4.6 Production of cake synthetic detergents by pressing method

The technology of production of cake synthetic detergents by method of pressing includes the following stages: 1) grinding of powders; 2) mixture of grinding powders; 3) pressing of dry mixture; 4) packaging of cake synthetic detergents.

The technological circuit of manufacture is resulted on fig.4.4. Loose raw material is preliminary crushed, sieved and loaded in necessary relations into the mixer of periodic action 3. After of loose raw material loading in mixer 3 the liquid raw material is loaded by proportioning pump 2 from reservoir 1. As liquid raw material alkyl benzene sulphoacids or a mixture of solutions of sodium alkyl benzene sulphonates with liquid glass and other components are used. The quantity of liquid glass, necessary for preparation of qualitative product, makes from 0,5 up to 35 %. It is very important, that moisture content in compounding was minimal, that moisture did not reduce the looseness of powder components in the mixer. For elimination of stickiness of powder mixture as additional components are entered the substances, connecting water in crystalline hydrates.

Loose mixture from the mixer 3 by tape conveyor 4 is loaded into intermediate bunker 5, then the mixture is given on hammer crusher 6 and a sieve. The sieve provides the riddling of particles with crushing degree 0,1-0,15 mm. The sieving powder by blover 10 is transported on pipelines in a cyclone 11 and through sluice bolts 12 is given to account bunkers 7. From account bunker 7 the loose mixture is fed on the press-machine 9 through filling funnel 8. For control of uniform feed and constant density of powder in bunkers 7 and filling funnel 8 vibrators are established.

Pressing is carried out in machine, equipped with a mould with cells. Into cells a powder is loaded (from 250 up to 400 g), where it is subjected to preliminary compression, and then - the final pressing. Pressing is carried out at pressure not below 3 MPa. The stage of preliminary compression of a powder is necessary for air removal. A plenty of air in a powder reduces the press productivity, air reduces durability of cakes, gives to it friability and porosity.

At air removal on stage of preliminary compression the volume of a powder decreases on 25 %.

After removal of cakes the mould is cleared by rotating brushes and internal parts are processed by talc or starch, it facilitates the removal of cakes. Ready pieces after the mould are directed on packing. Advantages of this method: simplicity of implementation of process and low charge of the electric power.

Keys: 1 – account reservoirs of liquid raw material; 2 – account bunkers of loose raw material; 3 – type weighers; 4 – type conveyer; 5 – mixer; 6 – five roll calender; 7 – elevator; 8 – extruder; 9 – machine for cakes cutting; 10 – after-ripening chamber; 11 – fans; 12 – press of cake forming; 13 – packing device.

Fig.4.3 – Technological scheme of cake synthetic detergent production by forming method

Keys: 1 – account reservoirs of liquid raw material; 2 – pump-weigher; 3 – mixer of loose and liquid raw materials; 4 – type conveyer; 5 – intermediate bunker; 6 – hammer crusher; 7 – account reservoirs; 8 – loading funnel; 9 – press-machine ; 10 – blower; 11 – cyclones; 12 – sluice gate.

Fig.4.4 – Technological scheme of cake synthetic detergent production by pressing method