| 摘要 |
The dispersion contains: (i) at least 55 wt.% pulverised coal, the surface of which has been modified by adsorption of switterionic or other hydrophobising substances, added during flotation and/or dewatering; (ii) water; and (iii) as dispersant, an additive whose mol. has a hydrophobic segment with a strong affinity for the coal surface, contg. at least 2 aromatic rings, and attached to it an anionic or nonionic hydrophilic polymer chain or an anionic or nonionic graft copolymer with amphiphilic properties. Coal flotation may be effected with the addn. of one or more of aliphatic alcohols, frothing agents, zwitterionic surfactants (e.g. lecithin) and alkyl sulphosuccinates. Surfactants which may be added during dewatering are alkylaryl sulphonates and alkylsulphosuccinates. The dispersion is useful for transporting coal, and as an alternative to oil for steam prodn. or heating. Only half the concn. of dispersant is needed for the same effect on rheology as of conventional dispersants. |
