Patent GB-435126-A (GB)
Title: Improvements relating to the treatment of waste effluents, such as sewage or coal-washery water
IPC: C02F1/52
Filed: 1934-03-16
Abstract: The separation of dispersed matter from liquid is promoted by the addition of a flocculating gel obtained by subjecting a mixture of amylaceous material and a neutral metal salt or salts to heat and agitation until the cells of the amylaceous material burst and the mixture forms a thick gummy paste.  The dispersion to be treated may be first rendered alkaline.  Suitable salts or salt mixtures are:--zinc, chloride, the thiocyanates of lithium, calcium, magnesium, strontium, manganese or cerium, the double thiocyanates of sodium and manganese, of barium and manganese and of sodium and zinc, calcium chloride in admixture with zinc chloride, mercuric chloride or the thiocyanates mentioned above, and magnesium chloride in admixture with mercuric chloride.  An organic material such as an essential oil, a phenol or an aliphatic or aromatic aldehyde is added to the flocculating agent to prevent decomposition of the starch. Oil of citronella, oil of cloves, oil of citral, phenol, cresol, benzaldehyde and formaldehyde are mentioned as suitable organic materials for this purpose.  The process is stated to be applicable for the treatment of oils containing fine dust and of suspensions of substances precipitated by chemical reagents, as for example in precipitating barium sulphate from acid or neutral solutions of sulphates by means of barium chloride.  The gel may be prepared by adding cream of starch in cold water to a hot solution of the metal salt, and agitating while the temperature is kept at from 50 to 150 DEG  C.  The gel so prepared is, for use, diluted with water. Specifications 157,887, 322,798, [both in Class 121], and 405,038 are referred to.  The first and second Provisional Specifications mention the use of iron and aluminium salts, and the second Provisional Specification that of Rochelle salt, in the preparation of the flocculating agent.ALSO:The separation of dispersed matter from liquids is promoted by the addition of a flocculating gel obtained by subjecting a mixture of amylaceous material and a neutral metal salt or salts to heat and agitation until the cells of the amylaceous material burst and the mixture forms a thick gummy paste.  Suitable salts or salt mixtures are: zinc chloride, the thiocyanates of lithium, calcium, magnesium strontium, manganese or cerium, the double thiocyanates of sodium and manganese, of barium and manganese and of sodium and zinc, calcium chloride in admixture with zinc chloride, mercuric chloride or the thiocyanates mentioned above, and magnesium chloride in admixture with mercuric chloride.  An organic material such as an essential oil, a phenol or an aliphatic or aromatic aldehyde is added to the flocculating agent to prevent decomposition of the starch.  Oil of citronella, oil of cloves, oil of citral, phenol, cresol, benzaldehyde and formaldehyde are mentioned as suitable organic materials for this purpose.  The gel may be prepared by adding cream of starch in cold water to a hot solution of the metal salt, and agitating while the temperature is kept at from 50 to 150 DEG  C. Specifications 157,887, 322,798, [both in Class 121], and 405,038, [Group I], are referred to.  The first and second Provisional Specifications mention the use of iron and aluminium salts, and the second Provisional Specification that of Rochelle salt, in the preparation of the flocculating agent.ALSO:The separation of dispersed matter from liquid is promoted by the addition of a flocculating gel obtained by subjecting a mixture of amylaceous material and a neutral metal salt or salts to heat and agitation until the cells of the amylaceous material burst and the mixture forms a thick gummy paste.  The dispersion to be treated may be first rendered alkaline.  Suitable salts or salt mixtures are zinc chloride, the thiocyanates of lithium, calcium, magnesium, strontium, manganese or cerium, the double thiocyanates of sodium and manganese, of barium and manganese and of sodium and zinc, calcium chloride in admixture with zinc chloride, mercuric chloride or the thiocyanates mentioned above, and magnesium chloride in admixture with mercuric chloride.  An organic material such as an essential oil, a phenol or an aliphatic or aromatic aldehyde is added to the flocculating agent to prevent decomposition of the starch.  Oil of citronella, oil of cloves, oil of citral, phenol, cresol, benzaldehyde and formaldehyde are mentioned as suitable organic materials for this purpose.  The process is stated to be applicable for the treatment of coal-washing water, sewage, effluent from dye works, p  suspensions of clay, slate, fine coal or flue dust, still waste, water from ore reduction plants, oils containing fine dust, suspensions of substances precipitated by chemical reagents, as for example in softening water or in precipitating barium sulphate from acid or neutral solutions of sulphates by means of barium chloride.  The gel may be prepared by adding cream of starch in cold water to a hot solution of the metal salt, and agitating while the temperature is kept at from 50 to 150 DEG  C.  The gel so prepared is, for use, diluted with water. Specifications 157,887, 322,798, [both in Class 2 (iii)], and 405,038 are referred to.  The first and second Provisional Specifications mention the use of iron and aluminium salts, and the second Provisional Specification that of Rochelle salt, in the preparation of the flocculating agent.