The Preparation And Application Of Cement Foaming Agent Based On Protein

In recectly years, China has became the largest tanning country in the world. The largest number of tannery waste especially chromium shavings(CS) were produced, which will course serious enviornment pollution. In this parper, CS were used as raw material to sythesis three types of protein-based foaming(PBF) formula through a continuous operation of hydrolysis, chromium removing and complex formulation. The performance of the PBF and the foamed concerts prepared with PBF(FC-P) were tested according to the construction materials profession standard. The results showed that the PBF and the FC-P meet the construction materials industry standard. The detail were as follows:First, physical and chemical p roperties of tannery waste were analyzed. The best hydrolysis conditions of CS using calcium oxide as hydrolysis agent was also determined: hydrolysis time is 10 h, the ratio of solid to liquid is 1:8, the calcium oxide dosage is 10%, the hydrolysis temperature is 80℃. The foam properties of hydrolysis solution were as follow: the initial foaming height is 64 mm, the half- life period is 12 min, and the molecular weight is 132 kDa.Then, three types of PBF formula were obtained with 6% dodecyl alcohol ether sodium sulfate(AES) and 6% lauryl sodium sulfate(SDS) as the foaming additives and the performances were used initial foaming height and half- life period as the technical indexes, which were as follows:ZW-1: 6%AES, 6%SDS, 4% hydroxyethyl cellulose(HEC), the initial Foaming height is 164 mm, the half-life period is 108.12 min.ZW-2: 6%AES, 6%SDS, 8% carboxy methyl cellulose(CMC), the initial Foaming height is 208 mm, the half-life period is 48.50 min.ZW-3: ZW-2: 6%AES, 6%SDS, 8% hydroxypropyl methyl cellulose(HPMC), the initial Foaming height is 212 mm, the half-life period is 54.53 min.In this paper, a commercial PBF called LH was used as a comparison sample.According to building material industry standard JC/T2199-2013, the foaming in foamed concrete, ZW-1 and ZW-3 are the first grade, ZW-2 and LH are qualified grade.At last, two kinds of foamed concretes were prepared with ZW-1 which has the the longest half- life period. The foamed concrete formulas and their performances were as follows:FC-P1: Air-entraining water-reducing agent HSN 15 g, bentonite 10 g, ZW-1 100 mL, tap water 300 mL, strength grade A7.5, density rating B10.FC-P2: Air-entraining water-reducing agent HSN 10 g, bentonite 30 g, ZW-1 150 mL, tap water 300 mL, strength grade A1.0, density rating B06.The hydrolytic residues(HR) could also be used in foamed concrete as water-reducing admixture, it could improve the workability of foamed concrete and reduce the oven-dry density. The FC-HR strength grade was A07, the Moisture Absorption grade was W40 and the compressive strength is C7.5.