization.  Specification 297,765 is referred to.ALSO:Alkali alginates and mineral matter are obtained simultaneously by extracting marine plants, without agitation, by a solution of alkali carbonate or other alkali on the counter-current principle, precipitating the alginates by alcohol, and extracting the mineral matter from the mother liquor.  Alcohol retained by the alginate is removed by a current of superheated alcohol vapour. The subdivided seaweed may be placed in receptacles 1, Fig. 2, which have perforated bottoms and are carried on wheels travelling on rails 5 above a row tanks C, a siding being provided for loading and unloading.  Between each pair of tanks is a compartment connected therewith by submerged conduits 11, 12; a pump draws alkali solution from the compartment and sprays it over the receptacle 1 on one side of the compartment, the liquid travelling through the series oppositely to the receptacles.  In the final stage or stages water only is used, and receives concentrated alkali solution at an intermediate point.  In a modification, the liquid flows directly over a weir from one tank to the next, and the spraying liquid from each receptacle is drawn from the tank below it.  Instead of pumps, there may be used air injectors, or steam injectors which also heat the liquid.  A hypochlorite may be added during extraction, or subsequently, for bleaching.  After cooling, concentration, or other treatment, the aqueous extract may be pumped from a storage tank 16, Fig. 4, into a baffle chamber 20 to which alcohol is pumped from a tank 19.  The mixture passes into a rotary <PICT:0355223/IV/1> press 21 having perforated cylinders 22 through which the liquid escapes, and is distilled for recovery of the alcohol, while the precipitated alginate, after an addition of strong alcohol from a pipe 24, is again treated in a second press 23, the liquid from which is used in the first alcohol treatment.  A conveyer 38 propels the alginate into a tunnel 28 containing a conveyer band 27.  Alcohol vapour is circulated by a fan 29 through the tunnel and through a steam heater 31 where its temperature may be raised to 110 DEG  C.  Excess of vapour passes to a condenser 33.  The dried alginate falls into a chamber 34, from which residual vapour can be exhausted into the condenser by a pump 37 before discharging the alginate.  Any loss of alcohol is made up by manufacture of alcohol from the cellulosic residues left after diffusion.  The liquid from the press 21, after de-alcoholization, can be used for the production of iodides and chlorides, for instance by fractional crystallization, the sodium carbonate being also recovered for re-use; or the liquid may be used several times in the diffusion treatment before crystallization. Specification 297,765, [Class 55 (ii), Gas manufacture &c.], is referred to.